Patent Publication Number: US-2023150568-A1

Title: Electric rotating machine apparatus and electric power steering apparatus

Description:
TECHNICAL FIELD 
     The present disclosure relates to an electric rotating machine apparatus and an electric power steering apparatus. 
     BACKGROUND ART 
     In an electric rotating machine apparatus in which in the axial direction of the output axle of a conventional electric rotating machine, the electric rotating machine and a control unit are integrated with each other in such a way as to be adjacent to each other, there exists a structure in which a stator, a rotor, and the like are contained in the case of the electric rotating machine and in which the control unit is assembled close to the electric rotating machine in a multi-layered manner. In addition, there has been disclosed an apparatus in which in consideration of redundancy, two groups of winding sets of an electric rotating machine are provided and in which two groups of so-called inverter circuits for driving the two groups of winding sets are also provided separately from each other (for example, Patent Document 1). 
     CITATION LIST 
     Patent Literature 
     Patent Document 1: Japanese Patent No. 5435284 
     In an electric rotating machine apparatus in which an electric rotating machine and a control unit are integrated with each other in such a way as to be adjacent to each other in an axial direction of the output axle of the electric rotating machine, voltage noise is generated in an inverter for driving the electric rotating machine, an inverter driving circuit, and the like. The generated voltage noise travels in a power source for the electric rotating machine apparatus, a signal terminal, and a board and then propagates to the outside of the electric rotating machine apparatus through a connector. Alternatively, the generated voltage noise travels in a heat sink and the case of the electric rotating machine and then propagates to the outside of the electric rotating machine apparatus through the flange of the electric rotating machine. Accordingly, in order to prevent the noise from propagating to the outside of the electric rotating machine apparatus, a filter circuit and an electromagnetic shield for attenuating the noise are required. 
     It is desirable that a power module such as the inverter for driving the electric rotating machine and a driving circuit for driving the power module are arranged near to the electric rotating machine so that the wiring leads therefor are shortened. Accordingly, the power module and a control circuit board on which the driving circuit for driving the power module are mounted are arranged adjacently to each other. In addition, it is required that the filter circuit is disposed close to the opening portion of the shield in order to prevent noise from being superimposed again on the wiring lead in which noise has been attenuated. Therefore, with regard to the filter circuit, it is required that a dedicated wiring board—on which the filter circuit is mounted and that is separated from the control circuit board on which the inverter driving circuit is mounted—is disposed close to the opening portion of the shield. It has been a hindrance to downsizing and cost reduction of an electric rotating machine apparatus to provide the dedicated wiring board. Accordingly, it has been a hindrance also to downsizing and cost reduction of a power steering apparatus provided with the electric rotating machine apparatus. 
     SUMMARY OF INVENTION 
     Therefore, the objective of the present disclosure is to obtain an electric rotating machine apparatus that requires no dedicated wiring board on which the filter circuit is mounted and that is provided with a filter circuit having a high noise-removal capability and to obtain an electric power steering apparatus provided with such the electric rotating machine apparatus. 
     Solution to Problem 
     An electric rotating machine apparatus according to the present disclosure includes
         an electric rotating machine having a rotation axle and windings,   a power module that is disposed at one axial-direction side of the rotation axle with respect to the electric rotating machine, that is fixed to the electric rotating machine, and that supplies electric power to the windings of the electric rotating machine,   a control circuit board on which a driving circuit for driving the power module is mounted and that has an extending portion extending toward the one axial-direction side of the rotation axle,   an electromagnetic shield that encloses the power module and the driving circuit and that has an external-connection opening portion through which the extending portion of the control circuit board passes,   an external connection terminal that is disposed outside the electromagnetic shield and is connected with the extending portion of the control circuit board, and   a filter circuit that is mounted on the extending portion of the control circuit board and attenuates noise components propagating to the external connection terminal.       

     An electric power steering apparatus according to the present disclosure includes the foregoing electric rotating machine apparatus. 
