Patent Publication Number: US-11387761-B2

Title: System and method for sinusoidal output and integrated EMC filtering in a motor drive

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of and claims priority to U.S. application Ser. No. 16/580,736 filed Sep. 24, 2019, the entire contents of which is incorporated herein by reference. 
    
    
     BACKGROUND INFORMATION 
     The subject matter disclosed herein relates to motor drive topologies with an improved output voltage waveform supplied by the motor drive. More specifically, the motor drive provides a sinusoidal output voltage waveform while containing radiated and conducted electromagnetic emissions within the motor drive. 
     As is known to those skilled in the art, motor drives are utilized to control operation of a motor. According to one common configuration, a motor drive includes a DC bus having a DC voltage of suitable magnitude from which an AC voltage may be generated and provided to an AC motor. The DC voltage may be provided as an input to the motor drive or, alternately, the motor drive may include a converter section which converts an AC voltage input to the DC voltage present on the DC bus. The converter section may be passive, including conventional diode rectification, or active, including controlled power electronic switching devices, either of which may convert an AC voltage input to a DC voltage for the DC bus. The power electronic switching devices in an active rectifier may be selected from transistors, such as insulated gate bipolar transistors (IGBTs) or metal oxide semiconductor field-effect transistors (MOSFETs), thyristors, or silicon-controlled rectifiers (SCRs). The power electronic switching device may also include a reverse conduction power electronic device, such as a free-wheeling diode, connected in parallel across the power electronic switching device. The reverse conduction power electronic device is configured to conduct during time intervals in which the power electronic switching device is not conducting. A controller in the motor drive generates switching signals to selectively turn on or off each switching device to generate a desired DC voltage on the DC bus. 
     The motor drive receives a command signal which indicates the desired operation of the motor. The command signal may be a desired torque, speed, or position at which the motor is to operate. The torque, speed, or position of the motor are controlled by varying the amplitude and frequency of the AC voltage applied to the stator. An inverter section is provided between the DC bus and the output of the motor drive to generate the controlled AC voltage. The inverter section includes power electronic switching devices, such as IGBTs, MOSFETs, thyristors, or SCRs, and a reverse conduction power electronic device connected in parallel across the power electronic switching device. The motor is connected to the output terminals of the motor drive, and the controller generates the switching signals to rapidly switch the switching devices in the inverter on and off at a predetermined switching frequency and, thereby, to alternately connect or disconnect the DC bus to the output terminals and, in turn, to the motor. By varying the duration during each switching period for which the output terminal of the motor drive is connected to the DC voltage, the magnitude of the output voltage is varied. The motor controller utilizes modulation techniques such as pulse width modulation (PWM) to control the switching and to synthesize waveforms having desired amplitudes and frequencies. 
     As is also known, the output voltage waveform generated by modulation techniques is a series of square waves, where the magnitude may be zero volts, a maximum positive voltage, or a maximum negative voltage. The duration for which the voltage is connected to zero voltage, the maximum positive voltage, or the maximum negative voltage within any switching period results in an average value of the output voltage for that switching period. The output voltage is regulated to provide a waveform having a fundamental component corresponding to a desired AC output voltage. The modulation typically occurs at frequencies ranging from the hundreds of hertz to tens of kilohertz while the desired fundamental frequency of the AC output voltage is typically in the tens to hundreds of hertz. While the AC output voltage contains a fundamental component, the modulation introduces components at the switching frequency and harmonics thereof. These components may be conducted, for example, via a cable connected between the motor drive and a motor to be controlled by the motor drive or radiated from the motor drive generating conducted or radiated electromagnetic interference (EMI) for other electronic components located near the motor drive, cabling, or motor. 
     As is also known to those skilled in the state of the art, the non-sinusoidal PWM output voltage includes high dv/dt voltage transitions which generate possible motor insulation failure and system ground current issues. First, high dv/dt transitions cause uneven voltage distributions across motor windings. A high percentage of the DC bus voltage is distributed across the first few incoming turns of the stator coil and the corresponding winding insulation, which may cause insulation failure. Second, high dv/dt transitions may cause doubling of the DC bus voltage magnitude to be observed on the output cable and at the motor terminals. The doubling of the DC bus voltage results from standing waves or reflected voltages present on the cable as a result of impedance mismatch as defined by well-known pulsed transmission line theory, leading to insulation failure. Third, high dv/dt transitions from conducted emissions along the cable and into the motor may be transmitted via stray ground capacitance and lead to uncontrolled external paths of ground noise current spikes that may adversely affect nearby sensitive equipment. Higher switching frequencies increase the dv/dt transitions and increase the magnitude of the ground noise current spikes. 
     Thus, it would be desirable to provide an improved motor drive topology that outputs a sinusoidal waveform which has a low dv/dt transition. 
     It would also be desirable to provide an improved motor drive topology that includes integrated EMI filtering to contain conducted or radiated EMI content resulting from modulation techniques within the motor drive. 
     BRIEF DESCRIPTION 
     The subject matter disclosed herein describes a motor drive that outputs a sinusoidal waveform and eliminates EMI conducted or radiated from the motor drive. The motor drive utilizes power switching devices operable at high switching frequencies. The switching devices may be operated, for example, between twenty kilohertz (20 kHz) and one megahertz (1 MHz). As a result of the high frequency switching, the conducted and radiated emissions generated are similarly in this high frequency range or multiples thereof. As previously indicated, the higher switching frequency results in a greater dv/dt transition and an increased magnitude of these conducted emissions. However, the higher frequency emissions can be attenuated by filtering components having a smaller physical size than emissions at a lower frequency. As a result, the present inventors have been able to incorporate the filtering components within the motor drive. 
     The motor drive includes multiple filters and shielding to contain conducted and radiated EMI content resulting from modulation techniques within the motor drive. A first filter is included at the output of the motor drive which has a bandwidth selected to attenuate voltage components at the output at the switching frequency or multiples thereof such that the output voltage waveform is generally sinusoidal. Additional filtering is included within the motor drive to establish a circulation path for common mode currents within the motor drive. Finally, an electromagnetic interference (EMI) shield is provided adjacent to those components within the motor drive that may experience voltage or current waveforms at the switching frequency or multiples thereof. The EMI shield is made of a conductive material such that radiated emissions establish eddy currents within the EMI shield rather than passing through the shield into the environment. The result is a motor drive with a sinusoidal voltage output that satisfies electromagnetic compatibility (EMC) requirements without requiring additional chokes, filters, or shielding external to the motor drive. 
