JP2005295688A - Motor controller, vehicle steering apparatus and disconnection detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller for stably continuing a control even if a disconnection occurs to power transmission lines. <P>SOLUTION: A microcontroller 15 is provided with a disconnection detecting section 38 for detecting the disconnection when it occurs to any power transmission lines 21-23. The disconnection detecting section 38 outputs a detected result to an ACT instruction angle calculating section 31. The ACT instruction angle calculating section 31 reduces an ACT instruction angle θta* as the ACT angle target control quantity in response to the detected disconnection state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor control device, a vehicle steering device, and a disconnection detection method.

  In recent years, a power steering device that applies assist force to a steering system of a vehicle or a gear ratio variable system that varies a transmission ratio (gear ratio) of a steered wheel with respect to a steering angle (steering angle) of a steering wheel as a drive source thereof The number using motors is increasing.

  However, in such an electric power steering device (EPS) and a variable gear ratio system, when the power supply is cut off due to the disconnection of the power supply wiring (power line), the motor that is the drive source stops, so the control is stopped. I have to. In particular, when disconnection occurs in the power line during the control, there is a risk that the steering operation suddenly becomes heavy, or that the steering characteristic changes discontinuously.

Conventionally, in order to avoid such an operation stoppage due to the interruption of the power supply, by providing a plurality of power lines in parallel, that is, by making a double line, even if one of them is disconnected, the power supply is continued. There is a motor that made it possible. By adopting such a motor in an EPS or a gear ratio variable system, the reliability can be improved, and the occurrence of problems due to the control stop as described above can be avoided (for example, patents). Reference 1).
JP-A-6-86583

  However, even if the power lines are doubled as described above, there is a problem in that heat is generated due to an increase in resistance if any of the power lines is disconnected. In particular, in a brushless motor, when a power line of any phase is disconnected, torque ripple is generated due to a decrease in the amount of current, and thus steering feeling is deteriorated. For this reason, conventionally, the control cannot be stably continued. After all, after the disconnection is detected, the fail safe is promptly achieved and the control is stopped.

  The present invention has been made to solve the above-described problems, and its object is to provide a motor control device capable of stably continuing the control even when the power line is disconnected, An object of the present invention is to provide a vehicle steering device and a disconnection detection method.

  In order to solve the above-mentioned problems, the invention described in claim 1 is a motor control device that controls the operation of a motor by supplying driving power via a double-lined power line, wherein the power line The present invention includes a disconnection detecting means for detecting at least the number of occurrences of disconnection as a disconnection state, and a control amount reducing means for reducing the control amount of the motor in accordance with the detected disconnection state.

  According to the above configuration, even if a break occurs in any of the power lines, the control amount of the motor is suppressed according to the break state, so that the drive power supplied to the motor is also small. Become. Thereby, heat_generation | fever of the power line in which the disconnection generate | occur | produced can be suppressed effectively. In addition, by reducing the drive power supplied, the difference in the amount of current between the winding coil of the phase in which the disconnection has occurred and the winding coil of the phase in which the disconnection has not occurred becomes small, so torque ripple is suppressed. Is done. As a result, even when the power line is disconnected, the control can be continued stably.

The gist of the invention according to claim 2 is that the control amount reducing means gradually reduces the control amount to zero when the number of remaining power lines is one.
According to the said structure, when there exists a possibility that a power line may be disconnected completely, it becomes possible to stop the control promptly and smoothly.

  The invention according to claim 3 is a motor control device that supplies three-phase driving power to the motor via a power line that is doubled for each phase, and the power line is disconnected as a disconnection state. A disconnection detecting means for detecting the phase and the number of phases, and a line voltage applied between each phase of the motor based on the detected disconnection state so that the amount of current flowing through the winding coil of the motor is balanced The gist of the present invention is to include a voltage control means.

  According to the above configuration, even when a break occurs in any of the power lines, the currents flowing through the winding coils of each phase of the motor are balanced, so that the generation of torque ripple is prevented. As a result, even when the power line is disconnected, the control can be continued stably.

The gist of the invention described in claim 4 is that the disconnection detecting means detects the disconnection state based on a terminal voltage of the motor or an energized current.
According to the above configuration, it is possible to accurately detect the phase and the number of the power lines in which the disconnection has occurred, and as a result, it is possible to flexibly change the control of the motor according to the disconnection state. Furthermore, since the detection is performed by the motor terminal voltage or the current supplied to the motor, it is possible to detect an increase in resistance due to partial disconnection that occurs before disconnection and a decrease in resistance due to rare short circuit.

  According to a fifth aspect of the present invention, the driving power is supplied by rectangular wave energization that sequentially switches between two driving phases to be energized, and the disconnection detecting means changes the terminal voltage. The gist is to detect the disconnection state based on a combination of non-driving phases and a value after the change.

  According to the above configuration, the combination of the non-driving phases in which the terminal voltage changes when a disconnection occurs and the value after the change differ depending on the phase where the disconnection occurred and the number of disconnections, so the phase of the power line where the disconnection occurred In addition, it is possible to specify the number thereof with high accuracy.

  The gist of the invention described in claim 6 is that the disconnection detecting means detects the terminal voltage of the non-driving phase after a predetermined angle or more has elapsed since the switching of the driving phase. To do.

According to the above configuration, it is possible to detect the terminal voltage of the non-driving phase with high accuracy by eliminating the influence of current disturbance due to phase switching.
The gist of the invention described in claim 7 is that the disconnection detecting means detects the disconnection state based on a combination of phases in which the peak value of the current has decreased and a value after the change.

  According to the above configuration, the combination of phases whose peak value decreases with the occurrence of disconnection and the value after the change differ depending on the phase where the disconnection occurred and the number of disconnections, so the phase of the power line where the disconnection occurred In addition, it is possible to specify the number thereof with high accuracy.

  According to the eighth aspect of the present invention, the second steering angle of the steering wheel based on the motor drive is added to the first steering angle of the steering wheel based on the steering angle of the steering wheel, thereby increasing the steering angle of the steering wheel. A transmission ratio variable device that varies a transmission ratio of a steered wheel, and a motor control device according to any one of claims 1 to 7 as control means for controlling the transmission ratio variable device. The gist of the present invention is a vehicle steering device.

  According to the above configuration, it is possible to stably continue the transmission ratio variable control even when any power line is disconnected. In particular, by applying the structure of claim 1 to this structure, it is possible to reduce the second rudder angle of the steered wheel based on the motor drive according to the disconnection state and suppress the vibration accompanying the generation of torque ripple. As a result, it becomes possible to improve the steering feeling when disconnection occurs. In addition, since the influence of torque ripple remains moderately, it is possible to notify the driver of the occurrence of abnormality through the change in steering feeling. Further, by applying the configuration of claim 3 to this configuration, it becomes possible to prevent the generation of torque ripple and maintain the steering feeling suitably even when a disconnection occurs.

  Furthermore, by applying the configuration of claim 2 to this configuration, when the number of remaining power lines is one, the transmission ratio variable device can be locked by quickly setting the second steering angle to zero. It becomes possible. As a result, it is possible to mitigate changes in the steering feeling that accompany the stop of the transmission ratio variable control, and further, the transmission ratio can be changed while the second steering angle remains, that is, the steering is offset. It becomes possible to prevent the device from being locked. As a result, it is possible to alleviate the uncomfortable feeling felt by the driver due to the stop of the transmission ratio variable control. In addition, by applying the configurations of claims 4 to 7 to this configuration, it becomes possible to detect the disconnection state with high accuracy, and as a result, it is possible to flexibly control the transmission ratio variable device according to the disconnection state. It becomes possible to change.

