JP5987432B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine such as a motor.

  Conventionally, as described in Patent Document 1, there is a motor including two types of coils for high-speed rotation and low-speed rotation. By switching between the two types of coils, the motor operating range (rotational speed control range) can be switched. When switched to a coil for high speed rotation, high rotation (low torque) is obtained, and when switched to a coil for low speed rotation, high torque (low rotation) is obtained.

  Further, as described in Patent Document 2, there is a motor having two power feeding systems. That is, the motor has two sets of coils each having three phases, and two sets of drive circuits that supply power to each coil. According to this motor, it is possible to rotate the motor through the other system even if the coil or the drive circuit of one system has failed.

Japanese Utility Model Publication No. 57-41498 JP-A-9-117184

  According to the motor of Patent Document 1, a wide range of output characteristics can be obtained by switching between two types of coils according to a required speed region. However, since the switching of the coil and the power supply to the coil are performed by a single drive circuit, it is difficult to drive the motor if this drive circuit fails. That is, there is room for improvement in terms of redundancy (redundancy).

  On the other hand, since the motor of Patent Document 2 has two independent power feeding systems, even if one system fails, the motor can be driven through the other system. However, it is difficult to obtain both high speed rotation and low speed rotation by switching the coil. In other words, there is room for improvement in terms of expanding the operating range.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a rotating electrical machine capable of expanding an operation region while ensuring redundancy.

  <1> According to one aspect of the present invention, first and second coil groups in which three-phase coils are connected in series with each other, and the second coil group on the opposite side of the first coil group A first inverter connected to the end, a second inverter connected between the first and second coil groups, and an end of the second coil group opposite to the first coil group; A switch circuit that is connected and switches between a state in which each phase coil of the second coil group is short-circuited and an open state; and a control circuit that controls each of the first and second inverters and the switch circuit, The control circuit normally forms a star connection composed of the first and second coil groups through the second inverter and the switch circuit, and then supplies power to the first and second coil groups through the first inverter. The state of First, a star connection consisting of the first coil group is formed, and then it is possible to switch between the second state in which power is supplied to the first coil group through the first inverter. After forming a star connection consisting of the first or second coil group through the two inverters and the switch circuit, power is supplied to the first or second coil group through the second inverter, and when the second inverter is abnormal, A rotating electrical machine that supplies power to at least one of the first and second coil groups in the same manner as in the first or second state is provided.

  According to this configuration, the operating state of the rotating electrical machine can be switched between the first state and the second state at normal times. In the first operating state, low rotation and high torque can be obtained by using all of the first and second coil groups. In the second operating state, since only the first coil is used, higher rotation and lower torque can be obtained than in the first operating state. That is, the operating range of the rotating electrical machine is expanded. When an abnormality in the first inverter is detected, the second inverter is used. Conversely, when an abnormality in the second inverter is detected, the first inverter is used to turn the rotating electrical machine. It can be driven. For this reason, redundancy is also ensured.

  <2> In the above rotating electric machine, a switching element is provided in each of the high potential side power supply paths in the first and second inverters, and when the control circuit detects an abnormality in the first or second inverter, It is preferable to turn off the switching element on the side where the abnormality is detected.

  According to this configuration, when an abnormality of the first or second inverter is detected, power supply to the first or second inverter is interrupted by turning off the abnormal switching element. Further, when the star connection consisting of the first coil group is formed when the first inverter is abnormal, it is necessary to form a neutral point by short-circuiting each phase coil of the first coil group. . At this time, it is not preferable that the power supply to the first inverter is maintained. In this regard, according to the present configuration, when an abnormality is detected in the first inverter, power supply to the inverter is interrupted, so that a star connection composed of the first coil group can be suitably formed.

Here, abnormalities in the first and second inverters include open faults and short-circuit faults of the switching elements of these inverters.
<3> Therefore, in the rotating electrical machine, when the first inverter is in an open failure, the control circuit electrically disconnects the first coil group from the second coil group through the first inverter and also through the switch circuit. By short-circuiting each phase coil of the second coil group to form a star connection composed of each phase coil of the second coil group, power is supplied to the second coil group through the second inverter.

  In addition, when the first inverter is short-circuited, the control circuit short-circuits each phase coil of the first coil group through the first inverter and connects the second coil group to the first coil group through the switch circuit. A star connection consisting of the first coil group is formed by electrical disconnection, and then the first coil group is supplied with power through the second inverter.