     According to one embodiment of the invention, a motor drive includes an input configured to receive an AC input voltage and a converter section having an input and an output. The input to the converter section is configured to receive the AC input voltage, and the output from the converter section is configured to output a DC voltage. The converter section is operative to convert the AC input voltage to the DC voltage. The motor drive also includes an input filter operatively connected between the input of the motor drive and the input of the converter section, where the input filter includes a common connection. The motor drive has a DC bus, a DC bus capacitance, and an inverter section. The DC bus has a positive rail connected to a first terminal of the output of the converter section and a negative rail connected to a second terminal of the output of the converter section. The DC bus capacitance is connected between the positive rail and the negative rail of the DC bus at the output of the converter section. The inverter section has an input and an output. The input of the inverter section is configured to receive the DC voltage from the DC bus, and the output from the inverter section is configured to output an AC output voltage. The inverter section is operative to covert the DC voltage to the AC output voltage. A high frequency capacitance is connected between the positive rail and the negative rail of the DC bus at the input of the inverter section, and an output from the motor drive is configured to supply the AC output voltage to a motor operatively connected to the motor drive. The motor drive also includes an output filter operatively connected between the output of the inverter section and the output of the motor drive. The output filter is connected to the common connection and common mode currents present in the motor drive circulate within the motor drive via the common connection between the input filter and the output filter. 
     According to another embodiment of the invention, a motor drive includes an input configured to receive an AC input voltage and a converter section having an input and an output. The input to the converter section is configured to receive the AC input voltage and the output from the converter section is configured to output a DC voltage. The converter section is operative to convert the AC input voltage to the DC voltage. The motor drive also includes a DC bus, a DC bus capacitance, and an inverter section. The DC bus has a positive rail connected to a first terminal of the output of the converter section and a negative rail connected to a second terminal of the output of the converter section. The DC bus capacitance is connected between the positive rail and the negative rail of the DC bus at the output of the converter section. The inverter section has an input and an output. The input of the inverter section is configured to receive the DC voltage from the DC bus and the output of the inverter section is configured to output an AC output voltage. The inverter section is operative to covert the DC voltage to the AC output voltage. A high frequency capacitance is connected between the positive rail and the negative rail of the DC bus at the input of the inverter section, and an output of the motor drive is configured to supply the AC output voltage to a motor operatively connected to the motor drive. The motor drive also includes a first filter and a second filter. The first filter is operatively connected between the output of the converter section and the high frequency capacitance, where the first filter includes a common connection. The second filter is operatively connected between the output of the inverter section and the output of the motor drive. The second filter is connected to the common connection, and common mode currents present in the motor drive circulate within the motor drive via the common connection between the first filter and the second filter. 
     According to still another embodiment of the invention, a motor drive includes an input, a converter section, an inverter section, and an output. The input is configured to receive an AC input voltage, and the converter section is configured to convert the AC input voltage to a DC bus voltage The inverter section is configured to convert the DC bus voltage to an AC output voltage using a modulation technique, where the modulation technique executes at a switching frequency, and the output is configured to supply an AC output voltage. A DC bus is operative to conduct the DC bus voltage between the converter section and the inverter section, and a sinusoidal output filter is operative to attenuate harmonic content on the AC output voltage at frequencies equal to or greater than the switching frequency. A first portion of an electromagnetic compatibility (EMC) filter operatively is connected between the input of the motor drive and the converter section, and a second portion of the EMC filter is operatively connected between the inverter section and the output of the motor drive. Both the first and second portions of the EMC filter are connected to a common connection, where common mode currents present in the motor drive circulate within the motor drive via the common connection between the first and second portions of the EMC filter. 
     These and other advantages and features of the invention will become apparent to those skilled in the art from the detailed description and the accompanying drawings. It should be understood, however, that the detailed description and accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various exemplary embodiments of the subject matter disclosed herein are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout, and in which: 
         FIG. 1  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to one embodiment of the invention; 
         FIG. 2  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 3  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 4  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 5  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 6  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 7  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 8  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 9  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 10  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 11  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 12  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 13  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 14  is a schematic representation of a motor drive with integrated EMC filtering configured to provide a sinusoidal voltage output according to another embodiment of the invention; 
         FIG. 15  is a schematic representation of a passive converter section for use in the motor drive of any one of  FIGS. 1 to 14 ; 
         FIG. 16  is a schematic representation of an active converter section for use in the motor drive of any one of  FIGS. 1 to 14 ; 
         FIG. 17  is a top view of a magnetic component integrated into a printed circuit board (PCB) for use as an inductive component in one of the filters according to one embodiment of the invention; 
         FIG. 18  is a top plan view of the PCB for the magnetic component of  FIG. 17 ; 
         FIG. 19  is an exploded view of the PCB for the magnetic component of  FIG. 17 ; 
         FIG. 20  is a sectional view of one embodiment of the PCB for the magnetic component of  FIG. 17 ; 
         FIG. 21  is a perspective view of a motor drive with an EMI shield extending over a portion of the internal circuit board; 
         FIG. 22  is a perspective view of a housing for the motor drive of  FIG. 21  with the EMI shield mounted to an interior surface of the housing; 
         FIG. 23  is a top plan view of the internal circuit board with a block diagram representation of an EMI shield covering a portion of the circuit board; 
         FIG. 24  is a schematic representation of the L-C filter of  FIG. 1  with the capacitors connected in a delta configuration; 
         FIG. 25  is a schematic representation of a distributed motor drive system with integrated EMC filtering configured to provide a sinusoidal voltage output from each inverter according to another embodiment of the invention; and 
         FIG. 26  is a schematic representation of another distributed motor drive system with integrated EMC filtering configured to provide a sinusoidal voltage output from each inverter according to another embodiment of the invention. 
