JP6436012B2 - Electric motor control device for vehicle - Google Patents

Description

  The present invention relates to an electric motor control device for a vehicle.

  2. Description of the Related Art Conventionally, an electric motor driving device for electric power steering in which an open relay is provided between a driving circuit (an inverter or the like) for driving the electric motor and the electric motor is known (for example, Patent Document 1). In Patent Document 1, for example, when it is impossible to stop energizing the electric motor due to an abnormality in the drive circuit, the energization to the electric motor is stopped by opening a mechanical open relay. (Fail-safe function).

JP 2014-201199 A

  However, since the mechanical open relay is normally closed, it is fixed ON (the contact of the open relay is fixed / welded and remains ON even if a command to turn OFF is issued). there is a possibility. Further, the ON sticking may be eliminated by vibration caused by normal traveling of the vehicle. Therefore, in order to analyze in which vibration state the ON sticking is maintained and resolved, the electric motor performs normal operation during normal driving of the vehicle and determines whether the ON relay is stuck in the ON state. It is desirable to record data relating to the vibration state of the vehicle at the time of fixing.

  Therefore, in view of the above problems, during normal driving of the vehicle, while performing normal operation of the electric motor, it is determined whether or not the open relay that can cut off the energization from the drive circuit to the electric motor is determined. An object of the present invention is to provide a vehicle electric motor control device capable of recording data relating to the vibration state of the vehicle.

In order to achieve the above object, in one embodiment, a vehicle electric motor control device includes:
An electric motor mounted on a vehicle and including two windings;
A drive circuit for energizing one of the two windings;
A mechanical relay capable of interrupting energization between the winding of the one system and the drive circuit;
A sensor for detecting a vibration state of the vehicle;
A storage unit;
A drive control unit for controlling the operation of the drive circuit;
A relay control unit for controlling the open / close state of the relay;
A recording processing unit that records the vibration state in the storage unit,
The drive control unit controls the drive circuit so that a predetermined current smaller than a predetermined value flows in the winding of the one system through the relay in a state where the relay control unit outputs an open command to the relay. Control
The recording processing unit energizes the windings of the one system through the relay in response to the drive control unit controlling the driving circuit so that the predetermined current flows through the windings of the one system. If there is, the vibration state is recorded in the storage unit.

  According to the present embodiment, during normal driving of the vehicle, while the normal operation of the electric motor is performed, it is determined whether or not the open relay that can cut off the energization from the drive circuit to the electric motor is ON, and at the time of ON fixing It is possible to provide a vehicle electric motor control device capable of recording data relating to the vibration state of the vehicle.

It is a figure showing roughly an example of composition of a steering device for vehicles containing an electric power steering device. It is a figure explaining an example of the basic control mode of an electric power steering device. It is a figure which shows an example of a structure of the electric power supply system in an electric power steering apparatus. It is a figure which shows an example of a structure of an assist motor with the connection aspect between a 1st inverter, a 2nd inverter, and an assist motor. It is a figure explaining the method of determining the presence or absence of ON adhesion. It is a figure showing an example of the aspect of the electric current which flows into an assist motor when it determines with ON fixation having generate | occur | produced. It is a timing chart which shows an example of operation of an electric power steering device at the time of judging the existence of ON adhesion.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically illustrating an example of a configuration of a vehicle steering device 10 including an electric power steering device 20 (an example of a vehicle electric motor control device) according to the present embodiment. The vehicle steering apparatus 10 includes a steering column 12 including a steering wheel 11 operated by a driver. The steering column 12 rotatably supports a steering shaft 14 that serves as a rotating shaft of the steering wheel 11. The steering shaft 14 is connected to an intermediate shaft (intermediate shaft) 16 via a rubber coupling 13 or the like. The intermediate shaft 16 is connected to a pinion shaft (output shaft), and a pinion 17 of the pinion shaft is engaged with a steering rack (rack bar) 18 in the steering gear box 31. One end of a tie rod 19 is connected to each end of the steering rack 18 and a steered wheel (not shown) is connected to the other end of each tie rod 19 via a knuckle arm or the like (not shown). The intermediate shaft 16 or the steering shaft 14 has a steering angle sensor 26 that generates a signal corresponding to the steering angle of the steering wheel 11 and a torque sensor 15 that generates a signal corresponding to the steering torque applied to the steering shaft 14. Is provided.

  The torque sensor 15 is provided on each of the intermediate shaft 16 (input shaft) and the pinion shaft (output shaft) coupled by, for example, a torsion bar, and a total of 2 that detects torque based on the rotation angle difference between these shafts. It may be composed of a single resolver sensor. The configuration of the vehicle steering device 10 shown in FIG. 1 is merely an example, and the configuration of the vehicle steering device 10 may be arbitrary as long as the electric power steering device 20 is provided.