  In addition, when an open failure occurs in the second inverter, the control circuit electrically disconnects the second inverter from the first and second coil groups and short-circuits each phase coil of the second coil group through the switch circuit. By forming a star connection consisting of the phase coils of the first and second coil groups, power is supplied to the first and second coil groups through the first inverter.

  When the second inverter is short-circuited, the control circuit short-circuits each phase coil of the first coil group through the second inverter and electrically opens the second coil group through the switch circuit. After forming a star connection composed of each phase coil of one coil group, power is supplied to the first coil group through the first inverter.

  Thus, even when an open failure or a short-circuit failure occurs in the first or second inverter, it is possible to continue the operation of the rotating electrical machine using the inverter that has not failed.

<4> In the rotating electrical machine, the first state and the second state are formed as follows. That is, in the first state, the control circuit electrically disconnects the second inverter from the first and second coil groups and shorts the phase coils of the second coil group through the switch circuit. To form a star connection comprising the respective phase coils of the first and second coil groups. In the second state, the control circuit short-circuits each phase coil of the first coil group through the second inverter and electrically opens the second coil group through the switch circuit. A star connection consisting of each phase coil of the coil group is formed.
<5> In the rotating electrical machine, the control circuit normally switches a coil group used for driving the rotating electrical machine through the control of the second inverter and the switch circuit.
<6> In the above rotating electrical machine, the control circuit normally disconnects the second inverter from the first and second coil groups through the second inverter and normally connects the second inverter in the second coil group through the switch circuit. The first coil group is short-circuited at one end opposite to the first coil group to form a star connection composed of the first and second coil groups, and then the first and second coil groups are fed through the first inverter. And the end of the first coil group opposite to the second coil group through the second inverter, and the second coil group is electrically disconnected from the first coil group through the switch circuit. Can be switched between the second state in which the first coil group is formed and then the first coil group is fed through the first inverter. .

  ADVANTAGE OF THE INVENTION According to this invention, an operating area | region can be expanded in a rotary electric machine, ensuring redundancy.

The circuit diagram of the motor in this Embodiment. Similarly, a cross-sectional view of the motor. The circuit diagram which shows the connection state of a drive circuit and each coil similarly. The circuit diagram which shows the conduction | electrical_connection state of a drive circuit and each coil similarly at the time of high torque and at the time of failure of a 2nd drive circuit (open failure). The circuit diagram which shows the conduction | electrical_connection state of a drive circuit and each coil similarly at the time of high speed rotation, and the time of failure of a 2nd drive circuit (high side short circuit failure or low side short circuit failure). The circuit diagram which shows the conduction | electrical_connection state of a drive circuit and each coil at the time of the failure of a 1st drive circuit (open failure). The circuit diagram which shows the conduction state of a drive circuit and each coil at the time of failure of a 1st drive circuit (a high side short circuit failure or a low side short circuit failure).

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment embodying a motor of the present invention will be described with reference to FIGS.
<Mechanical configuration>
First, the mechanical configuration of the motor will be described. As shown in FIG. 2, the motor 11 includes a cylindrical stator 13 that is fixed to the inner peripheral surface of the case 12, and a columnar rotor 14 that is inserted through the stator 13.

  The stator 13 includes a cylindrical core 15 and a plurality of coils 16 wound around the core 15. The core 15 is formed by arranging 12 divided cores 21 along the inner peripheral surface of the case 12 without a gap. Here, as indicated by the circled numbers in FIG. 2, the divided cores 21 are distinguished by attaching numbers 1 to 12. The twelve divided cores 21 are divided into two groups of systems A and B with a straight line PL extending in the radial direction of the core 15 as a boundary. The group A of the system A includes six divided cores 21 (No. 1 to No. 6) corresponding to the half of the 12 divided cores 21 provided on the same circumference, and the group of the system B is the remaining six of the half circumference. The divided cores 21 (Nos. 7 to 12) are included. A coil 16 is wound around each divided core 21. Each coil 16 is distinguished by attaching the number (No. 1 to No. 12) of the split core 21 in which these coils are provided. The 1st to 6th coils 16 belonging to the system A are collectively referred to as a first coil group 16A, and the 7th to 12th coils 16 belonging to the system B are collectively referred to as a second coil group 16B.

