JP2021035182A - Motor control device - Google Patents

Abstract

To provide a motor control device that, in a case where motor drive cannot be started due to a difference in control state between the own system and another system, can specify the cause and analyze an event.SOLUTION: A plurality of control units (microcomputers) of a motor control device can mutually communicate. Concerning a transition between control states of systems during starting, a control state in which a determination that drive start of a motor is possible is regarded as a "drive start standby state," and a control state in which a process for the drive start is stopped due to a determination that an operation power source for each control unit is cut off or has a voltage decrease (IGOFF) is regarded as a "drive stop state." The control unit of each system has a control-state determination unit that determines a combination of the own system and another system by mutual communication. If the own system is in a drive start standby state (S01) and another system is in a drive stop state (S04: YES), the control state determination unit determines that "a condition for different states has established" (S05), and the control unit stores this determination history in a recording medium (S06).SELECTED DRAWING: Figure 10

Description

The present invention relates to a motor control device.

Conventionally, in a motor control device that controls the drive of a motor by a control unit of a plurality of systems that can communicate with each other, there is known a technique of starting the motor drive after performing an initial check of each system at startup.

For example, the control unit of the control system disclosed in Patent Document 1 starts drive control when the initial check of its own system is completed and the end signal is acquired from another control unit. Further, when the initial check of the own system is completed and the end signal is not acquired from another control unit, the control unit starts the drive control after a predetermined time has elapsed from the start of the initial check of the own system.

Further, the motor control device disclosed in Patent Document 2 prohibits motor driving by a system determined to be abnormal by the initial check, and when only one system is normally determined by the initial check, one system determined to be normal. Start driving the motor with.

JP-A-2017-169386 Japanese Unexamined Patent Publication No. 2019-10213

In the prior art of Patent Documents 1 and 2, it is assumed that an end signal is not generated and motor driving is prohibited when an abnormality is actually detected in a switching element, a relay, various sensors, or the like in the initial check. However, in addition to this, there is a possibility that the operating power supply of the control unit of each system may be unintentionally cut off or the voltage may drop before or during the initial check.

For example, in the case of an engine vehicle, if the IG voltage of the other system drops due to a momentary interruption of the ignition switch or the like, the control unit of the own system cannot acquire the end signal from the other system. Therefore, in the prior art, the motor drive cannot be started until a predetermined time elapses. Further, since the cutoff of the operating power supply or the voltage drop is not an abnormality of the initial check, it is not recognized as an abnormality determination, and the motor drive is not started only in the normal system.

Hereinafter, in the present specification, the control state in which it is determined that the motor can be started is referred to as the "drive start waiting state", and the control state in which the drive cannot be started due to the interruption of the operating power supply of the control unit or the voltage drop is the "drive stop state". ". In the prior art of Patent Documents 1 and 2, there is no idea of paying attention to the combination of the control states of the own system and the other system. Therefore, if the motor drive cannot be started because the own system is in the drive start waiting state and the other system is in the drive stop state, the cause cannot be identified and the event analysis may not be performed correctly.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to identify the cause and enable event analysis when the motor drive cannot be started due to the difference in the control state between the own system and another system. The purpose is to provide a motor control device.

The motor control device of the present invention controls the drive of a motor (80) having one or more winding sets (801, 802). This motor control device includes a plurality of power converters (601, 602) and a plurality of control units (401, 402). Multiple power converters power the corresponding winding set. The plurality of control units can communicate with each other and calculate a drive signal commanding the corresponding power converter.

A unit of a group of components including a winding set, a power converter, and a control unit provided corresponding to each other is defined as a "system".

Regarding the transition of the control state of each system at the time of start-up, the control state in which it is determined that the motor can be started to be driven is defined as the “drive start waiting state”. Specifically, the state in which the initial check for the components of the own system is normally completed corresponds to the "drive start waiting state". Further, the control state in which the process for starting the drive is stopped due to the determination that the operating power supply of the control unit is cut off or the voltage is lowered is defined as the "drive stop state".

The control unit of each system has a control state determination unit (441, 442) that determines a combination of control states of the own system and another system by mutual communication. When the own system is in the drive start waiting state and the other system is in the drive stop state, the control state determination unit determines that "the state difference condition has been satisfied", and the control unit stores the determination history as a storage medium. Store in (461, 462).

The motor control device of the present invention pays attention to the combination of the control states of the own system and the other system, and stores the determination history that the state difference condition is satisfied. As a result, the cause of the event in which the motor drive cannot be started can be identified, and the event analysis becomes possible.

