JP2013017351A - Motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor drive device capable of driving a motor by implementing control according to the magnetic pole position of a motor rotor, even if the motor angle detector fails.SOLUTION: The motor drive device 20 is provided having a basic drive control unit 38 which controls in accordance with a magnetic pole position according to an angle detection value from a motor angle detector 36, regarding a motor 6 for driving wheels. The motor drive device is provided with: a wheel speed-ready motor angle estimation means 46 which estimates an angle of a motor rotor from a detection signal from a wheel rotation speed detector 24; a sensor failure determination means 48 which identifies the failure of the motor angle detector 36; and a sensor switching means 49 which, if the failure is identified, allows control by the basic drive control unit 38 to be performed using the motor rotor angle that is output from the wheel speed-ready estimation means 46, instead of the angle detection value from the motor angle detector 36.

Description

  The present invention relates to a motor drive device that controls a motor for driving wheels in an electric vehicle.

  In an electric vehicle, in order to drive the motor efficiently, an angle detector that detects the angle of the motor rotor is used, and control is performed according to the magnetic pole position of the motor rotor. As this control, for example, vector control is used.

Japanese Patent Laid-Open No. 10-14300 JP 2000-134716 A

In the motor drive device that performs control according to the magnetic pole position of the motor rotor as described above, if the angle detector of the motor rotor is damaged or the cable is disconnected, the angle detection value cannot be recognized correctly, and the motor It becomes impossible to drive. Or, a desired torque cannot be generated.
In an electric vehicle such as an in-wheel motor type equipped with a motor that individually drives each wheel, if a motor angle detector fails during traveling, the torque balance is lost, causing slip and skid.

  If the vehicle stops on the road and the motor cannot be driven as it is, it will be a traffic obstacle, etc., so even if the rotor angle detector and its wiring system fail, it will run on its own to a safe place beside the road Or if you can drive to the repair shop on your own, it will be easier to deal with the failure.

  An object of the present invention is to provide a motor drive device that can perform control according to the magnetic pole position of the motor rotor and drive the motor even if a failure occurs in the motor angle detector.

The motor drive device 20 of the present invention is a basic drive control that controls the motor 6 for driving wheels of an electric vehicle according to the magnetic pole position according to the angle detection value of the motor angle detector 36 provided in the motor 6. In the motor drive device 20 including the section 38,
A failure of the motor speed estimation means 46 for wheel speed corresponding to the angle of the motor rotor from the detection signal of the wheel rotational speed detector 24 for detecting the rotational speed of the wheel driven by the motor 6 and the motor angle detector 36 are detected. A sensor failure determination unit 48 for determining, and when the sensor failure determination unit 48 determines a failure, the control by the basic drive control unit 38 is replaced by the angle detection value by the motor angle detector 36, and the wheel speed. A sensor switching means 49 is provided which is operated using the motor rotor angle output from the corresponding motor angle estimating means 46. The wheel rotational speed detector 24 may be a detector used for controlling an antilock brake system.

According to this configuration, normally, according to the detected angle value of the motor angle detector 36, control according to the magnetic pole position is performed by the basic drive control unit 38, and efficient motor driving is performed. The failure of the motor angle detector 36 is monitored and determined by the sensor failure determination means 48. The failure determination by the sensor failure determination means 48 may be performed including the wiring system of the motor angle detector 36 or may be performed only for the motor angle detector 36. If the sensor failure determination means 48 determines that a failure has occurred, the sensor switching means 49 replaces the control by the basic drive control unit 38 with the angle detection value by the motor angle detector 36, and the wheel speed corresponding motor angle estimation means 46. The motor rotor angle output by Therefore, even if a failure occurs in the motor angle detector 36, control according to the magnetic pole position using the basic drive control unit 38 can be performed.
Therefore, in an electric vehicle such as an in-wheel motor type equipped with a motor 6 that individually drives each wheel 2, even if the motor angle detector 36 fails during traveling, the torque balance is prevented from being lost, slipping, Skid generation can be prevented. The motor rotor angle output from the wheel speed corresponding motor angle estimation means 46 may not be sufficiently accurate or reliable as compared to the angle detection value by the motor angle detector 36, but the vehicle repair location such as a repair shop, It is possible to run on its own to a safe evacuation site beside the road.

  The wheel speed corresponding motor angle estimation means 46 uses the detection signal of the wheel speed detector 24. The wheel speed detector 24 is generally used for controlling an anti-lock brake system or an attitude control system. Since it is provided in the vehicle, the wheel rotational speed detector 24 may be used, and there is no need to newly add sensors. Therefore, it is possible to drive the motor when a failure occurs in the motor angle detector 36 without adding sensors.

In the present invention, the sensor failure determination means 48 determines the amount of change in the detected angle value of the motor angle detector 36 over a predetermined time, or the motor current commands Iqref, Idref, (Vα, Vβ) and the motor currents Iq, Id, ( It is preferable to judge from both the difference of Iα, Iβ) or the change amount of the detected angle value and the difference between the motor current command and the motor current.
Since the amount of change in the detected angle value of the motor angle detector 36 in a certain time is in a certain range, if the amount of change becomes extremely large, it is considered that the motor angle detector 36 has failed. Therefore, an appropriate threshold value or the like may be set, and a failure may be determined when the amount of change exceeds the threshold value. The “certain time” may be designed as appropriate. Further, since the difference between the motor current commands Iqref, Idref, (Vα, Vβ) and the motor currents Iq, Id, (Iα, Iβ) is within a certain range, this also sets an appropriate threshold value, etc. A failure may be determined when the difference exceeds a threshold value. In this case, the accelerator operation may be monitored, and the case where the motor current commands Iqref and Idref change greatly due to the accelerator operation may be determined. The failure determination based on the amount of change in the detection value of the motor angle detector 36 and the failure determination based on the difference between the motor current command and the motor current can be performed using either of them. Even if the threshold value is set small, reliable determination can be performed and early failure determination can be performed.