     
    
    
     In describing the various embodiments of the invention which are illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word “connected,” “attached,” or terms similar thereto are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art. 
     DETAILED DESCRIPTION 
     The various features and advantageous details of the subject matter disclosed herein are explained more fully with reference to the non-limiting embodiments described in detail in the following description. 
     Turning initially to  FIG. 1 , a first embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     After the input  22  of the motor drive  20 , a first filter  24  and a second filter  30  are connected in series between the input  22  and a converter section  40  of the motor drive. The first filter  24  includes a capacitor  26  connected between each phase of the AC input voltage and a common connection point  25  for the first filter. For the three-phase AC input voltage  12  illustrated, the first filter  24  includes three capacitors  26  each connected between one phase of the input voltage and the common connection point  25 . Optionally, a fourth capacitor  28  may also be provided. The fourth capacitor  28  is connected between the common connection point  25  of the first filter  24  and a common connection  15  for the motor drive  20 . The common connection  15  shown in  FIG. 1  is a ground connection. As will be discussed in more detail below, connecting multiple filters to the common connection  15  will allow common mode currents  180  (shown in  FIG. 2 ) to circulate within the motor drive  20 . The second filter  30  includes an AC common mode inductor  32 , also referred to as an AC common mode choke, connected in series with the AC input voltage  12 . The AC common mode inductor  32  includes a winding for each phase of the AC input voltage which may be wrapped around a single core or, optionally, windings wrapped around separate cores. The windings for the common mode inductor  32  are connected between the first filter and an input  42  for the converter section  40 . 
     The converter section  40  may include any electronic device suitable for passive or active rectification as is understood in the art. With reference also to  FIG. 15 , the illustrated converter section  40 A is a passive converter and includes a set of diodes  44  forming a diode bridge. The converter section  40  receives the AC voltage at an input  42 , rectifies the three-phase AC voltage to a DC voltage, and provides the DC voltage to a DC bus  50  at an output of the converter section. With reference also to  FIG. 16 , the illustrated converter section  40 B is an active converter. An active converter  40 B includes switching devices including, but not limited to, thyristors, silicon-controlled rectifiers (SCRs), or transistors, such as IGBTs or MOSFETs, to convert the voltage at the input  42  from AC to a DC voltage for the DC bus  50 . According to the illustrated embodiment, a pair of transistors  46  is connected between each phase of the input voltage and the DC bus  50 . A first transistor in the pair is connected between the input voltage and a positive rail  52  of the DC bus  50 , and a second transistor in the pair is connected between the input voltage and a negative rail  54  of the DC bus  50 . Diodes  48  may be connected in a reverse parallel manner across each transistor  46 . A driver circuit  41  generates switching signals  45  to control operation of each transistor  46 . The active converter  40 B may both convert the AC voltage to a DC voltage as well as allow for bidirectional current flow between the input  42  of the converter section  40 B and the DC bus  50 . The DC bus  50  is connected to the output of the converter section, and the DC voltage output by the converter is present between the positive rail  52  and the negative rail  54  of the DC bus  50 . 
     A DC bus capacitor  55  is connected between the positive and negative rails,  52  and  54 , to reduce the magnitude of the ripple voltage resulting from converting the AC voltage to a DC voltage. It is understood that the DC bus capacitor  55  may be a single capacitor or multiple capacitors connected in parallel, in series, or a combination thereof. The magnitude of the DC voltage between the negative and positive rails,  54  and  52 , is generally equal to the magnitude of the peak of the AC input voltage. 
     As shown in  FIG. 1 , a DC bus charge circuit  57  may be connected on the DC bus  50 . In the illustrated embodiment, the DC bus charge circuit  57  is connected between the output of the converter section  40  and the DC bus capacitor  55 . Initially, a switch  56  is in a normally open state, establishing a conduction path from the output of the converter section  40  to the positive rail  52  via a charge resistor  58 . The charge resistor  58 , in combination with the DC bus capacitor  55  establishes a charging time constant, as is understood in the art, to allow the DC voltage on the DC bus  50  to charge from zero volts DC at power up to a voltage level approximately equal to the full DC bus voltage resulting from rectifying the AC input voltage. When the DC voltage level reaches a preset charged level, the switch  56  is closed, bypassing the charge resistor  58  and allowing current to flow directly from the converter section  40  onto the DC bus  50 . 
     The DC bus  50  is connected in series between the converter section  40  and an inverter section  100 . Also illustrated either in series with or parallel to the DC bus  50  between the converter section  40  and the inverter section  100  are a third filter  60 , fourth filter  70 , fifth filter  80 , and sixth filter  90 . The third filter  60  includes a first DC common mode inductor  62 , also referred to as a DC common choke, connected in series with the DC bus  50 . Conductors for both the positive rail  52  and the negative rail  54  are wrapped around a common core and connected in series with each rail. The fifth filter  80  similarly includes a second DC common mode inductor  82 , also referred to as a DC common choke, connected in series with the DC bus  50 . Conductors for both the positive rail  52  and the negative rail  54  are wrapped around a common core and connected in series with each rail. Optionally, a single filter may be provided with just one DC common mode inductor sized according to application requirements. In still other embodiments, no DC common mode inductor may be required as will be discussed in more detail below. 
     According to the embodiment illustrated in  FIG. 1 , the fourth filter  70  is positioned between the third filter  60  and the fifth filter  80  along the DC bus  50 . The fourth filter  70  includes a first DC bus filter capacitor  72  and a second DC bus filter capacitor  74 . A first terminal of the first DC bus filter capacitor  72  is connected to the positive rail  52  and a second terminal of the first DC bus filter capacitor  72  is connected to a common point  76  for the filter. A first terminal of the second DC bus filter capacitor  74  is connected to the negative rail  54  and a second terminal of the second DC bus filter capacitor  74  is connected to the common point  76  for the filter. The two DC bus filter capacitors  72 ,  74  are preferably equal in capacitance and create a balanced voltage potential across each capacitor. The common point  76  is connected to the common connection  15  of the motor drive  20 , establishing one additional flow path for common mode currents to circulate within the motor drive  20 . 