  The electric power steering apparatus 20 includes a steering assist actuator 22 (hereinafter referred to as an assist motor 22). The assist motor 22 may be composed of, for example, a three-phase brushless motor. The assist motor 22 may be provided in the steering gear box 31 coaxially with the steering rack 18. For example, the assist motor 22 may be engaged with the steering rack 18 via a ball screw nut. The assist motor 22 assists the movement of the steering rack 18 by its driving force. That is, when the assist motor 22 is operated, the ball screw nut is rotated by the rotation of the rotor, and thereby the steering rack 18 is moved (assisted) in the axial direction. The mechanical configuration itself of the electric power steering apparatus 20 may be arbitrary including the place where the assist motor 22 is disposed. For example, the assist motor 22 may be meshed with a steering shaft (such as a pinion shaft) or may transmit an assisting force via a hydraulic device. The assist motor 22 of the electric power steering apparatus 20 is controlled by an ECU (Electrical Control Unit) 80 (see FIGS. 2 to 4) described later. The control mode of the assist motor 22 will be described later.

  FIG. 2 is a diagram for explaining an example of a basic control mode of the electric power steering apparatus 20. The electric power steering apparatus 20 includes an ECU 80 that performs various controls described below. The ECU 80 includes a microcomputer 81 (see FIG. 3) and the like. For example, a CPU, a ROM that stores a control program, a readable / writable RAM that stores calculation results, a timer, a counter, an input interface, and an output interface. Etc.

  The ECU 80 may be realized by a single ECU that controls the steering system, or may be realized in cooperation with two or more ECUs. The ECU 80 receives information or data for realizing various controls described below. For example, the ECU 80 receives various sensor values from the torque sensor 15, the rotation angle sensor 24, the steering angle sensor 26, the vehicle speed sensor 50, the acceleration sensor 60 (an example of a sensor that detects the vibration state of the vehicle), etc. at predetermined intervals. May be entered. Further, the ECU 80 incorporates or is connected to current sensors 85 and 86 (see FIG. 3) that detect currents flowing through the UV, VW, and WU energization paths described later. In addition, the assist motor 22 is connected to the ECU 80 as a control target.

  The acceleration sensor 60 detects acceleration in the vibration direction (vertical direction) of the vehicle.

  The ECU 80 determines a target value related to assist torque (assist force) to be generated by the assist motor 22 based on output signals from the torque sensor 15 and the rotation angle sensor 24. The target value related to the assist torque may be any physical quantity including current, voltage, and the like, and may be an assist motor current value (motor drive duty) applied to the assist motor 22, for example. Further, the target value related to the assist torque may be determined in an arbitrary manner. For example, the target value related to the assist torque may be determined such that the assist torque increases as the steering torque increases by the driver, and may be determined such that the assist torque becomes smaller when the vehicle speed is large than when the vehicle speed is small. The assist motor current value applied to the assist motor 22 may be feedback controlled based on an output signal of the rotation angle sensor 24 that detects the rotation angle of the assist motor 22 (rotor).

  FIG. 3 is a diagram illustrating an example of the configuration of the power supply system according to the electric power steering apparatus 20.

  The ECU 80 includes a first inverter 71, a second inverter 72, a first switch 73, a second switch 74, an open relay 71u, 71v, 71w, 72u, 72v, 72w, a microcomputer 81, a first predriver IC 82, and a second predriver. IC 83, power supply circuit 84 and the like are included.

  As shown in FIG. 3, a first inverter 71 and a second inverter 72 are connected in parallel to the assist motor 22. Each of the first inverter 71 and the second inverter 72 is an example of a drive circuit for driving one of two windings (see FIG. 4) included in the assist motor 22. The first inverter 71 and the second inverter 72 are each connected to a power supply voltage (+ B).

  The power supply voltage may be an in-vehicle battery or an alternator.

  The first inverter 71 includes a three-phase bridge circuit composed of six switching elements S1 to S6. The switching elements S1 to S6 may be arbitrary switching elements such as transistors. The direct current applied to the first inverter 71 is converted into three-phase AC power by a three-phase bridge circuit. Switching elements S <b> 1 to S <b> 6 of the first inverter 71 are controlled by a microcomputer 81 (a drive control unit 811 described later) and a first pre-driver IC 82.

  Similarly, the second inverter 72 includes a three-phase bridge circuit composed of six switching elements S7 to S12. The switching elements S7 to S12 may be arbitrary switching elements such as transistors. The direct current applied to the second inverter 72 is converted into three-phase AC power by a three-phase bridge circuit. The switching elements S7 to S12 of the second inverter 72 are controlled by the microcomputer 81 (drive control unit 811) and the second pre-driver IC 83.

  Here, FIG. 4 is a diagram illustrating an example of the configuration of the assist motor 22 together with a connection mode between the first inverter 71 and the second inverter 72 and the assist motor 22.

  In FIG. 4, the pair of terminals U1 are electrically connected to each other, the pair of terminals V1 are electrically connected to each other, and the pair of terminals W1 are electrically connected to each other. . Similarly, in FIG. 4, the pair of terminals U2 are electrically connected to each other, the pair of terminals V2 are electrically connected to each other, and the pair of terminals W2 are electrically connected to each other. Yes.

  As shown in FIG. 4, the assist motor 22 has two windings (double winding configuration). Specifically, the assist motor 22 includes a first system winding and a second system winding that are independent of each other. For example, the first system winding and the second system winding are respectively wound around the stator of the assist motor 22.

  Note that the winding method is arbitrary, and for example, a winding method such as concentrated winding, distributed winding, or lap winding may be employed.

  The winding of the first system includes a U-phase coil U-V-1, a V-phase coil V-W-1, and a W-phase coil W-U-1 that are energized via the first inverter 71. The winding of the second system includes a U-phase coil U-V-2 that is energized via the second inverter 72, a V-phase coil V-W-2, and a W-phase coil W-U-2.

