Patent Publication Number: US-2022239244-A1

Title: Divided phase ac synchronous motor controller

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 17/020,444, entitled “Divided Phase AC Synchronous Motor Controller,” filed Sep. 14, 2022, which is a continuation of U.S. application Ser. No. 16/436,844, entitled “Divided Phase AC Synchronous Motor Controller,” filed Jun. 10, 2019, now U.S. Pat. No. 10,778,132, which is a continuation of U.S. application Ser. No. 15/894,848, entitled “Divided Phase AC Synchronous Motor Controller,” filed Feb. 12, 2018, now U.S. Pat. No. 10,320,318, which is a continuation of U.S. application Ser. No. 15/010,874, entitled “Divided Phase AC Synchronous Motor Controller,” filed Jan. 29, 2016, now U.S. Pat. No. 9,893,667, which is a continuation of U.S. application Ser. No. 14/080,785, entitled “Divided Phase AC Synchronous Motor Controller,” filed Nov. 14, 2013, now U.S. Pat. No. 9,300,237, which claims priority to U.S. Application No. 61/726,550, entitled “Divided Phase AC Synchronous Motor Controller,” filed Nov. 14, 2012, all of which are hereby incorporated by reference in their entirety. 
     This application is related to U.S. application Ser. No. 14/991,683, entitled “Divided Phase AC Synchronous Motor Controller,” filed Jan. 8, 2016, now U.S. Pat. No. 9,712,097, U.S. application Ser. No. 15/010,836, entitled “Divided Phase AC Synchronous Motor Controller, filed Jan. 29, 2016, now U.S. Pat. No. 9,787,239, and U.S. patent application Ser. No. 15/010,867, entitled Divided Phase AC Synchronous Motor Controller, now U.S. Pat. No. 9,705,441, filed Jan. 29, 2016, the entire contents of which are incorporated herein by reference. 
    
    
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     COMPACT DISK APPENDIX 
     Not Applicable. 
     BACKGROUND 
     In view of the growing proliferation of environmentally friendly laws, enhancements to various classes of motors are required. For example, refrigeration fan motors in a low wattage range, e.g. 4 to 16 watts, used in both the commercial and residential refrigeration markets, have traditionally been low efficiency, such as around 12%-26% efficient. It would be desirable to provide technologies to address enhancements required in different classes of motors. 
     SUMMARY 
     In one aspect, a circuit includes first and second phase windings, a direct current (DC) power supply to convert alternating current (AC) power to DC power, at least one power switch between the first and second phase windings, and a controller to control the at least one power switch. The circuit also includes a component to prevent the DC power supply from collapsing when the at least one power switch is on during a first portion of a cycle and a second component to prevent the DC power supply from collapsing when the at least one power switch is on during a second portion of the cycle. 
     In another aspect, a circuit for a motor includes first and second phase windings, a direct current (DC) power supply to receive alternating current (AC) power transferred from the first and second phase windings and convert the AC power to DC power, at least one power switch between the first and second phase windings to receive AC power from the first and second phase windings, and a controller to control the at least one power switch. The circuit also includes a first component connected to the DC power supply to prevent the DC power supply from collapsing when the at least one power switch is on during a first portion of an AC cycle and a second component connected to the DC power supply to prevent the DC power supply from collapsing when the at least one power switch is on during a second portion of the AC cycle. 
     In another aspect, a system for a motor includes first and second phase windings to receive alternating current (AC) power, a direct current (DC) power supply connected between the first and second phase windings to receive AC power transferred from the first and second phase windings and convert the AC power to DC power, at least one power switch between the first and second phase windings and outside of a current path between the first and second phase windings and the DC power supply, and a controller to control the at least one power switch. The circuit also includes a plurality of components in parallel with the DC power supply to prevent the DC power supply from collapsing when the at least one power switch is on during a first portion of a cycle and a second portion of the cycle. 
     In another aspect, a method for a circuit of a motor includes providing first and second phase windings, providing a direct current (DC) power supply to receive alternating current (AC) power transferred from the first and second phase windings and convert the AC power to DC power, providing at least one power switch between the first and second phase windings to receive AC power from the first and second phase windings, and providing a controller to control the at least one power switch. The method also includes providing a first component connected to the DC power supply to prevent the DC power supply from collapsing when the at least one power switch is on during a first portion of an AC cycle; and providing a component connected to the DC power supply to prevent the DC power supply from collapsing when the at least one power switch is on during a second portion of the AC cycle. 
     In another aspect, a method for a circuit of a motor includes providing first and second phase windings, the first and second phase windings receiving alternating current (AC) power, providing a direct current (DC) power supply connected between the first and second phase windings to receive AC power transferred from the first and second phase windings and to convert the AC power to a DC power, providing at least one power switch between the first and second phase windings, and providing a controller to control the at least one power switch. The method also includes providing a plurality of components in parallel with the DC power supply to prevent the DC power supply from collapsing when the at least one power switch is on during a first portion of a cycle and a second portion of the cycle. 
     The phase windings may be divided in half or in other portions or otherwise distributed and may be, for example, bifilar or lap wound. The non-collapsing DC power supply components may include one or more of a tap from the phase windings electrically connected to the DC power supply, a secondary phase coil winding connected to the DC power supply to power the power supply, one or more resistors between the phase windings and the power switch circuit, one or more Zener diodes between the phase windings and the power switch circuit, and/or one or more electrical components to create a voltage drop between the phase windings and the power switch circuit to prevent the power supply from collapsing when the at least one power switch in the power switch circuit is on and conducting. 