FIG. 6 is a configuration diagram of an electric power steering device in which the ECU of one embodiment is applied as a motor drive system integrated with mechatronics. FIG. 6 is a configuration diagram of an electric power steering device in which the ECU of one embodiment is applied as a motor drive system of a separate mechanical and electrical type. Axial sectional view of a two-system mechanical / electrical integrated motor. FIG. 3 is a sectional view taken along line IV-IV of FIG. The schematic diagram which shows the structure of a polyphase coaxial motor. The whole block diagram of the ECU (motor control device) by one Embodiment. FIG. 6 is a control block diagram of an ECU (motor control device) according to an embodiment. The figure of the transition example of the control state (status). The motor output characteristic diagram of (a) independent drive mode and (b) single system drive mode. Flowchart of start-up processing according to one embodiment. A time chart that starts driving only the own system when the state mismatch condition is satisfied. Time chart when the system that stopped driving is restored. A time chart when the other system returns from the (a) independent drive mode and (b) one system drive mode of the own system. The block diagram of the steering-by-wire system to which the ECU of another embodiment is applied.

As used herein, the term "embodiment" means an embodiment of the present invention. Hereinafter, embodiments of the motor control device will be described with reference to the drawings. In the embodiment, the ECU as the "motor control device" is applied to the electric power steering system of the vehicle and controls the drive of the steering assist motor. Here, it is assumed that an engine vehicle is typically used, and an ignition (hereinafter referred to as “IG”) switch is used as a switch for switching between an on state and an off state of the system.

[Composition of electric power steering system and motor]
The configuration of the electric power steering system, the configuration of the motor, and the like will be described with reference to FIGS. 1 to 4. 1 and 2 show the overall configuration of the steering system 99 including the electric power steering system (“EPS” in the figure) 901. FIG. 1 shows a “mechatronically integrated” configuration in which the ECU 10 is integrally configured on one side of the motor 80 in the axial direction, and FIG. 2 shows a “mechanical and electrical integrated type” configuration in which the ECU 10 and the motor 80 are connected by a harness. The configuration of the "mechanical and electrical separate type" is illustrated. Although the electric power steering system 901 of FIGS. 1 and 2 is a column assist type, it can be similarly applied to a rack assist type electric power steering system.

The steering system 99 includes a steering wheel 91, a steering shaft 92, a pinion gear 96, a rack shaft 97, wheels 98, an electric power steering system 901, and the like. A steering shaft 92 is connected to the steering wheel 91. The pinion gear 96 provided at the tip of the steering shaft 92 meshes with the rack shaft 97. A pair of wheels 98 are provided at both ends of the rack shaft 97 via a tie rod or the like. When the driver rotates the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into a linear motion of the rack shaft 97 by the pinion gear 96, and the pair of wheels 98 are steered at an angle corresponding to the displacement amount of the rack shaft 97.

The electric power steering system 901 includes a steering torque sensor 93, an ECU 10, a motor 80, a reduction gear 94, and the like. The steering torque sensor 93 is provided in the middle of the steering shaft 92 and detects the steering torque of the driver. In the embodiment shown in FIGS. 1 and 2, the duplicated steering torque sensor 93 includes the first torque sensor 931 and the second torque sensor 932, and detects the first steering torque trq1 and the second steering torque trq2 in duplicate. .. When the steering torque sensor is not provided redundantly, the detection value of one steering torque trq may be used in common for the two systems.

The ECU 10 controls the drive of the motor 80 so that the motor 80 generates a desired assist torque based on the steering torques trq1 and trq2. The assist torque output by the motor 80 is transmitted to the steering shaft 92 via the reduction gear 94. The ECU 10 acquires the electric angles θ1 and θ2 of the motor 80 detected by the rotation angle sensor and the steering torque trq1 and trq2 detected by the steering torque sensor 93. The ECU 10 controls the drive of the motor 80 based on such information and information such as the motor current detected inside the ECU 10.

The configuration of the mechatronically integrated motor 800 in which the ECU 10 is integrally configured on one side of the motor 80 in the axial direction will be described with reference to FIGS. 3 and 4. In the embodiment shown in FIG. 3, the ECU 10 is arranged coaxially with respect to the axis Ax of the shaft 87 on the side opposite to the output side of the motor 80. In another embodiment, the ECU 10 may be integrally configured with the motor 80 on the output side of the motor 80. The motor 80 is a three-phase brushless motor and includes a stator 840, a rotor 860, and a housing 830 for accommodating them.

The stator 840 has a stator core 845 fixed to the housing 830 and two sets of three-phase winding sets 801 and 802 assembled to the stator core 845. Lead wires 851, 853, and 855 extend from the phase windings constituting the first winding set 801. Lead wires 852, 854, and 856 extend from each phase winding constituting the second winding set 802. The rotor 860 has a shaft 87 supported by a rear bearing 835 and a front bearing 836, and a rotor core 865 into which the shaft 87 is fitted. The rotor 860 is provided inside the stator 840 and is rotatable relative to the stator 840. A permanent magnet 88 is provided at one end of the shaft 87.