     The sixth filter  90  includes a high frequency capacitance  92  connected between the positive rail  52  and the negative rail  54  of the DC bus  50 . It is understood that the high frequency capacitance  92  may be a single capacitor or multiple capacitors connected in parallel, in series, or a combination thereof. The high frequency capacitance  92  is connected at the input of the inverter section  100  and is used to reduce the magnitude of the ripple voltage present on the DC bus  50  as a result of the high frequency switching in the inverter section to convert the DC voltage back to an AC voltage. The output of the multi-stage filter section is a filtered DC bus and is shown as a positive filtered DC bus rail  102  and a negative filtered DC bus rail  104 . 
     The inverter section  100  consists of switching elements, such as transistors, thyristors, or SCRs as is known in the art. The illustrated inverter section  100  includes a power metal-oxide-semiconductor field-effect transistor (MOSFET)  106  and a reverse connected device  108 , which may be a free-wheeling diode or a MOSFET&#39;s inherent body diode, connected in pairs between the filtered positive rail  102  and each phase of the output voltage ( 110 U,  110 V,  110 W) as well as between the filtered negative rail  104  and each phase of the output voltage. Each of the transistors  106  receives switching signals  116  to selectively enable the transistors  106  and to convert the DC voltage from the DC bus  50  into a controlled three phase output voltage to the motor  10 . When enabled, each transistor  106  connects the respective rail  102 ,  104  of the DC bus to one output phase  110 , which is, in turn, connected between the inverter section  100  and the output terminal  160 . 
     According to the embodiment illustrated in  FIG. 1 , a processor  112  and a driver circuit  114  may include and manage execution of modules used to control operation of the motor drive  20 . The illustrated embodiment is not intended to be limiting and it is understood that various features of each module may be executed by another module and/or various combinations of other modules may be included in the processor  112  without deviating from the scope of the invention. The modules may be stored programs executed on one or more processors, logic circuits, or a combination thereof. The processor  112  may be implemented, for example, in a microprocessor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other such customizable device. The motor drive  20  also includes a memory device  115  in communication with the processor  112 . The memory device  115  may include transitory memory, non-transitory memory or a combination thereof. The memory device  115  may be configured to store data and programs, which include a series of instructions executable by the processor  112 . It is contemplated that the memory device  115  may be a single device, multiple devices, or incorporated, for example, as a portion of another device such as an application specific integrated circuit (ASIC). The processor  112  is in communication with the memory  115  to read the instructions and data as required to control operation of the motor drive  20 . 
     According to one embodiment of the invention, the processor  112  receives a reference signal identifying desired operation of the motor  10  connected to the motor drive  20 . The reference signal may be, for example, a torque reference (T*), a speed reference (ω*), or a position reference (θ*). The processor  112  also receives feedback signals indicating the current operation of the motor drive  20 . The motor drive  20  may include a voltage sensor and/or a current sensor operatively connected to the DC bus  50  and generating a feedback signal corresponding to the magnitude of voltage and/or current present on the DC bus. The motor drive  20  may also include one or more voltage sensors and/or current sensors  152  on each phase of the AC output voltage generating a feedback signal  154  corresponding to the magnitude of voltage and/or current present at the output  160  of the motor drive  20 . 
     The processor  112  utilizes the feedback signals and the reference signal to control operation of the inverter section  100  to generate an output voltage having a desired magnitude and frequency for the motor  10 . The processor  112  may generate a desired output voltage signal to a driver module  114 . The driver module  114 , in turn, generates the switching signals  116 , for example, by pulse width modulation (PWM) or by other modulation techniques. The switching signals  116  subsequently enable/disable the transistors  106  to provide the desired output voltage to the motor  10 , which, in turn, results in the desired operation of the motor  10 . 
     Between the inverter section  100  and the output terminal  160  are illustrated still additional filter sections either in series with or parallel to each phase of the AC output voltage. As illustrated, the motor drive  20  includes a seventh filter  120 , an eighth filter  130 , and a ninth filter  140 . Each of the seventh, eighth, and ninth filters serve as output filters for the motor drive  20 . The seventh filter  120  includes an inductor  122  and a capacitor  124  for each phase of the AC output voltage. Each inductor  122  is connected in series with one phase of the output voltage ( 110 U,  110 V,  110 W) at the output of the inverter section  100 . Capacitors  124  are then connected after the inductors  122  and between each phase of the AC output voltage and a common connection point  126  for the seventh filter in a wye configuration. For the three-phase AC output voltage illustrated, the seventh filter  120  includes three capacitors  124  each connected between one phase of the output voltage and the common connection point  126 . Alternately, the capacitors  124  may be connected in a delta configuration as shown in  FIG. 24 . Optionally, a fourth capacitor  128  may also be provided. The fourth capacitor  128  is connected between the common connection point  126  of the seventh filter  120  and the common connection  15  for the motor drive  20 . 
     The eighth filter  130  is connected in series with the output of the seventh filter on each phase of the AC output voltage ( 110 U,  110 V,  110 W). The eight filter includes an AC common mode inductor  132 , also referred to as an AC common mode choke. The AC common mode inductor  132  includes a winding for each phase of the AC output voltage which may be wrapped around a single core or, optionally, include windings wrapped around separate cores. 
     The ninth filter  140  includes three capacitors  142  each connected between one phase of the AC output voltage and a common connection point  144  for the ninth filter. The common connection point  144  of the ninth filter  140  is connected to the common connection  15  for the motor drive  20 . As previously indicated, connecting the common connection point  126 ,  144  of the seventh filter  120  or the ninth filter  140 , respectively, to the common connection  15  will allow common mode currents to circulate within the motor drive  20 . It is contemplated that only a portion of the filters (i.e., seventh, eighth, or ninth) are required in a particular embodiment to provide the necessary output filtering for the motor drive  20 . 
     A current sense module  150  is provided after the output filtering. The current sense module  150  includes a current sensor  152  on each phase of the AC output voltage. Each current sensor  152  generates a current feedback signal  154  corresponding to the current present at the output  160  of the motor drive for each phase of the AC output. 