     Advantage of Invention 
     In an electric rotating machine apparatus and a power steering apparatus according to the present disclosure, while no dedicated wiring board on which a filter circuit is mounted is required, a filter circuit having noise-removal capability can be provided close to an external-connection opening portion in an electromagnet shield. Accordingly, because no dedicated wiring board for mounting the filter circuit thereon is required, the present disclosure can contribute to downsizing and cost reduction. In addition, the present disclosure can contribute to downsizing and cost reduction of an electric power steering apparatus equipped with the electric rotating machine apparatus according to the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is an overall configuration diagram of an electric rotating machine apparatus according to Embodiment 1; 
         FIG.  2    is a circuit diagram of the electric rotating machine apparatus according to Embodiment 1; 
         FIG.  3    is an overall configuration diagram of an electric rotating machine apparatus according to Embodiment 2; 
         FIG.  4    is a circuit diagram of the electric rotating machine apparatus according to Embodiment 2; 
         FIG.  5    is a configuration diagram of an electric power steering apparatus according to Embodiment 3; and 
         FIG.  6    is an overall configuration diagram of a conventional electric rotating machine apparatus. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present disclosure will be explained with reference to the drawings. 
     1. Embodiment 1 
     Embodiment 1 will be explained.  FIG.  1    is an overall configuration diagram of an electric rotating machine apparatus  100  according to Embodiment 1.  FIG.  2    is a circuit diagram of the electric rotating machine apparatus  100  according to Embodiment 1. 
     &lt;Overall Configuration&gt; 
       FIG.  1    is a cross-sectional view for explaining the overall configuration of the electric rotating machine apparatus  100 . A power-source terminal  2  is incorporated in a power-source connector  1  for supplying a power source from a vehicle battery to the electric rotating machine apparatus  100 , so that an electric current is supplied to a power module  4 . A signal terminal  10  is incorporated in a signal connector  9  for exchanging signals with the vehicle and is connected with a control circuit board  19 . The power-source terminal  2  is also connected with the control circuit board  19  so that a power-source current is also supplied to a power-source circuit  15  mounted on the control circuit board. The electric rotating machine apparatus  100  may be either the one in which a control circuit and a Y-connected or delta-connected three-phase brushless motor are integrated with each other or the one that has a function of utilizing regenerative electric power, generated by being driven by a load, for charging a battery. The electric rotating machine apparatus  100  is utilized not only in an electric power steering apparatus  150  but also in various uses including vehicle-wheel driving. 
     In the present embodiment, the control circuit board  19  is a printed wiring board on which the power-source circuit  15 , an input/output circuit  14 , a CPU  16 , a driving circuit  17 , and a filter circuit  11  are mounted. The power-source circuit  15  is supplied with a power-source current by the power-source terminal  2  connected with the control circuit board  19  and then supplies constant-voltage electric currents to the respective circuits mounted on the control circuit board  19 . Through the signal terminal  10 , a vehicle sensor  31  supplies vehicle information items such as steering angle information, steering torque information, and vehicle speed information. Input signals are transferred to the CPU  16  by way of the input/output circuit  14 . The CPU  16  calculates information to be outputted in accordance with input information and then controls the driving circuit  17 . The output signal of the driving circuit  17  is transferred from a driving-signal terminal  18  connected with the control circuit board  19  to the power module  4 ; then, the power module  4  supplies electric power to windings  30  of an electric rotating machine  20  through power-supply terminals  6 . 
     When the electric rotating machine apparatus  100  is driven, noise is generated in the power module  4  and the driving circuit  17  for driving the power module  4 . In order to reduce the noise, an electromagnetic shield  3  is provided. The tubular peripheral portion of the bottomed tubular electromagnetic shield  3  is connected with the electric rotating machine  20  and encloses the power module  4  and the driving circuit  17  for driving the power module  4 . An external-connection opening portion  12  is provided in the bottom portion of the electromagnetic shield  3 . 