In the present invention, the wheel rotational speed detector 24 detects the rotational speed of the wheel by calculating the interval of pulses generated according to the rotation of the wheel, and can detect only a relative angular change, The wheel speed corresponding motor angle estimation means 46 compares the angle detection value of the motor rotor angle detector 36 with the detection signal of the wheel rotation number detector 24 during motor rotation, and compares the detected value of the motor rotor with respect to the detection signal of the wheel rotation number detector 24. When the magnetic pole position is determined and the sensor switching means 49 is switched to use the motor rotor angle output from the wheel speed corresponding motor angle estimating means 46, the angle of the motor rotor is determined from the detection signal of the wheel rotation number detector 24. You may make it guess.
When the output signal of the wheel rotational speed detector 24 is a relative angle output, if the rotor magnetic pole position is determined based on the signal of the motor rotor angle detector 36 at the normal time, the motor rotor angle detector 36 during a failure can be detected. By switching, the output signal of the wheel rotational speed detector 24 can be used for estimating the motor rotor angle.

In this case, the wheel speed corresponding motor angle estimation means 46 is based on the detected angle value of the motor rotor angle detector 36 while the sensor failure determination means 49 determines that it is normal. It is also possible to have a storage unit 46b that determines the magnetic pole position with respect to the detected signal and stores the correlation between the wheel rotational speed and the magnetic pole position.
When the motor 6 is a synchronous motor or the like, the rotation cannot be started unless the angle of the motor rotor can be detected, but the correlation of the magnetic pole position with respect to the detection signal of the wheel rotation number detector 24 in the storage unit 46a, that is, the positional relationship is obtained. By storing it, it is possible to start even after the power is turned on again. Further, in the configuration having the storage unit 46a, the motor rotor angle detector 24 and the wheel speed corresponding motor angle estimation means so that the magnetic pole position can be grasped even when the wheel is rotated by an external factor in the power off state. 46 is preferably configured to start operation when wheel rotation is sensed even when the power is off.

In the present invention, the wheel rotational speed detector 24 calculates the interval of pulses generated according to the rotation of the wheel to detect the rotational speed of the wheel. The angle of the motor rotor may be estimated by multiplying the pulse output from the wheel rotational speed detector 24.
Since the wheel rotational speed detector 24 is used for an anti-lock rake system or the like, generally, a high resolution is not necessary, and one having a lower resolution than the motor rotor angle detector 36 is used. However, when the wheel rotational speed detector 24 calculates the pulse interval and detects the rotational speed of the wheel, the detection angle resolution can be improved by multiplying the pulse, for example, a resolver or the like. The same resolution as that of the motor rotor angle detector 36 can be achieved.

In the present invention, the wheel rotational speed detector 24 calculates the interval of pulses generated according to the rotation of the wheel to detect the rotational speed of the wheel. The angle of the motor rotor may be estimated by measuring the time between pulses output from the wheel rotational speed detector 24.
In addition to multiplying the pulse, time is measured between pulses, and at the timing required for computation that performs control according to the magnetic pole position, such as vector control computation, the angle is accurately determined from the number of pulses from the reference and the time between pulses. Can be calculated.

In the present invention, when the motor 6 is started after the motor is stopped in a state where the failure is determined by the sensor failure determination means 48, the angle of the motor rotor is calculated from the counter electromotive voltage of the motor 6, and the basic angle is determined by the calculated angle. You may provide the rotor angle indexing means 102 at the time of starting to perform control by a drive control part.
Since the basic drive control unit 38 performs control according to the magnetic pole position according to the detected angle value, the motor 6 cannot be rotated if the angle is unknown. Even when the output signal of the wheel rotational speed detector 24 is a relative angle output and the storage unit 46b is not provided, it cannot be used at the time of starting after the stop. Therefore, when the motor stops, the motor 6 cannot be started immediately, but an electric vehicle having two or more motors 6 can perform a temporary run using the healthy motors 6. When running, the motor 6 in which the sensor failure has occurred is rotated by the rotation of the wheel 2. The magnetic pole position can be detected by detecting the back electromotive force of the motor 6 at this time. Since the magnetic pole position can be detected by one rotation of the electrical angle, for example, the angle can be detected by the counter electromotive force when the tire 2a is rotated by a fraction of a revolution, and the motor 6 can be driven. For this reason, the motor 6 can be driven until a straight-running obstacle occurs due to the one-wheel drive.

In the present invention, the motor 6 may be a motor 6 in an electric vehicle in which each motor 6 drives one wheel 2. In this case, the motor 6 may be a motor 6 that constitutes an in-wheel motor device 8 that is mounted close to the wheel 2.
In the case where there are a plurality of wheels 2 that are individually motor-driven, if the motor angle detector 36 fails during traveling, the torque balance is lost, causing slip and skid. Therefore, the effect of switching to the control based on the estimated angle value of the wheel speed corresponding motor angle estimating means 46 in the present invention becomes even more effective. In the case of an electric vehicle having a plurality of motors 6, the use of the starting rotor angle indexing means 102 using the motor back electromotive force is facilitated.

  The in-wheel motor device 8 may include a wheel bearing 4, the motor 6, and a speed reducer 7 interposed between the motor 6 and the wheel bearing 4. In the in-wheel motor device 8 with the speed reducer 7 interposed, since the motor 6 rotates at a high speed, it is more effective to control using the estimated value of the motor rotor angle by the wheel speed corresponding motor angle estimating means 46.

  The speed reducer 7 may be a cycloid speed reducer. The cycloid reducer can obtain a high reduction ratio with a smooth operation, but the motor 6 rotates at a higher speed because of the high reduction ratio. Therefore, it becomes more effective to control using the estimated value of the motor rotor angle by the wheel speed corresponding motor angle estimating means 46.

  The electric vehicle of the present invention is an electric vehicle on which the motor drive device 20 having any one of the above-described configurations of the present invention is mounted. According to this electric vehicle, it is possible to run even if a failure occurs in the motor angle detector 36 by the control using the motor rotor angle estimated value of the wheel speed corresponding motor angle estimating means 46 by the motor driving device 20 of the present invention.

  The motor drive device according to the present invention includes a basic drive control unit that controls a wheel driving motor of an electric vehicle according to a magnetic pole position in accordance with an angle detection value of a motor angle detector provided in the motor. In the motor drive device, a wheel speed corresponding motor angle estimation means for estimating an angle of the motor rotor from a detection signal of a wheel rotation number detector for detecting a rotation speed of a wheel driven by the motor, and a failure of the motor angle detector Sensor fault discrimination means for discriminating, and when the sensor fault discrimination means discriminates a fault, the control by the basic drive control unit is replaced with the angle detection value by the motor angle detector, the wheel speed corresponding motor angle. Sensor switching means that uses the motor rotor angle output from the estimation means to provide a motor angle detector even if a failure occurs. Control corresponding to the magnetic pole position of the rotor is performed, it is possible to perform motor drive.