     The motor drive embodiment, as illustrated in  FIG. 1  and described above, is not intended to be limiting. The described embodiment includes numerous filters of which various combinations and/or portions of the filters may be utilized to achieve a sinusoidal voltage output waveform while maintaining EMC compatibility. Satisfactory performance may be achieved with different combinations of the filters or with just a portion of the above-described filters. Although not intended to be exhaustive, several of the different embodiments will be described below. 
     Turning next to  FIG. 2 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 2  includes the first filter  24  and the second filter  30  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the third filter  60 , the fourth filter  70 , the fifth filter  80 , and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120 , eighth filter  130 , and ninth filter  140  are connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . The seventh filter  120  includes an inductor  122  and a capacitor  124  for each phase of the AC output voltage. Each inductor  122  is connected in series with one phase of the output voltage ( 110 U,  110 V,  110 W) at the output of the inverter section  100 . Capacitors  124  are then connected after the inductors  122  and between each phase of the AC output voltage and a common connection point  126  for the seventh filter in a wye configuration. In this embodiment, the optional fourth capacitor  128 , discussed above with respect to  FIG. 1 , is not included. 
     Turning next to  FIG. 3 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 3  includes the first filter  24  and the second filter  30  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the third filter  60 , the fourth filter  70 , the fifth filter  80 , and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  and ninth filter  140  are connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . The seventh filter  120  includes an inductor  122  and a capacitor  124  for each phase of the AC output voltage. Each inductor  122  is connected in series with one phase of the output voltage ( 110 U,  110 V,  110 W) at the output of the inverter section  100 . Capacitors  124  are then connected after the inductors  122  and between each phase of the AC output voltage and a common connection point  126  for the seventh filter in a wye configuration. In this embodiment, the optional fourth capacitor  128 , discussed above with respect to  FIG. 1 , is not included. 
     Turning next to  FIG. 4 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 4  includes the first filter  24  and the second filter  30  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the fourth filter  70 , the fifth filter  80 , and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  and ninth filter  140  are connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . The seventh filter  120  includes an inductor  122  and a capacitor  124  for each phase of the AC output voltage. Each inductor  122  is connected in series with one phase of the output voltage ( 110 U,  110 V,  110 W) at the output of the inverter section  100 . Capacitors  124  are then connected after the inductors  122  and between each phase of the AC output voltage and a common connection point  126  for the seventh filter in a were configuration. In this embodiment, the optional fourth capacitor  128 , discussed above with respect to  FIG. 1 , is not included. 
     Turning next to  FIG. 5 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 5  includes the first filter  24  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the third filter  60 , the fourth filter  70 , the fifth filter  80 , and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  and ninth filter  140  are connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . The seventh filter  120  includes an inductor  122  and a capacitor  124  for each phase of the AC output voltage. Each inductor  122  is connected in series with one phase of the output voltage ( 110 U,  110 V,  110 W) at the output of the inverter section  100 . Capacitors  124  are then connected after the inductors  122  and between each phase of the AC output voltage and a common connection point  126  for the seventh filter in a wye configuration. In this embodiment, the optional fourth capacitor  128 , discussed above with respect to  FIG. 1 , is not included. 
     Turning next to  FIG. 6 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 6  includes the first filter  24  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the fourth filter  70 , the fifth filter  80 , and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  and ninth filter  140  are connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . The seventh filter  120  includes an inductor  122  and a capacitor  124  for each phase of the AC output voltage. Each inductor  122  is connected in series with one phase of the output voltage ( 110 U,  110 V,  110 W) at the output of the inverter section  100 . Capacitors  124  are then connected after the inductors  122  and between each phase of the AC output voltage and a common connection point  126  for the seventh filter in a wye configuration. In this embodiment, the optional fourth capacitor  128 , discussed above with respect to  FIG. 1 , is not included. 
     Turning next to  FIG. 7 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 7  includes the first filter  24  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the fifth filter  80  and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  and ninth filter  140  are connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . The seventh filter  120  includes an inductor  122  and a capacitor  124  for each phase of the AC output voltage. Each inductor  122  is connected in series with one phase of the output voltage ( 110 U,  110 V,  110 W) at the output of the inverter section  100 . Capacitors  124  are then connected after the inductors  122  and between each phase of the AC output voltage and a common connection point  126  for the seventh filter in a wye configuration. In this embodiment, the optional fourth capacitor  128 , discussed above with respect to  FIG. 1 , is not included. 
     Turning next to  FIG. 8 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 8  includes the first filter  24  connected in series between the input  22  and the converter section  40  of the motor drive. The first filter  24  includes a capacitor  26  connected between each phase of the AC input voltage and a common connection point  25  for the first filter. In this embodiment, the optional fourth capacitor  28 , discussed above with respect to  FIG. 1 , is not included. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the fourth filter  70 , the fifth filter  80 , and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  and ninth filter  140  are connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . The seventh filter  120  includes an inductor  122  and a capacitor  124  for each phase of the AC output voltage. Each inductor  122  is connected in series with one phase of the output voltage ( 110 U,  110 V,  110 W) at the output of the inverter section  100 . Capacitors  124  are then connected after the inductors  122  and between each phase of the AC output voltage and a common connection point  126  for the seventh filter in a wye configuration. In this embodiment, the optional fourth capacitor  128 , discussed above with respect to  FIG. 1 , is not included. 
     Turning next to  FIG. 9 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 9  includes the first filter  24  and the second filter  30  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the third filter  60 , the fourth filter  70 , the fifth filter  80 , and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  is connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . 
     Turning next to  FIG. 10 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 10  includes the first filter  24  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the third filter  60 , the fourth filter  70 , the fifth filter  80 , and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  is connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . 
     Turning next to  FIG. 11 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 11  includes the first filter  24  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the fourth filter  70 , the fifth filter  80 , and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  is connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . 
     Turning next to  FIG. 12 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 12  includes the first filter  24  connected in series between the input  22  and the converter section  40  of the motor drive. The first filter  24  includes a capacitor  26  connected between each phase of the AC input voltage and a common connection point  25  for the first filter. In this embodiment, the optional fourth capacitor  28 , discussed above with respect to  FIG. 1 , is not included. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the fourth filter  70 , the fifth filter  80  and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  is connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . 
