JP7278693B2 - motor controller - Google Patents

Description

The present invention relates to a motor control device for controlling a synchronous motor.

A vehicle such as a hybrid vehicle (HV) or an electric vehicle (EV) is equipped with a motor as a drive source for running. Permanent magnet synchronous motors (PMSM) are widely used as motors.

In order to control this motor, it is necessary to detect the rotation angle of the rotor (rotational position of the motor). To detect the rotation angle, for example, a rotation angle sensor that outputs a signal that changes according to the rotation angle is used. Used. In order to control the motor efficiently and accurately, it is necessary to reduce the deviation between the rotation angle detected from the output signal of the rotation angle sensor and the actual rotation angle of the motor.

Therefore, generally, the mounting position of the rotation angle sensor is adjusted when the vehicle is shipped from the factory. During this adjustment, the d-axis current command value and the q-axis current command value of the motor are each set to zero. Then, the phase current value flowing through the motor is converted into a d-axis current value and a q-axis current value using the rotation angle detected from the output signal of the rotation angle sensor, and the difference between the d-axis current command value and the d-axis current value is calculated. And the d-axis voltage command value and the q-axis voltage command value are obtained from the difference between the q-axis current command value and the q-axis current value.

If there is no deviation between the rotation angle detected from the output signal of the rotation angle sensor and the actual rotation angle of the motor, the d-axis voltage command value will be 0, but if there is a deviation, the d-axis voltage command value will change. does not become 0. Therefore, when the d-axis voltage command value is not zero, the mounting position of the rotation angle sensor is adjusted so that the d-axis voltage command value becomes zero.

JP 2004-266935 A JP 2016-158393 A

In order to omit adjustment work at the vehicle factory, the d-axis current command value and the q-axis current command value are both fixed to 0 in the actual vehicle, and the offset amount added to the rotation angle detected from the output signal of the rotation angle sensor is set to change to bring the d-axis voltage command value closer to 0, find the offset amount when the d-axis voltage command value becomes 0, and rotate detected from the output signal of the rotation angle sensor with the found offset amount. Techniques for correcting the corners have been proposed.

However, when there is a discrepancy between the rotation angle detected from the output signal of the rotation angle sensor and the actual rotation angle of the motor, the q-axis voltage command value is clearly set to a value other than 0 to improve the determination accuracy. , the number of revolutions must be increased to the extent that the back EMF of the motor can be detected, and the vehicle may move back and forth.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control device capable of obtaining an offset amount used for correcting a rotation angle detected from an output signal of a rotation angle sensor while the vehicle is stopped.

To achieve the above object, a motor control device according to the present invention includes a battery, a motor, a three-phase bridge circuit and a smoothing capacitor, and is connected to the battery and the motor to convert DC power and AC power. It is equipped with an inverter, a rotation angle sensor that outputs a signal that changes according to the rotation angle of the motor, and an offset storage device for the rotation angle sensor. A motor control device in which a q-axis current command value is set to 0 and a d-axis current command value is set to a predetermined value while the vehicle is stopped, and the rotation angle is detected from the output signal of the rotation angle sensor. Then, using the rotation angle corrected by the offset storage device, the three-phase voltage command value corresponding to the d-axis current command value and the q-axis current command value is set, and based on the three-phase voltage command value, the inverter to the motor An energization process is executed to energize, and when the motor rotates due to energization by the energization process, the offset amount held in the offset storage device is updated with a value obtained by increasing or decreasing a predetermined angle.

According to this configuration, when the vehicle is stopped, the q-axis current command value is set to 0, the d-axis current command value is set to a predetermined value, and the energization process of energizing the motor from the inverter is executed. In the energization process, the rotation angle detected from the output signal of the rotation angle sensor is used to set the three-phase voltage command value according to the d-axis current command value and the q-axis current command value. Since the q-axis current command value is set to 0, if the rotation angle detected from the output signal of the rotation angle sensor matches the actual rotation angle of the motor, a current that does not include a torque current component will flow to the motor. is supplied, the output torque of the motor becomes 0, and the motor does not rotate. However, if the rotation angle detected from the output signal of the rotation angle sensor deviates from the actual rotation angle of the motor, a current containing a torque current component is supplied to the motor, causing the motor to rotate.

If the motor rotates due to energization to the motor by the energization process, it is considered that the offset amount used in the energization process cannot be corrected to the actual rotation angle, and the specified angle is increased or decreased as the offset amount used in the next energization process. updated with the new value.

If the motor does not rotate due to energization by the energization process, it is considered that the actual rotation angle can be corrected by the offset amount used in the energization process, and the rotation angle sensor used when rotating the motor is detected. The offset amount is used as the correction value of the value.