The housing 830 has a bottomed tubular case 834 including a rear frame end 837 and a front frame end 838 provided at one end of the case 834. The case 834 and the front frame end 838 are fastened to each other by bolts or the like. The lead wires 851, 852 and the like of the winding sets 801 and 802 pass through the lead wire insertion holes 839 of the rear frame end 837, extend toward the ECU 10, and are connected to the substrate 230.

The ECU 10 includes a cover 21, a heat sink 22 fixed to the cover 21, a substrate 230 fixed to the heat sink 22, and various electronic components mounted on the substrate 230. The cover 21 protects electronic components from external impacts and prevents dust, water, and the like from entering the ECU 10. The cover 21 has a connector portion 214 for external connection and a cover portion 213 for a power supply cable and a signal cable from the outside. The power supply terminals 215 and 216 of the external connection connector portion 214 are connected to the substrate 230 via a path (not shown).

The substrate 230 is, for example, a printed circuit board, which is provided at a position facing the rear frame end 837 and is fixed to the heat sink 22. The board 230 is provided with electronic components for two systems independently for each system, forming a completely redundant configuration. In this embodiment, the number of substrates 230 is one, but in other embodiments, two or more substrates may be provided. Of the two main surfaces of the substrate 230, the surface facing the rear frame end 837 is designated as the motor surface 237, and the surface opposite to the motor surface 237, that is, the surface facing the heat sink 22 is designated as the cover surface 238.

A plurality of switching elements 611-616, 621-626, rotation angle sensors 251 and 252, custom ICs 261, 262 and the like are mounted on the motor surface 237. In the present embodiment, the plurality of switching elements 611-616 and 621-626 are six for each system, and form a three-phase upper / lower arm of the motor drive circuit. The rotation angle sensors 251 and 252 are arranged so as to face the permanent magnet 88 provided at the tip of the shaft 87. The custom ICs 261 and 262 and the microcomputers 401 and 402 have a control circuit of the ECU 10.

Microcomputers 401, 402, capacitors 281, 282, inductors 271, 272, and the like are mounted on the cover surface 238. In particular, the first microcomputer 401 and the second microcomputer 402 are arranged on the cover surface 238, which is the same side surface of the same substrate 230, at predetermined intervals. The capacitors 281 and 282 smooth the electric power input from the power supply and prevent noise from flowing out due to the switching operation of the switching elements 611-616 and 621-626. The inductors 271 and 272 form a filter circuit together with the capacitors 281 and 282.

As shown in FIGS. 5 and 6, the motor 80 to be controlled by the ECU 10 is a three-phase brushless motor in which two sets of three-phase winding sets 801 and 802 are coaxially provided. The winding sets 801 and 802 have the same electrical characteristics, and are arranged on a common stator with an electrical angle of 30 [deg] offset from each other.

[Ignition configuration]
Next, the detailed configuration of the ECU 10 will be described. The ECU 10 is a two-system motor control device including inverters 601 and 602 as two "power converters" and two microcomputers 401 and 402, and is a motor 80 having two sets of winding sets 801 and 802. Supply power. Here, a unit of a group of components including a winding set, an inverter, and a microcomputer is defined as a "system". In the configuration example shown in FIG. 6, individual power supplies 111 and 112 are redundantly provided for each system.

In the specification, if necessary, the components or signals of the first system are distinguished by adding "first" to the beginning of the word, and the components or signals of the second system are distinguished by adding "second" to the beginning of the word. To do. Items common to each system are described together without adding "1st and 2nd". Further, except for the switching element, "1" is added to the end of the code of the component or signal of the first system, and "2" is added to the end of the code of the component or signal of the second system. Further, for a certain component, the system including the component is referred to as "own system", and the other system is referred to as "other system".

As shown in FIG. 6, the first power supply 111 functions as a power supply source of the first inverter 601 via the power power supply line PIG1, and also functions as an operating power supply of the first microcomputer 401 via the power supply line IG1. .. Similarly, the second power supply 112 functions as a power supply source for the second inverter 602 via the power power supply line PIG2, and also functions as an operating power supply for the second microcomputer 402 via the power supply line IG2.

IG switches 171 and 172 are provided in the middle of the power supply lines IG1 and IG2, respectively. The IG switches 171 and 172 switch between an on state, which is a vehicle starting state, and an off state, which is a stopped state. Basically, when the IG switches 171 and 172 are turned on from the off state, the microcomputers 401 and 402 are activated, an initial check is performed on the components of the own system, and then the driving of the motor 80 is started.