  The rotor 14 includes a cylindrical rotary shaft 31 that is rotatably supported by the case 12, and a cylindrical rotor magnet 32 that is fixed to the outer peripheral surface of the rotary shaft 31. The rotor magnet 32 is formed by arranging 14 permanent magnets 32 a along the outer peripheral surface of the rotating shaft 31 without a gap. Each permanent magnet 32a is magnetized along the radial direction of the rotating shaft 31, and is provided so that the magnetization directions of two permanent magnets 32a adjacent to each other are opposite to each other.

<Electrical configuration>
Next, the electrical configuration of the motor will be described. As shown in FIG. 1, in addition to the first and second coil groups 16A and 16B described above, the motor 11 includes a first drive circuit 41, a second drive circuit 42, a switch circuit 43, and a control circuit 44. It has.

  The first drive circuit 41 includes a three-phase inverter circuit 51 and an FET 52. The inverter circuit 51 has three sets of arms (single-phase half bridges) each including two FETs 53 and 53 connected in series, and connected in parallel between a + terminal 54 and a − terminal 55. . The + terminal 54 and the − terminal 55 are connected to a + terminal and a − terminal of a DC power source (not shown), respectively. The FET 52 is provided between the + terminal 54 and the inverter circuit 51.

  The second drive circuit 42 has the same configuration as the first drive circuit 41. For this reason, the components of the second drive circuit 42 are denoted by reference numerals in the 60s, and redundant description thereof is omitted.

  The switch circuit 43 includes a rectifier circuit (three-phase full-wave rectifier circuit) 71 and an FET 72. The rectifier circuit 71 is formed by connecting three sets of arms, each including two diodes 73 and 73 connected in series, in parallel. The FET 72 is connected to the rectifier circuit 71 in parallel.

  In the first and second coil groups 16A and 16B, the coils 16 having the same phase are connected in series with each other. The end of each phase coil 16 in the first coil group 16 </ b> A opposite to the second coil group 16 </ b> B is connected to the midpoint of each phase arm of the inverter circuit 51. The connection point between each phase coil 16 of the first coil group 16A and each phase coil 16 of the second coil group 16B is connected to each phase of the inverter circuit 61 via the lead wire 81 for three phases. Connected to the midpoint of the arm. The end of each phase coil 16 in the second coil group 16B opposite to the first coil group 16A is connected to the midpoint of each phase arm of the rectifier circuit 71. The connection method of each coil 16 will be described in detail later.

  The control circuit 44 controls power feeding to the coils 16 of the systems A and B through control of the first and second drive circuits 41 and 42 and the switch circuit 43. Normally, the control circuit 44 drives the motor 11 using the first drive circuit 41. Further, in a normal state, the control circuit 44 switches the coil group used when driving the motor 11 through the control of the second drive circuit 42 and the switch circuit 43. There are two switching patterns shown in the following (a) and (b).

(A) All of the first and second coil groups 16A and 16B are used.
(B) Only the first coil group 16A is used.
In addition, the control circuit 44 includes a detection unit 44a that detects abnormalities such as open faults and short circuit faults of the FETs of the inverter circuits 51 and 61. The control circuit 44 monitors the phase current of each phase coil in the first and second coil groups 16A and 16B or the voltage between the FETs in the inverter circuits 51 and 61 via the detection unit 44a. The control circuit 44 determines that an open failure or a short-circuit failure has occurred when the phase current or the voltage between the FETs does not change according to the switching of each FET.

<Connection method of each coil>
Next, a method for connecting the coils in the first and second coil groups 16A and 16B will be described.

  Each coil 16 of the first coil group 16 </ b> A is connected in series with two adjacent ones in the circumferential direction of the core 15. Two coils 16 and 16 connected in series correspond to one phase. Specifically, as shown in FIG. 3, the first and second coil pairs correspond to the U phase, the third and fourth coil pairs correspond to the V phase, and the fifth and sixth coil pairs correspond to the W phase. The same applies to the second coil group 16B. That is, the 7th and 8th coil pairs correspond to the U phase, the 9th and 10th coil pairs correspond to the V phase, and the 11th and 12th coil pairs correspond to the W phase.

  As described above, the coils 16 of the same phase in the first and second coil groups 16A and 16B are connected in series. Specifically, the 1st and 2nd coil pairs and the 7th and 8th coil pairs, the 3rd and 4th coil pairs and the 9th and 10th coil pairs, the 5th and 6th coil pairs and the 11th and 12th coil pairs are mutually connected. Connected in series. In addition, the coil group of each phase is not mutually connected.