  In the example shown in FIG. 4, the first system winding and the second system winding are each configured by star connection, but may be other configurations such as delta connection. U-phase coil U-V-1, V-phase coil V-W-1, W-phase coil W-U-1, U-phase coil U-V-2, V-phase coil V-W-2, W The phase coils W-U-2 may all be formed from coils having the same characteristics (for example, inductance). In the following, U-phase coil U-V-1, V-phase coil V-W-1, W-phase coil W-U-1, U-phase coil U-V-2, V-phase coil V-W-2, The description will be continued on the assumption that the W-phase coil W-U-2 is a coil having the same characteristics.

  According to the configuration shown in FIG. 4, since the first inverter 71 and the second inverter 72 are connected in parallel to the assist motor 22, only one of the first inverter 71 and the second inverter 72 is operated. Thus, the assist motor 22 can be operated. Moreover, according to the structure shown in FIG. 4, both the 1st inverter 71 and the 2nd inverter 72 can also operate | move simultaneously.

  The first inverter 71 and the second inverter 72 preferably have the same rating, and have the ability to independently generate the maximum value of assist torque (the maximum value intended by design). That is, both the first inverter 71 and the second inverter 72 can generate the maximum value of the assist torque when operating alone. The maximum value of the assist torque corresponds to the maximum value that can be taken by the target value related to the assist torque. Hereinafter, the description will be continued on the assumption that the first inverter 71 and the second inverter 72 have the same rating and have the ability to generate the maximum assist torque alone.

  Returning to FIG. 3, the first switch 73 is provided between the first inverter 71 and the power supply voltage. As shown in FIG. 3, the first switch 73 may be a relay-type switch (mechanical switch), or may be a semiconductor switching element such as a transistor.

  The second switch 74 is provided between the second inverter 72 and the power supply voltage. As shown in FIG. 3, the second switch 74 may be a relay-type switch (mechanical switch), or may be a semiconductor switching element such as a transistor.

  The first switch 73 and the second switch 74 are connected to the power supply voltage in parallel corresponding to the first inverter 71 and the second inverter 72.

  The open / close state of the first switch 73 and the second switch 74 is controlled by the microcomputer 81. Further, the first switch 73 and the second switch 74 may be omitted. Further, a DC-DC converter 90 may be connected as an arbitrary configuration between the first inverter 71 and the second inverter 72 and the power supply voltage. The DC-DC converter 90 boosts the power supply voltage and outputs it to the first inverter 71 and the second inverter 72. The configuration of the DC-DC converter 90 may be arbitrary, for example, a synchronous rectification type non-insulated DC / DC converter.

  The open relays 71u, 71v, 71w are mechanical relays provided between the first inverter 71 and the assist motor 22 and capable of interrupting energization from the first inverter 71 to the assist motor 22. The open relays 71u, 71v, 71w are output from the microcomputer 81 (a relay control unit 812, which will be described later) when the energization stop to the assist motor 22 becomes impossible due to failure of the switching elements S1 to S6. Opened in response to an open command.

  The open relays 72u, 72v, and 72w are mechanical relays that are provided between the second inverter 72 and the assist motor 22 and can cut off the energization from the second inverter 72 to the assist motor 22. The open relays 72u, 72v, 72w are open commands output from the microcomputer 81 (relay control unit 812) when the energization of the assist motor 22 cannot be stopped due to a failure of the switching elements S7 to S12. It is released according to

  The microcomputer 81 is a main control unit in the ECU 80, and various control processes can be realized by executing various programs on the CPU. The microcomputer 81 includes a drive control unit 811, a relay control unit 812, an abnormality determination unit 813, a recording processing unit 814, and a storage unit 815.

  Note that the drive control unit 811, the relay control unit 812, the abnormality determination unit 813, and the recording processing unit 814 are realized by executing one or more corresponding programs on the CPU. In addition, the storage unit 815 is realized by a storage area defined in advance in a nonvolatile memory or the like built in the microcomputer 81.

  The drive control unit 811 performs drive control of the first inverter 71 and the second inverter 72. Specifically, the drive control unit 811 determines a target value related to the assist torque as described above, and outputs a drive command to the first pre-driver IC 82 and the second pre-driver IC 83.

  When the assist motor 22 is operated only by the first inverter 71, when the drive control unit 811 determines the target value related to the assist torque to be generated by the assist motor 22 as described above, the drive control unit 811 turns on the first switch 73 and the second switch. 74 is turned off, and a switching pattern corresponding to the target value is applied to the switching elements S1 to S6 via the first pre-driver IC 82. When such a switching pattern is applied to the switching elements S1 to S6, the switching elements S1 to S6 are turned on / off according to the switching pattern, and the energized states of UV, VW, and WU are sequentially switched.

  When the assist motor 22 is operated only by the second inverter 72, when the drive control unit 811 determines the target value related to the assist torque to be generated by the assist motor 22 as described above, the drive control unit 811 turns off the first switch 73 and The switch 74 is turned on, and a switching pattern corresponding to the target value is applied to the switching elements S7 to S12 via the second pre-driver IC 83. When such a switching pattern is applied to the switching elements S7 to S12, the switching elements S7 to S12 are turned on / off according to the switching pattern, and the energized states of UV, VW, and WU are sequentially switched.