The ECU 10 includes power relays 141 and 142, inverters 601, 602, current sensors 741 and 742, and microcomputers 401 and 402 as "plurality of control units". The power relays 141 and 142 are provided in the power supply lines of the input units of the inverters 601 and 602.

In the inverters 601 and 602, six switching elements 611-616 and 621-626 such as MOSFETs are bridge-connected, respectively. The first inverter 601 performs a switching operation by a drive signal from the first microcomputer 401, converts the DC power of the first power supply 111, and supplies the DC power to the first winding set 801. The second inverter 602 performs switching operation by the drive signal from the second microcomputer 402, converts the DC power of the second power supply 112, and supplies it to the second winding set 802. Further, smoothing capacitors 281 and 282 are provided at the input portions of the inverters 601 and 602.

The first current sensor 741 detects the current Im1 energized in each phase of the inverter 601 and the winding set 801 of the first system, and outputs the current Im1 to the first microcomputer 401. The second current sensor 742 detects the current Im2 energized in each phase of the inverter 602 and the winding set 802 of the second system, and outputs the current Im2 to the second microcomputer 402.

The first rotation angle sensor 251 detects the electric angle θ1 of the motor 80 and outputs it to the first microcomputer 401. The second rotation angle sensor 252 detects the electric angle θ2 of the motor 80 and outputs it to the second microcomputer 402. When the rotation angle sensor is not provided redundantly, for example, based on the electric angle θ1 of the first system detected by the first rotation angle sensor 251, the electric angle θ2 of the second system is set by the formula “θ2 = θ1 + 30deg”. It may be calculated.

In FIG. 6, the steering torques trq1 and trq2 input from the steering torque sensor 93 to the microcomputers 401 and 402 are not shown. The first microcomputer 401 calculates a drive signal commanded to the first inverter 601 based on feedback information such as steering torque trq1, current Im1, and rotation angle θ1. The second microcomputer 402 calculates a drive signal commanded to the second inverter 602 based on feedback information such as steering torque trq2, current Im2, and rotation angle θ2.

FIG. 7 shows a more detailed control configuration of the ECU 10. In FIG. 7, the first system and the second system are all composed of two independent sets of element groups, and form a so-called "complete two system" redundant configuration. Regarding the code of the connector, in FIG. 7, a code different from that of the external connection connector portion 214 of FIG. 2 is used. The first connector portion 351 of the ECU 10 includes a first power supply connector 131, a first vehicle communication connector 311 and a first torque connector 331. The second connector portion 352 includes a second power supply connector 132, a second vehicle communication connector 312, and a second torque connector 332. The connector portions 351 and 352 may be formed as a single connector, or may be divided into a plurality of connectors.

The first power supply connector 131 is connected to the first power supply 111. The electric power of the first power supply 111 is supplied to the first winding set 801 via the power supply connector 131, the power supply relay 141, and the first inverter 601. Further, the electric power of the first power source 111 is also supplied to the first microcomputer 401 and the sensors of the first system.

The second power supply connector 132 is connected to the second power supply 112. The electric power of the second power source 112 is supplied to the second winding set 802 via the power supply connector 132, the power supply relay 142, and the second inverter 602. Further, the electric power of the second power source 112 is also supplied to the second microcomputer 402 and the sensors of the second system.

When the CAN is redundantly provided as the vehicle communication network, the first vehicle communication connector 311 is connected between the first CAN 301 and the first vehicle communication circuit 321. The second vehicle communication connector 312 is connected between the second CAN 302 and the second vehicle communication circuit 322. If the CAN is not redundantly provided, the two vehicle communication connectors 311 and 312 may be connected to a common CAN 30. Further, as a vehicle communication network other than CAN, a network of any standard such as CAN-FD (CAN with Flexible Data rate) or FlexRay may be used. The vehicle communication circuits 321 and 322 communicate information in both directions with the microcomputers 401 and 402 of the own system and other systems.

The first torque connector 331 is connected between the first torque sensor 931 and the first torque sensor input circuit 341. The first torque sensor input circuit 341 notifies the first microcomputer 401 of the steering torque trq1 detected by the first torque connector 331. The second torque connector 332 is connected between the second torque sensor 932 and the second torque sensor input circuit 342. The second torque sensor input circuit 342 notifies the second microcomputer 402 of the steering torque trq2 detected by the second torque connector 332.

Each process in the microcomputers 401 and 402 may be software processing by executing a program stored in advance in a physical memory device such as a ROM (that is, a readable non-temporary tangible recording medium) on the CPU. , It may be hardware processing by a dedicated electronic circuit.