The offset amount to be updated may be in the opposite direction or in the forward direction of the direction in which the motor rotates due to the energization in the energization process.

Therefore, in the actual vehicle, it is possible to obtain the offset amount used for correcting the rotation angle detected from the output signal of the rotation angle sensor. Moreover, the offset amount can be obtained in a safe state where the vehicle is stopped.

Further, the motor may be energized by discharging a smoothing capacitor provided in the inverter (discharge function) while the inverter is disconnected from the battery.

Furthermore, since the offset amount of the rotation angle sensor mounted on the vehicle is obtained in the state of the actual vehicle, if the motor, rotation angle sensor, or motor control device fails, the failed part can be replaced individually. , the offset amount of the rotation angle sensor can be determined after the replacement. Therefore, it is possible to replace the faulty part as a single item, and it is possible to suppress the cost for maintenance of the vehicle.

A vehicle is provided with a drive gear and a driven gear that meshes with the drive gear on a power transmission path between the motor and the drive wheels. It is preferable that the rotation is within the backlash between

With this configuration, it is possible to further prevent the vehicle from moving due to the rotation of the motor due to the energization of the energization process.

Even if the motor does not rotate due to energization in the energization process, the offset amount held in the offset storage device is increased or decreased by a predetermined angle, and the offset amount in the case that the motor does not rotate due to energization due to multiple energization processes is calculated. Based on the intermediate value, the offset amount to be held in the offset storage device may be determined.

As the difference between the rotation angle deviation ("actual rotation angle of the motor" and "rotation angle detected by the rotation angle sensor + offset amount") becomes smaller, the torque current component becomes smaller, and the frictional force of the bearing, etc. A phenomenon occurs in which the motor does not rotate due to the reaction force even if there is a deviation in the rotation angle.

Therefore, in order to increase the accuracy of the offset amount that corrects the amount of rotation angle deviation, energization processing is performed multiple times with different offset amounts to determine the upper and lower limits of the offset value when the motor does not rotate. This is the amount of offset.

According to the present invention, it is possible to determine the offset amount used for correcting the rotation angle detected from the output signal of the rotation angle sensor while the vehicle is stopped.

1 is a diagram showing the configuration of a main part of a vehicle according to one embodiment of the present invention; FIG. 3 is a circuit diagram showing the configuration of an inverter; FIG. 7 is a flowchart showing the flow of offset amount setting processing;

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Configuration of main parts of the vehicle>
FIG. 1 is a diagram showing the configuration of the essential parts of a vehicle 1 according to one embodiment of the present invention.

A vehicle 1 is an electric vehicle (EV) equipped with a motor 2 as a drive source for traveling and a battery 3 as a power source for the motor 2 . The motor 2 is, for example, a Permanent Magnet Synchronous Motor (PMSM) using a permanent magnet for its rotor. The battery 3 is an assembled battery in which a plurality of secondary batteries are combined, and outputs DC power of approximately 200 to 350V, for example.

The vehicle 1 includes a power transmission mechanism 5 that transmits the power of the motor 2 to the driving wheels 4 . The power transmission mechanism 5 includes an output gear 6 and a differential gear 7 . The output gear 6 meshes with the ring gear 8 of the differential gear 7 . Power of the motor 2 is transmitted to the ring gear 8 of the differential gear 7 via the output gear 6 and then transmitted from the differential gear 7 to the drive wheels 4 via the drive shaft 9 . The driving force of the driving wheels 4 causes the vehicle 1 to move forward or backward.

The vehicle 1 is also equipped with a PCU (Power Control Unit) 11 . The PCU 11 incorporates an inverter 12 , a drive circuit 13 that turns on/off a switching element included in the inverter 12 , and a switch 14 that switches connection/disconnection between the inverter 12 and the battery 3 .

During power running when the motor 2 functions as an electric motor, the DC power output from the battery 3 is converted to AC power by the inverter 12 while the inverter 12 is connected to the battery 3, and the AC power is supplied from the inverter 12 to the motor 2. supplied. On the other hand, during regenerative operation in which the motor 2 functions as a generator, the motor 2 converts the power from the drive wheels into AC power. At this time, the motor 2 acts as a resistance of the drive system, and the regenerative braking force due to the resistance acts on the drive wheels. The AC power generated by the motor 2 is converted into DC power by the inverter 12 and the battery 3 is charged with the DC power.

Further, the vehicle 1 is equipped with an ECU (Electronic Control Unit) 15 . The ECU 15 incorporates a CPU, a non-volatile memory such as a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory). Although only one ECU 15 is shown in FIG. 1, the vehicle 1 is equipped with a plurality of ECUs having the same configuration as the ECU 15 in order to control each part. A plurality of ECUs including the ECU 15 are connected so as to be capable of two-way communication using a CAN (Controller Area Network) communication protocol.