  According to a ninth aspect of the present invention, there is provided a steering force assisting device for applying an assist force for assisting a steering operation to a steering system of a vehicle by driving a motor, and a control means for controlling the steering force assisting device. It is a vehicle steering apparatus provided with the motor control apparatus as described in any one of -7.

  According to the above configuration, it is possible to continue the power assist control stably even if any power line is disconnected. In particular, by applying the configuration of claim 1 to this configuration, it is possible to reduce the assist torque generated by the motor in accordance with the disconnection state, and to suppress the vibration associated with the generation of torque ripple. This makes it possible to improve the steering feeling. In addition, since the influence of torque ripple remains moderately, it is possible to notify the driver of the occurrence of abnormality through the change in steering feeling. Further, by applying the configuration of claim 3 to this configuration, it becomes possible to prevent the generation of torque ripple and maintain the steering feeling suitably even when a disconnection occurs.

  Furthermore, by applying the configuration of claim 2 to this configuration, the assist torque can be quickly reduced to zero when the number of remaining power lines is one. As a result, the change in the assist force can be made smooth, and the uncomfortable feeling felt by the driver by stopping the power assist control can be alleviated. In addition, by applying the configurations of claims 4 to 7 to this configuration, it becomes possible to detect the disconnection state with high accuracy, and as a result, the power assist control can be flexibly changed according to the disconnection state. It becomes possible.

  The invention according to claim 10 is a disconnection detection method for detecting a disconnection state of a power line provided to supply three-phase drive power to a brushless motor and is double-tracked for each phase. The gist is to detect the phase and the number of the power lines in which the disconnection has occurred based on the terminal voltage of the brushless motor or the current supplied to the brushless motor.

  According to an eleventh aspect of the present invention, the three-phase driving power is supplied by rectangular wave energization that sequentially switches between the two-phase driving phases to be energized, and the non-driving phase in which the terminal voltage has changed. The gist is to detect the disconnection state based on the combination and the value after the change.

The gist of the invention described in claim 12 is that the terminal voltage of the non-driving phase is detected after a predetermined angle or more has elapsed since the switching of the driving phase.
The gist of the invention described in claim 13 is that the disconnection state is detected based on a combination of phases in which the peak value of the current has decreased and a value after the change.

  According to the configurations of the tenth to thirteenth aspects, it is possible to accurately detect the phase and the number of the power lines in which the disconnection has occurred. Furthermore, since it is configured to detect the terminal voltage of the brushless motor or the current supplied to the brushless motor, it is possible to detect an increase in resistance due to partial disconnection that occurs before disconnection or a decrease in resistance due to rare short circuit. .

  According to the present invention, it is possible to provide a motor control device, a vehicle steering device, and a disconnection detection method capable of stably continuing control even when a disconnection occurs in a power line.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is embodied in a vehicle steering apparatus (steering apparatus) including a gear ratio variable system will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a steering apparatus 1 according to the present embodiment. As shown in the figure, a steering shaft 3 to which a steering wheel (steering) 2 is fixed is connected to a rack 5 via a rack and pinion mechanism 4. It is converted into a reciprocating linear motion of the rack 5 by the and pinion mechanism 4. And the advancing direction of the vehicle is changed by changing the rudder angle of the steered wheels 6, that is, the tire angle, by the reciprocating linear motion of the rack 5.

  The steering device 1 of the present embodiment includes a gear ratio variable actuator 7 as a transmission ratio variable device that varies the transmission ratio (gear ratio) of the steered wheels 6 with respect to the steering angle (steering angle) of the steering 2, and the gear ratio variable actuator. ECU8 which controls the action | operation of 7 is provided. And in this embodiment, ECU8 comprises a control means and a motor control apparatus.

  More specifically, the steering shaft 3 includes a first shaft 9 to which the steering 2 is connected and a second shaft 10 connected to the rack and pinion mechanism 4. The gear ratio variable actuator 7 includes the first shaft 9 and the first shaft 9. A differential mechanism 11 that couples the two shafts 10 and a motor 12 that drives the differential mechanism 11 are provided. Note that the motor 12 of this embodiment is a brushless motor, and rotates by receiving supply of three-phase (U, V, W) driving power from a driving circuit 16 to be described later. The gear ratio variable actuator 7 adds the rotation driven by the motor to the rotation of the first shaft 9 accompanying the steering operation and transmits it to the second shaft 10, whereby the steering shaft input to the rack and pinion mechanism 4. The rotation of 3 is increased (or decelerated).

  That is, as shown in FIGS. 2 and 3, the gear ratio variable actuator 7 has the steering angle (ACT angle θta) of the steered wheels based on the motor drive to the steered angle (steer steered angle θts) of the steered wheels 6 based on the steering operation. ) Is added, the gear ratio of the steered wheels 6 with respect to the steering angle θs is varied. The ECU 8 controls the gear ratio variable actuator 7 by controlling the operation of the motor 12. That is, the ECU 8 varies the gear ratio by controlling the ACT angle θta (gear ratio variable control).

  In this case, “addition” is defined to include not only addition but also subtraction, and so on. In addition, when the “gear ratio of the steered wheels 6 with respect to the steering angle θs” is expressed as an overall gear ratio (steering angle θs / tire angle θt), an overall increase is made by adding an ACT angle θta in the same direction as the steering angle θts. The gear ratio is small (large tire angle θt, see FIG. 2). Then, the overall gear ratio is increased by adding the ACT angle θta in the reverse direction (small tire angle θt, see FIG. 3). In this embodiment, the steer turning angle θts constitutes the first rudder angle, and the ACT angle θta constitutes the second rudder angle.

As shown in FIG. 1, the ECU 8 includes a microcomputer 15 that outputs a motor control signal and a drive circuit 16 that supplies three-phase drive power to the motor 12 based on the motor control signal.
The microcomputer 15 is connected to a steering angle sensor 17, a speed sensor 18, and a rotation angle sensor 19 provided in the motor 12. The microcomputer 15 detects the steering angle θs, vehicle speed V, And a motor control signal is output to the drive circuit 16 based on the ACT angle θta.

  The drive circuit 16 is connected to the motor 12 via the cable 20. As shown to Fig.4 (a), the cable 20 of this embodiment has the power lines 21-23 of each phase for supplying drive electric power to the motor 12 doubled. Specifically, three power lines 21a to 21c, 22a to 22c, and 23a to 23c are provided for each of the U, V, and W phases. The drive circuit 16 supplies three-phase drive power to the motor 12 via these power lines 21 (21a to 21c), 22 (22a to 22c), and 23 (23a to 23c).

  4A is a plan view of a power wiring portion 20a that accommodates the power lines 21a to 21c, 22a to 22c, and 23a to 23c, and a signal wiring portion 20b that accommodates various signal wirings. However, a two-layer structure in which a power wiring portion 24a and a signal wiring portion 24b are stacked may be employed as in the cable 24 shown in FIG. 4B.