  Since the electric vehicle of the present invention uses the motor drive device of the present invention, the electric vehicle can travel even if a failure occurs in the motor angle detector.

1 is a block diagram of a conceptual configuration showing, in plan view, an electric vehicle equipped with a motor drive device according to a first embodiment of the present invention. It is a block diagram which shows the conceptual structure of the inverter apparatus of the same electric vehicle. It is a circuit diagram of the inverter device. It is explanatory drawing of the output waveform of the inverter apparatus. It is a block diagram of a conceptual composition of the motor drive device. It is a block diagram of a conceptual structure of the basic drive control part in the motor drive device. It is explanatory drawing which shows the output of the wheel speed detector in the motor drive device, and the pulse form after the process. It is explanatory drawing of the switching form to estimation of the motor rotor angle in the motor drive device. It is a block diagram of a conceptual structure of the motor drive device which concerns on other embodiment of this invention. It is a cross section which shows an example of the in-wheel motor apparatus of the same electric vehicle. It is the XI-XI sectional view taken on the line of FIG. It is a partial expanded sectional view of FIG. It is sectional drawing of an example of the rotation sensor in the same electric vehicle.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view showing a conceptual configuration of an electric vehicle equipped with the motor drive device of this embodiment. This electric vehicle is a four-wheeled vehicle in which the wheels 2 that are the left and right rear wheels of the vehicle body 1 are drive wheels and the wheels 3 that are the left and right front wheels are driven wheels. The front wheel 3 is a steering wheel. The left and right wheels 2 and 2 serving as driving wheels are driven by independent traveling motors 6. The rotation of the motor 6 is transmitted to the wheel 2 via the speed reducer 7 and the wheel bearing 4. The motor 6, the speed reducer 7, and the wheel bearing 4 constitute an in-wheel motor device 8 that is an assembly part. In the in-wheel motor device 8, the motor 6 is installed close to the wheel 2, and a part or the whole of the in-wheel motor device 8 is disposed in the wheel 2. Each of the wheels 2 and 3 is provided with a mechanical brake (not shown) such as an electric type. The “mechanical type” referred to here is a term for distinguishing from a regenerative brake, and includes a hydraulic brake.

  The control system will be described. A main ECU 21 that is an electric control unit that performs overall control of the entire vehicle, and a plurality (two in the illustrated example) of inverter devices 22 that respectively control the motors 6 for traveling according to commands from the ECU 21 1 is installed. The ECU 21 and the inverter device 22 constitute a motor drive device 20. The ECU 21 includes a computer, a program executed by the computer, various electronic circuits, and the like. The ECU 21 and the weak electric system of each inverter device 22 may be configured by a common computer or an electronic circuit on a common board.

  The ECU 21 has torque distribution means 48, which distributes the accelerator opening signal output from the accelerator operation section 16, the deceleration command output from the brake operation section 17, and the steering means 15. From the turning command, an acceleration / deceleration command to be given to the left and right wheel traveling motors 6, 6 is generated as a torque command value and is output to each inverter device 22. Further, the torque distribution means 48, when receiving a deceleration command output from the brake operation unit 17, a braking torque command value for causing the motor 6 to function as a regenerative brake and a braking for operating a mechanical brake (not shown). It has a function to distribute to torque command value. The braking torque command value that functions as a regenerative brake is reflected in the torque command value of the acceleration / deceleration command that is given to each traveling motor 6, 6. The accelerator operation unit 16 and the brake operation unit 17 are each composed of a pedal such as an accelerator pedal and a brake pedal, and a sensor that detects an operation amount of the pedal. The steering means 15 includes a steering wheel and a sensor that detects a rotation angle thereof. The battery 19 is used as a drive for the motor 6 and as a power source for the electrical system of the entire vehicle.

As shown in FIG. 2, the inverter device 22 includes a power circuit unit 28 that is a power conversion circuit unit provided for each motor 6, and a motor control unit 29 that controls the power circuit unit 28. . The motor control unit 29 has a function of outputting information such as detection values and control values relating to the in-wheel motor device 8 included in the motor control unit 29 to the ECU 21.
The power circuit unit 28 includes an inverter 31 that converts DC power of the battery 19 (FIG. 1) into three-phase AC power that is used to drive the motor 6, and a PWM driver 32 that is a means for controlling the inverter 31. The

  In FIG. 3, the motor 6 comprises a three-phase synchronous motor, for example, an IPM type (embedded magnet type) synchronous motor. The inverter 31 includes a plurality of drive elements 31a that are semiconductor switching elements, and outputs a drive current of each phase of the three phases (U, V, W phase) of the motor 6 in a pulse waveform. The PWM driver 32 performs pulse width modulation on the input current command and gives an on / off command to each of the drive elements 31a. The pulse width modulation is performed so as to obtain a current output driven by a sine wave as shown in FIG. In FIG. 3, the PWM driver 32 that is a weak electric circuit portion of the power circuit portion 28 and the motor control unit 29 constitute an arithmetic unit 33 that is a weak electric circuit portion in the inverter device 22. The calculation unit 33 includes a computer, a program executed on the computer, and an electronic circuit. In addition to this, the inverter device 22 is provided with a smoothing unit 33 using a smoothing capacitor interposed between the battery 19 and the inverter 31 in parallel.

  The motor 6 is provided with a motor angle detector 36 that detects the angle of the motor rotor. As the motor rotor angle detector 36, a highly accurate detector such as a resolver is used. As shown in FIG. 2, a wheel rotation number detector 24 that detects the rotation of the wheel 2 is provided on a support member such as a wheel bearing 4 or a knuckle (not shown) that supports the wheel bearing 4. ing. The wheel speed detector 24 is sometimes used as an ABS sensor because it is used in an antilock brake system (not shown). The wheel rotational speed detector 24 is a detector having a lower resolution than the motor rotor angle detector 36.