  In addition, when the assist motor 22 is operated by both the first inverter 71 and the second inverter, the drive control unit 811 turns on the first switch 73 and turns on the second switch 74 and sets a target value related to the assist torque. The distribution target value obtained by distributing the target value at a predetermined ratio is supplied to the first pre-driver IC 82 and the second pre-driver IC 83. For example, when the first inverter 71 and the second inverter 72 are operated at a ratio of 1: 9, a switching pattern corresponding to 10% of the target value is applied to the switching elements S1 to S6 and corresponds to 90% of the target value. The switching pattern to be applied is applied to the switching elements S7 to S12. At this time, the current flowing through the U-V energization path, the V-W energization path, and the W-U energization path according to the first inverter 71, and the U-V energization path, the V-W energization path, and W according to the second inverter 72. Although the currents flowing through the -U energization path flow independently of each other, they cooperate to form a rotating magnetic field. Thereby, energization is performed so that 100% of the target value is realized as a whole.

  In addition, the drive control unit 811 performs an abnormality determination process (a process for determining whether any of the open relays 71u, 71v, 71w, 72u, 72v, 72w is fixed ON), which will be described later, by the abnormality determination unit 813. In this case, a switching pattern for energizing any one of the open relays 71u, 71v, 71w, 72u, 72v, 72w that is an abnormality determination target is determined, and a drive command is output to the first pre-driver IC 82 or the second pre-driver IC 83. .

  Further, when the drive control unit 811 determines that the abnormality determination unit 813 has the ON sticking in any of the open relays 71u, 71v, 71w, 72u, 72v, 72w, the direction opposite to the energization in the abnormality determination process The first inverter 71 or the second inverter 72 is drive-controlled so that the energization is performed (hereinafter referred to as first drive control). Specifically, a switching pattern corresponding to the first drive control is determined, and a drive command (hereinafter referred to as a first drive command) is output to the first pre-driver IC 82 or the second pre-driver IC 83. Details of the first drive control will be described later.

  Further, when the drive control unit 811 determines that the abnormality determination unit 813 has ON sticking occurring in any of the open relays 71u, 71v, 71w, 72u, 72v, and 72w, after executing the first drive control, The first inverter 71 or the first inverter 71 so that a minute current (a predetermined current smaller than a predetermined value) flows to the assist motor 22 through the open relays 71u, 71v, 71w, 72u, 72v, 72w determined to be fixed ON. The second inverter 72 is drive-controlled (hereinafter referred to as second drive control). Specifically, a switching pattern corresponding to the second drive control is determined, and a drive command (hereinafter referred to as a second drive command) is output to the first pre-driver IC 82 or the second pre-driver IC 83. Details of the second drive control will be described later.

  Note that the minute current (predetermined current smaller than a predetermined value) means that the assist motor 22 operates normally in either the first system winding or the second system winding (for assisting the steering operation). When the operation is performed, the current is such that even if the other winding is energized, the normal operation is not affected. In addition, the minute current is larger than the noise level in the current sensors 85 (85u, 85v, 85w) and 86 (86u, 86v, 86w) (the current sensors 85u, 85v, 85w, 86u, 86v, 86w are energized even in the noise). Current that can be determined).

  The relay control unit 812 controls the open / closed states of the open relays 71u, 71v, 71w, 72u, 72v, 72w. The open relays 71u, 71v, 71w, 72u, 72v, 72w are normally closed mechanical relays, and the relay controller 812 opens any of the open relays 71u, 71v, 71w, 72u, 72v, 72w ( In the case of OFF), an open command (OFF command) is output to any one of the target open relays 71u, 71v, 71w, 72u, 72v, 72w. Further, the relay control unit 812 outputs a closing command (ON command) to any of the opening relays 71u, 71v, 71w, 72u, 72v, 72w opened by the opening command, thereby opening the target opening. Any of the relays 71u, 71v, 71w, 72u, 72v, 72w can be returned to the closed state. As described above, when the energization stop from the first inverter 71 or the second inverter 72 to the assist motor 22 becomes impossible, the relay control unit 812 opens the relays 71u, 71v, 71w, or the open relays 72u, 72v, An open command is output at 72w. In addition, when the abnormality determination unit 813 executes an abnormality determination process described later, the relay control unit 812 issues an opening command to any of the open relays 71u, 71v, 71w, 72u, 72v, and 72w that are the targets of the abnormality determination process. Is output. In addition, when the drive control unit 811 performs the second drive control described above, the relay control unit 812 is one of the open relays 71u, 71v, 71w, 72u, 72v, and 72w that are energized by the second drive control. The release command is output to.

  In the abnormality determination unit 813, the release relays 71u, 71v, 71w, 72u, 72v, and 72w are fixed to ON at a predetermined timing from the ignition on (IG-ON) to the ignition off (IG-OFF) of the vehicle. A process (abnormality determination process) for determining whether or not it is performed is executed. Since the open relays 71u, 71v, 71w, 72u, 72v, 72w are normally closed (normally closed), there is a possibility that ON sticking may occur due to some factor. If ON sticking occurs, it becomes impossible to open the open relays 71u, 71v, 71w, 72u, 72v, 72w when an abnormality occurs in either the first inverter 71 or the second inverter 72. Therefore, the abnormality determination unit 813 executes such abnormality determination processing.