Next, a control aspect of the steering device of the present embodiment will be described.
FIG. 5 is a control block diagram of the steering device of the present embodiment. Each control block in the figure is realized by a computer program executed by the microcomputer 15. And in this embodiment, the microcomputer 15 comprises a disconnection detection means and a control amount reduction means.

As shown in the figure, the microcomputer 15 includes an ACT command angle calculation unit 31, an FB control calculation unit 32, and a motor control signal output unit 33.
The ACT command angle calculation unit 31 calculates an ACT command angle θta * that is a control target amount of the ACT angle θta based on the steering angle θs and the vehicle speed V. As shown in FIG. 6, in this embodiment, the ACT command angle calculation unit 31 sets the original gear ratio, that is, the overall gear ratio (for example, 18) when the gear ratio variable actuator 7 is not operated to “1”. A control map 34 is provided in which the ratio of the actual overall gear ratio to this, that is, the gear ratio variable ratio α and the vehicle speed V are associated with each other. The ACT command angle calculation unit 31 determines a gear ratio variable ratio α corresponding to the input vehicle speed V based on the control map 34. Then, based on the steering angle θs, the value of the ACT angle θta that becomes the gear ratio variable ratio α is calculated, and the value is set as the ACT command angle θta *. Then, the ACT command angle calculation unit 31 outputs the ACT command angle θta * to the FB control calculation unit 32.

  In the present embodiment, the control map 34 is set such that the lower the vehicle speed V, the lower the gear ratio variable ratio α, and the higher the vehicle speed V, the higher the gear ratio variable ratio α. Accordingly, an ACT command angle θta * that decreases the overall gear ratio (large tire angle θt) is output as the vehicle speed V is low, and the overall gear ratio is increased (tire angle θt is small) as the vehicle speed V is high. ACT command angle θta * is output.

  As shown in FIG. 5, an ACT command angle θta * and an ACT angle θta are input to the FB control calculation unit 32. Then, the FB control calculation unit 32 calculates a current command by a feedback calculation based on a deviation between the ACT command angle θta * and the ACT angle θta. Then, the FB control calculation unit 32 outputs the calculated current command to the motor control signal output unit 33, and the motor control signal output unit 33 outputs a motor control signal to the drive circuit 16 based on the input current command. To do.

  On the other hand, the drive circuit 16 includes a plurality of (six) power MOSFETs (hereinafter simply referred to as FETs) corresponding to the number of phases of the motor 12, and more specifically, a series circuit of FETs 35a and 35d, and FETs 35b and 35e. A series circuit and FETs 35c and 35f are connected in parallel. The connection point 36u of the FETs 35a and 35d is connected to the U-phase coil of the motor 12 via the power line 21, and the connection point 36v of the FETs 35c and 35f is connected to the V-phase coil of the motor 12 via the power line 22. Yes. The connection point 36 w of the FETs 35 b and 35 e is connected to the W-phase coil of the motor 12 via the power line 23.

  The motor control signal output from the microcomputer 15 (motor control signal output unit 33) is applied to the gate terminals of the FETs 35a to 35f. The FETs 35a to 35f are turned on / off in response to the motor control signal, whereby the DC voltage supplied from the DC power source 37 is converted into three-phase (U, V, W) driving power, and the motor 12 is turned on. Supplied to.

  In the present embodiment, rectangular wave energization control is adopted in which two of the U, V, and W phases are drive phases (phases in which energization is performed), and the microcomputer 15 sequentially switches the drive phases. The operation of the motor 12 is controlled by outputting a motor control signal.

  The microcomputer 15 includes a disconnection detection unit 38 that detects the disconnection state when any of the power lines 21 to 23 is disconnected. In this embodiment, voltage sensors 40u, 40v, and 40w are provided at the output terminals 39u, 39v, and 39w of each phase, and the disconnection detection unit 38 converts the voltages at the output terminals 39u, 39v, and 39w to the motor 12. It is detected as the terminal voltage. And the disconnection detection part 38 detects a disconnection state based on the terminal voltages Vu, Vv, and Vw of each phase (disconnection detection process).

Next, an aspect of disconnection detection in the present embodiment will be described.
FIG. 7 is a waveform diagram of the terminal voltage of each phase in a normal state, and FIG. 8 is a waveform diagram of the terminal voltage of each phase when a disconnection occurs in the U phase.

  As shown in FIG. 7, when no disconnection occurs in any of the power lines 21 to 23 of each phase, that is, the terminal voltage of the non-driving phase in the normal state is an intermediate value of each terminal voltage of the driving phase. . For example, if the terminal voltage of each driving phase is 12V and 0V, the terminal voltage of the non-driving phase is 6V.

  On the other hand, as shown in FIG. 8, for example, when a disconnection occurs in any one of the U-phase power lines 21, when the U-phase is set as the drive phase due to an increase in the resistance value (U The terminal voltage (Vw or Vv) of the non-driving phase in phase-V phase energization and U-phase-W phase energization changes.

  For example, if the resistance value of the winding coil of each phase is 40 mΩ and the resistance value of each power line 21 to 23 is 30 mΩ, the total resistance value of each phase in the normal state is 70 mΩ, whereas the U-phase When one of the power lines 21 is disconnected, the resistance value of the U-phase power line 21 is 45 mΩ, and the total resistance value is 85 mΩ.

  Accordingly, the terminal voltage of the non-driving phase when the U phase is the driving phase, that is, the terminal voltage Vw of the W phase when the U phase-V phase is the driving phase, or when the U phase-W phase is the driving phase. The V-phase terminal voltage Vv is 5.42V or 6.58V depending on the energization direction to each drive phase. Further, when two disconnections occur in the U-phase power line 21, that is, when the remaining U-phase power line 21 is one, the terminal voltage of the non-driving phase when the U-phase becomes the driving phase is 4 .2V or 7.8V.

  Changes in the terminal voltages Vu, Vv, Vw of the non-driving phase accompanying the occurrence of disconnection in each of the power lines 21 to 23, that is, combinations of non-driving phases in which the terminal voltages Vu, Vv, Vw change when the disconnection occurs, and changes thereof The subsequent values differ depending on the disconnection state, that is, the phase where the disconnection occurs and the number of disconnections. The disconnection detection unit 38 of the present embodiment detects the disconnection state based on the change patterns of the terminal voltages Vu, Vv, and Vw of the non-driving phase.

  Specifically, as shown in FIG. 9, the disconnection detecting unit 38 is a combination of terminal voltages Vu, Vv, and Vw of the non-driving phase that changes when the power lines 21 to 23 are disconnected (in detail, The combination for every energization direction to a drive phase) and its change rate (beta) have the determination table 41 recorded for every disconnection state. Note that the combination of the terminal voltages Vu, Vv, and Vw of the non-driving phase that change and the rate of change thereof are obtained by experiments, simulations, and the like and recorded in the determination table 41.

  Then, the disconnection detection unit 38 detects the terminal voltages Vu, Vv, Vw when each phase becomes the non-driving phase, and any of the detected terminal voltages Vu, Vv, Vw is normal. If not, the change pattern is checked against the determination table 41 to detect the phase in which the disconnection has occurred and the number of disconnections.