The first microcomputer 401 calculates a drive signal for operating the switching operation of the first inverter 601 and commands the first inverter 601. Further, the first microcomputer 401 controls the opening and closing of the first power supply relay 141. The second microcomputer 402 calculates a drive signal for operating the switching operation of the second inverter 602, and commands the second inverter 602. Further, the second microcomputer 402 controls the opening and closing of the second power supply relay 142. The microcomputers 401 and 402 can communicate with each other by communication between microcomputers (that is, "communication between control units"). As the means for communication between microcomputers, any means such as CAN communication or a dedicated signal line may be used.

The microcomputers 401 and 402 of the present embodiment have control state determination units 441 and 442 that determine a combination of control states of the own system and another system by mutual communication with respect to the "control state at startup" described later. Further, the microcomputers 401 and 402 have storage media 461 and 462 in which the determination history by the control state determination units 441 and 442 is stored. When the communication between the microcomputers is abnormal, the control state determination units 441 and 442 stop the success / failure determination of the state difference condition. Hereinafter, when describing an unspecified system, the reference numerals of the microcomputers 401 and 402, the control state determination units 441 and 442, and the storage media 461 and 462 are appropriately omitted.

An example of the transition of the control state will be described with reference to FIG. Hereinafter, the control state is also referred to as "status". In FIG. 8, a plurality of statuses at the time of startup are shown in a thick line frame, and transitions between statuses are indicated by arrows. When the microcomputer is started by turning on the IG switch starting from "no status" when it is not started, the status changes to "before the start of driving" and the initial check is performed. “Before driving start” is a state in which the initial check is not completed, in other words, a control state in which it is unknown whether or not the driving of the motor can be started.

As described in Patent Document 2 (Japanese Unexamined Patent Publication No. 2019-103213), in the initial check, the switching elements 611-616 and 621-626 of the inverters 601 and 602, the power supply relays 141 and 142, and the current sensors 741 and 742 And the rotation angle sensors 251 and 252 and the like are checked. When the initial check is completed normally, the status transitions to the "waiting for drive start" status, which is the "control state in which it is determined that the motor can be started."

When the own system is "waiting for drive start" and the communication between the microcomputers is normal, the control state determination units 441 and 442 acquire the control state of the other system. When the other system is (a) "waiting for drive start", that is, when the two systems are in the same status, the own system transitions to "driving". Then, the driving of the motor 80 in the two systems is started, and the assist in the electric power steering system 901 is started.

Further, when the own system is "waiting for drive start" and the other system is (b) "drive stop" or (c) "driving", the own system transitions to "driving". In particular, when "the own system is in the drive start waiting state and the other system is in the drive stop state" shown in (b), the control state determination unit of the own system determines that "the state difference condition has been satisfied". .. At this time, at least the microcomputer of the own system, which is in the drive start waiting state, stores the determination history in the storage medium.

Here, with reference to FIG. 9, each drive mode of cooperative drive, independent drive, and single system drive (half assist) during “driving” will be described. In the present specification, a drive mode in which two microcomputers 401 and 402 share a command value and two systems output the same torque is defined as a "cooperative drive mode". A technique for coordinating driving a motor by communicating control signals including command values between a plurality of microcomputers is disclosed in Japanese Patent Application Laid-Open No. 2018-130007. Further, a drive mode in which one or more microcomputers 401 and 402 output torque for one system in the cooperative drive mode for the own system is defined as an "independent drive mode".

As shown in FIG. 9A, in the independent drive mode, each system outputs a half assist torque with respect to the total assist torque of the two systems in the cooperative drive mode. That is, the total value of the assist torques of the two systems in the independent drive mode is equal to the assist torque in the cooperative drive mode. Similarly, in the case of three or more N systems, each system outputs an assist torque of 1 / N during cooperative drive during independent drive.

The one-system drive mode is a drive mode in which the motor is driven by only the other one system on the premise that one of the two systems is stopped. As shown in FIG. 9B, in the one-system drive mode, the assist torque corresponding to the total of the two systems during cooperative drive is output in the region _{where the steering torque is equal to or less than the limit value trq LIM.} Further, in the _{region where the steering torque exceeds the limit value trq LIM} , the upper limit value of the assist torque during single system drive is set to half or less of the upper limit value of the assist torque during cooperative drive.

Returning to FIG. 8, next, the state transition when the IGOFF determination is made in each status will be described. In the present embodiment, attention is paid to an event in which the operating power supply of the microcomputers 401 and 402 is unintentionally cut off or the voltage drops below the threshold value due to a momentary interruption of the IG switches 171 and 172 that are turned on at the time of startup. .. When such an event occurs, the microcomputer of the system makes an "IGOFF determination". When the microcomputer of the other system determines IGOFF, the microcomputer of the own system cannot normally acquire the signal from the other system. However, since the IGOFF event is temporary and often recovers over time, it is recognized on the premise that there is a possibility of recovery, distinguishing it from the permanent abnormality determination.

