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CN-122001273-A - Control method of three-phase current of vehicle motor, motor controller and vehicle

CN122001273ACN 122001273 ACN122001273 ACN 122001273ACN-122001273-A

Abstract

The application discloses a control method of three-phase current of a vehicle motor, a motor controller and a vehicle, and belongs to the technical field of vehicle engineering. The control method comprises the steps of detecting whether three-phase line voltages of the motor are balanced, acquiring currents of a first phase and a second phase of the motor under the condition that the three-phase line voltages of the motor are balanced, acquiring currents of a third phase of the motor based on the currents of the first phase and the second phase, and detecting whether three-phase currents of the motor are balanced based on the currents of the first phase, the second phase and the third phase. According to the control method for the three-phase current of the vehicle motor, the motor controller and the vehicle, whether the motor is balanced or not is identified by detecting the three-phase voltage, and under the condition that the three-phase voltage of the motor is balanced, the current of the third phase is reversely pushed by utilizing a three-phase balance current formula and the two-phase current, and whether the current state of the reverse-push motor reaches the three-phase balance state is detected by the three-phase current, so that whether the three-phase current of the motor is balanced or not can be determined more timely and accurately.

Inventors

  • ZHANG LITING
  • WANG JIN
  • YAN HONGWEI
  • YANG PAN
  • CAO QI

Assignees

  • 比亚迪股份有限公司

Dates

Publication Date
20260508
Application Date
20251230

Claims (15)