     The control circuit board  19  has an extending portion that extends toward the side opposite to the output axle  21  of the electric rotating machine  20 . The extending portion of the control circuit board  19  passes through the external-connection opening portion  12  in the electromagnetic shield  3  and is connected with the power-source terminal  2  and the signal terminal  10 . The filter circuit  11  is mounted at a position, on the control circuit board  19 , that is before the connection portion between the control circuit board  19  and each of the power-source terminal  2  and the signal terminal  10 ; the filter circuit  11  cuts off propagation of noise to the outside. 
     The power module  4  is cooled by a heat sink  7 ; the power module  4  and the heat sink  7  are adhered to each other through the intermediary of a mica sheet or the like in such a way as to be electrically insulated from each other, while heat transfer is secured therebetween. The heat sink  7  is electrically connected with the electric rotating machine  20  so as to have an electric potential the same as that of the electric rotating machine  20 . 
     A control unit, of the electric rotating machine  20 , that mainly includes the control circuit board  19 , various kinds of circuits and components mounted on the control circuit board  19 , the power module  4 , and the heat sink  7  is covered with a frame  5  assembled to the electric rotating machine  20  and is connected with the outside through the power-source connector  1  and the signal connector  9 . A flange  8  is provided in the electric rotating machine  20 ; the electric rotating machine apparatus  100  is assembled to a vehicle by means of the flange  8 . 
     &lt;Example of Conventional Apparatus&gt; 
     Here, a conventional noise countermeasure will be pointed out.  FIG.  6    is an overall configuration diagram of an electric rotating machine apparatus  102  as an example of a conventional one. 
     To date, a noise countermeasure has been implemented by means of such a configuration as illustrated in  FIG.  6   . In order to reduce noise that propagates from the power-source terminal  2  to the outside of the electric rotating machine apparatus  102  by way of the power-source connector  1 , a filter-circuit mounting board  22  that is separated from the control circuit board  19  and on which the filter circuit  11  is mounted has been required. 
     In addition, the filter circuit  11  for reducing noise that propagates from the signal terminal  10  to the outside of the electric rotating machine apparatus  102  by way of the signal connector  9  is mounted on the control circuit board  19 ; thus, it has been difficult to dispose the filter circuit  11  close to the external-connection opening portion  12  in the electromagnetic shield  3 . Accordingly, because, for example, magnetic noise is superimposed on the signal terminal  10  in which noise has been attenuated by the filter circuit  11 , noise cannot sufficiently be attenuated. 
     &lt;Propagation Mechanism of Noise&gt; 
     A propagation mechanism of noise generated in the electric rotating machine apparatus  100  will be explained. A major noise source in the electric rotating machine apparatus  100  is the power module  4  for driving the electric rotating machine  20 . 
     In  FIG.  1   , a power source supplied from the outside of the electric rotating machine apparatus  100  to the power-source connector  1  is supplied to the power module  4  by way of the power-source terminal  2 . A signal related to vehicle information transferred from the vehicle sensor  31  by way of the signal connector  9  is transferred to the CPU  16  by way of the input/output circuit  14 . The CPU  16  that has calculated the output in accordance with input information controls the driving circuit  17 ; a driving signal of the driving circuit  17  is transferred to the power module  4  by way of the driving-signal terminal  18 ; then, the power module  4  supplies an electric current to the electric rotating machine  20  in accordance with the inverter driving signal. When the electric rotating machine  20  is driven, there occur a fluctuation in the power-source voltage supplied to the power module  4  and a change in the current supplied to the electric rotating machine  20 ; then the respective changes in the voltage and the current become voltage noise and magnetic noise that propagate to the surroundings. 
     By way of the power-source terminal  2 , the signal terminal  10 , the control circuit board  19 , and the like, voltage noise propagates to the outside of the electric rotating machine apparatus  100  through the power-source connector  1  and the signal connector  9 . Moreover, voltage noise propagating from the power-supply terminals  6  passes through the electric rotating machine  20  and then propagates to the outside of the electric rotating machine apparatus  100  through the flange  8  in a mounting portion of the electric rotating machine apparatus  100 . Furthermore, because the power module  4  is mounted to the heat sink  7  for heat radiation, voltage noise that has propagated from the power module  4  to the heat sink  7 , due to capacitive coupling, passes through the electric rotating machine  20  and then further propagates to the outside of the electric rotating machine apparatus  100  through the flange  8  in the motor mounting portion. 