  Here, FIG. 5 is a diagram for explaining a method for determining whether or not the open relays 71u, 71v, 71w, 72u, 72v, 72w are fixed ON.

  As shown in FIG. 5, when the abnormality determination unit 813 determines whether or not the open relays 71u, 71v, and 71w are stuck ON, the relay control unit 812 includes the open relays 71u, An open command is output to either 71v or 71w, and the drive control unit 811 drives the first inverter 71 via the first pre-driver IC 82 so that the windings of the first system are energized through the open relay. Control. Further, when the abnormality determination unit 813 determines whether or not the open relays 72u, 72v, and 72w are fixed to ON, the relay control unit 812 determines whether any of the open relays 72u, 72v, and 72w that are abnormality determination targets. While outputting an opening command, the drive control unit 811 drives and controls the second inverter 72 via the second pre-driver IC 83 so that the windings of the second system are energized through the opening relay. The abnormality determination unit 813 detects energization by current sensors 85 (85u, 85v, 85w) and 86 (86u, 86v, 86w) that detect currents flowing through the U-V, V-W, and W-U energization paths. If not, it can be determined that the ON relay has not been generated because it can be determined that the open relay that is the object of abnormality determination is open according to the open command. On the other hand, the abnormality determination unit 813, when energization is detected by the current sensors 85 (85u, 85v, 85w), 86 (86u, 86v, 86w), the open relay is not normally opened according to the open command. Since it can be determined that it remains in the ON state, it is determined that ON sticking has occurred.

  When it is determined that there is ON sticking, the ECU 80 (microcomputer 81) may output warning information indicating that ON sticking has occurred in the in-vehicle LAN to which the ECU 80 is connected. As a result, for example, the meter ECU connected to the vehicle-mounted LAN can receive warning information and display a warning that ON sticking has occurred in the meter, so the driver can bring the vehicle to a dealer or the like for repair. I can have you.

  Returning to FIG. 3, the recording processing unit 814 receives an input from the acceleration sensor 60 when it is determined by the abnormality determination unit 813 that any one of the open relays 71u, 71v, 71w, 72u, 72v, 72w is fixed ON. A process of recording acceleration data in the storage unit 815 (vibration state recording process) is started. Then, the recording processing unit 814 energizes the assist motor 22 through one of the open relays 71u, 71v, 71w, 72u, 72v, 72w determined to be fixed ON (the first of the drive control unit 811 described above). The acceleration data input from the acceleration sensor 60 is recorded in the storage unit 815 until there is no more power supply due to the two-drive control. The recording processing unit 814 updates and records the value of the maximum acceleration G1 in the storage unit 815 when the detected acceleration value input from the acceleration sensor 60 is the maximum value from the start of recording. The recording processing unit 814 records the detected acceleration value input from the acceleration sensor 60 as the final acceleration G2 when the energization by the second drive control of the drive control unit 811 is stopped.

  Note that the recording processing unit 814 may record all of the acceleration data input from the acceleration sensor 60 as time-series data during the vibration state recording process, for example, when the storage unit 815 has sufficient capacity. Further, data (data of maximum acceleration G1 and final acceleration G2) recorded in the storage unit 815 by each vibration state recording process is, for example, from a failure diagnosis tool connected to the in-vehicle LAN from the outside via a DLC3 connector or the like. By sending a command to the ECU 80, it can be taken out. In addition, even if a predetermined time T elapses, energization (drive control) to the assist motor 22 through any of the open relays 71u, 71v, 71w, 72u, 72v, 72w determined to be fixed ON. If the energization by the second drive control of the part 811 does not disappear, the vibration state recording process is terminated (the data on the final acceleration G2 is not recorded on the assumption that the ON relay is not eliminated due to the vibration) .

  The first pre-driver IC 82 applies a switching pattern corresponding to the drive command input from the drive control unit 811 to the switching elements S1 to S6.

  The second pre-driver IC 83 applies a switching pattern corresponding to the drive command input from the drive control unit 811 to the switching elements S7 to S12.

  The power supply circuit 84 generates power (drive voltage lower than the power supply voltage) for driving the microcomputer 81, the first predriver IC 82, and the second predriver IC from the power supply voltage.

  Note that the first pre-driver IC 82 and the second pre-driver IC 83 may be integrated. In the example shown in FIG. 3, the first inverter 71, the second inverter 72, the microcomputer 81, the first predriver IC 82, the second predriver IC 83, and the power supply circuit 84 are constituent elements of the ECU 80. Is not limited. That is, the ECU 80 may include other components, or some components may be provided outside. For example, the first inverter 71 and the second inverter 72 may be provided outside the ECU 80. Further, the ECU 80 may be modularized integrally with the assist motor 22.

  Next, the first drive control method by the drive control unit 811, that is, the normal operation of the assist motor 22 in one of the windings of the first system and the second system (the steering operation by the driver). The outline of the control method for performing ON sticking determination of the open relay provided between the other winding and the drive circuit (one of the first inverter 71 and the second inverter 72) is explained. To do. Thereafter, by operating the first inverter 71, the open motors 72u, 72v, 72v, 72v provided between the second system winding and the second inverter 72 while operating the assist motor 22 with only the first system winding. A case will be described in which it is determined whether or not ON fixation occurs in any of 72w.