<How to connect each coil to each circuit>
Next, a method for connecting each coil 16 to the first and second drive circuits 41 and 42 and the switch circuit 43 will be described.

  As described above, the end of the coil 16 of each phase in the first coil group 16 </ b> A opposite to the second coil group 16 </ b> B is connected to the midpoint of the arm of each phase of the inverter circuit 51. Specifically, the end of the U-phase 1 and 2 coil pair opposite to the 7 and 8 coil pairs is connected to the midpoint of the U-phase arm of the inverter circuit 51. The end of the V-phase third and fourth coil pair opposite to the seventh and eighth coil pairs is connected to the midpoint of the V-phase arm of the inverter circuit 51. The ends of the W-phase fifth and sixth coil pairs opposite to the eleventh and twelfth coil pairs are connected to the midpoint of the W-phase arm of the inverter circuit 51.

  As described above, the connection point between the coil 16 of each phase of the first coil group 16A and the coil 16 of each phase of the second coil group 16B is the midpoint of each phase arm of the inverter circuit 61. It is connected to the. Specifically, in the U phase, the midpoint between the first and second coil pairs and the seventh and eighth coil pairs is connected to the midpoint of the U-phase arm of the inverter circuit 61. In the V-phase, the midpoint between the third and fourth coil pairs and the 9.10th coil pair is connected to the midpoint of the V-phase arm of the inverter circuit 61. In the W phase, the midpoint between the fifth and sixth coil pairs and the eleventh and twelfth coil pairs is connected to the midpoint of the W phase arm of the inverter circuit 61.

  Further, as described above, the end of the coil 16 of each phase in the second coil group 16B opposite to the first coil group 16A is connected to the midpoint of each phase arm of the rectifier circuit 71. Yes. Specifically, in the U phase, the end of the seventh and eighth coil pairs on the opposite side to the first and second coil pairs is connected to the midpoint of the U phase arm of the rectifier circuit 71. In the V phase, the end of the 9th and 10th coil pair opposite to the 3.4th coil pair is connected to the midpoint of the V phase arm of the rectifier circuit 71. In the W phase, the ends of the 11th and 12th coil pairs opposite to the 5th and 6th coil pairs are connected to the midpoint of the W phase arm of the rectifier circuit 71.

<Motor operation>
Next, a method for driving the motor configured as described above will be described.
The control circuit 44 switches the coil 16 to be used according to various uses of the motor 11 or according to the presence or absence of abnormality detection.

<1. During normal operation>
First, the operation of the motor 11 during normal operation will be described. There are two operating states in normal operation. The first operating state is an operating state when low rotation and high torque are required. The second operating state is an operating state when high rotation and low torque are required. In any operation state, the motor 11 is driven using the first drive circuit. Only the coil group to be used is different.

<1-1. First operating state>
In the first operating state, the first and second coil groups 16A and 16B are used. When the motor 11 is driven in the first operation state, the control circuit 44 turns off all the FETs 63 of the second drive circuit 42 and turns on the FETs 72 of the switch circuit 43.

  As indicated by a two-dot chain line in FIG. 4, when the second drive circuit 42 is turned off, the second drive circuit 42 is electrically disconnected from the first and second coil groups 16A and 16B. It is. Also, as shown in FIG. 4, when the FET 72 is turned on, the ends of the second coil group 16B opposite to the first coil group 16A in the three-phase coil pair are short-circuited to each other. That is, a neutral point is formed. As a result, the first and second coil pairs and the seventh and eighth coil pairs are U-phase, the third and fourth coil pairs and the ninth and tenth coil pairs are V-phase, the fifth and sixth coil pairs and the eleventh and twelfth coils. A star connection is formed with the coil pair as the W phase.

  The control circuit 44 turns on the FET 52 of the first drive circuit 41 and controls the switching of each FET 53 of the inverter circuit 51, thereby supplying three-phase AC power to the first and second coil groups 16A and 16B. Supply. In the first and second coil groups 16A and 16B, an induced voltage corresponding to the total number of turns of each phase coil is generated. At this time, the motor 11 rotates at a low speed, but a large torque is obtained.