     Magnetic noise generated by an electric current supplied to the electric rotating machine  20  is emitted to the periphery of the power module  4 . Noise signals generated in the driving circuit  17 , the CPU  16 , and the power-source circuit  15 , which are noise sources other than the power module  4 , propagate to the outside of the electric rotating machine apparatus  100  by way or the signal terminal  10  and the control circuit board  19 . 
     &lt;Noise Reduction&gt; 
     The electric rotating machine apparatus  100  according to the present disclosure is provided with the electric rotating machine  20  having the output axle  21  and the windings  30 . Moreover, the electric rotating machine apparatus  100  is provided with the power module  4  that is disposed at the axial-direction anti-output side of the output axle  21  with respect to the electric rotating machine  20 , that is fixed to the electric rotating machine  2 , and that supplies electric power to the windings  30  of the electric rotating machine  20 . Moreover, the electric rotating machine apparatus  100  is provided with the control circuit board  19  on which the driving circuit  17  for driving the power module  4  is mounted and that has the extending portion extending to the axial-direction anti-output side of the output axle  21 . Furthermore, the electric rotating machine apparatus  100  is provided with the electromagnetic shield  3  that encloses the power module  4  and the driving circuit  17  and that has the external-connection opening portion  12  through which the extending portion of the control circuit board  19  passes. Moreover, the electric rotating machine apparatus  100  is provided with the power-source terminal  2  and the signal terminal  10  that are arranged outside the electromagnetic shield  3  and are connected with the extending portion of the control circuit board  19 . Still moreover, the electric rotating machine apparatus  100  is provided with the filter circuit  11  that is mounted on the extending portion of the control circuit board  19  and that attenuates noise components propagating to the power-source terminal  2  and the signal terminal  10 . 
     The filter circuit  11  is mounted in order to attenuate voltage noise that propagates to the outside of the electric rotating machine apparatus  100  by way of the power-source connector  1 , the signal connector  9 , and the electric rotating machine  20 . It is made possible to reduce emission, to the outside of the electric rotating machine apparatus  100 , of noise that is generated and propagates. 
     Providing the electromagnetic shield  3 , the control circuit board  19 , and the filter circuit  11  in such a manner as described above makes it possible to effectively remove noise without utilizing any additional board for the filter circuit. 
     In addition, the electric rotating machine apparatus  100  according to the present disclosure is provided with the heat sink  7  that is situated between the power module  4  and the electric rotating machine  20 , performs heat transfer with the power module  4 , and has an electric potential the same as that of the electric rotating machine  20 . The electromagnetic shield  3  has a bottomed tubular shape; the tubular peripheral portion thereof is connected with the electric rotating machine  20 ; the bottom portion thereof has the external-connection opening portion  12 . 
     Because the electromagnetic shield  3  is connected with the electric rotating machine  20 , noise emission from the electromagnetic shield  3  can be reduced; thus, a high shield effect can be obtained. 
     In the electric rotating machine apparatus  100  according to the present disclosure, the tubular peripheral portion of the electromagnetic shield  3  is connected with the electric rotating machine  20  or the heat sink  7  at a portion that is closer to the output of the output axle  21  than the heat transfer portion between the heat sink  7  and the power module  4 . 
     Because the electromagnetic shield  3  is connected with the electric rotating machine  20  or the heat sink  7  having an electric potential the same as that of the electric rotating machine  20  at the position that is closer to the electric rotating machine  20  than the assembly position between the heat sink  7  and the power module  4 , noise that propagates from the power module  4  to the heat sink  7  does not flow into the electromagnetic shield  3 ; therefore, a stabilized-potential return path can be obtained and hence a high filter effect can be obtained. 
     In addition, in the electric rotating machine apparatus  100  according to the present disclosure, the power-source terminal  2  and the signal terminal  10  is connected with the extending portion of the control circuit board  19  at the position that is more outside than the external-connection opening portion  12  of the electromagnetic shield  3 . 