A rotation angle sensor 16 is connected to the PCU 11 to detect the rotation angle of the motor 2 . The rotation angle sensor 16 is, for example, a resolver, has a rotor attached to the rotation shaft of the motor 2, and outputs changes in the rotation angle of the motor 2 as changes in two-phase AC voltage. The connection destination of the rotation angle sensor 16 may be the ECU 15 .

The ECU 15 includes an offset storage device 17 that stores the rotation angle of the motor 2 and the offset amount of the rotation angle detected by the rotation angle sensor 16 . Offset storage device 17 may be provided in PCU 11 .

The PCU 11 controls the operation of the inverter 12 via the drive circuit 13 of the PCU 11 in order to control the driving of the motor 2 based on the detection signal of the rotation angle sensor 16 and information received from other ECUs.

FIG. 2 is a circuit diagram showing a configuration of inverter 12. Referring to FIG.

The inverter 12 has a circuit configuration of a three-phase voltage source inverter. That is, the inverter 12 has a three-phase bridge circuit 21 and a smoothing capacitor 22 .

The three-phase bridge circuit 21 includes a series circuit of two switching elements 23U and 24U, a series circuit of two switching elements 23V and 24V, and a series circuit of two switching elements 23W and 24W. These series circuits are provided corresponding to the U-phase, V-phase and W-phase of the motor 2 . A series circuit corresponding to the U phase is connected to the U phase winding of the motor 2 at the connection point of the two switching elements 23U and 24U. A series circuit corresponding to the V-phase is connected to the V-phase winding of the motor 2 at the connection point of the two switching elements 23V and 24V. A series circuit corresponding to the W phase is connected to the W phase winding of the motor 2 at the connection point of the two switching elements 23W and 24W.

IGBTs (insulated gate bipolar transistors), for example, can be used for switching elements 23U, 23V, 23W, 24U, 24V, and 24W. The drive circuit 13 (see FIG. 1) turns on/off the switching elements 23U, 23V, 23W, 24U, 24V, and 24W by voltage applied to the gates of the switching elements 23U, 23V, 23W, 24U, 24V, and 24W. .

Series circuits corresponding to each of the U-phase, V-phase and W-phase are connected in parallel between plus wiring 25 and minus wiring 26 . The positive wiring 25 and the negative wiring 26 are connected to the positive terminal and the negative terminal of the battery 3, respectively. Smoothing capacitor 22 is connected to plus wiring 25 and minus wiring 26 between battery 3 and inverter 12 . A switch 14 is interposed in each of the positive wiring 25 and the negative wiring 26 between the battery 3 and the smoothing capacitor 22 .

<Offset amount setting processing>
FIG. 3 is a flowchart showing the flow of offset amount setting processing.

Depending on the mounting position of the rotation angle sensor 16 with respect to the motor 2 , a deviation occurs between the rotation angle of the motor 2 detected from the output signal of the rotation angle sensor 16 by the PCU 11 and the actual rotation angle of the motor 2 . In order to control the motor 2 efficiently and accurately, it is necessary to correct the rotation angle detected from the output signal of the rotation angle sensor 16 so as to match the actual rotation angle of the motor 2 .

Therefore, the ECU 15 executes offset amount setting processing for setting the offset amount used for the correction. The offset amount setting process may be performed when the ignition switch of the vehicle 1 is turned on for the first time, or may be performed periodically at appropriate timing.

The offset amount setting process is executed while the vehicle 1 is stopped. Further, when the offset amount setting process is executed, the switch 14 incorporated in the PCU 11 may be turned off to disconnect the inverter 12 from the battery 3 .

In this state, the q-axis current command value is set to 0, and the d-axis current command value is set to a predetermined value (step S1). Further, the rotation angle of the motor 2 is detected from the output signal of the rotation angle sensor 16, and an offset value is added to the rotation angle to calculate the current rotation angle necessary for calculating the energized voltage (step S2). Using this calculated rotation angle, the d-axis voltage command value and the q-axis voltage command value are obtained so that the d-axis current command value and the q-axis current command value are satisfied. A U-phase voltage command value, a V-phase voltage command value and a W-phase voltage command value are set by dq/three-phase AC coordinate conversion of the d-axis voltage command value and the q-axis voltage command value. Based on the U-phase voltage command value, the V-phase voltage command value, and the W-phase voltage command value, the operation of inverter 12 (on/off operation of switching elements 23U, 23V, 23W, 24U, 24V, and 24W) is controlled. As a result, current is supplied from the inverter 12 to the motor 2 (step S3: motor energization).

Since the q-axis current command value is set to 0, if the rotation angle detected from the output signal of the rotation angle sensor 16 matches the actual rotation angle of the motor 2, the current that does not contain the torque current component is It is supplied to the motor 2, the output torque of the motor 2 becomes 0, and the motor 2 does not rotate. However, if the rotation angle detected from the output signal of the rotation angle sensor 16 deviates from the actual rotation angle of the motor 2, a current containing a torque current component is supplied to the motor, causing the motor 2 to rotate.

It is determined whether or not the motor 2 has rotated by energizing the motor (step S4).

If the motor 2 rotates (YES in step S4), the offset amount used in calculating the rotation angle to be used in the next motor energization is updated (step S5).

<Effect>
As described above, in the actual vehicle, the offset amount used for correcting the rotation angle detected from the output signal of the rotation angle sensor 16 can be obtained. Moreover, the offset amount can be obtained in a safe state in which the vehicle 1 is stopped.

The motor 2 may be energized while the inverter 12 is disconnected from the battery 3, and the smoothing capacitor 22 provided in the inverter 12 may be discharged (discharge function) for the energization. In this case, the electric power of the battery 3 is not consumed and an additional configuration is not required to obtain the offset amount.

Furthermore, since the offset amount of the rotation angle sensor 16 mounted on the vehicle 1 is obtained in the state of the actual vehicle, when the motor 2, the PCU 11 or the rotation angle sensor 16 breaks down, the broken parts can be replaced individually. However, the offset amount of the rotation angle sensor 16 can be obtained after the replacement. Therefore, it is possible to replace the faulty part individually, and the maintenance cost of the vehicle 1 can be suppressed.

Further, whether or not the motor 2 is rotated by the motor energization is determined by the rotation within the backlash between the gears included in the power transmission mechanism 5 . As a result, it is possible to prevent the load from being applied to the motor 2 and to prevent the vehicle 1 from moving due to the rotation of the motor 2 .

<Modification>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

For example, even when the motor 2 does not rotate due to motor energization, the offset amount held in the offset storage device 17 is increased or decreased by a predetermined angle, and the offset amount is calculated when the motor does not rotate due to multiple times of motor energization. The offset amount to be finally held in the offset storage device 17 may be obtained based on the intermediate value.

As the difference between the rotation angle deviation ("actual rotation angle of the motor" and "rotation angle detected by the rotation angle sensor + offset amount") becomes smaller, the torque current component becomes smaller, and the frictional force of the bearing, etc. A phenomenon occurs in which the motor 2 does not rotate due to the reaction force even if there is a deviation in the rotation angle.

Therefore, in order to increase the accuracy of the offset amount for correcting the deviation amount of the rotation angle, energization processing is performed a plurality of times with different offset amounts, and the upper and lower limits of the offset value when the motor 2 does not rotate are adjusted. Defined offset amount.

Further, in the above-described embodiment, the vehicle 1 is an electric vehicle, but the vehicle 1 may be a hybrid vehicle (HV) equipped with a motor 2 as a drive source for running.

In addition, various design changes can be made to the above configuration within the scope of the matters described in the claims.

1: Vehicle 2: Motor 3: Battery 4: Driving Wheel 12: Inverter 15: ECU (Motor Control Device)
16: Rotation angle sensor 17: Offset storage device 21: Three-phase bridge circuit 22: Smoothing capacitor

Claims (2)

An inverter that includes a battery, a motor, a three-phase bridge circuit and a smoothing capacitor, is connected to the battery and the motor and converts DC power and AC power, and a signal that changes according to the rotation angle of the motor. and an offset storage device for the rotation angle sensor, and is used in a vehicle that travels by transmitting the power of the motor to drive wheels,
With the vehicle stopped, the q-axis current command value is set to 0, the d-axis current command value is set to a predetermined value, and the rotation angle detected from the output signal of the rotation angle sensor is stored in the offset storage device. A three-phase voltage command value corresponding to the d-axis current command value and the q-axis current command value is set using the rotation angle corrected by the above, and based on the three-phase voltage command value, from the inverter to the motor Execute the energization process to energize,
updating the offset amount held in the offset storage device with a value obtained by increasing or decreasing a predetermined angle when the motor rotates due to the energization by the energization process ;
increasing or decreasing the offset amount held in the offset storage device by a predetermined angle even when the motor does not rotate due to the energization by the energization process;
A motor control device that obtains an offset amount held in the offset storage device based on an intermediate value of offset amounts when the motor does not rotate due to energization by the energization process a plurality of times. The vehicle is provided with a drive gear and a driven gear that meshes with the drive gear on a power transmission path between the motor and the drive wheels,
2. The motor control device according to claim 1, wherein rotation of said motor due to energization by said energization process is rotation within a backlash between said driving gear and said driven gear.

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