  The motor control unit 29 of the inverter device 22 in FIGS. 2 and 3 is configured as shown in FIG. The motor control unit 29 has a basic drive control unit 38 that performs control according to the magnetic pole position in accordance with the angle detection value of the motor angle detector 36 provided in the motor 6, and the motor control unit 29 performs vector control. Do. Vector control is a control system that realizes high-speed response and high-precision control by dividing torque current and magnetic flux current and controlling them independently. FIG. 6 is a diagram in which the basic drive control unit 38 is extracted from FIG. 5 and others are omitted.

  In FIG. 6, the basic drive control unit 38 includes a current command calculation unit 39, a torque current control unit 40, a magnetic flux current control unit 41, an αβ coordinate conversion unit 42, a two-phase / three-phase coordinate conversion unit 43, and a three-phase on the detection side. A / 2-phase coordinate conversion unit 44 and a rotation coordinate conversion unit 45 are included.

  The current command calculation unit 39 includes a torque current command unit 39a and a magnetic flux current setting unit 39b, as shown in the block diagram in FIG. The torque current command unit 39a is a means for outputting a torque current command value Iqref in accordance with a torque command value given from the host control means. The host control means is the ECU 21, and when the ECU 21 has the torque distribution means 48 as shown in FIG. The torque command given from the host control means is a torque command value calculated from the accelerator opening, the braking command of the brake, and the like. The magnetic flux current setting unit 39b is a means for outputting a command value Idref in which the magnetic flux current is determined. The command value Idref of the magnetic flux current is appropriately set according to the characteristics of the motor 6 and is normally set to “0”. The torque current is hereinafter referred to as “q-axis current”. The magnetic flux current is hereinafter referred to as “d-axis current”. Regarding the voltage, the torque voltage is referred to as “q-axis voltage”, and the magnetic flux voltage is referred to as “d-axis voltage”. The q axis is an axis in the motor rotation direction, and the d axis is an axis perpendicular to the q axis. The magnetic flux current is also called an exciting current.

The torque current control unit 40 is a three-phase / two-phase coordinate conversion unit based on the detection value of the current detection unit 35 that detects the drive current of the motor 6 with respect to the q-axis current command value Iqref given from the current command calculation unit 39. 44 and a means for controlling the q-axis current detection value Iq obtained via the rotation coordinate conversion unit 45 to follow, and outputs a q-axis voltage command value Vq as an output.
The torque current control unit 40 includes a subtraction unit 40b that subtracts the q-axis current detection value Iq, and an arithmetic processing unit 40a that performs a predetermined arithmetic process on the output of the subtraction unit 40b. In this example, the arithmetic processing unit 40a performs a proportional integration process.

The magnetic flux current control unit 41 is a three-phase / two-phase coordinate conversion unit based on the detection value of the current detection unit 35 that detects the drive current of the motor 6 with respect to the d-axis current command value Idref given from the current command calculation unit 39. 44 and a means for controlling the d-axis current detection value Id obtained via the rotation coordinate conversion unit 45 to follow, and outputs a d-axis voltage command value Vd as an output.
The magnetic flux current control unit 41a is a subtraction unit 41b that subtracts the d-axis current detection value Id, and an arithmetic processing unit 41a that performs a predetermined arithmetic process on the output of the subtraction unit 41b. In this example, the arithmetic processing unit 41a performs a proportional integration process.

The three-phase / two-phase coordinate conversion unit 44 includes two or three phase currents of the current flowing through the U phase, V phase, and W phase of the motor 6, for example, the U phase current Iu and the V phase current. This is means for converting the detected value of the current Iv into the detected values Iα and Iβ of the actual current (actual current on the α axis and actual current on the β axis) of the stationary quadrature two-phase coordinate component.
Based on the motor rotor angle θa detected by the motor angle detector 36, the rotational coordinate conversion unit 45 converts the detected values Iα and Iβ of the static quadrature two-phase coordinate component into the detected values Iq, It is a means for converting to Id.

The αβ coordinate converter 42 converts the q-axis voltage command value Vq and the d-axis voltage command value Vd into the real voltage of the fixed two-phase coordinate component based on the motor rotor angle θ detected by the motor angle detector 36, that is, the motor rotor phase. It is means for converting into command values Vα and Vβ.
The two-phase / three-phase converter 43 uses the actual voltage command values Vα and Vβ output from the αβ coordinate converter 42 as the three-phase AC voltage command values Vu for controlling the U phase, V phase, and W phase of the motor 6. , Vv, Vw.

  The power circuit section 28 converts the voltage command values Vu, Vv, and Vw output from the two-phase / three-phase conversion section 43 of the basic drive control section 38 as described above to convert the motor drive currents Iu, Iv, Iw. Is output.

In this embodiment, the motor drive device 20 including the basic drive control unit 38 having the above-described configuration is provided with a wheel speed corresponding motor angle estimation means 46 and a sensor failure determination sensor switching unit 47 as shown in FIG. It is.
The wheel speed corresponding motor angle estimating means 46 is a means for estimating the angle of the motor rotor from the detection signal of the wheel rotation number detector 24 that detects the rotation speed of the wheel driven by the motor 6.
The sensor failure determination sensor switching unit 47 includes a sensor failure determination unit 48 for determining a failure of the motor angle detector 36, and the control by the basic drive control unit 38 when the sensor failure determination unit 48 determines a failure. Instead of the detected angle value by the motor angle detector 36, a sensor switching means 49 is provided which performs the motor rotor angle output from the wheel speed corresponding motor angle estimating means 46.

For example, the sensor failure determination means 48 determines whether or not there is a failure from the amount of change in the detected angle value of the motor angle detector 36 over a certain period of time. Since the amount of change in the detected angle value of the motor angle detector 36 in a certain time is in a certain range, if the amount of change becomes extremely large, it is considered that the motor angle detector 36 has failed. Therefore, an appropriate threshold value or range may be set, and a failure may be determined when the amount of change exceeds the threshold value or range. The “certain time” may be designed as appropriate.
In addition to this, the sensor failure determination means 48 may determine whether there is an abnormality from the difference between the motor current commands Vα, Vβ (Iqref, Idref) and the motor currents Iα, Iβ (Iq, Id). . The motor current commands to be compared are, for example, the commands Vα and Vβ converted into the actual voltage values by the αβ coordinate conversion unit 42, or the motor current commands Iqref and Idref output from the current command calculation unit 39. Also good. The motor currents to be compared are motor currents Iα and Iβ obtained by coordinate conversion of the detected current values into actual currents, or values obtained by coordinate conversion into the same q-axis current and d-axis current as the motor current command. Since the difference between the motor current command and the motor current detection value that is the current that has actually flowed is within a certain range, this also sets an appropriate threshold value, etc., and if the above difference exceeds the threshold value, a failure occurs. May be determined. In this case, the accelerator operation may be monitored, and the case where the motor current commands Iqref and Idref change greatly due to the accelerator operation may be determined.
The sensor failure determination means 48 further determines from both the amount of change in the detected angle value and the difference between the motor current commands Vα, Vβ (Iqref, Idref) and the motor currents Iα, Iβ (Iq, Id). There may be. If both are used for discrimination, even if each of the threshold values is set small, reliable failure discrimination can be performed and early failure discrimination can be performed.

  The sensor switching means 49 replaces the detected value of the motor angle detector 36 with the estimated value of the motor rotor angle output from the wheel speed corresponding motor angle estimating means 46 when the sensor failure determining means 48 determines that there is a failure. The current command calculation unit 39, the αβ coordinate conversion unit 42, and the rotation coordinate conversion unit 45 are input.

  Specifically, the wheel speed corresponding motor angle estimating means 46 has the following configuration, for example. The case where the wheel rotation number detector 24 detects the rotation speed of the wheel by calculating the interval of pulses generated according to the rotation of the wheel, that is, the case where only the relative angle change can be detected. explain. In this case, the wheel speed corresponding motor angle estimation means 46 compares the angle detection value θ of the motor rotor angle detector 36 with the detection signal of the wheel rotation number detector 24 when the motor rotates, and the detection signal of the wheel rotation number detector 24. The magnetic rotor position of the motor rotor is determined, and the angle of the motor rotor is estimated from the detection signal of the wheel rotational speed detector 24 when the sensor switching means is switched to use the motor rotor angle output from the wheel speed corresponding motor angle estimating means 48. To do.

  More specifically, the wheel speed corresponding motor angle estimation means 46 is based on the detected angle value of the motor rotor angle detector 24 while the sensor failure determination means 48 determines normal. The storage unit 46a stores the correlation between the wheel rotational speed and the magnetic pole position, that is, the positional relationship. The storage unit 46a can maintain the memory even when the power is off. Further, in the configuration having the storage unit 46a, the motor rotor angle detector 24 and the wheel speed corresponding motor angle estimation means so that the magnetic pole position can be grasped even when the wheel is rotated by an external factor in the power off state. 46 is preferably configured to start operation when wheel rotation is sensed even when the power is off.

  The wheel speed corresponding motor angle estimating means 46 has a comparison part 46c (in the figure, shown as a block separately from the wheel speed corresponding motor angle estimating means 46), and the sensor failure determining means 48 determines that it is normal. Meanwhile, the estimated motor rotor angle estimated by the wheel speed corresponding motor angle estimating means 46 is compared with the detected value of the motor rotor of the motor rotor angle detector 36 by the comparison unit 46c. The wheel speed corresponding motor angle estimating means 46 corrects the correlation between the wheel rotational speed detected by the wheel rotational speed detector 24 and the magnetic pole position based on the comparison result, and stores the corrected correlation in the storage unit 46a.

  More specifically, the wheel speed corresponding motor angle estimation means 46 has a multiplication processing unit 46b, which multiplies the pulse (FIG. 7A) output from the wheel rotational speed detector 24 to give a multiplication pulse. (FIG. 7B) is generated and the angle of the motor rotor is estimated. The wheel rotational speed detector 24 calculates the interval of pulses generated according to the rotation of the wheel as described above and detects the rotational speed of the wheel.

  When the wheel rotational speed detector 24 detects the rotational speed of the wheel by calculating the interval of the pulses generated according to the rotation of the wheel, the wheel speed corresponding motor angle estimating means 24 includes the multiplication processing unit 46b. The angle of the motor rotor may be estimated by measuring the time between pulses output from the wheel rotational speed detector 24, and the motor rotor angle may be detected with high accuracy.

  According to the motor drive device 20 having the above configuration, as shown in FIG. 6, normally, the basic drive control unit 38 performs the control according to the magnetic pole position in accordance with the angle detection value of the motor angle detector 36, and the motor with high efficiency. Driving is performed. The failure of the motor angle detector 36 is monitored and determined by the sensor failure determination means 48. The failure determination by the sensor failure determination means 48 may be performed including the wiring system of the motor angle detector 36 or may be performed only for the motor angle detector 36.

  If the sensor failure determination means 48 determines that a failure has occurred, the sensor switching means 49 replaces the control by the basic drive control unit 38 with the detected angle value by the motor angle detector 36 and the wheel speed corresponding motor angle estimation means 46. The motor rotor angle to be output is used (FIG. 8). That is, in FIG. 5, the motor rotor angle estimated by the wheel speed corresponding motor angle estimating means 46 is input to the current command calculating unit 39, the αβ coordinate converting unit 42 and the rotating coordinate converting unit 45. Therefore, even if a failure occurs in the motor angle detector 36, control according to the magnetic pole position using the basic drive control unit 38 can be performed.

  Therefore, in an electric vehicle such as an in-wheel motor type equipped with a motor 6 that individually drives each wheel 2, even if the motor angle detector 36 fails during traveling, the torque balance is prevented from being lost, slipping, Skid generation can be prevented. The motor rotor angle output from the wheel speed corresponding motor angle estimation means 46 may not be sufficiently accurate or reliable as compared to the angle detection value by the motor angle detector 36, but the vehicle repair location such as a repair shop, It is possible to run on its own to a safe evacuation site beside the road.

  The wheel speed corresponding motor angle estimation means 46 uses the detection signal of the wheel speed detector 24. The wheel speed detector 24 is generally used for controlling an anti-lock brake system or an attitude control system. Since it is provided in the vehicle, the wheel rotational speed detector 24 may be used, and there is no need to newly add sensors. Therefore, it is possible to drive the motor when a failure occurs in the motor angle detector 36 without adding sensors.

  In this embodiment, the motor 6 constitutes an in-wheel motor device 8 having a speed reducer 7. However, when the speed reducer 7 is interposed, the motor 6 rotates at a high speed, so that the motor angle estimation for wheel speed is performed. Control using the estimated value of the motor rotor angle by the means 46 becomes more effective. Further, when the speed reducer 7 is a cycloid speed reducer, a high speed reduction ratio can be obtained with a smooth operation, but the motor 6 rotates at a higher speed because of the high speed reduction ratio. Therefore, it becomes more effective to control using the estimated value of the motor rotor angle by the wheel speed corresponding motor angle estimating means 46.

  Further, when the output signal of the wheel speed detector 24 is a relative angle output, the wheel speed corresponding motor angle estimation means 46 determines the rotor magnetic pole position (that is, the magnetic pole reference position) based on the signal of the motor rotor angle detector 36 at the normal time. ) Is determined (FIG. 8B), so that the motor rotor angle detector 36 can be switched during failure while the output signal of the wheel rotational speed detector 24 is used to estimate the motor rotor angle.

  Further, the wheel speed corresponding motor angle estimating means 46 responds to the detection signal of the wheel rotational speed detector 24 based on the detected angle value of the motor rotor angle detector 24 while the sensor failure determining means 49 determines normal. Since the storage unit 46b for determining the magnetic pole position and storing the correlation between the wheel rotation speed and the magnetic pole position is provided, it can be started even after the power is turned on again. That is, when the motor 6 is a synchronous motor or the like, the rotation cannot be started unless the angle of the motor rotor can be detected, but the correlation of the magnetic pole position with respect to the detection signal of the wheel speed detector 24 in the storage unit 46b, that is, the positional relationship. Can be started even after the power is turned on again. Further, in the configuration having the storage unit 46a, the motor rotor angle detector 24 and the wheel speed corresponding motor angle estimation means so that the magnetic pole position can be grasped even when the wheel is rotated by an external factor in the power off state. 46 is preferably configured to start operation when wheel rotation is sensed even when the power is off.

  In this embodiment, since it has the multiplication processing part 46b, the wheel speed corresponding | compatible motor angle estimation means 46 multiplies the pulse which the wheel rotation speed detector 24 outputs, and estimates the angle of a motor rotor. Also, high resolution can be obtained by the wheel speed corresponding motor angle estimating means 46. Since the wheel rotational speed detector 24 is used for an anti-lock rake system or the like, generally, a high resolution is not necessary, and one having a lower resolution than the motor rotor angle detector 36 is used. However, when the wheel rotational speed detector 24 calculates the pulse interval and detects the rotational speed of the wheel, the detection angle resolution can be improved by multiplying the pulse, for example, a resolver or the like. The same resolution as that of the motor rotor angle detector 36 can be achieved.

  When the wheel rotational speed detector 24 detects the rotational speed of the wheel by calculating the interval of the pulses generated according to the rotation of the wheel, the wheel speed corresponding motor angle estimating means 46 includes the multiplication processing unit 46b. The angle of the motor rotor may be estimated by measuring the time between pulses output from the wheel rotational speed detector 24, and the angle may be calculated with high accuracy. FIG. 7C shows an example of such a situation, and the angle can be calculated with high accuracy by measuring the time ΔT from the falling edge of the pulse every vector calculation timing. Note that the timing of vector calculation is several tens to several hundreds between pulses. For example, if the angular velocity is estimated from the previous pulse interval, the rotor absolute angle between pulses can be estimated by measuring the time from the edge of the pulse. The vector calculation timing is a dotted line timing.

  In the above embodiment, when it is determined that the failure is detected by the sensor failure determining means 48 and the wheel speed corresponding motor angle estimating means 46 is used, a means (not shown) for reporting the fact to the ECU 21 may be provided. preferable. The ECU 21 also informs the driver of information that the motor angle detector 36 has failed and is using the wheel speed correspondence motor angle estimating means 46 by using a liquid crystal display device or a lamp (not shown) of the console. It is preferable to do so.

  FIG. 9 shows a configuration of a motor control unit 29 according to another embodiment of the present invention. In this embodiment, in the first embodiment shown in FIG. 1 to FIG. 8, a starting rotor angle indexing means 102 is provided. The starting rotor angle indexing means 102 determines the angle of the motor rotor from the counter electromotive voltage of the motor 6 when the motor 6 is started after the motor is stopped in a state where the failure is determined by the sensor failure determining means 48. This is means for controlling the basic drive control unit 38 at an angle. The counter electromotive voltage of the motor 6 is detected by voltage detection means 103 provided in the wiring between the inverter 31 and the motor 6. The angle of the motor rotor determined by the starting rotor angle indexing means 102 is replaced with the current command calculation unit 39, αβ coordinate conversion instead of the output estimated by the wheel speed corresponding motor angle estimating means 46 and the detected value of the motor angle detector 36. To the unit 42 and the rotation coordinate conversion unit 45. At the same time, the angle of the motor rotor determined by the starting rotor angle indexing means 102 is input to the wheel speed corresponding motor angle estimating means 46 to determine the correlation between the wheel rotational speed detector 24 and the magnetic pole position.

The basic drive control unit 38 is controlled by the angle determined by the starting rotor angle indexing means 102 until a predetermined time or motor rotation angle at the time of starting, and thereafter, the motor angle estimating means corresponding to the wheel speed. 46 estimated outputs are used. Further, the ECU 21 sends a torque command to the inverter device 2 of each motor 6 from the torque distribution means 48 (FIG. 1) or the like even after the traveling is stopped in a state where the failure is determined by the sensor failure determination means 48. To give.
In addition, when the storage unit 46a is provided in the wheel speed correspondence motor angle estimation means 46, starting is possible, and therefore, this embodiment has a configuration in which the storage unit 46a is not provided in the first embodiment. Applied.

  In the case of this embodiment, the following advantages are obtained. Since the basic drive control unit 38 performs control according to the magnetic pole position according to the detected angle value, the motor 6 cannot be started if the angle is unknown. The wheel speed corresponding motor angle estimating means 46 cannot be used at the time of starting after the stop. Therefore, when the motor stops, the motor 6 cannot be started immediately, but an electric vehicle having two or more motors 6 can perform a temporary run using the healthy motors 6. When running, the motor 6 in which the sensor failure has occurred is rotated by the rotation of the wheel 2. The magnetic pole position can be detected by detecting the back electromotive force of the motor 6 at this time. Since the magnetic pole position can be detected by one rotation of the electrical angle, for example, the angle can be detected by the counter electromotive force when the tire 2a is rotated by a fraction of a revolution, and the motor 6 can be driven. Other structural effects in this embodiment are the same as those in the first embodiment.

  Next, a specific example of the in-wheel motor device 8 in each of the above embodiments will be shown together with FIGS. The in-wheel motor device 8 has a reduction gear 7 interposed between the wheel bearing 4 and the motor 6, and the hub of the drive wheel 2 supported by the wheel bearing 4 and the rotation output shaft 74 of the motor 6 are coaxial. It is connected in mind. The speed reducer 7 is a cycloid speed reducer, in which eccentric portions 82a and 82b are formed on a rotational input shaft 82 that is coaxially connected to a rotational output shaft 74 of the motor 6, and bearings 85 are respectively provided on the eccentric portions 82a and 82b. The curved plates 84a and 84b are mounted, and the eccentric motion of the curved plates 84a and 84b is transmitted to the wheel bearing 4 as rotational motion. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side.

  The wheel bearing 4 includes an outer member 51 in which a double row rolling surface 53 is formed on the inner periphery, an inner member 52 in which a rolling surface 54 facing each of the rolling surfaces 53 is formed on the outer periphery, and these The outer member 51 and the inner member 52 are composed of double-row rolling elements 55 interposed between the rolling surfaces 53 and 54 of the inner member 52. The inner member 52 also serves as a hub for attaching the drive wheels. The wheel bearing 4 is a double-row angular ball bearing, and the rolling elements 55 are made of balls and are held by a cage 56 for each row. The rolling surfaces 53 and 54 have a circular arc cross section, and the rolling surfaces 53 and 54 are formed so that the contact angles are aligned with the back surface. An end on the outboard side of the bearing space between the outer member 51 and the inner member 52 is sealed with a seal member 57.

  The outer member 51 is a stationary raceway, has a flange 51a attached to the housing 83b on the outboard side of the speed reducer 7, and is formed as an integral part. The flange 51a is provided with bolt insertion holes 64 at a plurality of locations in the circumferential direction. Further, the housing 83b is provided with a bolt screw hole 94 whose inner periphery is threaded at a position corresponding to the bolt insertion hole 64. The outer member 51 is attached to the housing 83b by screwing the mounting bolt 65 inserted into the bolt insertion hole 94 into the bolt screwing hole 94.

  The inner member 52 is a rotating raceway, and the outboard side member 59 having a hub flange 59a for wheel mounting and the outboard side member 59 are fitted to the inner periphery of the outboard side member 59. The inboard side material 60 is integrated with the outboard side material 59 by fastening. In each of the outboard side material 59 and the inboard side material 60, the rolling surface 54 of each row is formed. A through hole 61 is provided in the center of the inboard side member 60. The hub flange 59a is provided with press-fit holes 67 for hub bolts 66 at a plurality of locations in the circumferential direction. In the vicinity of the base portion of the hub flange 59a of the outboard side member 59, a cylindrical pilot portion 63 that guides driving wheels and braking components (not shown) protrudes toward the outboard side. A cap 68 that closes the outboard side end of the through hole 61 is attached to the inner periphery of the pilot portion 63.

  As described above, the speed reducer 7 is a cycloid speed reducer, and two curved plates 84a and 84b formed with a wavy trochoid curve having a gentle outer shape as shown in FIG. The shaft 82 is attached to each eccentric part 82a, 82b. A plurality of outer pins 86 for guiding the eccentric movements of the curved plates 84a and 84b on the outer peripheral side are provided across the housing 83b, and a plurality of inner pins 88 attached to the inboard side member 60 of the inner member 2 are provided. The curved plates 84a and 84b are engaged with a plurality of circular through holes 89 provided in the inserted state. The rotation input shaft 82 is spline-coupled with the rotation output shaft 74 of the motor 6 and rotates integrally. The rotary input shaft 82 is supported at both ends by two bearings 90 on the inboard side housing 83a and the inner diameter surface of the inboard side member 60 of the inner member 52.

  When the rotation output shaft 74 of the motor 6 rotates, the curved plates 84a and 84b attached to the rotation input shaft 82 that rotates integrally therewith perform an eccentric motion. The eccentric motions of the curved plates 84 a and 84 b are transmitted to the inner member 52 as rotational motion by the engagement of the inner pins 88 and the through holes 89. The rotation of the inner member 52 is decelerated with respect to the rotation of the rotation output shaft 74. For example, a reduction ratio of 1/10 or more can be obtained with a single-stage cycloid reducer.

  The two curved plates 84a and 84b are attached to the eccentric portions 82a and 82b of the rotary input shaft 82 so as to cancel out the eccentric motion with respect to each other. A counterweight 91 that is eccentric in the direction opposite to the eccentric direction of the eccentric portions 82a and 82b is mounted so as to cancel the vibration caused by the eccentric movement of the curved plates 84a and 84b.

  As shown in an enlarged view in FIG. 12, bearings 92 and 93 are mounted on the outer pins 86 and the inner pins 88, and outer rings 92a and 93a of the bearings 92 and 93 are respectively connected to the curved plates 84a and 84b. It comes into rolling contact with the outer periphery and the inner periphery of each through-hole 89. Therefore, the contact resistance between the outer pin 86 and the outer periphery of each curved plate 84a, 84b and the contact resistance between the inner pin 88 and the inner periphery of each through hole 89 are reduced, and the eccentric motion of each curved plate 84a, 84b is smooth. Can be transmitted to the inner member 52 as a rotational motion.

  In FIG. 10, the motor 6 is a radial gap type IPM motor in which a radial gap is provided between a motor stator 73 fixed to a cylindrical motor housing 72 and a motor rotor 75 attached to the rotation output shaft 74. The rotation output shaft 74 is cantilevered by two bearings 76 on the cylindrical portion of the housing 83 a on the inboard side of the speed reducer 7.

  The motor stator 73 includes a stator core portion 77 and a coil 78 made of a soft magnetic material. The stator core portion 77 is held by the motor housing 72 with its outer peripheral surface fitted into the inner peripheral surface of the motor housing 72. The motor rotor 75 includes a rotor core portion 79 that is fitted on the rotation output shaft 74 concentrically with the motor stator 73, and a plurality of permanent magnets 80 that are built in the rotor core portion 79.

  The motor 6 is provided with an angle sensor 36 that detects a relative rotation angle between the motor stator 73 and the motor rotor 75. The angle sensor 36 detects and outputs a signal representing a relative rotation angle between the motor stator 73 and the motor rotor 75, and an angle calculation circuit 71 that calculates an angle from the signal output from the angle sensor body 70. And have. The angle sensor main body 70 includes a detected portion 70a provided on the outer peripheral surface of the rotation output shaft 74, and a detecting portion 70b provided in the motor housing 72 and disposed in close proximity to the detected portion 70a, for example, in the radial direction. Become. The detected portion 70a and the detecting portion 70b may be arranged close to each other in the axial direction. Here, a magnetic encoder or a resolver is used as each angle sensor 36. The rotation control of the motor 6 is performed by the motor control unit 29 (FIGS. 2, 5, and 7). Note that the motor current wiring of the in-wheel motor device 8 and various sensor system and command system wiring are collectively performed by a connector 99 provided in the motor housing 72 or the like.

  FIG. 13 shows an example of the wheel rotational speed detector 24 shown in FIGS. The wheel rotational speed detector 24 includes a magnetic encoder 24a provided on the outer periphery of the inner member 52 in the wheel bearing 4, and a magnetic sensor 24b provided on the outer member 51 so as to face the magnetic encoder 24a. Become. The magnetic encoder 24a is a ring-shaped member in which magnetic poles N and S are alternately magnetized in the circumferential direction. In this example, the rotation sensor 24 is disposed between both rows of rolling elements 55, 55, but may be installed at the end of the wheel bearing 4.

  In the above-described embodiment, the case where the present invention is applied to a four-wheel electric vehicle in which two rear wheels are individually driven by a motor is described. However, the electric vehicle to which the present invention is applied is a front wheel. It is also possible to apply the motor individually driven by the motor, the motor driven by all four wheels individually, or the motor driven by one motor.

DESCRIPTION OF SYMBOLS 1 ... Vehicle body 2, 3 ... Wheel 4 ... Wheel bearing 6 ... Motor 7 ... Reduction gear 8 ... In-wheel motor device 20 ... Motor drive device 21 ... ECU
DESCRIPTION OF SYMBOLS 22 ... Inverter apparatus 24 ... Wheel rotation speed detector 28 ... Power circuit circuit part 29 ... Motor control part 31 ... Inverter 32 ... PWM driver 36 ... Motor angle detector 35 ... Current detection means 39 ... Command electric current calculation part 38 ... Basic drive control Numeral 46: Wheel speed corresponding motor angle estimation means 46a ... Storage section 46b ... Multiplication processing section 46c ... Comparison section 47 ... Sensor failure determination sensor switching section 48 ... Sensor failure determination means 49 ... Sensor switching means 102 ... Rotor angle index at start-up Means 103 ... Voltage detection means

Claims (13)

For a motor for driving a wheel of an electric vehicle, in accordance with an angle detection value of a motor angle detector provided in the motor, a motor drive device including a basic drive control unit that performs control according to a magnetic pole position,
Wheel speed corresponding motor angle estimating means for estimating the angle of the motor rotor from a detection signal of a wheel rotation number detector for detecting the rotation speed of the wheel driven by the motor, and a sensor failure for determining a failure of the motor angle detector When the determination unit and the sensor failure determination unit determine that there is a failure, the control by the basic drive control unit is output by the wheel speed correspondence motor angle estimation unit instead of the angle detection value by the motor angle detector. A motor drive device comprising: a sensor switching unit that performs using a motor rotor angle.   2. The sensor failure determination unit according to claim 1, wherein the sensor failure determination means is a change amount of the detected angle value of the motor angle detector during a predetermined time, a difference between the motor current command and the motor current of the basic drive control unit, or the detected angle value. A motor drive device that judges from both the amount of change and the difference between the motor current command and the motor current.   3. The motor drive device according to claim 1, wherein the wheel rotation speed detector is a detector used for controlling an antilock brake system.   The relative angle change according to any one of claims 1 to 3, wherein the wheel rotation number detector detects a rotation speed of the wheel by calculating an interval between pulses generated according to the rotation of the wheel. The wheel speed corresponding motor angle estimation means compares the angle detection value of the motor rotor angle detector with the detection signal of the wheel rotation speed detector when the motor rotates, and The magnetic pole position of the motor rotor with respect to the detection signal is determined, and when the sensor switching means is switched to use the motor rotor angle output from the wheel speed corresponding motor angle estimation means, the detection signal of the motor rotor is detected from the detection signal of the wheel rotational speed detector. A motor drive device that estimates the angle.   5. A detection signal of a wheel rotation number detector according to claim 4, wherein the wheel speed correspondence motor angle estimation means is based on the detected angle value of the motor rotor angle detector while the sensor failure determination means determines normal. A motor drive device having a storage unit for determining the magnetic pole position with respect to and storing the correlation between the wheel rotation speed and the magnetic pole position.   The wheel rotational speed detector according to any one of claims 1 to 5, wherein the wheel rotational speed detector detects a rotational speed of the wheel by calculating an interval between pulses generated according to the rotation of the wheel, The wheel speed corresponding motor angle estimation means is a motor drive device that estimates the angle of the motor rotor by multiplying the pulse output from the wheel rotation number detector.   The wheel rotational speed detector according to any one of claims 1 to 5, wherein the wheel rotational speed detector detects a rotational speed of the wheel by calculating an interval between pulses generated according to the rotation of the wheel, The wheel speed corresponding motor angle estimation means is a motor drive device that estimates the angle of the motor rotor by measuring the time between pulses output from the wheel rotation number detector.   In any one of claims 1 to 7, when the motor is started after the motor is stopped in the state determined as the failure by the sensor failure determination means, the angle of the motor rotor is determined from the back electromotive voltage of the motor, A motor driving device provided with a starting rotor angle indexing means for performing control by the basic drive control unit at the indexed angle.   9. The motor driving device according to claim 1, wherein the motor is a motor in an electric vehicle in which each motor drives one wheel.   The motor drive device according to claim 9, wherein the motor is a motor that constitutes an in-wheel motor device that is mounted in proximity to a wheel.   11. The motor drive device according to claim 10, wherein the in-wheel motor device includes a wheel bearing, the motor, and a speed reducer interposed between the motor and the wheel bearing.   The motor drive device according to claim 10, wherein the speed reducer is a cycloid speed reducer.   The electric vehicle carrying the motor drive device of any one of Claims 1 thru | or 11.

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