     The electromagnetic shield  3  is provided in order to reduce an effect, of magnetic noise emitted from the power module  4 , that is provided to the power-source terminal  2 , the signal terminal  10 , and the control circuit board  19  that are situated at the positions closer to the power-source connector  1  and the signal connector  9  than the filter circuit  11  inside the electric rotating machine apparatus  100  and in order to reduce the effect to be provided to the outside of the electric rotating machine apparatus  100 . 
     As a result, noise can effectively be removed. 
     2. Embodiment 2 
     Embodiment 2 will be explained.  FIG.  3    is an overall configuration diagram of an electric rotating machine apparatus  101  according to Embodiment 2.  FIG.  4    is a circuit diagram of the electric rotating machine apparatus  101  according to Embodiment 2. 
       FIG.  4   , which is the circuit diagram of the electric rotating machine apparatus  101  according to Embodiment 2, is different from  FIG.  2   , which is the circuit diagram of the electric rotating machine apparatus  100  according to Embodiment 1, only in that one end of a relay member  13  is connected with the electromagnetic shield  3  and the other end thereof is connected with grounding portion of the control circuit board  19 . 
       FIG.  3   , which is the configuration diagram of the electric rotating machine apparatus  101  according to Embodiment 2, is different from  FIG.  1   , which is the configuration diagram of the electric rotating machine apparatus  100  according to Embodiment 1, in the following three points. 
     (1) The relay member  13  is connected with the external-connection opening portion  12  of the electromagnetic shield  3  and with the periphery of the filter circuit  11  on the extending portion of the control circuit board  19 .
 
(2) The filter circuit  11  is disposed at a position, on the extending portion of the control circuit board  19 , that passes through the external-connection opening portion  12  of the electromagnetic shield  3 .
 
(3) The tubular peripheral portion is connected with the heat sink  7  but is not connected directly with the electric rotating machine  20 .
 
     &lt;Noise Reduction in Embodiment 2&gt; 
     In the electric rotating machine apparatus  101  according to the present disclosure, the filter circuit is disposed at the position, on the extending portion of the control circuit board  19 , that passes through the external-connection opening portion  12  of the electromagnetic shield  3 . 
     The filter circuit  11  is mounted in order to attenuate voltage noise that propagates to the outside of the electric rotating machine apparatus  101  by way of the power-source connector  1 , the signal connector  9 , and the electric rotating machine  20 . In addition, because the filter circuit  11  is mounted at the position close to the external-connection opening portion  12  of the control circuit board  19  that is disposed in parallel with the output axle  21  and is extended to the position closer to the power-source connector  1  and the signal connector  9  than the external-connection opening portion  12 , magnetic noise is not superimposed on the control circuit board  19 , the power-source terminal  2 , and the signal terminal  10  that are arranged closer to the power-source connector  1  and the signal connector  9  than the filter circuit  11  in which noise has been attenuated; thus, because the front and rear portions with respect to the filter circuit  11  can be separated by the filter circuit  11  and the inner and outer portions with respect to the external-connection opening portion  12  can be separated by the electromagnetic shield  3 , a high filter effect can be obtained. 
     In the electric rotating machine apparatus  101  according to the present disclosure, the filter circuit  11  is connected with the electromagnetic shield  3  by way of the relay member  13 . 
     The filter circuit  11  and the electromagnetic shield  3  are electrically connected with each other by use of the relay member  13 , so that the relay member  13  works as a path for returning, to the filter circuit  11 , voltage noise that passes through the heat sink  7  and the electric rotating machine  20  from the power module  4  and then propagates to the outside of the electric rotating machine apparatus  101  by way of the flange  8  or voltage noise that passes through the electric rotating machine  20  from the power-supply terminals  6  and then propagates to the outside of the electric rotating machine apparatus  101  by way of the flange  8 . 
     As a result, noise can be suppressed from propagating to the outside. 
     In the electric rotating machine apparatus  101  according to the present disclosure, the relay member  13  is connected with the external-connection opening portion  12  of the electromagnetic shield  3 . 