  As a matter of course, the first system winding and the second system winding are used to determine whether or not the winding for realizing the normal operation of the assist motor 22 and the open relay is fixed. The windings may be interchanged. In other words, while the normal operation of the assist motor 22 is realized with the second winding, the ON relay is fixed to any one of the open relays 71u, 71v, 71w provided between the first winding and the first inverter 71. It may be determined whether or not it has occurred.

  FIG. 6 is a diagram illustrating an example of a mode of a current flowing in the assist motor when it is determined that ON sticking occurs. Specifically, in the state where current is flowing through the U-phase coil U-V-1 of the first system (solid line arrow in the figure), whether or not ON fixation occurs in any of the open relays 72u and 72w. This indicates a mode of current (broken arrows and dotted arrows in the figure) flowing in the second phase W-phase coil W-U-2 when it is determined that ON sticking has occurred. .

  The determination of whether or not the open relays 72u, 72v, 72w are ON is not only in a state where a current is flowing through the U-phase coil U-V-1 of the first system but also with the V-phase coil V-W-1 or You may perform in the state in which the electric current is flowing into W phase coil W-U-1. Further, when it is determined whether or not any of the open relays 72u, 72v, 72w is stuck ON, the drive control unit 811 causes the current to flow through the U-phase coil U-V-2 of the second system. By outputting a drive command to the second inverter 72 (second pre-driver IC 83), it may be determined whether or not any of the open relays 72u and 72v is fixed. Similarly, the drive control unit 811 outputs a drive command to the second inverter 72 (second pre-driver IC 83) so that a current flows through the V-phase coil V-W-2 of the second system, whereby the open relay 72v, The presence / absence of any ON fixation of 72w may be determined.

  In the example shown in FIG. 6, in the state where current flows from the U phase (U1 phase) to the V phase (V1 phase) of the first system, an opening command is output to either of the opening relays 72u and 72w. It is determined whether or not the relay is stuck on. And since the electric current which goes to a U phase (U2 phase) flows from the W phase (W2 phase) to the W phase coil W-U-2 of the 2nd system as shown by the broken line arrow of FIG. Based on the detection signals of the current sensors 86u and 86v, it is determined that the open relay is stuck on.

  Here, since the assist motor 22 performs a normal operation using the winding of the first system, that is, an operation of assisting the steering operation by the driver, a current as indicated by a broken line arrow flows in the second system. If it does, it will affect the operation | movement by the coil | winding of 1st system | strain. Therefore, when the drive control unit 811 determines that the ON relay is stuck in the open relay, the drive control unit 811 immediately stops the drive command to the second inverter 72 (second pre-driver IC 83) for performing the ON sticking determination. The first drive command for suppressing the influence on the operation by the winding of the first system is output to the second inverter 72 (second pre-driver IC 83). Specifically, the second inverter 72 is controlled so that a current in a direction opposite to the current direction corresponding to the drive command for performing the ON sticking determination flows in the second system winding (first drive control). .

  In the example illustrated in FIG. 6, as indicated by a dotted arrow, in response to the first drive command from the drive control unit 811, it is opposite to the current that has flowed through the second system W-phase coil W-U-2 at the ON fixation determination. Directional current (current from the U2 phase toward the W2 phase) flows.

  Thus, in order to cancel the magnetic field due to the current flowing in the second system winding when determining ON fixation, a current in the opposite direction flows through the second system winding. The influence of the flowing current on the operation of the first system winding can be suppressed. In other words, whether or not the ON relay is fixed to the open relays 72u, 72v, and 72w provided between the second system winding and the second inverter 72 while suppressing the influence on the operation by the first system winding. Can be determined.

  Next, details of the first drive control and the second drive control by the drive control unit 811 and the vibration state recording process by the recording processing unit 814 will be described with reference to FIG.

  FIG. 7 is a timing chart showing an example of the operation of the electric power steering apparatus 20 (ECU 80) when determining whether or not the open relay 72u provided between the winding of the second system and the second inverter 72 is ON. is there. Specifically, the total output (FIG. 7A) of both the first system winding and the second system winding in the assist motor 22 and a drive command to the first inverter 71 (first pre-driver IC 82). (FIG. 7 (b)), a current monitor (FIG. 7 (c)) showing the state of the current flowing through the windings of the first system, and the state of the command (ON command / OFF command) to the open relay 72u (FIG. 7 ( d)), a drive command to the second inverter 72 (second pre-driver IC 83) (FIG. 7 (e)), a current monitor indicating the state of the current flowing in the winding of the second system, (FIG. 7 (f)) , Vehicle vibration (detection value of the acceleration sensor 60), each time change is represented.

  Before the time t1 in the figure, the open relay 72u is in a closed state (ON state) based on a close command (ON command) from the microcomputer 81 (relay control unit 812). Further, at time t5 in the figure (black arrow on the time axis in the figure), the open relay 72u is stuck on.