     Turning next to  FIG. 13 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 13  includes the first filter  24  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the fifth filter  80  and the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  is connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . 
     Turning next to  FIG. 14 , another embodiment of a motor drive  20  incorporating EMI filtering and producing a sinusoidal voltage output is illustrated. An AC voltage  12  is provided at an input  22  to the motor drive  20 . According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The motor drive supplies a sinusoidal output voltage from an output  160  of the motor drive to a motor  10  operatively connected to the motor drive  20  via a cable  14 . The output voltage is a three-phase AC output voltage with individual conductors shown extending between the motor  10  and drive  20  for each phase as well as for a ground conductor. It is understood that the illustrated conductors may be combined within a cable  14 , run as individual conductors, or a combination thereof according to the application requirements. 
     The motor drive  20  illustrated in  FIG. 14  includes the first filter  24  and the second filter  30  connected in series between the input  22  and the converter section  40  of the motor drive. The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The motor drive further includes the sixth filter  90  connected in series between the DC bus capacitor  55  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120  is connected in series between the output of the inverter section  100  and the current sensing segment  150  of the motor drive  20 . 
     Turning next to  FIGS. 17-19 , one embodiment of an inductor, or set of inductors for a multi-phase voltage, integrated into a PCB for use in one or more of the filters discussed above is illustrated. Integrating the magnetic components into a PCB is discussed in detail in a co-pending application, which is also owned by Applicant, the co-pending application assigned U.S. Ser. No. 16/398,486 was filed Apr. 30, 2019 is titled System and Method for Reducing Power Losses for Magnetics Integrated in a Printed Circuit Board and is incorporated herein by reference in its entirety. The magnetic component shown in  FIGS. 17-19  includes a coil  250  integrated on a printed circuit board (PCB)  220  for use within the motor drive  20 . The PCB includes multiple layers  230  and traces  252  on each layer are joined together to form a single coil  250  or to form multiple coils on the magnetic component. The PCB further includes at least one opening  224  in the PCB through which a core component  282  may pass. The traces  252  forming the coils may be laid out to encircle the opening and the core material, such that the magnetic component is defined by the coils and the core material. The dimensions of traces on a layer may be varied within the coil to reduce eddy currents within the traces resulting from air-gap fringing flux. The air-gap fringing flux is greatest proximate the opening in the PCB and at the air-gap in the core component. By making the width of individual traces that are closest to the opening within the coil narrower than traces that are further from the opening, the conductive material of the coil located within the region of high air-gap fringing flux is reduced. As a result, the eddy currents induced within the coil due to the air-gap fringing flux is reduced. Optionally, the position of traces between layers of the PCB are varied. The locations of individual traces are selected such that the trace is located in a region having a lower magnetic field component and, therefore, reducing coupling to leakage fluxes within the magnetic component. A floating conductive layer may also be positioned between the coil and the core material. The floating conductive layer may be a conductive sheet or series of traces located on one layer of the PCB and where the conductive layer is not connected to the coil. The conductive layer is preferably located near a surface of the PCB such that eddy currents and the resulting heat induced within the conductive layer are more readily dissipated out of the PCB. 
     With reference again to  FIGS. 17-19 , the PCB  220  is a multi-layer board where a coil  250  is defined by multiple loops of circuit traces  252  on the PCB. A first opening  224  extends through the PCB  220  which is configured to receive a center portion of a core  280 . A pair of side openings  229  also extend through the PCB  220  with a first side opening  229  positioned to one side of the first opening  224  and a second side opening  229  positioned on the opposite side of the first opening  224 . An “E-shaped” member  284  of the core  280  may be inserted into the openings with a central portion  281  of the core  280  extending through the first opening  224  and a pair of side members  283  of the core  280  extending through the side openings  229 . A second member of the core, such as an “I-shaped” member  282  of the core  280  may be positioned on the reverse side of the PCB  220 . Clips  227  extending up through the side openings  229  secure the two members of the core  280  together and positively retain the core  280  to the PCB  220 . Optionally, an adhesive material may be applied between contacting surfaces of the “E-shaped” and “I-shaped” members to secure the core members together. 
     With reference also to  FIG. 20 , an exemplary sectional view of such an E-I core configuration is illustrated. The E-shaped member  284  is illustrated on the lower surface and the I-shaped member  282  is illustrated on the upper surface. It is understood that terms such as upper and lower, left and right, front and back, and the like are intended to be relational with respect to a figure and are not intended to be limiting. The illustrated magnetic component  210  may be rotated around a vertical axis, horizontal axis, or about any other axis of rotation for installation within a power converter and the associated components will similarly be rotated. It is further contemplated that various other configurations of the core  280  may be utilized. For example, other shapes including, but not limited to, U-shaped members, C-shaped members, R-shaped members, T-shaped members, D-shaped members, F-shaped members, and the like may be utilized according to the application requirements. Suitable openings may be cut through the PCB  220  and a suitable arrangement of traces  252  on each layer  230  of the PCB  220  may be implemented to complement the corresponding members of the core  280 . 
     The circuit traces  252  are distributed on the PCB  220  such that they loop around the opening  224 . Multiple loops may be formed on each layer  230  of the PCB  220  where an inner trace  254  is closest to the opening  224  and outer trace  258  is furthest from the opening  224 . Various numbers of intermediate traces  256  may be defined between the inner trace  254  and the outer trace  258 . Vias extending between layers of the PCB  220  may join coils on different layers to form a single coil spanning multiple layers  230 . The illustrated embodiment illustrated in  FIGS. 17-19  includes 4 loops on a layer for ease of illustration. It is contemplated that various other numbers of loops may be utilized according to the application requirements. Similarly, the illustrated embodiment includes eight layers on the PCB. A top layer  226  and a bottom layer  228  each include solder pads to which wires or other electrical conductors may be connected. Six intermediate layers  230   a - 230   f  are illustrated between the top and bottom layers, where each of the intermediate layers  230   a - 230   f  includes four loops. It is contemplated that the PCB  220  may include various other numbers of layers  230  according to the length of the traces and number of loops desired. The PCB  20  may include, for example, twenty layers or more. The number, length, and cross-section of the traces defining loops on a layer  230  and further the number of layers  230  on which loops are present define an inductance for the magnetic component. The layout and selection of the number of loops and number of layers, therefore, are selected according to the filtering requirements of the application in which the magnetic component is integrated. 