     The filter circuit  11  and the electromagnetic shield  3  are electrically connected with each other along the shortest route by use of the relay member  13 , so that the relay member  13  efficiently works as a shortest path for returning voltage noise that is to propagate to the outside of the electric rotating machine apparatus  101  to the filter circuit  11 . 
     As a result, noise can effectively be suppressed from propagating to the outside. 
     In the electric rotating machine apparatus  101  according to the present disclosure, the electric potential of the electromagnetic shield  3  is utilized as the ground potential of the filter circuit  11 . 
     Because the filter circuit  11  and the electromagnetic shield  3  are electrically connected with each other by use of the relay member  13 , the electromagnetic shield  3  can be utilized as the ground potential of the filter circuit  11 . As a result, the relay member  13  works as a path for returning, to the filter circuit  11 , voltage noise that passes through the heat sink  7  and the electric rotating machine  20  from the power module  4  and then propagates to the outside of the electric rotating machine apparatus  101  by way of the flange  8  or voltage noise that passes through the electric rotating machine  20  from the power-supply terminals  6  and then propagates to the outside of the electric rotating machine apparatus  101  by way of the flange  8 . 
     As a result, noise can more effectively be suppressed from propagating to the outside. 
     In addition, the tubular peripheral portion of the bottomed tubular electromagnetic shield  3  is connected with the heat sink  7 ; thus, because even when not directly connected with the electric rotating machine  20 , the heat sink  7  is electrically connected with the electric rotating machine  20  and hence the electric rotating machine  20  and the heat sink  7  are kept on one and the same electric potential, there can be obtained an effect the same as that at a time when the tubular peripheral portion of the electromagnetic shield  3  is directly connected with the electric rotating machine  20 . 
     3. Embodiment 3 
       FIG.  5    is a configuration diagram of an electric power steering apparatus  150  according to Embodiment 3. There will be explained an example in which the electric rotating machine apparatus  100  is applied to the electric power steering apparatus  150  to be mounted in a vehicle. 
       FIG.  5    is an overall configuration diagram of the electric power steering apparatus  150  and illustrates an example of the rack-type electric power steering apparatus  150 . When a driver makes the steering mechanism of a vehicle generate steering torque by means of a steering wheel  151 , a torque sensor  152  detects the steering torque and then outputs it to the electric rotating machine apparatus  100 . In addition, a speed sensor  153  detects the traveling speed of the vehicle and then outputs it to the electric rotating machine apparatus  100 . Based on the inputs from the torque sensor  152  and the speed sensor  153 , the electric rotating machine apparatus  100  generates auxiliary torque for supplementing the steering torque and then supplies it to the steering mechanism of front wheels  154  of the vehicle. The torque sensor  152  and the speed sensor  153  are included in the vehicle sensor  31  in  FIG.  2   . It may be allowed that the electric rotating machine apparatus  100  generates auxiliary torque based on inputs other than the inputs from the torque sensor  152  and the speed sensor  153 . 
     Downsizing of the electric rotating machine apparatus  100  to be applied to the electric power steering apparatus  150  raises the mountability for the vehicle. The cost reduction of the electric rotating machine apparatus  100  results in cost reduction of the whole electric power steering apparatus  150 . The same effect can be demonstrated even when instead of the electric rotating machine apparatus  100 , the electric rotating machine apparatus  101  is utilized. 
     Although the present application is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects and functions described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations to one or more of the embodiments. Therefore, an infinite number of unexemplified variant examples are conceivable within the range of the technology disclosed in the present disclosure. For example, there are included the case where at least one constituent element is modified, added, or omitted and the case where at least one constituent element is extracted and then combined with constituent elements of other embodiments. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
           2 : power-source terminal 
           3 : electromagnetic shield 
           4 : power module 
           7 : heat sink 
           10 : signal terminal 
           11 : filter circuit 
           12 : external-connection opening portion 
           13 : relay member 
           17 : driving circuit 
           19 : control circuit board 
           20 : electric rotating machine 
           21 : output axle 
           100 ,  101 : electric rotating machine apparatus 
           150 : electric power steering apparatus