  As shown in FIGS. 7A and 7B, the assist motor 22 operates from time t1 to time t4 according to the steering operation by the driver. During this time, the assist motor 22 is operated only by the first system winding out of the first system winding and the second system winding. Specifically, the drive control unit 811 causes the current to flow through the U-phase coil U-V-1 from the U1 phase to the V1 phase from time t1 to time t2, and from time t2 to time t3. Further, from time T3 to time t4, the current flows from the W1 phase to the U1 phase to the W phase coil W-U-1 so that the current flows from the V1 phase to the W1 phase. Is output to the first inverter 71 (first pre-driver IC 82).

  On the other hand, as shown in FIGS. 7D, 7 </ b> E, and 7 </ b> F, between time t <b> 1 and time t <b> 2, the abnormality determination unit 813 opens using the second system winding of the assist motor 22. It is determined whether or not the relay 72u is stuck on.

  At time t1, the relay control unit 812 outputs an open command (OFF command) to the open relay 72u. Then, during the period from time t1 to time t2, the drive control unit 811 causes the second inverter 72 (second pre-driver IC 83 to flow the current through the U-phase coil U-V-2 from the U2 phase toward the V2 phase. ) Drive command is output. At this time, no current flows through the U-phase coil U-V-2 through the open relay 72u from time t1 to time t2, so the abnormality determination unit 813 has the ON relay 72u stuck to the open relay 72u. Judge that there is no.

  As shown in FIGS. 7A and 7B, at time t5, after the ON relay is fixed to the open relay 72u, from the time t6 to the time t12, the assist motor according to the steering operation by the driver. 22 is activated. As in the period from time t1 to time t4, the assist motor 22 is operated only by the first system winding among the first system winding and the second system winding. Specifically, the drive control unit 811 causes the current to flow in the U-phase coil U-V-1 from the U1 phase to the V1 phase from time t6 to time t9, and from time t9 to time t10. Further, from time t10 to time t12, a current flows from the W1 phase to the U1 phase to the W phase coil W-U-1 so that a current flows from the V1 phase to the W1 phase. Is output to the first inverter 71 (first pre-driver IC 82). Similarly to the period from time t6 to time t12, the drive control unit 811 operates the assist motor 22 with only the first system winding from time t14 to time t16.

  On the other hand, as shown in FIGS. 7D, 7E, and 7F, between time t6 and time t7 (before reaching time t9), abnormality determination unit 813 performs winding of the second system. Is used to determine whether the open relay 72u is stuck on. Specifically, the drive control unit 811 sets the second inverter so that the current flows through the U-phase coil U-V-2 from the U2 phase to the V2 phase from the time t6 to the time t7. The drive command is output to 72 (second pre-driver IC 83). At this time, since the current flows to the U-phase coil U-V-2 through the open relay 72u from time t6 to time t7, the abnormality determination unit 813 is stuck ON in the open relay 72u. And the drive control unit 811 stops the drive command to the second inverter 72 (second pre-driver IC 83) for flowing a current through the U-phase coil U-V-2 from the U2 phase to the V2 phase. . Then, during the period from time t7 to time t8 (period having the same length as from time t6 to time t7), the drive control unit 811 causes the current in the opposite direction to flow through the U-phase coil U-V-2 ( First drive control is performed to control the second inverter 72 (so that a current flows through the U-phase coil U-V-2 from the V2 phase toward the U2 phase) (a first drive command is output to the second pre-driver IC 83) To do). Therefore, as shown in FIG. 7 (f), between time t7 and time t8, current in the opposite direction (current from the V2 phase to the U2 phase) flows through the open relay 72u to the U-phase coil U-V-2. ing.

  As shown in FIG. 7A, since current flows from the U2 phase to the V2 phase in the second phase U-phase coil U-V-2 between time t6 and time t7, The total output of the assist motor 22 increases. On the other hand, since the current in the opposite direction flows from the V2 phase to the U2 phase in the second phase U-phase coil U-V-2 between time t7 and time t8, from time t6 to time t7. The total output decreases so as to cancel out the increase in output. Thereby, the output (integrated value) as a whole period during which the assist motor 22 operates from time t6 to time t12 can be kept constant, and the total output of the assist motor 22 can be stabilized.

  Also, as shown in FIG. 7 (g), when the abnormality determination unit 813 determines that the open relay 72u is fixed ON at time t6 (actually between time t6 and time t7), the recording process is performed. The unit 814 starts a process of recording acceleration data (acceleration data input from the acceleration sensor 60) representing the vibration state of the vehicle in the storage unit 815 (vibration state recording process). As shown in FIG. 7E, when the drive control unit 811 determines that the abnormality determination unit 813 has the open relay 72u fixed to ON, at time t11 (between time t10 and time t12). Then, the second drive control for controlling the second inverter 72 is started so that a minute current flows through the U-phase coil U-V-2 from the U2-phase toward the V2-phase (the second drive to the second pre-driver IC 83 is performed). Start command output). For this reason, as shown in FIG. 7 (f), a minute current flows through the U-phase coil U-V-2 through the open relay 72u that is fixed ON.

  As shown in FIG. 7 (g), the vibration state of the vehicle changes from moment to moment. Therefore, when the vibration level of the vehicle increases, the contact point of the open relay 72u in the fixed state is released depending on the degree of ON fixation. Sticking may be eliminated. As shown in FIG. 7E, the drive control unit 811 continues the second drive control after time t15, but at time t15, the drive control unit 811 moves to the U-phase coil U-V-2 through the open relay 72u. Is no longer detected. This indicates that the ON relay of the open relay 72u has been eliminated due to the vibration of the vehicle. As shown in FIG. 7 (g), the recording processing unit 814 until the release of ON fixation in the open relay 72u, that is, until time t15 when the U-phase coil U-V-2 is not energized through the open relay 72u. In between, the vibration state recording process is executed.