     Turning next to  FIGS. 21-23 , the motor drive  20  includes a radiated emissions shield  320 . With reference first to  FIG. 21 , the motor drive  20  includes a chassis  300  configured to be mounted within a control cabinet. The chassis  300  includes a generally flat plate  301  to be mounted to a surface within the control cabinet. A mounting hole  302  near one end of the plate  301  and a mounting slot  304  near the other end of the plate are configured to receive a fastener, such as a screw, through the hole or slot to secure the chassis to the surface of the control cabinet. A primary PCB  330  within the motor drive  20  includes electronic components for operation of the motor drive  20  mounted thereto. The electronic components are mounted to a front surface  332  of the primary PCB  330  and face inwards to the motor drive  20 , while a rear surface  334  of the primary PCB  330  faces outwards from the motor drive  20 . 
     In  FIG. 21 , a first embodiment of a radiated emissions shield  320  is illustrated mounted to the rear surface  334  of the primary PCB  330 . The radiated emissions shield  320  is a conductive surface which is operative to absorb radio frequency (RF) energy emitted from the PCB  330  creating eddy currents in the shield  320 . The shield  320  is tied to a common connection, such as a ground connection, in order that currents induced in the shield are carried to the ground connection. The radiated emissions shield  320  may be, for example, a metal plate mounted by standoffs to the rear surface  334  of the primary PCB  330 . Optionally, the radiated emissions shield  320  may be a conductive coating, where an insulative coating may first be applied to the rear surface  334  to prevent establishing conduction paths between traces, vias, and the like, and the conductive coating is then applied over the insulative coating to the rear surface  334  of the primary PCB  330 . 
     In  FIG. 22 , a second embodiment of the radiated emissions shield  320  is illustrated mounted to an inside surface of a housing  310  for the motor drive  20 . The housing  310  may mount over the chassis  300  shown in  FIG. 21  and position the radiated emissions shield  320  with respect to the primary PCB  330 . The shield  320  is tied to a common connection, such as a ground connection, in order that currents induced in the shield are carried to the ground connection. The radiated emissions shield  320  may be, for example, a metal plate mounted to the interior surface of the housing  310 . Optionally, the radiated emissions shield  320  may be a conductive coating applied to surface. 
     Turning next to  FIG. 23 , the orientation of the radiated emission shield  320  with respect to the primary PCB  330  is illustrated. The radiated emissions shield  320  is shown covering at least a portion of the primary PCB  330 . Electrical components located behind the shield  320  include, for example, the driver module  114 , inverter section  100 , seventh filter  120 , eighth filter  130 , located at the output of the motor drive  20  and, in which, high frequency current and/or voltage components may be present as a result of the operation of the inverter section  100 . Although illustrated as covering only a portion of the primary PCB  330 . It is contemplated that the shield  320  may take other shapes and cover, for example, the entire primary PCB  330 . In some embodiments of the invention, it is also contemplated that the motor drive  20  may include a first and a second radiated emission shield, where a first shield  320  is located on one side of the primary PCB  330  and a second shield  320  is located on the other side of the primary PCB  330 . 
     In operation, the motor drive  20  is configured to generate a sinusoidal output voltage waveform to control operation of a motor  10  connected to the motor drive. Switching devices in the inverter section  100  are selected which are suitable for high frequency switching. The switching device may be, for example, field-effect transistors (FETs) made of Silicon Carbide (SiC) MOSFET or Gallium Nitride (GaN FET) where the switching frequencies may increase to tens or hundreds of kilohertz (e.g., 20 kHz-1 MHz) in contrast to traditional IGBTs which are typically limited to upper switching frequencies in the range of 10 kHz-20 kHz. The greater the frequency at which the power switching devices are able to be modulated, the lower the amplitude of the harmonic content present on the output of the motor drive. Thus, including switching devices suitable for switching in the tens to hundreds of kilohertz range reduces the magnitude of the harmonic content that requires filtering and similarly reduces the amount of heat generated in the magnetic component as a result of the power being dissipated in that magnetic component. 
     Integration of a magnetic device, such as the inductors  122  in the seventh filter  120  at the output of the inverter section  100  in the motor drive  20  may attenuate or eliminate the harmonic content of the output voltage while allowing the desired fundamental component to be provided at the output  160  to the motor  10 . Each inductor  122  may be implemented as one of the magnetic components  210  illustrated in  FIGS. 17-20 . Implementing the inductor windings as traces  254  on the PCB  220  and providing the magnetic cores  280  as shown allow three magnetic components  210  to be positioned next to each other in a stacked fashion (as shown in  FIG. 23 ), reducing the surface are required on the primary PCB  330 . 
     As previously indicated, connecting multiple filters to the common connection  15  allows common mode currents  180  to circulate within the motor drive  20 . As illustrated in  FIGS. 2-14 , various conduction paths exist for the common mode currents to circulate from the output filter(s), through the common connection  15  to the input filter(s). Additionally, in some embodiments, multiple conduction paths exist between the input filter(s), output filter(s), and/or an intermediate filter(s), where the input filter is located before the converter section  40 , the intermediate filter is located between the converter section  40  and the inverter section  120 , and the output filter is located after inverter section. Circulation of the common mode currents within the motor drive  20  eliminates the requirement of an external overall shield conductor surrounding the other conductors within the output cable  14 . 