     In another aspect, a method is for a circuit for a motor comprising first and second phase windings. The method comprises receiving alternating current (AC) power from the first and second phase windings at a direct current (DC) power supply and converting the AC power to DC power and receiving AC power from the first and second phase windings by at least one power switch between the first and second phase windings and switching the AC power by the at least one power switch. The method further comprises preventing the DC power supply from collapsing, by a first component connected to the DC power supply, when the at least one power switch is on during a first portion of an AC cycle and preventing the DC power supply from collapsing, by a second component connected to the DC power supply, when the at least one power switch is on during a second portion of the AC cycle. 
     In another aspect, a method is for a circuit for a motor comprising first and second phase windings. The method comprises receiving alternating current (AC) power at first and second phase windings, receiving AC power transferred from the first and second phase windings at a direct current (DC) power supply connected between the first and second phase windings and converting the AC power to a DC power, receiving AC power from the first and second phase windings by at least one power switch between the first and second phase windings and switching the AC power by the at least one power switch, and controlling the at least one power switch with a controller. The method further includes preventing the DC power supply from collapsing by a plurality of components in parallel with the DC power supply when the at least one power switch is on during a first portion of a cycle and a second portion of the cycle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts motor phase windings divided with a control circuit located at a mid-point in the motor phase windings. 
         FIG. 2  depicts a single phase electronically commutated motor (ECM). 
         FIG. 3  depicts a divided phase winding circuit. 
         FIG. 4  depicts a divided phase winding circuit with a tap from the divided phase winding coil to the direct current (DC) power supply. 
         FIG. 5  depicts a divided phase winding circuit with resisters between the divided phase windings and the power switch(es). 
         FIG. 6  depicts a divided phase winding circuit with a secondary coil. 
         FIG. 7  depicts a control of phase current direction during start up and continuous operation below synchronous speeds in a divided phase winding circuit. 
         FIG. 8  depicts a control of phase current direction at a synchronous speed of 1800 revolutions per minute (RPM) in a four pole divided phase winding circuit. 
         FIG. 9  depicts a control of phase current direction at a synchronous speed of 3600 revolutions per minute (RPM) in a two pole divided phase winding circuit. 
         FIG. 10  depicts DC supply storage capacitor charging periods. 
         FIG. 11  depicts a divided phase winding circuit with a secondary coil and one power switch. 
         FIG. 12  depicts a divided phase winding circuit with a secondary coil and one power switch. 
         FIGS. 13 and 13A  depict a divided phase winding circuit with a secondary coil and one power switch. 
         FIG. 14  depicts a divided phase winding circuit with two power switches. 
         FIG. 15  depicts a divided phase winding circuit with one power switch. 
         FIG. 16  depicts a divided phase winding circuit with two power switches in series. 
         FIG. 17  depicts a divided phase winding circuit with a tap from the divided phase winding coil to the direct current (DC) power supply and two power switches in series. 
         FIG. 18  depicts a divided phase winding circuit with two power switches in parallel. 
         FIG. 19  depicts a divided phase winding circuit with a tap from the divided phase winding coil to the direct current (DC) power supply and two power switches in parallel. 
         FIG. 20  depicts a motor with a divided phase winding circuit having a primary AC phase winding and secondary winding to create a non-collapsing DC power supply. 
         FIG. 21  depicts a motor with a divided phase winding circuit having a primary AC phase winding and secondary winding to create a non-collapsing DC power supply wound on only one pole. 
         FIG. 22  depicts a motor with a divided phase winding circuit with a tapped primary phase winding to create a non-collapsing DC power supply. 
         FIG. 23  depicts a motor with a divided phase winding circuit with resisters to create a non-collapsing DC power supply. 
         FIG. 24  depicts a motor with a divided phase winding circuit with Zener diodes to create a non-collapsing DC power supply. 
     
    
    
     DETAILED DESCRIPTION 
     New and useful circuits are disclosed that provide advantages over the prior art for controlling synchronous brushless permanent magnet motors. One embodiment of the present disclosure includes one or more circuits for an electronically commutated motor (ECM). Another embodiment of the present disclosure includes one or more circuits for a shaded pole motor. In one aspect, a motor has multiple motor phases (i.e., motor phase windings) and a supply line voltage through the phases. The motor phases are divided in half and both the motor controller for the motor and the power electronics for the motor are placed at a “mid-point” or “center point” in the supply line voltage between the divided phases. The direct current (DC) power supply (e.g. for the electronics used in the motor controller) are also located between the divided phases. The motor phases provide current limiting and the voltage drop from the line voltage supply lines to low voltage DC to the DC power supply, thereby reducing the DC power supply component count and allowing for the use of low voltage components for the DC power supply and for the motor controller. 
     Prior systems used a Zener diode or other voltage regulator located in series with a power switch and the motor phases, which limited the maximum power of the motor to the maximum wattage value of the Zener diode. Circuits in the present disclosure eliminate the Zener diode voltage regulator from the primary current path for the motor phases so that a Zener diode voltage regulator is not located in series with a power switch and the motor phases, which eliminates the need to lower the wattage specification otherwise needed for a Zener diode. Instead, the Zener diode or other voltage regulator is located in parallel with the power switch(es) in some embodiments of the present disclosure. 
     Circuits in the present disclosure eliminate the need for an opto-isolator to allow switching between sensing/control electronics of a motor controller and a power switch of the motor controller. Prior systems had two neutral reference values, one for sensing/control electronics and one for a power switch. 
     Circuits in the present disclosure have improved line phase angle detection, eliminating the need for a precision resistance bridge linked to the input of an opto-isolator. Thus, the circuits of this aspect have more accurate line phase angle detection. 
     Circuits in the present disclosure reduce different electrical neutral values for the power switches and motor controller to one value. This guarantees that the power switch(s) of the circuits with this aspect will reliably transition from completely “off” to fully saturated. 
     Prior systems that included two switches have a difficult time turning one switch off completely for one half of an AC cycle. Circuits in the present disclosure place one or more switches outside of a DC power supply and motor controller circuit, resulting in proper switching. 
     Each of these improvements not only increases the reliability of the operation of the motor controller, but also serves to improve the combined motor/motor controller efficiency. 
     The divided phase winding circuits in the present disclosure can be used in a variety of motors, such as DC brushless motors/electronically communicated motors (ECMs), shaded pole motors, other synchronous motors, permanent-split capacitor (PSC) motors, etc. 
     For example,  FIG. 1  depicts a motor  102  with divided motor phase windings  104 ,  106  and a motor control circuit  108  located at a mid-point  110  in the divided motor phase windings. The motor  102  includes a stator  112  and a rotor  114  mounted on a shaft  116 . The rotor  114  is mounted for rotation in a core structure, such as laminated core structure or other core structure. The rotor  114  has a body portion which is shown as cylindrical in shape. Around the periphery of the body are located arcuately shaped permanent magnetic portions. The magnetic portion has its north magnetic pole adjacent to the outer surface of the rotor and the magnetic portion has its south magnetic pole located adjacent to outer periphery of the rotor  114 . A winding or pair of windings are mounted on the connecting portion of the core structure. The motor  102  also includes a Hall Effect switching device, a portion of which extends to adjacent the periphery of the rotor  114  for responding to the magnetic polarity of the respective rotor magnetic portions. In the construction as shown, the Hall Effect switch is located adjacent the outer periphery of the magnetic portion during half of each revolution of rotor  114  and adjacent the outer periphery of the magnetic portion during the remaining half of each revolution of rotor. 
     The motor  102  can operate below, at, or above synchronous speeds. This is due to the fact that fractions of half cycles can flow through the phase windings. 
     The divided phase winding circuit of  FIG. 1  includes input connections on leads L 1  and L 2  connected to a source of alternating current (AC) energy during operation, such as AC line voltage. The leads L 1  and L 2  are connected across a series circuit that includes divided phase windings  104 ,  106  shown connected in series across a control circuit  108 . For example, the control circuit  108  may include a full wave diode rectifier bridge circuit connected in series to the divided phase windings  104 ,  106  and a power switch(es) circuit having one or more switches or other power controllable switching devices connected to the output of the full wave diode rectifier bridge circuit. 
     The divided phase windings  104 ,  106  can be bifilar or lap wound. The alternating current power source has its lead L 1  connected to the start side S 1  of the first winding  104 . The other end of the winding  104 , labeled F 1 , is connected to one of the inputs of the control circuit  108 . The other input side of the control circuit  108  is attached to the start side S 2  of the second divided phase winding  106  and the finish side of the same divided phase winding, labeled F 2 , is attached to the input lead L 2  of the AC power source. 
     As another example,  FIG. 2  depicts a single phase ECM  202  in which the motor phase windings are divided and a motor controller (motor control circuit) is located at a mid-point in the divided motor phase windings. 
       FIG. 3  discloses a divided phase winding circuit  302  for dividing motor phase windings  304 ,  306  (also referred to as motor phases or phase coils herein) of a motor in half and placing both a motor controller  308  for the motor and power electronics for the motor, including the DC power supply  310  and a power switch(es) circuit  312  with one or more power switches, at a “mid-point” or “center point”  314  in the supply line voltage between the divided phases  304 ,  306 . In the example of  FIG. 3 , the motor phase winding is divided in half. Some variation from the half division is allowable, such as between zero and plus/minus 20% of the halfway point. 
     The divided phase winding circuit  302  of  FIG. 3  includes two divided phase windings  304 ,  306 , each connected to AC line voltage L 1  and L 2  respectively. A DC power supply  310  is electrically connected to the divided phase windings  304 ,  306 , such as at the finish side of the first phase winding  304  and the start side of the second phase winding  306 . The divided phase winding  304 ,  306  operates to lower the AC line voltage to a voltage compatible with the DC power supply  310 . Thus, the number of windings in the divided phase winding  304 ,  306  can be selected to reduce the AC line voltage received at L 1  and L 2  to a selected lower voltage to be received by the DC power supply  310 . The divided phase winding  304 ,  306  also operates to filter noise from the AC line voltage received at L 1  and L 2 . 
     The DC power supply  310  converts the low voltage AC power received from the divided phase windings  304 ,  306  to a DC voltage configured to power the DC powered components of the divided phase winding circuit, including the motor controller  308 . The DC power supply  310  then supplies power to the motor controller  308 . 
     The motor controller  308  controls the start-up and operation of the divided phase winding circuit  302 . For example, the motor controller  308  controls start-up, including where the motor is a synchronous motor. The motor controller  308  determines the location of the rotor relative to the stator. The motor controller  308  also determines and monitors the speed of the rotor, such as in revolutions per minute (RPMs), to determine operational parameters of the motor, such as when the motor has reached synchronous speed, and controls the motor based on the location of the rotor and or speed of the motor. In one example, the motor controller  308  has a Hall effect switch and/or other rotation determining device to determine the position of the rotor and/or rotation counting or speed determining device to determine the speed of the rotor. 
     The power switch(es) circuit  312  includes one or more power switches, such as one or more metal-oxide-semiconductor field-effect transistors (MOSFETs), silicon-controlled rectifiers (SCRs), transistors, or other switches or switching devices. The one or more switches are on or off or one is on while the other is off. For example, in one half cycle of an AC cycle, a first power switch is on and conducting while the second switch is off and not conducting. In the other half cycle of the AC cycle, the second power switch is on and conducting while the first switch is off and not conducting. In circuits with one switch, the switch may be on and conducting or off and not conducting during one or more portions of the AC cycle. 
     The power switch(es) circuit  312  is isolated from (outside of) the DC power supply  310 , which makes the divided phase winding circuit  302  more stable than circuits having the power switch(es) circuit within (and not isolated from) the DC power supply. 
     Normally, when the power switch(es) of a circuit turn on, there is only a slight voltage drop through the power switch(es) due to the minor resistance of the power switch(es). Therefore, if the input voltage for the DC power supply is developed by connecting the DC power supply leads to both sides of a power switch (or power switches), this would result in the DC power supply collapsing when the power switch is in an ‘on’ state or not being able to receive power and power the DC components of the circuit. The divided phase winding circuit  302  includes one or more non-collapsing DC power supply components  316 ,  318 , including voltage drop components or direct DC power supply powering components to create a non-collapsing DC power supply. Examples of non-collapsing DC power supply components  316 ,  318  include a tap from the primary phase winding  304 ,  306  electrically connected to the DC power supply  310 , a secondary phase coil winding connected to the DC power supply to power the power supply, resistors between the divided phase windings and the power switch(es) circuit  312 , one or more Zener diodes between the divided phase windings and the power switch(es) circuit, or other components to create a voltage drop between the primary divided phase windings and the power switch(es) circuit to prevent the power supply from collapsing when the power switch(es) in the power switch(es) circuit is/are on and conducting. The divided phase winding circuit  302  therefore provides a constant flow of power regardless of whether the power switch(es) circuit is on and conducting or off and not conducting. 
     Many electronically controlled synchronous motors have circuits that detect the zero crossing of the AC voltage applied to the phase windings. This zero crossing detection circuit sends a signal to the motor controller  308  to determine when the motor is at synchronous speed. If the AC supply voltage has electrical noise riding on, usually due to other equipment operating on the same circuit, this electrical noise can cause the zero crossing detector to operate incorrectly affecting the control of the motor which normally appears as acoustical noise in the motor. 
     In one example, the divided phase winding circuit  302  is part of a synchronous motor. The synchronous motor receives line power (that is, AC power) at L 1  and L 2 . In a synchronous motor using a divided phase winding using the associated circuit of the present disclosure does not rely upon detecting the zero crossing of the applied AC voltage to control the motor but rather detects the polarity of the voltage, i.e., whether the polarity L 2  is higher or less than L 1  allowing for quiet operation even when electrical noise is present in the AC supply. 
     The DC power supply  310  in  FIG. 3  is electrically connected directly to the divided phase windings  304 ,  306 . Thus, the DC power supply  310  is powered by the divided phase windings  304 ,  306  regardless of the status of the power switch(es) circuit  312 . 
       FIG. 4  discloses another divided phase winding circuit  402  for dividing motor phase windings  404 ,  406  of a motor in half and placing both a motor controller  408  for the motor and power electronics for the motor, including the DC power supply  410  and a power switch(es) circuit  412  with one or more power switches, at a “mid-point” or “center point”  414  in the supply line voltage between the divided phases. The divided phase winding circuit  402  of  FIG. 4  includes a tap  416 ,  418  from the primary divided phase winding  404 ,  406  electrically connected to the DC power supply  410  to create a non-collapsing DC power supply. 
     In some circuits, when the motor reaches synchronous speed, the one or more power switch(es) turn off and thereby cause the low voltage power to stop flowing to the motor controller. In one example, the path from one divided phase winding through the power switch(es) to another divided phase winding is shorted, such as at synchronous speed, resulting the DC power supply and motor controller no longer receiving the low power supply voltage from the phase windings, such as in the event there is no capacitor to hold a charge during the short or a capacitor that is present is not large enough to hold enough charge during the short. The circuit  402  of  FIG. 4  includes a tap  416 ,  418  from the coils of the phase windings  404 ,  406  to the DC power supply  410  so that the low voltage power supply flows directly from the phase windings to the DC power supply, bypassing the power switch(es) (“divided motor phase controller”). The circuit  402  of  FIG. 4  thereby guarantees that the low voltage power supply is supplied to the DC power supply  410 , for example at synchronous speed. 
     In one example, a DC power supply  410  for a divided motor phase controller is formed by a Zener diode and a storage capacitor that receives power during a portion of an alternating current (AC) cycle when the power switch(es) are off. When the motor is operating at synchronous speed, the power switch(es) are continuously conducting. Therefore, the amount of voltage being supplied to the DC power supply is equal to the voltage drop across the switch(es), which can result in a low voltage when using low on resistance (RDS(on)) power MOSFETs. 
       FIG. 5  discloses another divided phase winding circuit  502  for dividing motor phase windings  504 ,  506  of a motor in half and placing both a motor controller  508  for the motor and power electronics for the motor, including the DC power supply  510  and a power switch(es) circuit  512  with one or more power switches, at a “mid-point” or “center point”  514  in the supply line voltage between the divided phases. The circuit  502  of  FIG. 5  includes resistors R 1  and R 2  between the motor phase windings  504 ,  506  and the power switch(es) circuit  512  to hold up and therefore maintain the low voltage power supply supplied from the phase windings to the DC power supply  510  and create a non-collapsing DC power supply. The circuit of  FIG. 5  thereby maintains the low voltage power supply to the DC power supply  510 , for example at synchronous speed. 
       FIG. 6  discloses another divided phase winding circuit  602  for dividing motor phase windings  604 ,  606  of a motor in half and placing both a motor controller  608  for the motor and power electronics for the motor, including the DC power supply  610  and a power switch(es) circuit  612  with one or more power switches, at a “mid-point” or “center point”  614  in the supply line voltage between the divided phases. The primary divided phase winding  604 ,  606  limits the current that can flow to the DC power supply  610  eliminating the need for current limiting components that waste power. The divided phase winding circuit  602  of  FIG. 6  includes a secondary phase winding  616 ,  618  electrically connected to the DC power supply  610  to create a non-collapsing DC power supply. 
     In one example, the power switch(es) circuit  612  includes a Zener diode or other voltage regulator and a power switch in parallel, whereas prior systems included the power circuit in series with other components. Because the power switch is in parallel with the Zener diode and not in series, it can always be on. However, if the power switch is off, current can still flow through the Zener diode. 
     The circuit of  FIG. 6  includes one or more secondary coils (also referred to as a secondary winding)  616 ,  618  that provide a low voltage power supply to the DC power supply  610 , such as when the motor is at start-up. The one or more secondary coils  616 ,  618  also act as a high frequency noise filter to filter out high frequency noise from the low power voltage supplied to the DC power supply  610 . 
     The secondary winding  616 ,  618  may be distributed anywhere, such as evenly between the first and second divided phase windings  604 ,  606 , all on one pole, or unevenly between the first and second divided phase windings, such as a greater number of turns or coils on one secondary winding than another secondary winding. 
     In the example of  FIG. 6 , the divided phase winding circuit  602  can turn off the DC electronics, including the motor controller  608 , when the motor is on and at synchronous speed. Thus, the motor controller  608  of the divided phase winding circuit  602  determines the speed of the motor and whether the motor is or is not at synchronous speed. For example, 1800 RPM may be the synchronous speed for a motor with four stator poles (two north stator poles and two south stator poles). Every half AC cycle, power is supplied to one of the magnetic poles. Therefore, it takes two cycles to provide power to the four magnetic poles. Thus, the synchronous speed is 1800 RPM if the motor is synced to line AC. Similarly, the synchronous speed for an eight-pole stator would be 900 RPMs. 
       FIG. 7  depicts a control of phase current direction during start up and continuous operation below synchronous speeds in a divided phase winding circuit  702 . 
     As shown in  FIG. 7 , the current will always flow across both divided phase windings  704 ,  706  and control circuit in the same direction. The divided phase windings  704 ,  706 , being in series with the control circuit, represent one winding with the control circuit placed at the mid-point or center point between the divided phase windings. The current and voltage applied to the divided phase windings will always be in the same direction through both coils, and the magnetic polarity of the divided phase windings will likewise be the same. 
     As discussed below, the control circuit may include a diode rectifier bridge circuit whose output is connected to one or more power switches. As shown in  FIG. 7 , if the output terminals of the diode bridge rectifier of the control circuit are shorted when the voltage on lead L 1  is positive, the current will only flow through the winding  704 ,  706  in one direction, but in half cycle increments. If the voltage across leads L 1  and L 2  is 60 cycles, then the outputs of the diode bridge rectifier circuit in the control circuit will be shorted only when lead L 1  is positive, and current flow will flow only in one direction and for 8 milliseconds. No current will flow for 8 milliseconds on the alternate half cycles. Then current would flow for another 8 milliseconds and so on. If the output of the diode bridge circuit of the control circuit is shorted when lead L 2  is positive, then power will flow in exactly the same manner. If the shorting of the output of the bridge is accomplished selectively, that is based on the angular position of the magnetic rotor, continuous motor action will be produced. If the diode bridge rectifier circuit output in the control circuit is shorted for a fraction of a half cycle selectively based on the angular position of the magnetic rotor as described above, and only when lead L 1  is positive, then any desired speed can be accomplished including speeds higher than the synchronous speed. The characteristics of such a motor would be similar to a DC motor with pulsating current applied to the inputs. However, rather than having multiple power switching components achieve the switching of the divided phase windings, the divided phase winding circuit makes use of the fact that alternating current in conjunction with one power switching component can accomplish the switching. 
       FIG. 8  depicts an example of control of phase current direction at a synchronous speed of 1800 revolutions per minute (RPM) in a four pole divided phase winding circuit. At synchronous speed, the controlled phase is synchronized with the AC line input. 
       FIG. 9  depicts a control of phase current direction at a synchronous speed of 3600 revolutions per minute (RPM) in a two pole divided phase winding circuit. At synchronous speed, the controlled phase is synchronized with the AC line input. 
       FIG. 10  depicts an example of DC power supply storage capacitor charging periods in a divided phase winding circuit. Note the correlation to the wave form of  FIG. 7 . 
       FIG. 11  depicts a divided phase winding circuit  1102  with a secondary coil  1104 ,  1106  and one power switch  1108 . The primary divided phase winding  1110 ,  1112  limits the current that can flow to the DC power supply. 
     The control circuit  1114  controls switching for the power switch(es) circuit based on timing of the input frequency and rotor position. The control circuit  1114  controls the start-up and operation of the divided phase winding circuit. For example, the control circuit  1114  controls start-up, including where the motor is a synchronous motor. The control circuit  1114  determines the location of the rotor relative to the stator. The control circuit  1114  also determines and monitors the speed of the rotor, such as in revolutions per minute (RPMs), to determine operational parameters of the motor, such as when the motor has reached synchronous speed, and controls the motor based on the location of the rotor and or speed of the motor. In one example, the control circuit  1114  has a Hall effect switch and/or other rotation determining device to determine the position of the rotor and/or rotation counting or speed determining device to determine the speed of the rotor. 
     In one example, the power switch(es) circuit includes a Zener diode  1116  or other voltage regulator and a power switch  1108  in parallel, whereas prior systems included the power circuit in series with other components. Because the power switch  1108  is in parallel with the Zener diode  1116  and not in series, it can always be on. However, if the power switch is off, current can still flow through the Zener diode. 
     The circuit of  FIG. 11  includes one or more secondary coils (also referred to as a secondary winding)  1104 ,  1106  that provide a low voltage power supply to the DC power supply, such as when the motor is at start-up. The one or more secondary coils  1104 ,  1106  also act as a high frequency noise filter to filter out high frequency noise from the low power voltage supplied to the DC power supply. 
     The secondary winding  1104 ,  1106  may be distributed anywhere, such as evenly between the first and second divided phase windings  1110 ,  1112 , all on one pole, or unevenly between the first and second divided phase windings, such as a greater number of turns or coils on one secondary winding than another secondary winding. 
     The way that the coils are connected to the circuit via the diode bridge rectifier  1118  allow for current to flow through the coils in only one direction at any given time. The improvements that have been made to this motor and controller greatly improve the DC logic power supply which enables a more reliable logic control circuit. Secondary coils  1104 ,  1106  are wound with the motor coils in a method that creates a transformer using the motor coils as primary  1110 ,  1112 . 
     The improvements that have been made to this motor and controller greatly improve the DC logic power supply which enables a more reliable logic control circuit. Secondary coils are wound with the motor coils in a method that creates a transformer using the motor coils as primary. The example of  FIG. 11  uses a 20:1 ratio. The example of  FIG. 11  includes 1000 turns per motor primary coil and 50 turns per secondary coil that are wound on the same stator pole. However, other turn ratios may be used, higher or lower. The ratio between the primary motor coils  1110 ,  1112  and secondary coils  1104 ,  1106  may change with AC input power and/or DC power requirements. This circuit not only isolates all DC circuitry from high voltages from the line, but also creates a non-collapsible DC power supply to the control circuit when power is applied to inputs L 1  and L 2 . 
     The power switch(es) circuit consists of 2 main components, a full wave bridge rectifier  1118  and a MOSFET power switch  1108 . The full wave bridge rectifier  1118  guarantees that no negative voltage will be supplied to the drain (top) of the power switch  1108 . The full wave bridge rectifier  1118  also guarantees that no positive voltage will be supplied to the source (bottom) of the power switch  1108  so that current can only flow from the drain to the source of the power switch  1108  when biased by a positive voltage on the gate of the power switch  1108  via resistor R 1 . Simultaneously, as a positive rectified AC power supply is present at the drain of the power switch  1108 , the power switch  1108  is biased by the same voltage signal via resistor R 1 . Diode  1116  protects the gate of the power switch  1108  by guaranteeing that any voltage on the gate of the power switch  1108  will be greater than −0.7 VDC, as anything less could damage or destroy the power switch  1108 . Resistor R 11  and capacitor C 5  are used as a “snubber” to filter out transients or high frequency noise. R 11  and C 5  provide added protection for the MOSFET power switch  1108 , especially in noisy environments. 
       FIG. 12  depicts a divided phase winding circuit  1202  with a secondary coil  1104 ,  1106  and one power switch  1108 . The circuit of  FIG. 12  includes the same power switch(es) circuit of  FIG. 11  and the same secondary coils  1104 ,  1106 . In addition, the control circuit  1114 A of  FIG. 12  includes a logic control circuit  1204  to control operation of the motor, including through synchronous speed, a logic control shut off circuit  1206  to control when the power switch(es) circuit is turned off, and a non-collapsing DC power supply  1208  to supply DC power to the logic control circuit and login control shut off circuit. The logic control circuit  1204  and logic control shut off circuit  1206  may be configured as a single logic control circuit. 
     In one embodiment, one purpose of this divided phase windings circuit  1202  is to allow a motor to run synchronously to the AC power supply line frequency (for example, for a 4 pole motor, 60 Hz=1800 rpm and 50 Hz=1500 rpm). Without any control circuitry, the power switch(es) circuit would allow current to flow as if coil pairs L 1  and L 2  were shorted together through the power switch(es) circuit. The control circuitry simply turns power switch(es) circuit off until the rotor is in the proper position compared to the line voltage. For this reason, in one aspect, the power switch(es) circuit is rated for the AC power supply line voltage. The control circuitry components can all be at the logic level voltage (VCC). Logic power is supplied by secondary coils  1104 ,  1106  that are wound on the same poles as the primary motor coils  1110 ,  1112 . Secondary coils  1104 ,  1106  could be wound on any number of poles as long as the secondary power meets logic power requirements. Since the control circuit is only needed to start the motor and bring it to synchronous speed, the logic control shut off circuit optionally is included to shut off the main control circuit. The logic control shut off circuit is optional. By shutting the control circuit off, the power switch(es) circuit will allow full line power to the motor minus any losses in the power switch(es) circuit. This will increase total efficiency and the life of components especially when the motor runs for long periods. 
       FIGS. 13 and 13A  depict a divided phase winding circuit with a secondary coil and one power switch. The circuit has two AC supply line inputs L 1  and L 2 , which are connected to an AC power source during operation of the motor. 
     Power Switch 
     The Power Switch block consists of 2 main components, a full wave bridge rectifier BR 1  and a MOSFET power switch Q 1 . The full wave bridge rectifier BR 1  guarantees that no negative voltage will be supplied to the drain (top) of the power switch Q 1 . The full wave bridge rectifier BR 1  also guarantees that no positive voltage will be supplied to the source (bottom) of the power switch Q 1  so that current can only flow from the drain to the source of the power switch Q 1  when biased by a positive voltage on the gate of the power switch Q 1  via resistor R 1 . Simultaneously, as a positive rectified AC power supply is present at the drain of the power switch Q 1 , the power switch Q 1  is biased by the same voltage signal via resistor R 1 . Diode D 5  protects the gate of the power switch Q 1  by guaranteeing that any voltage on the gate of the power switch Q 1  will be greater than −0.7 VDC, as anything less could damage or destroy the power switch Q 1 . Resistor R 11  and capacitor C 5  are used as a “snubber” to filter out transients or high frequency noise. R 11  and C 5  provide added protection for the MOSFET power switch Q 1 , especially in noisy environments. 
     DC Power Supply 
     As soon as power is applied to the motor and current is flowing through the motor phase windings (motor primary coils), there is power on the secondary windings (secondary coils) in the same manner as the operation of a transformer. The value of voltage on the secondary coils is directly proportional to the input voltage and the primary to secondary turn count ratio. Using the example in  FIG. 11 , if the input voltage to the primary coils is 120 VAC and the turn count ratio from primary to secondary is 20:1, then the voltage on the secondary coils would calculate to approximately 6 VAC minus any losses. Power from the secondary coils is supplied directly from the secondary coils to the DC power supply. The full wave bridge rectifier BR 2  rectifies the low voltage AC power supply from the secondary coils. The full wave bridge rectifier BR 2  can be a low power component based on the DC supply requirements. 
     Zener diodes Z 1  and Z 2  are connected in series with each other anode to anode, and each cathode is connected to the AC power supply inputs of the full wave bridge rectifier BR 2 . This method is used to protect the full wave bridge rectifier BR 2  from AC power supply inputs that could exceed maximum ratings for the component. The negative output from the full wave bridge rectifier BR 2  is connected to the circuit ground, which is also connected to the same ground as the power switch block. The positive output from the full wave bridge rectifier BR 2  is connected to the low drop-out regulator LDO 1  and capacitor C 1 . Capacitor C 1  is provided to smooth the rectified AC power supply signal going to the input of the low drop-out regulator LDO 1 . A bypass capacitor C 7  could be used on the output of the low drop-out regulator LDO 1  to help reduce noise on the positive DC rail (VCC). Also, a larger capacitor C 10  could be used on the output of the low drop-out regulator LDO 1  to smooth the positive DC rail and ensure power during some low voltage situations. C 7  and C 10  are not required but are provided to add reliability and protection for low voltage DC components, especially in a noisy environment. 
     Logic Control 
     The control circuit controls switching for the power switch(es) circuit based on timing of the AC supply line input frequency and rotor position. Timing of the AC supply line input frequency is sensed using an AC buffer that consists of bi-polar junction transistors (BJTs) Q 2  and Q 3  and diodes D 6  and D 7 . Current to the AC buffer input is limited by a high value resistor R 3 . Diode D 6  ensures that the AC buffer input is not greater than the positive DC supply voltage. Diode D 7  ensures the AC buffer input is greater than −0.7 volts referenced to the DC supply ground. 
     When the input to the AC buffer is logic high, BJT Q 2  is biased, and the output of the AC buffer is also logic high. When the input to the AC buffer is logic low, BJT Q 3  is biased, and the output of the AC buffer is logic low. The output the AC buffer is connected to a filter consisting of capacitor C 6  and resistor R 13 . The filter is not required but provides protection and reliability in noisy environments. 
     Rotor magnet polarity is sensed using Hall-effect switch IC 1 . Though, another switch or sensing device may be used to sense rotor magnet polarity and/or rotor position and/or determine speed and/or determine rotor revolutions. The Hall-effect switch IC 1  is an open-collector output and therefore requires a pull-up to the positive DC rail (VCC). Resistor R 2  provides the pull-up required for the open-collector output. 
     The output of the Hall-effect switch IC 1  and the output of the AC buffer are compared using a single circuit logic XOR IC 2 . The output of the XOR IC 2  is the difference between the Hall-effect switch IC 1  and the AC buffer, which will bias MOSFET power switch Q 1  of the power switch(es) circuit. When the Hall-effect switch IC 1  output is logic low, the power switch Q 1  will only be biased when the AC supply input L 1  to the motor is negative. When the output of the Hall-effect switch IC 1  is logic high, the power switch Q 1  will only be biased when the AC supply input L 1  to the motor is positive. During motor start up, there can be multiple input AC cycles where either only the positive or only the negative inputs from AC supply input L 1  will pass through the power switch Q 1 . 
     Using the power switch Q 1 , waveforms can be “chopped” or shut off at any time when the drain and gate voltage of the power switch Q 1  is above biasing voltage. For example, see  FIG. 7 . The gate of the power switch Q 1  is held logic low when the output of the XOR IC 2  is logic high by biasing BJT Q 4 . When BJT Q 4  is biased, any current flowing from resistor R 1  will bypass the gate of the power switch Q 1  and flow through BJT Q 4  from collector to emitter electrically connecting the gate of the power switch Q 1  to its source and will shut off the power switch Q 1  immediately. 
     When the frequency of the Hall-effect switch IC 1  matches the frequency of the input AC supply, the motor is running synchronously. If the motor is running synchronously, the control circuit is not needed until either the motor falls out of sync or the motor is stopped and restarted. When the frequency to voltage regulator IC 3  senses synchronous speed or greater from the Hall-effect switch IC 1 , the output of the XOR IC 2  is held logic low via the open-collector output of the voltage regulator IC 3 . If the sensor speed is less than that of the input AC supply, the open-collector output of the voltage regulator IC 3  is off, which will leave the output of the XOR IC 2  unaffected. 
     This method ensures that when the motor is running at a synchronous speed, the power switch Q 1  is not shut off by the logic control. But, if the motor slows down below synchronous speeds, then the logic controller will control the motor timing as it does for start-up. Using this method improves overall motor efficiency and the expected lifetime of components in the circuit. 
     External components are required to set timing for the voltage regulator IC 3 . Resistors R 4 , R 5 , R 6  and R 7  may be 1% tolerance so that the voltage regulator IC 3  operates within accurate parameters. Capacitor C 1  operates in conjunction with the resistors R 6  and R 7  to set the frequency at which the open-collector output of the voltage regulator IC 3  will turn on. Capacitor C 3  is used for an internal charge pump in the voltage regulator IC 3 . Capacitor C 4  is used to AC couple the input to the voltage regulator IC 3  since the voltage regulator IC 3  will only detect frequencies that have a zero-voltage crossing. Resistor R 8  limits current to the AC couple C 4  at the input of the voltage regulator IC 3 . 
       FIG. 14  depicts a divided phase winding circuit with two power switches. 
       FIG. 15  depicts a divided phase winding circuit with one power switch. 
       FIG. 16  depicts a divided phase winding circuit with two power switches in series. Diodes D 1  &amp; D 2  are 1N4003 and diodes D 3  &amp; D 4  are 1N914. Transistors Q 3  and Q 4  are 2N3904. IC 1  is a Hall-effect switch/sensor. Diodes D 5  and D 6  are used to increase the current capacity for the internal diodes in switches Q 1  and Q 2  (d 1  &amp; d 2 ) if the phase current exceeds the internal diodes forward current rating. Capacitors C 2  and C 3  are optional in one embodiment. Capacitors C 2  and C 3  are used to create a ‘turn on’ delay for switches Q 1  and Q 2  to add additional charge time for capacitor C 1  if necessary to insure a solid 3.3 VDC or 5 VDC supply for Hall switch/sensor IC 1 , depending upon the device choice for Hall switch/sensor IC 1 . In prior systems, 5 VDC was necessary to switch on the logic level power MOSFET switch. 
     Diodes D 1 , D 2 , d 1 , and d 2  perform the rectification of the AC power for the DC power supply for Hall switch/sensor IC 1 . 
     Zener diode ZD 1  provides the voltage regulator for the Hall switch/sensor IC 1 &#39;s DC supply. 
     RL provides current limiting for the DC power supply. It should be set to approximately limit the current to 10 mA. The Hall switch/sensor IC 1  uses 6 mA, including the base drive current for the internal open collector output transistor. Additional DC current will be used to switch Q 3  and is supplied through the ‘pull up’ resistor R 3 . The collector to emitter current for switch Q 3  and the base and collector to emitter current for switch Q 4  is not supplied by the DC power supply but is supplied by the current through the motor phase windings. It is preferable to assure that transistors Q 3  and Q 4  turn completely ‘off’ at the proper times. It is preferred in one embodiment, but not a requirement, that the switches turn fully ‘on’ or in saturation at the proper times for maximum operational efficiency. 
       FIG. 17  depicts a divided phase winding circuit with a tap from the divided phase winding coil to the direct current (DC) power supply and two power switches in series. 
       FIG. 18  depicts a divided phase winding circuit with two power switches in parallel. 
       FIG. 19  depicts a divided phase winding circuit with a tap from the divided phase winding coil to the direct current (DC) power supply and two power switches in parallel. 
       FIG. 20  depicts a motor with a divided phase winding circuit having a primary AC phase winding and secondary winding to create a non-collapsing DC power supply. In the motor of  FIG. 20 , the secondary winding is wound on all poles. However, the secondary winding can be wound on just one pole, two poles, three poles, or another number of poles. The secondary winding is connected in series with the primary phase winding in the motor of  FIG. 20 . However, the secondary winding also may be connected in parallel or with a combination of both series and parallel. The motor of  FIG. 20  is a four pole permanent magnet synchronous motor. The synchronous speed for the motor when operating at 60 Hz AC is 1800 RPM. 
       FIG. 21  depicts a motor with a divided phase winding circuit having a primary AC phase winding and secondary winding to create a non-collapsing DC power supply wound on only one pole. The motor of  FIG. 21  is a four pole permanent magnet synchronous motor. The synchronous speed for the motor when operating at 60 Hz AC is 1800 RPM. 
       FIG. 22  depicts a motor  2202  with a divided phase winding circuit with a tapped primary phase winding to create a non-collapsing DC power supply. The motor of  FIG. 22  is a four pole permanent magnet synchronous motor. The synchronous speed for the motor when operating at 60 Hz AC is 1800 RPM. 
     The motor has a stator  2204  with 4 poles  2206 - 2212  and a rotor  2214  with 4 magnets N, S, N, S  2216 - 2222  facing the stator. The motor  2202  has a shaft (center circle)  2224  and rotor back iron (the area between the shaft and the magnets)  2226 . The primary divided phase windings  2228 ,  2230  are connected to an AC power supply at L 1  and L 2 , respectively. A secondary winding  2232 ,  2234  is connected to the DC power supply  2236 . 
       FIG. 23  depicts a motor with a divided phase winding circuit  2302  with resisters  2304 ,  2306  between the divided phase windings  2308 ,  2310  and the power switch(es) circuit  2312  to create a non-collapsing DC power supply. The motor of  FIG. 23  is a four pole permanent magnet synchronous motor. The synchronous speed for the motor when operating at 60 Hz AC is 1800 RPM. 
       FIG. 24  depicts a motor with a divided phase winding circuit  2402  with Zener diodes  2404 ,  2406  between the divided phase windings  2408 ,  2410  and the power switch(es) circuit  2412  to create a non-collapsing DC power supply. The motor of  FIG. 24  is a four pole permanent magnet synchronous motor. The synchronous speed for the motor when operating at 60 Hz AC is 1800 RPM. 
     Those skilled in the art will appreciate that variations from the specific embodiments disclosed above are contemplated by the invention. The invention should not be restricted to the above embodiments, but should be measured by the following claims.