<1-2. Second operation state>
In the second operating state, only the first coil group 16A is used. When the motor 11 is driven in the second operation state, the control circuit 44 turns off the three FETs 63 on the low side (−terminal 65 side) of the second drive circuit 42 and also turns the high side (+ terminal 64). 3 side FETs 63 are turned on, and the FET 62 is turned off. Further, the control circuit 44 turns off the FET 72 of the switch circuit 43.

  As shown in FIG. 5, when the high-side FET 63 of the second drive circuit 42 is turned on and the low-side FET 63 is turned off, the second coil group 16B in the three-phase coil pair of the first coil group 16A. The opposite ends are short-circuited with each other. That is, a neutral point is formed. Further, as indicated by a two-dot chain line in FIG. 5, when the FET 72 of the switch circuit 43 is turned off, the second coil group 16B is electrically disconnected from the first coil group 16A. As a result, a star connection is formed in which the first and second coil pairs are U-phase, the third and fourth coil pairs are V-phase, and the fifth and sixth coil pairs are W-phase.

  The control circuit 44 supplies the three-phase AC power to the first coil group 16A by turning on the FET 52 of the first drive circuit 41 and controlling the switching of each FET 53 of the inverter circuit 51. In the first coil group 16A, an induced voltage corresponding to the number of turns of each phase coil is generated. Here, the number of turns of each phase coil is smaller by the number of turns of each coil 16 of the second coil group 16B than in the first operating state. For this reason, although the motor 11 has a smaller torque than that in the first operating state, the motor 11 can rotate at a high speed.

<2. When one system fails>
Next, the operation of the motor 11 when one of the first drive circuit 41 (system A) and the second drive circuit 42 (system B) fails will be described. The failure has three states. First, the FETs 53 and 63 are in an open failure state, secondly, the high-side FETs 53 and 63 are short-circuited, and thirdly, the low-side FETs 53 and 63 are short-circuited.

<2-1. System A failure>
<Open failure>
First, a case where an open failure has occurred in any one of the six FETs 53 of the inverter circuit 51 will be described.

  In this case, the control circuit 44 turns off all of the FETs 52 of the first drive circuit 41 and the six FETs 63 of the inverter circuit 51. Further, the control circuit 44 turns on the FET 72 of the switch circuit 43.

  As indicated by a two-dot chain line in FIG. 6, when the first drive circuit 41 is turned off, the first coil group 16A is electrically disconnected from the second coil group 16B. In addition, when the FET 72 is turned on, the ends on the opposite side of the first coil group 16A in the three-phase coil pair of the second coil group 16B are short-circuited to each other. That is, a neutral point is formed. As a result, a star connection is formed in which the 7th and 8th coil pairs are the U phase, the 9th and 10th coil pairs are the V phase, and the 11th and 12th coil pairs are the W phase.

The control circuit 44 drives the motor 11 by supplying three-phase AC power to the second coil group 16 </ b> B through the second drive circuit 42.
<High side short circuit failure>
Next, a case where a short-circuit fault has occurred in any one of the three high-side FETs 53 in the inverter circuit 51 will be described.

  In this case, the control circuit 44 turns off the FET 52 of the first drive circuit 41 and turns on the three low-side FETs 53 in the inverter circuit 51. Further, the control circuit 44 turns off the FET 72 of the switch circuit 43.

  As indicated by a two-dot chain line in FIG. 7, the power supply to the first drive circuit 41 is interrupted by turning off the FET 52. In addition, when the three FETs 53 on the low side of the inverter circuit 51 are turned on, the ends of the three-phase coil pair of the first coil group 16A opposite to the second coil group 16B are short-circuited to each other. That is, a neutral point is formed. Further, when the FET 72 of the switch circuit 43 is turned off, the second coil group 16B is electrically disconnected from the first coil group 16A. As a result, a star connection is formed in which the first and second coil pairs are U-phase, the third and fourth coil pairs are V-phase, and the fifth and sixth coil pairs are W-phase.

The control circuit 44 drives the motor 11 by supplying three-phase AC power to the first coil group 16 </ b> A through the second drive circuit 42.
<Low side short circuit failure>
Next, a case where a short-circuit failure occurs in any one of the three low-side FETs 53 in the inverter circuit 51 will be described.

  In this case, the control circuit 44 turns off the FET 52 of the first drive circuit 41 and turns on the three high-side FETs 53 in the inverter circuit 51. Further, the control circuit 44 turns off the FET 72 of the switch circuit 43.

  As indicated by the two-dot chain line in FIG. 7, the power supply to the first drive circuit 41 is cut off by turning off the FET 52. In addition, when the three FETs 53 on the high side of the inverter circuit 51 are turned on, the ends of the three-phase coil pair of the first coil group 16A opposite to the second coil group 16B are short-circuited to each other. That is, a neutral point is formed. Further, when the FET 72 of the switch circuit 43 is turned off, the second coil group 16B is electrically disconnected from the first coil group 16A. As a result, a star connection is formed in which the first and second coil pairs are U-phase, the third and fourth coil pairs are V-phase, and the fifth and sixth coil pairs are W-phase.

The control circuit 44 drives the motor 11 by supplying three-phase AC power to the first coil group 16 </ b> A through the second drive circuit 42.
<2-2. System B failure>
<Open failure>
Next, a case where an open failure occurs in any one of the six FETs 63 of the inverter circuit 61 will be described.

  In this case, the control circuit 44 turns off all of the FETs 62 of the second drive circuit 42 and the six FETs 63 of the inverter circuit 61. Further, the control circuit 44 turns on the FET 72 of the switch circuit 43.

  As indicated by the two-dot chain line in FIG. 4, when the second drive circuit 42 is turned off, the second drive circuit 42 is electrically connected to the first and second coil groups 16A and 16B. Separated. In addition, when the FET 72 is turned on, the ends on the opposite side of the first coil group 16A in the three-phase coil pair of the second coil group 16B are short-circuited to each other. That is, a neutral point is formed. As a result, the first and second coil pairs and the seventh and eighth coil pairs are U-phase, the third and fourth coil pairs and the ninth and tenth coil pairs are V-phase, the fifth and sixth coil pairs and the eleventh and twelfth coils. A star connection is formed with the coil pair as the W phase.

  The control circuit 44 drives the motor 11 by supplying three-phase AC power to the first and second coil groups 16A and 16B through the first drive circuit 41. That is, the control circuit 44 can operate the motor 11 through the first drive circuit 41 in the same manner as in the first operation state.

<High side short circuit failure>
Next, a case where a short circuit fault has occurred in any one of the three high-side FETs 63 in the inverter circuit 61 will be described.

  In this case, the control circuit 44 turns off the FET 62 of the second drive circuit 42 and turns on the three low-side FETs 63 in the inverter circuit 61. Further, the control circuit 44 turns off the FET 72 of the switch circuit 43.

  When the FET 62 is turned off, the power supply to the second drive circuit 42 is interrupted. In addition, when the three FETs 63 on the low side of the inverter circuit 61 are turned on, as shown in FIG. 5, the connection with the second coil group 16B in the three-phase coil pair of the first coil group 16A is performed. The points are shorted together. That is, a neutral point is formed.

  Further, as indicated by the two-dot chain line in FIG. 5, the second coil group 16B is electrically disconnected from the first coil group 16A when the FET 72 of the switch circuit 43 is turned off. . As a result, a star connection is formed in which the first and second coil pairs are U-phase, the third and fourth coil pairs are V-phase, and the fifth and sixth coil pairs are W-phase.

  The control circuit 44 drives the motor 11 by supplying three-phase AC power to the first coil group 16 </ b> A through the first drive circuit 41. That is, the control circuit 44 can drive the motor 11 through the first drive circuit 41 as in the second operation state.

<Low side short circuit failure>
Next, a case where a short circuit fault has occurred in any one of the three low-side FETs 63 in the inverter circuit 61 will be described.

  In this case, the control circuit 44 turns off the FET 62 of the second drive circuit 42 and turns on the three high-side FETs 63 in the inverter circuit 61. Further, the control circuit 44 turns off the FET 72 of the switch circuit 43.

  When the FET 62 is turned off, the power supply to the second drive circuit 42 is interrupted. In addition, when the three FETs 63 on the high side of the inverter circuit 61 are respectively turned on, as shown in FIG. 5, the second coil group 16B in the three-phase coil pair of the first coil group 16A Connection points are shorted together. That is, a neutral point is formed.