     Providing a sinusoidal output voltage waveform and eliminating the conducted emissions at the output  160  of the motor drive  20  provides several advantages to the motor  10  and motor drive  20  system. Electromagnetic noise seen on the motor cable  14  is significantly reduced or eliminated. As is understood in the art, the electromagnetic noise may introduce ripple currents at the output  160  of the motor drive at the switching frequency or harmonics thereof. In traditional motor drives, these ripple currents may generate excessive acoustic noise or cause reflected waveforms on the motor cables  14  thereby limiting the length of the cables  14 . Certain applications may impose cable length restrictions, for example, of ten to fifty meters (10-50 m). Additionally, the motor cables  14  are typically shielded cables requiring a shield conductor and/or a braided shield extending the length of the cable and secure connections to ground at the end of the cable  14 . By providing a sinusoidal output voltage and causing the reduced magnitude common mode currents to circulate within the motor drive  20 , the shielding requirements on the motor cables  14  may be eliminated. Similarly, the maximum cable length restrictions resulting from harmonic content may be removed. Cable length restrictions due solely to the voltages output at the fundamental frequency extend to miles of cable length. Further, the elimination of the current ripple, in turn, eliminates torque ripple at the motor  10  resulting from the current ripple. A purely sinusoidal output voltage as opposed to a modulated output voltage reduces stress on motor insulation and motor bearings as well, increasing the life of the motor  10  connected to the motor drive  20 . 
       FIGS. 1-14 , as discussed above, discuss a first embodiment of a motor drive topology that provides an improved sinewave output voltage waveform and its associated benefit to motor operation. The disclosed motor drive topology also provides improvements resulting from integrated differential mode and common mode filtering EMC filtering and radiated emission shielding for a single motor drive system. It is contemplated that the disclosed motor drive topology may be connected to a common AC bus utility line and a separate motor drive  20  may be provided to control each motor  10  in the system. 
     However, many controlled machines and processes find it advantageous to utilize a distributed motor drive topology. In a distributed motor drive topology, individual inverter sections are connected to a common dc bus. In a common dc bus system, when a first motor, also referred to as an axis, is motoring in steady state and a second axis is decelerating, generating excess regenerative energy which is supplied back onto the dc bus, the first axis can utilize that energy. This topology eliminates the need for DC brake resistor circuits for every axis to dissipate regenerative energy, resulting in reduction of energy cost, material cost, system size, and system weight. Further, certain applications, such as a roll wind—rewind configuration, operate one axis continuously in a motoring mode and another axis continuously in a regenerative mode. The connection to the AC utility can be smaller since it only needs to be rated to supply system energy losses, reducing cost of energy supplied by the AC utility.  FIG. 25  and  FIG. 26  show two possible embodiments with a common dc bus and distributed inverter section configuration. 
     Turning first to  FIG. 25 , one embodiment for a Common DC bus topology is illustrated with two axes, or motors  10 , controlled by distributed motor drives  220 . Each distributed motor drive  220  is connected, via a common DC bus  250  to a single rectifier module  240 . However, it is contemplated that various numbers of axes may connected to the common DC bus  250  without deviating from the scope of the invention. Each distributed motor drive  220  includes a portion of the blocks discussed above with respect to  FIGS. 1-14  to provide an improved sinusoidal output voltage waveshape at each set of output terminals  160  for each motor  10 . Each distributed motor drive  220  further includes an integrated radiated shield protection over the high frequency inverter section  150  on the PCB, as discussed previously. Each distributed motor drive  220  illustrated in  FIG. 25  includes the third filter  60 , the fourth filter  70 , the fifth filter  80 , and the sixth filter  90  connected in series between the common DC bus  250  and the inverter section  100 . The processor  112  and driver circuit  114  control operation of the inverter section  100  as discussed above. The seventh filter  120 , eighth filter  130 , and ninth filter  140  are connected in series between the output of the inverter section  100  and the current sensing segment  150  of the distributed motor drive  220 . The fourth filter  70  and the sixth filter operate to provide significant reduction in differential mode noise voltage within each distributed motor drive  220 . The fourth, fifth, and seventh through ninth filters attenuate and capture a majority of common mode noise current emissions within each axis. Common mode chokes, such as the inductors  132  in the eighth filter  130 , attenuate the magnitude of the common mode current, and capacitors connected to the common connection point  15  within the distributed motor drive  220  circulate and contain a significant portion of the remaining common mode current within each axis. The embodiment illustrated in  FIG. 25  includes a third filter  60  within each distributed motor drive  220 . The DC common mode choke  62  in each filter reduces any remaining common mode current flowing from the axis onto the shared DC bus  250  and prevents common currents from one axis interacting with another axis. 
     The rectifier module  240  receives an AC voltage  12  at an input  22  to the module. According to the illustrated embodiment, the AC voltage  12  is a three-phase AC input voltage. The rectifier module  240  illustrated in  FIG. 25  includes the first filter  24  and the second filter  30  connected in series between the input  22  and the converter section  40  of the rectifier module  240 . The converter section  40  may be a passive converter section  40 A or an active converter section  40 B as discussed above. The DC bus charge circuit  57  is connected at an output of the converter section  40  and between the converter section and the DC bus capacitor  55 . The DC bus  50  from the rectifier module  240  is then connected to the common DC bus  250  at an output of the rectifier module  240 . The common Dc bus  250  is, in turn, configured to supply DC voltage to each of the distributed motor drive  220 . 
     Turning next to  FIG. 26 , another embodiment for a common DC bus topology is illustrated. This embodiment is configured in much the same manner as  FIG. 25  except the third filter  60  and the corresponding DC common mode choke  62  is connected in the rectifier module  240  rather than being repeated in each distributed motor drive  200 . This embodiment may desirable if there is no appreciable interaction of common mode current circulating between different axis. It may further be desirable in an application in which one axis is configured to supply energy generated in a regenerative operating mode to the common DC bus  250  and another axis is configured to draw this regenerative energy from the common DC bus  250  for operation in a motoring mode. Although only two embodiments of a common DC bus topology are illustrated, it is further contemplated that various other arrangements of the system illustrated in  FIGS. 2-14  may be employed in a common bus topology. 
     It should be understood that the invention is not limited in its application to the details of construction and arrangements of the components set forth herein. The invention is capable of other embodiments and of being practiced or carried out in various ways. Variations and modifications of the foregoing are within the scope of the present invention. It also being understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention.