CN-122001272-A - Motor driving system and fault diagnosis method thereof

Abstract

The present invention relates to a motor drive system and a failure diagnosis method thereof. The motor driving system includes a driving unit including a motor, a first inverter and a second inverter respectively connected to both ends of each of the plurality of windings, and a control unit configured to control outputs of the first inverter and the second inverter based on a zero sequence current instruction, and further configured to diagnose a failure of the driving unit based on a phase current flowing in each of the plurality of windings as a result of the control.

Inventors

• Gao Rongzhu
• An Junmo
• Bai Xuanyou

Assignees

• 现代自动车株式会社
• 起亚株式会社

Dates

Publication Date

20260508

Application Date

20250617

Priority Date

20241106

Claims (20)

1. 1. A motor drive system, comprising: A drive unit including a motor having a plurality of windings corresponding to a plurality of phases, a first inverter connected to a first end of each of the plurality of windings, and a second inverter connected to a second end of each of the plurality of windings, and And a control unit configured to control outputs of the first inverter and the second inverter based on a zero-sequence current instruction causing phase currents having the same magnitude and phase to flow in the plurality of windings, and further configured to diagnose a failure of the driving unit based on the phase currents flowing in the plurality of windings as a result of the control.
2. 2. The motor drive system according to claim 1, wherein the control unit is configured to maintain the value of the d-axis current command and the value of the q-axis current command at "0" when controlling the outputs of the first inverter and the second inverter based on the zero-sequence current command.
3. 3. The motor drive system of claim 1, wherein the zero sequence current command imparts a sinusoidal shape to each of the phase currents flowing in the plurality of windings.
4. 4. The motor drive system according to claim 1, wherein the control unit is configured to control the outputs of the first inverter and the second inverter based on the zero-sequence current instruction in a state where the rotational speed of the motor exceeds "0".
5. 5. The motor drive system according to claim 1, wherein the control unit is configured to control the outputs of the first inverter and the second inverter based on the zero-sequence current command before the start of the driving of the motor.
6. 6. The motor drive system of claim 1, wherein the control unit is configured to diagnose a failure of the drive unit when an error between a value of a phase current flowing in at least one of the plurality of phases and a value of the zero sequence current command exceeds a predetermined tolerance.
7. 7. The motor drive system according to claim 6, wherein the control unit is configured to diagnose that a phase corresponding to a winding through which the phase current flows is malfunctioning when an error between a value of the phase current flowing through at least one of the plurality of phases and a value of the zero-sequence current command exceeds a predetermined tolerance.
8. 8. The motor drive system of claim 1, wherein the drive unit further comprises a plurality of switches, each switch having a first end connected to a second end of a respective winding of the plurality of windings, each switch having a second end, wherein the second ends of the plurality of switches are connected to each other to form a node, The control unit is configured to control the switching states of the plurality of switching switches to electrically connect or disconnect the motor with the second inverter.
9. 9. The motor drive system according to claim 8, wherein the control unit is configured to control the outputs of the first inverter and the second inverter based on the zero sequence current command with the plurality of transfer switches turned off and the second inverter electrically connected with the plurality of windings.
10. 10. The motor drive system according to claim 1, wherein the control unit is configured to stop driving of the motor when a failure of the drive unit is diagnosed.
11. 11. A method for diagnosing a fault in a motor drive system having a drive unit including a motor having a plurality of windings corresponding to a plurality of phases, a first inverter connected to a first end of each of the plurality of windings, and a second inverter connected to a second end of each of the plurality of windings, the method comprising: controlling outputs of the first inverter and the second inverter based on a zero-sequence current command causing phase currents having the same magnitude and phase to flow in the plurality of windings; The failure of the drive unit is diagnosed based on the phase currents flowing in the plurality of windings as a result of the control.
12. 12. The method of claim 11, wherein controlling the output of the first inverter and the second inverter comprises setting the value of the d-axis current command and the value of the q-axis current command to "0" when controlling the output of the first inverter and the second inverter based on the zero sequence current command.
13. 13. The method of claim 11, wherein the zero sequence current command causes each of the phase currents flowing in the plurality of windings to have a sinusoidal shape.
14. 14. The method of claim 11, wherein controlling the output of the first inverter and the second inverter comprises controlling the output of the first inverter and the second inverter based on the zero sequence current command in a state where the rotational speed of the motor exceeds "0".
15. 15. The method of claim 11, wherein controlling the output of the first inverter and the second inverter comprises controlling the output of the first inverter and the second inverter based on the zero sequence current command before the driving of the motor begins.
16. 16. The method of claim 11, wherein diagnosing the failure of the drive unit comprises diagnosing the failure of the drive unit when an error between a value of phase current flowing in at least one of the plurality of phases and a value of the zero sequence current command exceeds a predetermined tolerance.
17. 17. The method of claim 16, wherein diagnosing the failure of the drive unit includes diagnosing that a phase corresponding to a winding through which the phase current flows is failed when an error between a value of the phase current flowing through at least one of the plurality of phases and a value of the zero sequence current command exceeds a predetermined tolerance.
18. 18. The method of claim 11, wherein the drive unit further comprises a plurality of switches, each switch having a first end connected to a second end of a respective winding of the plurality of windings, each switch having a second end, wherein the second ends of the plurality of switches are connected to each other to form a node, The method further includes controlling the switching states of the plurality of transfer switches to electrically connect or disconnect the motor from the second inverter.
19. 19. The method of claim 18 wherein controlling the output of the first inverter and the second inverter comprises controlling the output of the first inverter and the second inverter based on the zero sequence current command with the plurality of transfer switches off and the second inverter electrically connected to the plurality of windings.
20. 20. The method of claim 11, further comprising stopping the driving of the motor when the failure of the driving unit is diagnosed.

Description

Motor driving system and fault diagnosis method thereof Technical Field The present invention relates to a motor driving system for diagnosing a fault by using a zero sequence current command and a fault diagnosis method thereof. Background In the case of windings of the phases in the motor, one end of each winding is connected to one inverter, and the other ends of the windings are connected to each other to form a Y-connection. During motor driving, switching elements in an inverter are turned on and off by pulse width modulation control to apply a line-to-line voltage (line-to-line voltage) to Y-connected windings of the motor, thereby generating alternating current and generating torque. Further, instead of forming a Y-connection at the other end of the motor, two inverters may be connected to both ends of the motor, respectively, and the motor may be driven by the two inverters to increase the output of the motor. The fault diagnosis of the motor drive system including the motor and the inverter may be performed by applying a current command for fault diagnosis and identifying a value of a phase current flowing in each winding (for example, actual) in response to the current command. The foregoing is intended to help provide background to the invention and should not be construed as an admission that it is prior art that is already known to those of skill in the art. Disclosure of Invention The present invention provides a motor driving system and a fault diagnosis method thereof, which are capable of simultaneously (e.g., substantially) preventing vibration and noise caused by torque (e.g., instantaneous torque) while diagnosing faults. The present invention may not be limited to the subject matter provided herein, and other subject matter not mentioned may be understood from the following description. In an exemplary embodiment, a motor driving system includes a driving unit including a motor having a plurality of windings corresponding to a plurality of phases, a first inverter connected to one end (e.g., a first end) of each of the plurality of windings, and a second inverter connected to the other end (e.g., a second end) of each of the plurality of windings, and a control unit configured to control outputs of the first inverter and the second inverter based on a zero-sequence current instruction causing phase currents having the same magnitude and phase to flow in the plurality of windings, and diagnose a failure of the driving unit based on the phase currents flowing in the plurality of windings as a result of the control. In an exemplary embodiment, a method for diagnosing a fault of a motor drive system having a drive unit is provided. The driving unit includes a motor having a plurality of windings corresponding to a plurality of phases, a first inverter connected to one end of each of the plurality of windings, and a second inverter connected to the other end of each of the plurality of windings. The method further includes controlling outputs of the first inverter and the second inverter based on a zero-sequence current command causing phase currents having the same magnitude and phase to flow in the plurality of windings, and diagnosing a failure of the driving unit based on the phase currents flowing in the plurality of windings as a result of the control. According to the exemplary embodiment of the present invention, whether or not a motor driving system is malfunctioning can be diagnosed even when the motor is driven, and furthermore, a malfunctioning phase among the phases of the motor can be identified (e.g., explicitly pointed out). Further, according to the exemplary embodiment, by diagnosing whether the motor drive system is malfunctioning based on the zero-sequence current instruction, vibration and noise caused by the instantaneous torque during the malfunction diagnosis can be (e.g., substantially) prevented. The present invention may not be limited to the above-described modifications, and other modifications not mentioned may be understood from the description herein. Drawings Aspects and features of the present invention can be provided from the description herein and the accompanying drawings, wherein: fig. 1 and 2 provide configurations of a motor driving system according to an exemplary embodiment of the present invention. Fig. 3 provides a configuration of a control unit according to an exemplary embodiment of the present invention. Fig. 4 provides a graph of phase current and torque obtained by fault diagnosis of a motor drive system according to an exemplary embodiment of the present invention. Fig. 5 is a flowchart providing a method for diagnosing a failure of a motor drive system according to an exemplary embodiment of the present invention. Detailed Description Exemplary embodiments of the present invention are provided herein. The exemplary embodiments according to the present invention may be provided in various forms, and the present invention should not be limi