  Further, as indicated by the two-dot chain line in FIG. 5, the second coil group 16B is electrically disconnected from the first coil group 16A when the FET 72 of the switch circuit 43 is turned off. . As a result, a star connection is formed in which the first and second coil pairs are U-phase, the third and fourth coil pairs are V-phase, and the fifth and sixth coil pairs are W-phase.

  The control circuit 44 drives the motor 11 by supplying three-phase AC power to the first coil group 16 </ b> A through the first drive circuit 41. That is, the control circuit 44 can drive the motor 11 through the first drive circuit 41 as in the second operation state.

<Effect of Embodiment>
Therefore, according to the present embodiment, the following effects can be obtained.
(1) During normal operation, the operation state of the motor 11 can be switched between the first operation state and the second operation state. In the first operating state, low rotation and high torque can be obtained by using all of the first and second coil groups 16A and 16B. In the second operating state, since only the first coil group 16A is used, higher rotation and lower torque can be obtained than in the first operating state. That is, the operating range of the motor 11 is expanded. When an abnormality of the inverter circuit 51 of the system A is detected, the inverter circuit 61 of the system B is used. Conversely, when an abnormality of the inverter circuit 61 of the system B is detected, the inverter circuit of the system A is detected. 51 can be used to drive the motor 11. For this reason, redundancy is also ensured.

  (2) FETs 52 and 62 are provided on the high-side (high potential side) feeding paths in the inverter circuits 51 and 61 of the systems A and B, respectively. When an abnormality is detected in the inverter circuit 51 of the system A or the inverter circuit 61 of the system B, the control circuit 44 turns off the FET 52 or FET 62 on the abnormality detection side.

  For this reason, when an abnormality of the inverter circuit 51 of the system A or the inverter circuit 61 of the system B is detected, the power supply to the abnormal inverter is cut off by turning off the abnormal FET. For this reason, the motor circuit is protected.

  In addition, when forming a star connection composed of the first coil group 16A when the inverter circuit 51 of the system A is abnormal (at the time of a short circuit failure), by short-circuiting each phase coil of the first coil group 16A. It is necessary to form a neutral point. At this time, it is not preferable that the power supply to the inverter circuit 51 of the system A is maintained. In this regard, according to this example, when an abnormality is detected in the inverter circuit 51 of the system A, the power supply to the inverter circuit 51 is cut off, so that a star connection composed of the first coil group 16A is suitably formed. can do.

  (3) Since redundancy is provided as described above, the motor 11 of this example is suitable for an electric power steering device (EPS), for example. In this case, even if an abnormality occurs in one of the first and second drive circuits 41 and 42, the operation of the motor 11 can be continued by the other. The force required for steering operation does not increase suddenly.

  Note that the motor 11 of this example may be employed as a drive source for another electric device such as an electric pump or a variable gear ratio steering (VGRS) of an automobile. VGRS is a device that changes the steering gear ratio steplessly in accordance with the vehicle speed and the steering angle.

<Other embodiments>
The embodiment described above may be modified as follows.
In this example, the rotor magnet 32 composed of a plurality of permanent magnets 32a is adopted, but a single cylindrical magnet may be adopted.

  -In this example, although the core 15 which consists of the some division | segmentation core 21 was employ | adopted, you may employ | adopt a single core. Even in this case, the coils 16 can be divided into two groups of systems A and B.

  In the present example, a so-called 14-pole 12-coil brushless motor has been described as an example, but the number of coils 16 and the number of magnetic poles of the rotor magnet 32 may be changed as appropriate. In this case, it is preferable to set the number of coils 16 to a natural number multiple of 12, and the number of magnetic poles of the rotor magnet 32 to a natural number of 2, 10 or 14.

  In this example, the inner rotor type brushless motor is taken as an example, but an outer rotor type brushless motor may be used. In the same type of motor, a stator is provided inside a cylindrical rotor.

  In this example, the switch circuit 43 is employed as a short-circuit means for short-circuiting the three-phase coils of the second coil group 16B. However, a mechanical switch having three terminals may be employed. As the mechanical switch, for example, there is an electromagnetic contactor that simultaneously opens and closes three phases.

  ・ In this example, six of the 12 coils 16 provided on the same circumference for the half circumference (No. 1 to No. 6) are system A, and the remaining half of the six (No. 7 to No. 12) Is divided as a system B, but a plurality of continuous cores 15 in the circumferential direction of the core 15 may not be grouped. For example, the odd numbered coils 16 may be divided into the A system and the even numbered coils 16 may be divided into the B system.

In this example, the power supply system for the motor 11 is two systems A and B, but may be three systems, four systems or more. In this case, as many drive circuits as the number of systems are provided.
<Other technical ideas>
Next, the technical idea that can be grasped from the above embodiment will be added below.

  -In electric devices, such as an electric power steering device, it has the rotary electric machine as described in any one of Claims 1-4 as a drive source.

  DESCRIPTION OF SYMBOLS 11 ... Motor (rotary electric machine), 16 ... Coil, 16A ... 1st coil group, 16B ... 2nd coil group, 43 ... Switch circuit, 44 ... Control circuit, 51, 61 ... Inverter, 52, 62 ... FET ( Switching element).

Claims (6)

First and second coil groups in which three-phase coils are connected in series with each other; a first inverter connected to an end of the first coil group opposite to the second coil group; A second inverter connected between the first and second coil groups, and each phase coil of the second coil group connected to the end of the second coil group opposite to the first coil group A switch circuit that switches between a short-circuited state and an opened state, and a control circuit that controls the first and second inverters and the switch circuit, respectively,
The control circuit normally forms a star connection composed of the first and second coil groups through the second inverter and the switch circuit, and then supplies power to the first and second coil groups through the first inverter. It is possible to switch between this state and the second state in which the first coil group is similarly formed and then the first coil group is fed through the first inverter.
When an abnormality occurs in the first inverter, a star connection composed of the first or second coil group is formed through the second inverter and the switch circuit, and then the first or second coil group is fed through the second inverter. A rotating electrical machine that supplies power to at least one of the first and second coil groups in the same manner as in the first or second state when the second inverter is abnormal. In claim 1,
A switching element is provided in each of the power supply paths on the high potential side in the first and second inverters,
When the abnormality of the first or second inverter is detected, the control circuit turns off the switching element on the side where the abnormality is detected. In the rotating electrical machine according to claim 1 or 2,
In the abnormality of the first and second inverters, there are open failure and short-circuit failure of each switching element of the first and second inverters,
The control circuit
At the time of an open failure of the first inverter, the first coil group is electrically disconnected from the second coil group through the first inverter, and each phase coil of the second coil group is short-circuited through the switch circuit After forming a star connection consisting of each phase coil of the second coil group, power is supplied to the second coil group through the second inverter,
When the first inverter is short-circuited, each phase coil of the first coil group is short-circuited through the first inverter, and the second coil group is electrically disconnected from the first coil group through the switch circuit. After forming a star connection consisting of the first coil group, power is supplied to the first coil group through the second inverter,
In the event of an open failure of the second inverter, the first inverter is electrically disconnected from the first and second coil groups and the first and second coils of the second coil group are short-circuited through the switch circuit. After forming a star connection composed of the respective phase coils of the second coil group, the first and second coil groups are fed through the first inverter,
At the time of a short circuit failure of the second inverter, each phase coil of the first coil group is short-circuited through the second inverter and each of the first coil group is electrically opened through the switch circuit. A rotating electrical machine that forms a star connection composed of phase coils and supplies power to a first coil group through a first inverter. In the rotating electrical machine according to any one of claims 1 to 3,
The control circuit
In the first state, the second inverter is electrically disconnected from the first and second coil groups, and each phase coil of the second coil group is short-circuited through the switch circuit. Form a star connection consisting of each phase coil of the coil group,
In the second state, each phase coil of the first coil group is short-circuited through the second inverter, and the second coil group is electrically opened through the switch circuit. A rotating electrical machine that forms a star connection. In the rotating electrical machine according to claim 1,
The control circuit is a rotating electrical machine that switches a coil group to be used for driving the rotating electrical machine through control of the second inverter and the switch circuit in a normal state. In the rotating electrical machine according to claim 5,
The control circuit normally disconnects the second inverter from the first and second coil groups through the second inverter, and on the opposite side of the second coil group from the first coil group through the switch circuit. A first state in which the ends are short-circuited to form a star connection composed of the first and second coil groups, and then the first and second coil groups are fed through the first inverter;
The end of the first coil group opposite to the second coil group is short-circuited with each other through the second inverter, and the second coil group is electrically disconnected from the first coil group through the switch circuit. A rotating electrical machine that is switchable between a second state in which a star connection made of a coil group is formed and then power is supplied to the first coil group through a first inverter.