  1. 1. A method for controlling three-phase current of a motor of a vehicle, comprising: detecting whether the three-phase line voltage of the motor is balanced or not; Under the condition that the voltages of three phase lines of the motor are balanced, acquiring the current of a first phase and the current of a second phase of the motor; acquiring the current of a third phase of the motor based on the current of the first phase and the current of the second phase; Based on the current of the first phase, the current of the second phase and the current of the third phase, it is detected whether the three-phase currents of the motor are balanced.
  2. 2. The method according to claim 1, wherein the obtaining the current of the third phase of the motor based on the current of the first phase and the current of the second phase includes: Acquiring a first conversion voltage corresponding to the current of the first phase based on a supply voltage, the current of the first phase and a conversion coefficient, and acquiring a second conversion voltage corresponding to the current of the second phase based on the supply voltage, the current of the second phase and the conversion coefficient, wherein the conversion coefficient is used for indicating a conversion relation between the voltage and the current; acquiring a third conversion voltage based on the power supply voltage, the first conversion voltage and the second conversion voltage; And acquiring the current of a third phase of the motor based on the power supply voltage, the third conversion voltage and the conversion coefficient.
  3. 3. The control method of three-phase current of a motor of a vehicle according to claim 1 or 2, wherein the detecting whether or not three-phase voltages of the motor are balanced includes: Acquiring an average value of the three-phase line voltage as an average line voltage; And determining a three-phase line voltage balance of the motor in a case where a ratio of a maximum value in a difference between the three-phase line voltage and the average line voltage to the average line voltage is greater than a first threshold value.
  4. 4. The control method of three-phase current of a vehicle motor according to claim 1 or 2, characterized in that the detecting whether three-phase current of the motor is balanced based on current of the first phase, current of the second phase, and current of the third phase, includes: acquiring an effective value of an average current based on the current of the first phase, the current of the second phase and the current of the third phase; The three-phase current imbalance of the motor is determined in the case that the ratio of the maximum value of the difference between the effective value of the current of the first phase, the effective value of the current of the second phase, and the effective value of the current of the third phase and the effective value of the average current is greater than a second threshold value, and the three-phase current imbalance of the motor is determined in the case that the ratio of the maximum value of the difference between the effective value of the current of the first phase, the effective value of the current of the second phase, and the effective value of the current of the third phase and the effective value of the average current is less than or equal to a second threshold value.
  5. 5. The motor controller is characterized by comprising a control module and a conversion circuit, wherein the input end of the control module is respectively connected with the output end of a voltage sensor, the output end of a first current sensor, the output end of a second current sensor and the output end of the conversion circuit; the voltage sensor is used for collecting and outputting three-phase line voltage signals of the motor; The first current sensor is used for acquiring and outputting a first signal, wherein the first signal is a signal used for indicating the current of a first phase of the motor; the second current sensor is used for acquiring and outputting a second signal, wherein the second signal is a signal for indicating the current of a second phase of the motor; the conversion circuit outputs a third signal based on the first signal and the second signal, wherein the third signal is a signal for indicating the current of a third phase of the motor; The control module is used for detecting whether the three-phase line voltage of the motor is balanced or not based on the three-phase line voltage signals of the motor, and detecting whether the three-phase current of the motor is balanced or not based on the first signal, the second signal and the third signal.
  6. 6. The motor controller of claim 5 further comprising a first protection circuit and a second protection circuit, wherein the first protection circuit and the second protection circuit are connected with a trigger of a power module of the motor, and wherein an input end of the first protection circuit is connected with an output end of the first current sensor, an output end of the second current sensor and an output end of the conversion circuit, respectively; The first protection circuit is used for triggering the trigger to turn off a control signal sent by the control module to the power module under the condition that the current of any one phase of the motor exceeds a corresponding current threshold value; And the second protection circuit is used for triggering the trigger to turn off the control signal sent by the control module to the power module under the condition that the temperature of the switching device of any phase in the power module exceeds a temperature threshold value.
  7. 7. The motor controller of claim 6 wherein the second protection circuit comprises a first comparator, a second comparator, and a third comparator; The input signal of the second input end of the first comparator is a signal corresponding to the current threshold value corresponding to the current of the first phase; the input signal of the second input end of the second comparator is a signal corresponding to the current threshold value corresponding to the current of the second phase; The input signal of the second input end of the third comparator is a signal corresponding to the current threshold value corresponding to the current of the third phase; The output ends of the first comparator, the second comparator and the third comparator are all connected with the trigger.
  8. 8. The motor controller of claim 6 wherein the first protection circuit comprises a comparison circuit; The input end of the comparison circuit is respectively connected with the first temperature sensor, the second temperature sensor and the third temperature sensor, and the output end of the comparison circuit is connected with the trigger; The first temperature sensor, the second temperature sensor and the third temperature sensor are respectively used for acquiring the temperature of a switching device of one phase in the power module.
  9. 9. The motor controller of claim 8 wherein the comparison circuit comprises a multiplexer and a fourth comparator; The three input ends of the multiplexer are respectively connected with the first temperature sensor, the second temperature sensor and the third temperature sensor, the output end of the multiplexer is connected with the first input end of the fourth comparator, the input signal of the second input end of the fourth comparator is a signal corresponding to the temperature threshold value, and the output end of the fourth comparator is connected with the trigger.
  10. 10. The motor controller of claim 8 wherein the comparison circuit includes a maximum value detection circuit and a fifth comparator; Three input ends in the maximum value detection circuit are respectively connected with the first temperature sensor, the second temperature sensor and the third temperature sensor; the output end of the maximum value detection circuit is connected with the first input end of the fifth comparator, and the input signal of the second input end of the fifth comparator is a signal corresponding to the temperature threshold value; and the maximum value of the signals input by the input ends of the maximum value detection circuit is output from the output end of the maximum value detection circuit.
  11. 11. The motor controller of claim 10 wherein the maximum detection circuit comprises at least three branches, the branches comprising a first operational amplifier and a unidirectional conductive component; The first input end of each first operational amplifier in the three branches is respectively connected with the first temperature sensor, the second temperature sensor and the third temperature sensor; the second input end of the first operational amplifier in the branch is connected with the second end of the unidirectional conduction component, and the output end of the first operational amplifier is connected with the first end of the unidirectional conduction component; And the unidirectional conduction assembly is in a conduction state under the condition that the voltage of the first end of the unidirectional conduction assembly is larger than the voltage of the second end of the unidirectional conduction assembly.
  12. 12. The motor controller according to any one of claims 5 to 11, wherein the conversion circuit includes a second operational amplifier, the second operational amplifier includes a first operational amplification unit and a second operational amplification unit, an input signal of a first input terminal of the first operational amplification unit is a power supply voltage signal, an output terminal of the first current sensor and an output terminal of the second current sensor are respectively connected with a second input terminal of the first operational amplification unit, an output terminal of the first operational amplification unit is connected with a first input terminal of the second operational amplification unit, a second input terminal of the second operational amplification unit is grounded, and an output terminal of the second operational amplification unit is connected with an output terminal of the conversion circuit; The first operational amplification unit is used for subtracting the first signal and the second signal from the power supply voltage signal to obtain a third signal, and outputting the third signal after the target proportion is reduced; the second operational amplification unit is used for amplifying an input signal by a target multiple and outputting the signal, wherein the target multiple is the reciprocal of the target proportion.
  13. 13. A vehicle comprising a generator, a drive motor and two motor controllers as claimed in any one of claims 5 to 11, the two motor controllers being arranged to control the generator and the drive motor respectively.
  14. 14. The vehicle of claim 13, further comprising a power module of the generator, a power module of the drive motor, two sensor groups, wherein the sensor groups include one current sensor, a second current sensor, a first temperature sensor, a second temperature sensor, and a third temperature sensor; the two motor controllers are integrated on the control board, the conversion circuit and the first protection circuit of the two motor controllers are integrated into a current sampling processing unit, and the second protection circuit of the two motor controllers are integrated into a temperature sampling processing unit.
  15. 15. The vehicle of claim 14, wherein the first current sensor and the second current sensor each employ a hall sensor; The first current sensor and the second current sensor are arranged on a Hall magnetic induction circuit board, a plurality of pairs of shielding plates are arranged on the Hall magnetic induction circuit board, and each pair of shielding plates is used for isolating the first current sensor or the second current sensor from other first current sensors and other second current sensors.