  For example, the terminal voltage (Vw) of the non-driving phase when the U phase-V phase is the driving phase is normal, the terminal voltage (Vv) of the non-driving phase and the V phase when energizing from the U phase to the W phase The terminal voltage (Vu) of the non-driving phase when energizing from the W phase to the W phase is higher than normal, the terminal voltage (Vv) of the non-driving phase when energizing from the W phase to the U phase, and the W phase to V phase The terminal voltage (Vu) of the non-driving phase when energized is lower than normal. When the rate of change is ± β1, it can be specified that any one of the W-phase power lines 23 is disconnected.

  Similarly, when the combination of the non-driving phases in which the terminal voltage has changed is the same as in the above example and the rate of change is ± β2, two of the W-phase power lines 23 are disconnected, that is, W It can be specified that there is only one remaining phase power line 23.

  Further, as shown in FIG. 8, in the present embodiment, the settling from the transition point p from the driving phase to the non-driving phase to a predetermined angle (electrical angle, for example, about 20 °) from the transient term to the steady term. An angle θsta is set, and a voltage level detection angle θob, which is a detection point of the terminal voltage of the non-driving phase, is set to a position whose phase is advanced from the switching point p by a settling angle θsta or more.

  That is, the disconnection detecting unit 38 detects the terminal voltage of the non-driving phase after a predetermined angle or more has elapsed since the switching of the driving phase. Thereby, it becomes possible to detect the terminal voltage of the non-driving phase with high accuracy by eliminating the influence of the current disturbance accompanying the phase switching. In the present embodiment, the voltage level detection angle θob is set to an angle substantially equal to the settling angle θsta, but is not limited to this and may be equal to or greater than the settling angle θsta.

Next, a procedure for detecting disconnection by the disconnection detection unit will be described in detail.
As shown in the flowchart of FIG. 10, the disconnection detection unit 38 first detects the terminal voltages Vu, Vv, and Vw when the U, V, and W phases become non-driving phases.

  Specifically, the disconnection detection unit 38 first determines whether or not the U phase has been switched from the driving phase to the non-driving phase (step 101), and when the switching has been performed (step 101: If YES, the U-phase terminal voltage Vu is detected (step 102). Specifically, the U-phase terminal voltage Vu is detected after the settling angle θsta has elapsed from the switching point p (hereinafter, the same applies to the V-phase and W-phase terminal voltages Vv and Vw).

  On the other hand, if the U phase is not switched from the driving phase to the non-driving phase in step 101 (step 101: NO), the V phase is switched from the driving phase to the non-driving phase. If the switching is performed (step 103: YES), the V-phase terminal voltage Vv is detected (step 104).

  If the V phase is not switched from the driving phase to the non-driving phase (step 103: NO), then the W phase is switched from the driving phase to the non-driving phase. If the switching is performed (step 105: YES), the W-phase terminal voltage Vw is detected (step 106).

  In step 105, when the W phase is not switched from the driving phase to the non-driving phase (step 105: NO), any of the U, V, and W phases is changed from the driving phase to the non-driving phase. Steps 101, 103, and 105 are repeated until switching is performed.

  Next, when the terminal voltages Vu, Vv, and Vw at the time of becoming the non-driving phase are detected in any of the phases U, V, and W in the above steps 102, 104, and 106, the disconnection detecting unit 38 Subsequently, for all phases U, V and W, it is determined whether or not the terminal voltages Vu, Vv and Vw when the non-driving phase has been detected are detected (step 107). Then, in this step 107, the above steps are determined until it is determined that the terminal voltages Vu, Vv, Vw when all the phases U, V, W are in the non-driving phase are detected (step 107: YES). 101 to step 107 are repeated.

  When the terminal voltages Vu, Vv, and Vw when all the phases U, V, and W are set to the non-driving phase are detected by the processing in steps 101 to 107, the disconnection detection unit 38 detects next. It is determined whether or not all the values of the terminal voltages Vu, Vv, Vw of these non-driving phases are normal (step 108). If all values of the terminal voltages Vu, Vv, Vw of the non-driving phase are normal (step 108: YES), no breakage has occurred in each of the power lines 21 to 23, that is, “no breakage”. (Step 109).

  On the other hand, if it is determined in step 108 that any of the terminal voltages Vu, Vv, Vw of the non-driving phase is not normal (step 108: NO), the terminal voltages Vu, Vv, Vw change. Based on the combination of the non-driving phases and the value after the change, the phase of the power line in which the disconnection has occurred and the number of the disconnected lines are determined (step 110). Then, the disconnection detection unit 38 outputs the determination result in step 109 or the determination result in step 110 as a detection result (step 111).

Next, a control mode after disconnection detection in the present embodiment will be described.
As shown in FIG. 5, in this embodiment, the microcomputer 15 performs lock control for locking the notification control unit 42 that performs notification control for notifying the vehicle occupant of the occurrence of abnormality and the gear ratio variable actuator 7. The lock control unit 43 is provided, and the result (detection result) of the disconnection detection by the disconnection detection unit 38 is input to the notification control unit 42 and the lock control unit 43.

  Then, when the detection result indicates that the disconnection has occurred in any of the power lines 21 to 23 of each phase, the notification control unit 42 turns on the warning lamp 44 provided in the passenger compartment, and locks it. The control unit 43 locks the gear ratio variable actuator 7 when the detection result indicates that any one of the power lines 21 to 23 of each phase is completely disconnected.

  The disconnection detection unit 38 outputs the detection result to the ACT command angle calculation unit 31. Then, the ACT command angle calculation unit 31 reduces the control target amount of the ACT angle θta, that is, the ACT command angle θta * output to the FB control calculation unit 32 according to the detection result, that is, the disconnection state.

  More specifically, as shown in FIG. 11, the ACT command angle calculation unit 31 of the present embodiment has a change ratio of the gear ratio variable ratio α that is greater than that of the control map 34 other than the control map 34 used in the normal state. The control map 34a is set so that the ACT command angle θta * is smaller, that is, smaller than when the normal control map 34 is used.

  When the detection result input from the disconnection detection unit 38 indicates that a disconnection has occurred in any of the power lines 21 to 23 of each phase, the ACT command angle calculation unit 31 controls the control map 34a. Is used to reduce the ACT command angle θta * output to the FB control calculation unit 32.

  As a result, the control amount of the ACT angle θta is reduced, and the drive power supplied to the motor 12 is also reduced, so that the heat generation of the power line is suppressed. In addition, the reduction in drive power supplied reduces the difference in the amount of current between the phase where the disconnection occurred and the phase where the disconnection did not occur, and torque ripple is suppressed. Is improved. In addition, since the influence of torque ripple remains moderately, it is possible to notify the driver of the occurrence of abnormality through the change in steering feeling.

  In addition, when the detection result input from the disconnection detection unit 38 indicates that the remaining number of the power lines 21 to 23 of each phase is one, the ACT command angle calculation unit 31 The ACT command angle θta * is gradually reduced to zero. That is, the ACT command angle θta * is gradually changed to zero.

  Further, in the present embodiment, the lock control unit 43 receives the ACT angle θta in addition to the detection result by the disconnection detection unit 38. And the lock control part 43 assumes that the detection result by the disconnection detection part 38 has one remaining number of the power lines 21 to 23 of each phase, and the ACT angle θta is zero. In this case, the gear ratio variable actuator 7 is locked.

  Thereby, when the remaining number of any of the power lines 21 to 23 of each phase becomes 1, it becomes possible to quickly lock the gear ratio variable actuator 7 by setting the ACT angle θta to zero. As a result, the change in steering feeling when locking the gear ratio variable actuator 7 can be reduced.

Next, a processing procedure after disconnection detection in the present embodiment will be described.
As shown in the flowchart of FIG. 12, the microcomputer 15 executes a disconnection detection process (step 201), and first determines whether or not the detection result is “disconnected” (step 202). In step 202, if the detection result is “disconnected” (step 202: YES), first, the warning lamp 44 is turned on to notify the vehicle passenger of the occurrence of the abnormality (step 202). Step 203). If the detection result is “no disconnection” in step 202 (step 202: NO), the microcomputer 15 does not execute the processing after step 203.

  Next, the microcomputer 15 determines whether or not the detection result in step 201 is that any of the power lines 21 to 23 of each phase is completely disconnected (step 204). If the detection result indicates that any of the power lines 21 to 23 of each phase is completely disconnected (step 204: YES), the gear ratio variable actuator 7 is locked and the gear ratio is variable. Control is stopped (step 205).

  On the other hand, in the above step 204, when the detection result does not indicate that any of the power lines 21 to 23 of each phase is completely disconnected (step 204: NO), the microcomputer 15 continues to detect the detection result. However, it is determined whether or not at least two power lines 21 to 23 of each phase remain (step 206). When it is assumed that at least two or more power lines 21 to 23 of each phase remain (step 206: YES), the ACT command angle θta * that is the control target amount is reduced (step 207). .

  Further, in step 206, the microcomputer 15 determines that the detection result does not indicate that at least two power lines 21 to 23 of each phase remain, that is, if any one of the remaining power lines is one. If so (step 206: NO), the control target angle ACT command angle θta * is gradually changed to zero (step 208). Then, it is determined whether or not the ACT angle θta is zero (step 209). If it is determined that the ACT angle θta is zero (step 209: YES), the gear ratio variable actuator 7 is locked, and the gear The variable ratio control is stopped (step 210).

As described above, according to the present embodiment, the following features can be obtained.
(1) The microcomputer 15 includes a disconnection detection unit 38 that detects the disconnection state when any of the power lines 21 to 23 is disconnected, and the disconnection detection unit 38 calculates an ACT command angle calculation result of the detection. To the unit 31. Then, the ACT command angle calculation unit 31 reduces the ACT command angle θta *, which is a control target amount of the ACT angle θta, according to the detected disconnection state.

  With such a configuration, even if a disconnection occurs in any of the power lines, the control amount of the motor 12 is suppressed according to the disconnection state, so the drive power supplied to the motor 12 Will also be small. Thereby, heat_generation | fever of the power line in which the disconnection generate | occur | produced can be suppressed effectively. In addition, by reducing the drive power supplied, the difference in the amount of current between the winding coil of the phase in which the disconnection has occurred and the winding coil of the phase in which the disconnection has not occurred becomes small, so torque ripple is suppressed. Is done. Thereby, the steering feeling at the time of disconnection generation can be improved. As a result, even when the power line is disconnected, the control can be continued stably. In addition, since the influence of torque ripple remains moderately, the driver can be informed of the occurrence of abnormality through the change in steering feeling.

(2) The disconnection detection unit 38 detects the disconnection state of each of the power lines 21 to 23 based on the combination of the non-driving phases in which the terminal voltages Vu, Vv, and Vw have changed and the value after the change.
With such a configuration, the combination of the non-driving phases in which the terminal voltages Vu, Vv, and Vw change when a disconnection occurs and the value after the change depend on the disconnection state, that is, the phase where the disconnection occurred and the number of disconnections. Since they are different, it is possible to accurately identify the phase and the number of power lines in which the disconnection has occurred. As a result, the control of the motor 12 and the gear ratio variable actuator 7 can be flexibly changed according to the disconnection state. Further, since the change in the resistance value of the power lines 21 to 23 due to the occurrence of disconnection is detected by the change in the terminal voltage of the non-driving phase and its value, an increase in resistance due to partial disconnection that occurs before disconnection or a rare short It is also possible to detect a decrease in resistance due to.

  (3) The disconnection detection unit 38 detects the terminal voltage of the non-driving phase after a predetermined angle or more has elapsed since the switching of the driving phase. As a result, it is possible to accurately detect the terminal voltage of the non-driving phase by eliminating the influence of the current disturbance caused by the phase switching.

  (4) When the detection result input from the disconnection detecting unit 38 indicates that the remaining number of the power lines 21 to 23 of each phase is one, the ACT command angle calculating unit 31 The ACT command angle θta * is gradually changed to zero.

  With such a configuration, when any of the power lines 21 to 23 may be completely disconnected, the gear ratio variable actuator 7 can be locked quickly with the ACT angle θta set to zero. Therefore, the change in the steering feeling accompanying the stop of the variable gear ratio control can be mitigated, and the variable gear ratio actuator 7 is locked while the ACT angle θta remains, that is, the steering 2 is offset. Can be prevented. As a result, the uncomfortable feeling felt by the driver due to the stop of the gear ratio variable control can be alleviated.

(Second Embodiment)
Hereinafter, a second embodiment in which the present invention is embodied in an electric power steering device (EPS) will be described with reference to the drawings. For convenience of explanation, the same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 13, the steering device 45 of the present embodiment controls an EPS actuator 47 as a steering force assisting device that applies an assist force for assisting a steering operation to the steering system, and the operation of the EPS actuator 47. This is an electric power steering device equipped with an ECU 48. And in this embodiment, ECU48 comprises a control means and a motor control apparatus.

  The EPS actuator 47 of the present embodiment is a so-called rack-type EPS actuator in which a motor 52 that is a driving source thereof is arranged coaxially with the rack 5, and an assist torque generated by the motor 52 is a ball feeding mechanism (not shown). Is transmitted to the rack 5 via. Note that the motor 52 of this embodiment is a brushless motor as in the first embodiment, and rotates by receiving supply of three-phase (U, V, W) driving power. The ECU 48 controls the assist force applied to the steering system by controlling the assist torque generated by the motor 52 (power assist control).

  The ECU 48 includes a microcomputer 55 that outputs a motor control signal and a drive circuit 56 that supplies three-phase drive power to the motor 52 based on the motor control signal. The drive circuit 56 is connected to the motor 52 via the cable 20 having the power lines 21 to 23 that are doubled as in the first embodiment.

  In the present embodiment, a torque sensor 57, a speed sensor 58, and a rotation angle sensor 59 provided in the motor 52 are connected to the microcomputer 55, and the microcomputer 55 detects the steering torque τ, A motor control signal is output to the drive circuit 56 based on the vehicle speed V and the motor rotation angle (electrical angle) θm. Then, the drive circuit 56 supplies three-phase drive power based on this motor control signal to the motor 52.

Next, a control aspect of the steering device of the present embodiment will be described.
FIG. 14 is a control block diagram of the steering device of the present embodiment. Each control block in the figure is realized by a computer program executed by the microcomputer 55 as in the first embodiment. And in this embodiment, the microcomputer 55 comprises a disconnection detection means and a control amount reduction means.

As shown in the figure, the microcomputer 55 includes a current command calculation unit 61, a phase voltage command calculation unit 62, and a motor control signal output unit 63.
The steering torque τ and the vehicle speed V are input to the current command calculation unit 61. Based on the steering torque τ and the vehicle speed V, the current command calculation unit 61 calculates an assist current command Iq * that is a target amount of power assist control, that is, a control target amount of assist torque generated by the motor 52, and The assist current command Iq * is output to the phase voltage command calculation unit 62.

  In addition to the assist current command Iq *, the motor rotation angle θm is input to the phase voltage command calculation unit 62. The phase voltage command calculation unit 62 calculates U, V, and W phase voltage commands Vu *, Vv *, and Vw * based on the assist current command Iq * and the motor rotation angle θm. Each phase voltage command Vu *, Vv *, Vw * is obtained by solving a known motor voltage equation. Then, the phase voltage command calculation unit 62 outputs each phase voltage command Vu *, Vv *, Vw * calculated by the calculation to the motor control signal output unit 63.

  The motor control signal output unit 63 outputs a motor control signal to the drive circuit 56 based on these phase voltage commands Vu *, Vv *, Vw *. In this embodiment, the motor control signal output unit 63 outputs a motor control signal so that sine wave energization is performed. The drive circuit 56 supplies three-phase (U, V, W) drive power to the motor 52 based on the motor control signal.

Next, an aspect of disconnection detection in the present embodiment will be described.
In the present embodiment, the disconnection detector 68 receives the phase currents Iu, Iv, Iw detected by the current sensors 64u, 64v, 64w. The disconnection detector 68 detects the disconnection state based on the phase currents Iu, Iv, and Iw.

  More specifically, as shown in FIG. 15, when no disconnection occurs in any of the power lines 21 to 23 of each phase, that is, the respective phase currents Iu, Iv, and Iw in a normal state are in equilibrium. That is, the peak values Iup, Ivp and Iwp are equal to each other.

  On the other hand, for example, when a break occurs in any one of the U-phase power lines 21, as shown in FIG. 16, current increases to phase currents Iv and Iw other than the U-phase due to an increase in the resistance value. A decrease occurs, and the peak values Ivp and Iwp decrease. That is, the phase currents Iu, Iv, and Iw are not balanced. In the line-to-line current, the line-to-line current including the U-phase where the disconnection has occurred decreases. Needless to say, the “peak value” here is an absolute value thereof.

  The change pattern of each phase current Iu, Iv, Iw accompanying the occurrence of disconnection in each of these power lines 21 to 23, that is, the combination of phases whose peak value decreases when the disconnection occurs and the value after the change are the disconnection state, That is, it differs depending on the phase where the disconnection occurs and the number of disconnections. And the disconnection detection part 68 of this embodiment detects the disconnection state based on the change pattern of each phase current Iu, Iv, Iw.

  The disconnection detection unit 68 of the present embodiment has a determination table in which the combination of phases in which the peak value of the phase current decreases when the disconnection occurs and the rate of change thereof are recorded for each disconnection state. When the currents Iu, Iv, and Iw are not balanced, the change pattern is checked against this determination table to detect the phase where the disconnection has occurred and the number of disconnections.

  In the present embodiment, the result (detection result) of the disconnection detection by the disconnection detection unit 68 is input to the notification control unit 42 and the current command calculation unit 61. The notification control unit 42 turns on the warning lamp 44 based on the detection result, and the current command calculation unit 61 determines the assist current command Iq that is the control target amount of the assist torque according to the detection result, that is, the disconnection state. * Reduce.

Next, the disconnection detection in this embodiment and the processing procedure after the disconnection detection will be described.
As shown in the flowchart of FIG. 17, the microcomputer 55 first detects each phase current Iu, Iv, Iw (step 301), and whether or not each phase current Iu, Iv, Iw is balanced, It is determined whether or not the peak values Iup, Ivp, and Iwp are equal to each other (step 302).

  When the phase currents Iu, Iv, and Iw are not balanced (step 302: NO), it is assumed that a break has occurred in any of the power lines 21 to 23 of each phase, and the vehicle occupant is abnormal. The warning lamp 44 is turned on to notify the occurrence (step 303). If the microcomputer 55 determines in step 302 that the phase currents Iu, Iv, and Iw are in equilibrium (step 302: YES), the microcomputer 55 does not execute the processing after step 303.

  Next, the microcomputer 55 determines the phase of the power lines 21 to 23 in which the disconnection has occurred based on the changes in the phase currents Iu, Iv, and Iw, specifically, the combination of phases whose peak values have decreased and the value after the change. And the number of them is detected (step 304). Then, it is determined whether or not the detection result is that any of the power lines 21 to 23 of each phase is completely disconnected (step 305), and any of the power lines 21 to 23 of each phase is determined. When it is assumed that the cable is completely disconnected (step 305: YES), the power assist control is stopped (step 306).

  On the other hand, in step 305, if the detection result does not indicate that any of the power lines 21 to 23 of each phase is completely disconnected (step 305: NO), the microcomputer 55 continues to detect the detection result. However, it is determined whether or not at least two power lines 21 to 23 of each phase remain (step 307). When it is assumed that at least two or more power lines 21 to 23 of each phase remain (step 307: YES), the assist current command Iq that is the target assist torque, that is, the control target amount of the assist torque. * Is reduced (step 308).

  In step 307, the microcomputer 55 determines that the detection result does not indicate that at least two power lines 21 to 23 of each phase remain, that is, one of the remaining number is one. If it is to be performed (step 307: NO), the power assist control is stopped. Specifically, the power assist control is stopped after the assist current command Iq * is gradually reduced to zero, that is, gradually changed to zero (step 309).

As described above, according to the present embodiment, the following features can be obtained.
(1) The current command calculation unit 61 reduces the assist current command Iq *, which is the control target amount of the assist torque, according to the detected disconnection state of each of the power lines 21 to 23.

  With such a configuration, even if a disconnection occurs in any of the power lines, the control amount of the motor 52 is suppressed according to the disconnection state, so the drive power supplied to the motor 52 Will also be small. Thereby, heat_generation | fever of the power line in which the disconnection generate | occur | produced can be suppressed effectively. In addition, by reducing the drive power supplied, the difference in the amount of current between the winding coil of the phase in which the disconnection has occurred and the winding coil of the phase in which the disconnection has not occurred becomes small, so torque ripple is suppressed. Is done. Thereby, the steering feeling at the time of disconnection generation can be improved. As a result, even when the power line is disconnected, the control can be continued stably.

  (2) The microcomputer 55 stops the power assist control when the remaining number of any of the power lines 21 to 23 of each phase is one. Specifically, the assist current command Iq *, which is the control target amount of the assist torque, is gradually reduced to zero, that is, after gradually changing to zero, the power assist control is stopped. Thereby, the change of the assist force can be made smooth, and the uncomfortable feeling felt by the driver by stopping the power assist control can be alleviated.

(3) The disconnection detection unit 68 detects the disconnection state of each of the power lines 21 to 23 based on the combination of phases in which the peak values of the phase currents Iu, Iv, and Iw have decreased and the value after the change.
With such a configuration, the combination of phases in which the peak values of the phase currents Iu, Iv, and Iw decrease along with the occurrence of disconnection and the value after the change differ depending on the phase in which the disconnection occurred and the number of disconnections. Therefore, the phase of the power line and the number of the power lines in which the disconnection has occurred can be specified with high accuracy. It is also possible to detect rare shorts.

(Third embodiment)
Hereinafter, a third embodiment in which the present invention is embodied in a vehicle steering apparatus (steering apparatus) provided with a gear ratio variable system will be described with reference to the drawings. For convenience of explanation, the same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 18 is a control block diagram of the steering device of the present embodiment. As shown in the figure, the hardware configuration of the steering device 71 of the present embodiment is the same as that of the steering device 1 of the first embodiment, and only the ECU 72, specifically, the control block in the microcomputer 75 is different. And in this embodiment, the microcomputer 75 comprises a disconnection detection means and a voltage control means. Each control block in the figure is realized by a computer program executed by the microcomputer 75 as in the first embodiment.

  In the present embodiment, the disconnection detection unit 78 outputs the result of the disconnection detection to the motor control signal output unit 83. And the motor control signal output part 83 is applied between each phase so that the electric current which flows into each winding coil of the motor 12 may be balanced based on the input detection result, ie, the disconnection state of each power line 21-23. A motor control signal is output to change the line voltage to be changed.

  More specifically, when a break occurs in any of the power lines 21 to 23 of each phase, the current flowing through the winding coil of the drive phase is not balanced due to the increase in resistance value. The motor control signal output unit 83 of the present embodiment outputs a motor control signal to change the line voltage applied between the phases so that the current flowing through the winding coils of each phase is balanced even when such disconnection occurs. Output. Specifically, the line voltage applied between the phases of the motor 12 so that the current amount of the other driving phase is equal to the current amount of the driving phase in which the amount of current flowing through the winding coil is reduced most due to the occurrence of disconnection. To change.

  For example, the resistance value of the winding coil of each phase is 40 mΩ, the resistance value of each power line 21 to 23 is 30 mΩ, the terminal voltage of each driving phase is 12V, 0V, that is, the line voltage applied to the driving phase is 12V. As a result, the total resistance value of the drive phase in a normal state is 140 mΩ, and the currents flowing through the winding coils of each phase are balanced.

[Example 1]
On the other hand, when a disconnection occurs in any one of the U-phase power lines 21 (when one U-phase line is disconnected), the total resistance value of the drive phase is as follows depending on the combination.

・ When U phase-V phase is the driving phase: 155mΩ
・ When U phase-W phase is driving phase: 155mΩ
・ When V phase and W phase are driving phases: 140mΩ
Therefore, when the U phase-V phase and the U phase-W phase are drive phases, the amount of current flowing through the winding coil is about 90.3% of the value when the V phase-W phase is the drive phase. Become.

  At this time, the line voltage applied to the V phase and the W phase is reduced to 10.84 V (12 V × 0.903), that is, each terminal voltage when the V phase and the W phase are the driving phases is 10.84 V, By setting the voltage to 0 V, the amount of current flowing through the winding coil can be made equal to the U phase-V phase and U phase-W phase, which are the drive phases where the amount of current flowing through the winding coil is the smallest.

[Example 2]
Similarly, when one disconnection occurs in each of the U-phase and V-phase power lines 21 and 22 (when one U-phase and one V-phase disconnect), the total resistance of the drive phase is as follows depending on the combination thereof: Become.

・ When U phase-V phase is the driving phase: 170mΩ
・ When U phase-W phase is driving phase: 155mΩ
・ When V phase and W phase are driving phases: 155mΩ
Therefore, when the U phase-V phase is the driving phase, the amount of current flowing through the winding coil is about 91.2% of the value when the U phase-W phase and the V phase-W phase are the driving phases. Become.

  In this case, the line voltage applied to the U phase-W phase, V phase-W phase is reduced to 10.94 V (12 V × 0.912), that is, the U phase-W phase, V phase-W phase is the driving phase. When each terminal voltage is set to 10.94V and 0V, the amount of current flowing through the winding coil is the value of the U phase-V phase, which is the driving phase with the smallest amount of current flowing through the winding coil. Can be equal.

  In other words, it is applied to the other drive phases based on the ratio (relative current ratio) between the current amount of the drive phase in which the amount of current flowing through the winding coil decreases most due to the occurrence of disconnection and the current amount of the other drive phase. By reducing the line voltage to be applied, the current flowing through the winding coils of each phase can be balanced.

As shown in FIG. 19, the motor control signal output unit 83 of the present embodiment has a control table 84 in which the relative current amount ratio γ at the time of such disconnection is recorded for each disconnection state.
Specifically, for example, in the case of “Example 1 (when one U-phase is disconnected)”, when the V-phase-W-phase, whose total resistance has not changed due to the disconnection, is the driving phase, Assuming that the amount of current flowing is “1”, the relative current amount ratio γ1 of the amount of current flowing through the winding coil when the U phase-V phase and the U phase-W phase are the driving phases is “0. 903 ".

  Further, in the case of “Example 2 (when one U and V phases are each disconnected)”, when the U-phase-W phase and the V-phase-W-phase where the amount of current flowing through the winding coil is the highest are the driving phases. If the value of “1” is “1”, the relative current amount ratio γ3 flowing through the winding coil when the U-phase to the V-phase is the driving phase is “0.912”. In the control table 84, the relative current amount ratio γ (γ1, γ2, γ3, γ4,...) Is recorded for each disconnection state.

  The motor control signal output unit 83 applies the line voltage applied to the motor 12 based on the detection results input from the control table 84 and the disconnection detection unit 78 so that the currents flowing through the winding coils of each phase are balanced. A motor control signal is output to change the value.

  Specifically, the motor control signal output unit 83 sets the drive phase other than the drive phase in which the amount of current flowing through the winding coil is reduced most due to the occurrence of disconnection based on the relative current amount ratio γ stored in the control table 84. A motor control signal is output so as to reduce the applied line voltage. The drive circuit 16 supplies drive power to the motor 12 based on the motor control signal, so that the current flowing through the winding coils of each phase of the motor 12 is balanced.

As described above, according to the present embodiment, the following features can be obtained.
(1) The motor control signal output unit 83 is applied between the phases of the motor 12 so that the currents flowing through the winding coils of the phases are balanced based on the detected disconnection states of the power lines 21 to 23. A motor control signal is output to change the line voltage.

  With such a configuration, even if a break occurs in any of the power lines 21 to 23, the currents flowing through the winding coils of each phase of the motor 12 are balanced, so that torque ripple is generated. Thus, the steering feeling can be suitably maintained.

  (2) Based on the relative current amount ratio γ, the motor control signal output unit 83 reduces the line voltage applied to the drive phase other than the drive phase where the amount of current flowing through the winding coil is the smallest due to the occurrence of disconnection. The motor control signal is output. Thereby, the electric current which flows into the winding coil of each phase of the motor 12 can be balanced.

In addition, you may change each said embodiment as follows.
In the present embodiment, the power lines 21 to 23 are each doubled into three lines, but the degree of double line may be two or four or more.

  In the first and third embodiments, the present invention is embodied in a vehicle steering apparatus having a gear ratio variable system, and in the second embodiment, the present invention is embodied in an electric power steering apparatus (EPS). Turned into. However, the present invention is not limited to this, and the configuration of the present invention may be embodied in any motor control device. For example, a configuration that detects disconnection based on the current supplied to the motor may be applied to the ECU of the variable gear ratio actuator, a configuration that detects disconnection based on the terminal voltage of the motor, and a motor that depends on the disconnection state. You may apply the structure which changes the line voltage applied to to ECU of an EPS actuator.

  In the first and second embodiments, the motor 12 (52) is a brushless motor to which three-phase driving power is supplied. However, the present invention is not limited to this, and the control after the disconnection detection (reduction of the control target amount) may be embodied by a DC brush motor control device (ECU). In that case, for example, at least the power line The number of disconnections may be detected, and the control amount may be reduced according to the number of disconnections.

  In the second embodiment, the disconnection detection based on the current supplied to the motor is embodied in the case of sine wave energization control, but may be used in the case of rectangular wave energization control. What is necessary is just to set it as the structure which detects the electric current amount of a drive phase as a peak value of electric current.

In the second embodiment, the disconnection detection is performed based on the phase currents Iu, Iv, Iw. However, the disconnection detection may be performed based on the line current.
In the third embodiment, the change of the line voltage after the disconnection is detected is embodied when the rectangular wave energization control is used. However, the present invention is not limited to this, and any control method that does not involve current feedback may be used in the case of sine wave energization control.

  -The disconnection detection in each said embodiment and the change of the line voltage in the said 3rd Embodiment are tables other than the above-mentioned determination table and control table, for example, the resistance value of each power line 21-23, and the motor 12 It is good also as a structure performed by calculating sequentially using the table regarding the resistance value of each winding coil of (52).

  In the first embodiment, when a disconnection occurs in any of the power lines 21 to 23 of each phase, the control map to be used is switched to the control map 34a. A plurality of maps may be provided, and a control map to be used may be switched according to the disconnection state.

-Moreover, it is good also as a structure which reduces a control target amount by multiplying a predetermined coefficient according to a disconnection state.
Next, technical ideas other than the claims that can be grasped from the above embodiments will be described.

  (A) In the motor control device according to claim 3, the three-phase driving power is supplied by rectangular wave energization that sequentially switches between two energized driving phases, and the voltage control means Is based on the relative ratio between the current amount of the drive phase in which the current amount is reduced most and the current amount of the other drive phase in the drive phase other than the drive phase in which the current amount is reduced most. A motor control device characterized by reducing a line voltage to be applied. With such a configuration, the currents flowing through the winding coils of the respective phases of the motor can be balanced.

The schematic block diagram of the steering device of 1st Embodiment. Explanatory drawing of gear ratio variable control. Explanatory drawing of gear ratio variable control. (A) (b) Sectional drawing of a cable. The control block diagram of the steering device of a 1st embodiment. Explanatory drawing which shows schematic structure of the control map used at the time of normal. The wave form diagram of the terminal voltage of each phase at the time of normal. The wave form diagram of the terminal voltage of each phase when a disconnection occurs in the U phase. Explanatory drawing which shows schematic structure of a determination table. The flowchart which shows the process sequence of a disconnection detection in 1st Embodiment. Explanatory drawing which shows schematic structure of the control map used at the time of disconnection generation | occurrence | production. The flowchart which shows the process sequence after the disconnection detection in 1st Embodiment. The schematic block diagram of the steering device of 2nd Embodiment. The control block diagram of the steering device of a 2nd embodiment. Waveform diagram of normal phase current. The waveform diagram of the phase current when the disconnection occurs in the U phase. The flowchart which shows the process sequence after the disconnection detection and disconnection detection in 2nd Embodiment. The control block diagram of the steering device of a 3rd embodiment. Explanatory drawing which shows schematic structure of a control table.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,45,71 ... Steering device, 2 ... Steering wheel (steering), 6 ... Steering wheel, 7 ... Gear ratio variable actuator, 8, 48, 72 ... ECU, 12, 52 ... Motor, 15, 55, 75 ... Microcomputer , 21 (21a-21a), 22 (22a-22a), 23 (23a-23a) ... power line, 31 ... ACT command angle calculation unit, 38, 68 ... disconnection detection unit, 39u, 39v, 39w ... output terminal, 40u, 40v, 40w ... voltage sensor, 47 ... EPS actuator, 61 ... current command calculation unit, 64u, 64v, 64w ... current sensor, 83 ... motor control signal output unit, [theta] ta ... ACT angle, [theta] ta * ... ACT command angle, Iq *: assist current command, Vu, Vv, Vw: terminal voltage, p: switching point, θsta: settling angle, θob: voltage level detection angle, Iu, Iv, Iw: phase current, Iup, I vp, Iwp: Peak value, θs: Steering angle, θts: Steer turning angle.

Claims (13)

A motor control device that controls the operation of a motor by supplying drive power via a doubled power line,
A disconnection detecting means for detecting at least the number of disconnections generated as a disconnection state of the power line;
Control amount reducing means for reducing the control amount of the motor according to the detected disconnection state;
A motor control device comprising: The motor control device according to claim 1,
The control amount reducing means gradually reduces the control amount to zero when the number of remaining power lines is one. A motor control device that supplies three-phase driving power to a motor via a power line that is doubled for each phase,
Disconnection detection means for detecting the phase where the disconnection has occurred as the disconnection state of the power line and the number thereof,
Voltage control means for changing a line voltage applied between the phases of the motor so that the amount of current flowing through the winding coil of the motor is balanced based on the detected disconnection state;
A motor control device. In the motor control device according to any one of claims 1 to 3,
The disconnection detecting means detects the disconnection state based on a terminal voltage of the motor or a current supplied to the motor. The motor control device according to claim 4,
The drive power is supplied by rectangular wave energization that sequentially switches between the two-phase drive phases to be energized,
The disconnection detection means detects the disconnection state based on a combination of non-driving phases in which the terminal voltage has changed and a value after the change. The motor control device according to claim 5,
The disconnection detecting means detects the terminal voltage of the non-driving phase after a predetermined angle or more has elapsed since the switching of the driving phase;
A motor control device. The motor control device according to claim 4,
The disconnection detection means detects the disconnection state based on a combination of phases in which the peak value of the current has decreased and a value after the change. Transmission that varies the transmission ratio of the steering wheel to the steering angle of the steering wheel by adding the second steering angle of the steering wheel based on the motor drive to the first steering angle of the steering wheel based on the steering angle of the steering wheel A variable ratio device;
A vehicle steering apparatus comprising: the motor control device according to any one of claims 1 to 7 as control means for controlling the transmission ratio variable device. A steering force assisting device for applying an assisting force for assisting a steering operation to a steering system of the vehicle by driving a motor;
A vehicle steering apparatus comprising: the motor control apparatus according to any one of claims 1 to 7 as control means for controlling the steering force assisting apparatus. A disconnection detection method for detecting a disconnection state of a power line that is provided to supply three-phase drive power to a brushless motor and is doubled for each phase,
Detecting the phase of the power line and the number of the broken power lines based on the terminal voltage of the brushless motor or the current supplied to the brushless motor;
The disconnection detection method characterized by this. In the disconnection detection method according to claim 10,
The three-phase drive power is supplied by rectangular wave energization that sequentially switches between the two-phase drive phases to be energized,
A disconnection detection method comprising detecting the disconnection state based on a combination of non-driving phases in which the terminal voltage has changed and a value after the change. The disconnection detection method according to claim 11,
A disconnection detection method, wherein the terminal voltage of the non-driving phase is detected after a predetermined angle or more has elapsed since the switching of the driving phase. In the disconnection detection method according to claim 10,
A disconnection detection method, wherein the disconnection state is detected based on a combination of phases in which the peak value of the current is reduced and a value after the change.

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