Therefore, from any of the states of "before starting drive", "waiting for start of drive", and "during drive", when the IGOFF determination is made, the transition to "stop drive A" occurs. After that, when the IGOFF determination is canceled, the status returns to "Before driving start" or "Waiting for driving start" as shown by the broken line. Here, "driving stop" is not limited to the case where the driving is actually stopped from "during driving", but also the case where "processing for starting driving" is stopped from "before starting driving" or "waiting for starting driving". Including.

Further, "drive stop A" means a state of "no half request" in "drive stop". The half request means that a transition to the single system drive (half assist) mode is requested assuming that there is no possibility of dual system drive anymore. The "no half request" means that the transition to the one-system drive mode is not required at this stage because there is a possibility of return.

On the other hand, if it is determined that there is an abnormality that interferes with the motor drive in that system from any of the states of "before starting drive", "waiting for start of drive", and "during drive", "half request is required". Transition to "Drive stop B". In "drive stop B", the stop of motor drive by the system determined to be abnormal is confirmed.

Subsequently, with reference to FIGS. 10 to 13, an example of the start-up process according to the present embodiment will be described. In the description of the flowchart of FIG. 10, the symbol “S” represents a step. In the time charts of FIGS. 11 and 12, the first system is referred to as "own system" and the second system is referred to as "other system" to show changes in IG voltage, PIG voltage, and status at startup. FIG. 11 shows the operation of S10 in the case of NO in S08 via S01 to S07 in FIG. FIG. 12 also shows the operation of S09 in the case of YES in S08 via S01 to S07.

In FIG. 11, when not activated, the IG switches 171 and 172 are in the off state, and the status is "none". When the IG switches 171 and 172 are turned on, the IG voltage rises from Lo to Hi at time t1, and the PIG voltage rises from Lo to Hi at time t3 later. At time t2 in the meantime, the status changes to "before the start of driving" and the initial check is performed.

The IG voltage drops to the Lo level at time t4 during the initial check. As a result, the second microcomputer 402 makes an IGOFF determination, and the status changes from "before the start of driving" to "stop driving A (no half request)". On the other hand, the initial check of the first microcomputer 401 is completed at time t5, and the status changes from "before the start of driving" to "waiting for the start of driving". The processing after this time t5 is shown in the flowchart of FIG.

In S01 of FIG. 10, the own system is in the drive start waiting state. In S02, it is determined whether the communication between the microcomputers is normal. If NO in S02 due to a communication error, the process ends. Therefore, the determination of S05 by the control state determination units 441 and 442 is stopped. In S03, it is determined whether the other system is in the drive start waiting state or is being driven, that is, whether the transition condition (a) or (c) from the “drive start wait” in FIG. 8 is satisfied. If YES in S03, cooperative drive is started in S09.

If NO in S03, it is determined in S04 whether the other system is in the drive stop state, that is, whether the transition condition (b) from the “waiting for drive start” in FIG. 8 is satisfied. As in the example of FIG. 11, when NO in S03 and YES in S04, the control state determination unit 441 determines in S05 that "the state difference condition is satisfied", and the first microcomputer 401 stores the determination history in S06. .. Although it is not basically assumed, if NO in S04, the process ends. Following S06, in S07, the first microcomputer 401 starts driving only its own system. At this time, the drive is preferably started in the independent drive mode. The reason will be described later. In FIG. 11, at time t6, the status of the first microcomputer changes from “waiting for start of driving” to “during driving-independent driving”.

After that, it is determined in S08 whether the other system is restored, that is, whether the operating power supply of the second microcomputer 402 in the second system of "drive stop A (no half request)" is restored and the IGOFF determination is canceled. If NO in S08 as in the example of FIG. 11, the own system continues to drive independently in S10. For example, if the other system does not return even after the return waiting upper limit time has elapsed, the own system may shift to the one-system drive mode in S10. In addition, a return from "drive stop B (with half request)" is not assumed.

The time chart of FIG. 12 is the same as that of FIG. 11 until time t6, but the IG voltage of the second system returns from Lo to Hi at time t7. Then, the status of the second system is from "drive stop A (no half request)" to "before drive start" at time t7, "waiting for drive start" at time t8, and "driving-independent drive" at time t9. Transition.

In this way, if YES in S08 of FIG. 10, the own system and the other system transition to the cooperative drive mode in S09. In FIG. 12, at time t10, both the first system and the second system transition from “driving-independent drive” to “driving-cooperative drive”. Therefore, the assist by the motor drive in two systems is realized without leaving the influence of the IGOFF determination at the time of starting.

Here, with reference to FIG. 13, the reason why the independent drive mode is used when the drive is started only by the own system at S07 in FIG. 10 and the time t6 in FIGS. 11 and 12 will be described. When the second system returns from the state in which the first system is driven in the independent drive mode as shown in FIG. 13A, the output characteristics of the second system are equivalent to the output characteristics of the first system. The total assist torque of the two systems is equal to the assist torque of the cooperative drive mode. Therefore, an appropriate assist torque is output before and after switching the drive mode.

As a comparison, when the second system recovers from the state in which the first system is driven in the one-system drive mode as shown in FIG. 13B, the total assist torque of the two systems is higher than the assist torque of the cooperative drive mode. Is also large, resulting in excessive output. Therefore, over-assist by the steering assist motor may occur, and the steering feeling of the driver may be deteriorated.

[Action and effect of this embodiment]
(1) In the present embodiment, the microcomputers 401 and 402 of each system have control state determination units 441 and 442 that determine a combination of control states of the own system and another system by mutual communication. When the own system is in the drive start waiting state and the other system is in the drive stop state, the control state determination unit determines that "the state difference condition has been satisfied". When the control state determination unit determines that the "state difference condition has been satisfied", the microcomputer stores the determination history in the storage medium. As a result, the cause of the event in which the motor drive cannot be started can be identified, and the event analysis becomes possible.

(2) When it is determined by the control state determination unit that "the state difference condition is satisfied", the system in the drive start waiting state starts driving only by its own system. As a result, the assist can be started only by the own system.

(3) When it is determined by the control state determination unit that "the state difference condition is satisfied", the system in the drive start waiting state starts driving in the independent drive mode. Then, when the microcomputer operating power supply of the system in the drive stop state is restored, both the system that started driving in the independent drive mode and the system that has returned from the drive stop state transition to the cooperative drive mode. The "drive stop" here means "drive stop A (no half request)". This prevents the total output of the two systems after restoration from becoming excessive with respect to the total output during cooperative driving.

(4) When the communication between the microcomputers is abnormal, the control state determination unit stops the success / failure determination of the state difference condition. This prevents erroneous determination.

(Other embodiments)
(A) When it is determined in S05 of FIG. 10 that "the state difference condition is satisfied", the microcomputer of the own system may perform at least S06 of storing the determination history in the storage medium, and the drive is started only by the own system. It is not necessary to carry out S07. That is, the minimum requirement is to be able to analyze the cause of an event that does not lead to the start of driving at startup, and the assist itself does not necessarily have to be realized.

(B) The initial check is not limited to performing a specific check process for switching elements, relays, sensors, etc., as long as it includes some stage for transitioning from the state before the start of driving to the state waiting for the start of driving. Good. For example, the integrity verification (secure boot) of the program as shown in Japanese Patent Application Laid-Open No. 2015-55898 may be used.

(C) As shown in FIG. 14, the motor control device of the present invention has a reaction force motor 80R or rolling in a steer-by-wire system (“SBW” in the figure) 904 in which the steering mechanism and the steering mechanism are mechanically separated. It may be applied as ECUs 10R and 10T for driving the steering motor 80T. The reaction force motor 80R is connected to the handle 91 via the steering shaft 92. In the steer-by-wire system 904, the driver cannot directly sense the reaction force against steering, so the reaction force motor 80R rotates the steering wheel 91 so as to apply the reaction force to steering, and gives the driver an appropriate steering feeling. give. The rotation of the steering motor 80T is converted into a linear motion of the rack shaft 97 to steer the wheels 99.

The reaction force motor 80R and the steering motor 80T are composed of a mechatronics integrated type and a mechatronics separate type as in the EPS motor 80 of the above embodiment. The ECUs 10R and 10T each have a plurality of systems of microcomputers capable of communicating with each other. Further, information is transmitted and received between the reaction force motor ECU 10R and the steering motor ECU 10T by communication between the microcomputers. The control state determination unit of the present invention may be used for either one of the reaction force motor ECU 10R or the steering motor ECU 10T, or may be provided on both of them.

(D) Further, the motor control device of the present invention is not limited to the electric power steering system and the steer-by-wire system, and may be applied to a motor for any other purpose.

(E) The present invention is not limited to the configuration of the two systems exemplified in the above embodiment, and is similarly applicable to the configuration of three or more systems. For example, it is assumed that there are three systems, the first system, the second system, and the third system, including the first, second, and third microcomputers, respectively. In this configuration, for example, when the first and second microcomputers are in the drive start waiting state and the third microcomputer is in the drive stop state, it is determined that the state difference condition is satisfied, and the determination history is stored. Then, both the first and second systems start driving in the independent drive mode. In this case, the independent drive mode is interpreted to include two cooperative drive modes.

(F) The configuration of the power supply is not limited to the configuration redundantly provided for each system, and as shown in FIG. 15 of Patent Document 2, a common power supply may be provided for the two systems. In that case, an IG switch of each system is provided in the middle of the power supply lines IG1 and IG2 which are branched from the common power source and connected to each system.

(G) When mounted on a hybrid vehicle or an electric vehicle other than an engine vehicle, the IG switch of the above embodiment is interpreted as being extended to a "vehicle switch" including a ready switch and the like. Furthermore, in general systems other than vehicles, the IG switch is interpreted as being extended to a "system switch" that switches between the on state and the off state of the system. Regarding the off determination of a vehicle switch or system switch other than the IG switch, the "IGOFF determination" of the above embodiment can be generally read and interpreted as "off determination".

(H) The motor 80 to be controlled according to the above embodiment is a multi-winding motor in which two sets of winding sets 801 and 802 are arranged on a common stator with an electric angle of 30 [deg]. The motor to be controlled in other embodiments may have two or more winding sets arranged in the same phase. Power may be supplied to one winding set from a plurality of power supply devices. Further, the configuration is not limited to a configuration in which two or more winding sets are arranged on a common stator of one motor, for example, a plurality of winding sets in which torque is output in cooperation with a plurality of stators wound separately. It may be applied to the motor of. Further, the number of phases of the multi-phase brushless motor is not limited to three phases, and may be four or more phases. Further, the motor to be driven is not limited to the AC brushless motor, and may be a DC motor with a brush. In that case, an H-bridge circuit may be used as the "power converter".

As described above, the present invention is not limited to such embodiments, and can be implemented in various embodiments without departing from the spirit of the present invention.

The controls and methods thereof described in the present disclosure are realized by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. May be done. Alternatively, the controls and methods thereof described in the present disclosure may be implemented by a dedicated computer provided by configuring the processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and method thereof described in the present disclosure may be a combination of a processor and memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. It may be realized by one or more dedicated computers configured. Further, the computer program may be stored in a computer-readable non-transitional tangible recording medium as an instruction executed by the computer.

10 ... ECU (motor control device),
401 ... 1st microcomputer (control unit), 402 ... 2nd microcomputer (control unit),
441, 442 ... Control state determination unit,
461, 462 ... Storage medium,
601, 602 ... Inverter (power converter),
80 ・ ・ ・ Motor, 801, 802 ・ ・ ・ Winding set.

Claims (6)

A motor control device that controls the drive of a motor (80) having one or more winding sets (801, 802).
A plurality of power converters (601, 602) that supply power to the corresponding winding set, and
A plurality of control units (401, 402) that can communicate with each other and calculate a drive signal that commands the corresponding power converter, and
With
A system is defined as a unit of a group of components including the winding set, the converter, and the control unit provided so as to correspond to each other.
About the transition of the control state of each system at the time of startup
The control state in which it is determined that the motor can be started is set as the drive start waiting state.
When the control state in which the process for starting the drive is stopped due to the determination that the operating power supply of the control unit is cut off or the voltage is lowered is set as the drive stop state,
The control unit of each system has a control state determination unit (441, 442) that determines a combination of the control states of the own system and another system by mutual communication.
When the own system is in the drive start waiting state and the other system is in the drive stop state, the control state determination unit determines that the state difference condition is satisfied, and determines that the state difference condition is satisfied.
The control unit is a motor control device that stores the determination history in a storage medium (461, 462). When the control state determination unit determines that the state difference condition is satisfied,
The motor control device according to claim 1, wherein the system in the drive start waiting state starts driving only by its own system. A drive mode in which a plurality of the control units share a command value and a plurality of systems output the same torque is defined as a cooperative drive mode.
When the drive mode in which one or more control units output the torque for one system in the cooperative drive mode for the own system is defined as the independent drive mode.
When the control state determination unit determines that the state difference condition is satisfied,
The motor control device according to claim 2, wherein the system in the drive start waiting state starts driving in the independent drive mode. After the system in the drive start waiting state starts driving in the independent drive mode,
When the operating power supply of the control unit of the system in the drive stop state is restored.
The motor control device according to claim 3, wherein both the system that started driving in the independent drive mode and the system that returned from the drive stop state both transition to the cooperative drive mode. The motor control device according to any one of claims 1 to 4, wherein when the communication between the control units is abnormal, the control state determination unit cancels the success / failure determination of the state difference condition. The motor control device according to any one of claims 1 to 5, which is used to drive a steering assist motor of an electric power steering system, or a reaction force motor or a steering motor of a steer-by-wire system.

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