Description

Control method of three-phase current of vehicle motor, motor controller and vehicle Technical Field The application belongs to the technical field of vehicle engineering, and particularly relates to a control method of three-phase current of a vehicle motor, a motor controller and a vehicle. Background In the related art, as the integration level of the electric automobile is higher, the reliability requirement on the power domain controller is higher. The three-phase current of the motor in the electric automobile is in a balanced state, and is a key for ensuring reliable operation and driving safety of the power domain controller. Currently, it is common to determine whether or not three-phase currents reach balance by monitoring three-phase currents of a motor, and in the case of unbalance of three-phase currents, to stop three-phase current output by controlling the motor. However, the method has the defects of high false alarm rate, large delay and the like, and is difficult to timely and accurately judge whether the three-phase current of the motor is balanced or not. Disclosure of Invention The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a control method of three-phase current of a motor of a vehicle, a motor controller and the vehicle, and whether the three-phase current of the motor is balanced or not can be determined more timely and accurately. In a first aspect, the present application provides a method for controlling three-phase current of a motor of a vehicle, the method comprising: detecting whether the three-phase line voltage of the motor is balanced or not; Under the condition that the voltages of three phase lines of the motor are balanced, acquiring the current of a first phase and the current of a second phase of the motor; acquiring the current of a third phase of the motor based on the current of the first phase and the current of the second phase; Based on the current of the first phase, the current of the second phase and the current of the third phase, it is detected whether the three-phase currents of the motor are balanced. According to the control method for the three-phase current of the vehicle motor, whether the motor is balanced or not is firstly detected by the three-phase voltage, then under the condition that the three-phase line voltage of the motor is balanced, the current of the third phase is reversely pushed according to the two-phase current obtained by hard line monitoring by utilizing a three-phase balance current formula, whether the current state of the reverse motor reaches the three-phase balance state is detected through the three-phase current, and whether the motor belongs to the three-phase balance state or not can be more timely and accurately determined through redundant monitoring of the three-phase balance system, namely, through double detection of whether the motor belongs to the three-phase balance state or not according to the three-phase voltage and the three-phase current. In addition, through the mode of double detection and double monitoring, the abnormal state of the motor can be found at the first time, the alarm prompt is carried out more timely to solve the problem, the power side abnormality, the motor side (namely the load side) abnormality or the internal analysis abnormality of the motor controller can be further clarified, the reliability of the motor controller in an application scene can be greatly improved, the reliability of motor control and the stability of motor operation can be improved, and the severe requirements of a new energy automobile in a high-power scene can be effectively met. According to one embodiment of the present application, the obtaining the current of the third phase of the motor based on the current of the first phase and the current of the second phase includes: Acquiring a first conversion voltage corresponding to the current of the first phase based on a supply voltage, the current of the first phase and a conversion coefficient, and acquiring a second conversion voltage corresponding to the current of the second phase based on the supply voltage, the current of the second phase and the conversion coefficient, wherein the conversion coefficient is used for indicating a conversion relation between the voltage and the current; acquiring a third conversion voltage based on the power supply voltage, the first conversion voltage and the second conversion voltage; And acquiring the current of a third phase of the motor based on the power supply voltage, the third conversion voltage and the conversion coefficient. According to one embodiment of the present application, the detecting whether the three-phase line voltage of the motor is balanced includes: Acquiring an average value of the three-phase line voltage as an average line voltage; And determining a three-phase line voltage balance of the motor in a case where a rati