  As shown in FIG. 7G, the detection value of the acceleration sensor 60 corresponding to the vibration state of the vehicle increases from time t6 to time t13. The detected value of the acceleration sensor 60 becomes smaller than the maximum value at time t13 after time t13, but is larger than the maximum value at time t13 when the ON sticking is resolved at time t15. That is, during the period (time t6 to time t15) in which the vibration state recording process is performed by the recording processing unit 814, the detected value of the acceleration sensor 60 at the time t15 is the maximum, and thus the maximum recorded by the vibration state recording process. The acceleration G1 and the final acceleration G2 are detected values of the acceleration sensor 60 at the same time t15.

  Further, as shown in FIGS. 7B, 7C, and 7F, the assist motor 22 is operated only by the first system from time t11 to time t12 and from time t14 to time t15. The current flows through the open relay 72u in the second system. However, the current flowing through the open relay 72u by the second drive control of the drive control unit 811 is a minute current that does not affect the normal operation of the assist motor 22. For this reason, as shown in FIG. 7A, even if a current flows to the winding of the second system through the open relay 72u in which the ON sticking occurs due to the second drive control of the drive control unit 811, the total of the assist motor 22 is increased. There is no effect on the output.

  In this way, by monitoring whether or not the second system is energized through the open relay 72u by the second drive control, whether or not the open relay 72u is stuck on while performing the normal operation of the assist motor 22 by the first system. Can be judged. Further, by making the current flowing through the second system through the open relay 72u through the second drive control a very small current, it is possible to check whether the open relay 72u is fixed without affecting the normal operation of the assist motor 22 by the first system. Judgment can be made. Further, by recording in the storage unit 815 the vibration state of the vehicle (detected value of the acceleration sensor 60) when the open relay 72u is fixed to ON, the degree of ON fixation (sticking level) can be grasped later. Therefore, it can be used to determine whether or not the part where the ON sticking has occurred can be used continuously or to investigate the cause of the occurrence of the ON sticking. For example, if the ON sticking is not resolved even when the vehicle vibration state is relatively large, it is determined that the sticking state is strong, and if the ON sticking is eliminated when the vehicle vibration state is relatively large, the weak sticking state is determined. If the ON sticking is resolved when the vibration state of the vehicle is relatively small, it can be determined that the sticking state is very weak. Further, when the maximum acceleration G1 is larger than the final acceleration G2, it is in a fixed state in which the fixed state is not eliminated by one relatively large vibration (impact), and the continuous use of the component in which the ON fixing has occurred. Can be taken into account.

  In the present embodiment, when the abnormality determination unit 813 determines that the open relay 72u is fixed ON, the second drive control by the drive control unit 811 and the vibration state recording process by the recording processing unit 814 are executed. However, the abnormality determination process by the abnormality determination unit 813 may be omitted. For example, at a predetermined timing between IG-ON and IG-OFF of the vehicle, the drive control unit 811 performs the second drive control in a state where the relay control unit 812 outputs an open command to the open relay 72u. The recording processing unit 814 performs the vibration state recording process when energization to the U-phase coil U-V-2 through the open relay 72u is detected according to the second drive control. Also good. Also in this mode, the vibration state of the vehicle (detected value of the acceleration sensor 60) when the open relay 72u is fixed to ON can be recorded, so that the fixing level can be grasped later, and the same effect can be obtained. Play.

  As mentioned above, although the form for implementing this invention was explained in full detail, this invention is not limited to this specific embodiment, In the range of the summary of this invention described in the claim, various Can be modified or changed.

10 Vehicle Steering Device 20 Electric Power Steering Device (Vehicle Electric Motor Control Device)
22 Assist motor (electric motor)
60 Acceleration sensor (sensor)
71 First inverter (drive circuit)
71u, 71v, 71w Open relay (relay)
72 Second inverter (drive circuit)
72u, 72v, 72w Open relay (relay)
73 1st switch 74 2nd switch 80 ECU
81 Microcomputer 811 Drive control unit 812 Relay control unit 813 Abnormality determination unit 814 Recording processing unit 85, 85u, 85v, 85w, 86, 86u, 86v, 86w Current sensor 90 DC-DC converter

Claims (1)

An electric motor mounted on a vehicle and including two windings;
A drive circuit for energizing one of the two windings;
A mechanical relay capable of interrupting energization between the winding of the one system and the drive circuit;
A sensor for detecting a vibration state of the vehicle;
A storage unit;
A drive control unit for controlling the operation of the drive circuit;
A relay control unit for controlling the open / close state of the relay;
A recording processing unit that records the vibration state in the storage unit,
The drive control unit controls the drive circuit so that a predetermined current smaller than a predetermined value flows in the winding of the one system through the relay in a state where the relay control unit outputs an open command to the relay. Control
The recording processing unit energizes the windings of the one system through the relay in response to the drive control unit controlling the driving circuit so that the predetermined current flows through the windings of the one system. If there is, record the vibration state in the storage unit,
Electric motor control device for vehicles.

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