US-20260126488-A1 - MOTOR DRIVING SYSTEM AND METHOD FOR DIAGNOSING FAULT THEREOF

Abstract

A motor driving system and a method for diagnosing a fault thereof are provided. The motor driving system includes a driving unit including a motor, and a first inverter and a second inverter connected to both ends of each of multiple windings, respectively, and a control unit configured to control outputs of the first inverter and the second inverter based on a zero-sequence current command and further configured to diagnose a fault in the driving unit based on a phase current flowing in each of the multiple windings as a result of the control.

Inventors

• Young Su KO
• Jun Mo An
• Hyun Woo Paik

Assignees

• HYUNDAI MOTOR COMPANY
• KIA CORPORATION

Dates

Publication Date

20260507

Application Date

20250605

Priority Date

20241106

Claims (20)

1. 1 . A motor driving system including: a driving unit including a motor having multiple windings corresponding to multiple phases, a first inverter connected to a first end of each of the multiple windings, and a second inverter connected to a second end of each of the multiple windings; and a control unit configured to control 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 multiple windings, and the control unit further configured to diagnose a fault in the driving unit based on the phase currents flowing in the multiple windings as a result of the control.
2. 2 . The motor driving system of claim 1 , wherein the control unit is configured to maintain values of a d-axis current command and a q-axis current command at “0” while controlling the outputs of the first inverter and the second inverter based on the zero-sequence current command.
3. 3 . The motor driving system of claim 1 , wherein the zero-sequence current command has a sinusoidal wave.
4. 4 . The motor driving system of 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 with a rotational speed of the motor exceeding “0”.
5. 5 . The motor driving system of 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 when driving of the motor is started.
6. 6 . The motor driving system of claim 1 , wherein the control unit is configured to diagnose that a fault has occurred in the driving unit, when an error between a value of a phase current flowing in at least one of the multiple phases and a value of the zero-sequence current command exceeds a predetermined tolerance.
7. 7 . The motor driving system of claim 6 , wherein the control unit is configured to diagnose that a fault has occurred in a phase corresponding to a winding where a phase current, with the error exceeding the predetermined tolerance, flows.
8. 8 . The motor driving system of claim 1 , wherein the driving unit further includes multiple changeover switches, each changeover switch having a first end connected to the second end of a corresponding winding among the multiple windings, each changeover switch having a second end, wherein the second ends of the changeover switches are interconnected to form a node, and wherein the control unit is configured to control switching states of the multiple changeover switches to electrically connect or disconnect the motor and the second inverter.
9. 9 . The motor driving system of 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 multiple changeover switches turned off and the second inverter electrically connected to the multiple windings.
10. 10 . The motor driving system of claim 1 , wherein the control unit is configured to stop driving of the motor when a fault is diagnosed to have occurred in the driving unit.
11. 11 . A method for diagnosing a fault in a motor driving system having a driving unit, the driving unit includes a motor having multiple windings corresponding to multiple phases, a first inverter connected to a first end of each of the multiple windings, and a second inverter connected to a second end of each of the multiple windings, the method including: 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 multiple windings; and diagnosing a fault in the driving unit based on the phase currents flowing in the multiple windings as a result of the control.
12. 12 . The method of claim 11 , wherein the controlling of the outputs includes providing values of a d-axis current command and a q-axis current command at “0” while controlling the outputs 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 provides each of the phase currents flowing in the multiple windings to have a sinusoidal shape.
14. 14 . The method of claim 11 , wherein the controlling of the outputs includes controlling the outputs of the first inverter and the second inverter based on the zero-sequence current command with a rotational speed of the motor exceeding “0”.
15. 15 . The method of claim 11 , wherein the controlling of the outputs includes controlling the outputs of the first inverter and the second inverter based on the zero-sequence current command before driving of the motor is started.
16. 16 . The method of claim 11 , wherein the diagnosing of the fault includes diagnosing that a fault has occurred in the driving unit, when an error between a value of a phase current flowing in at least one of the multiple phases and a value of the zero-sequence current command exceeds a predetermined tolerance.
17. 17 . The method of claim 16 , wherein the diagnosing of the fault includes diagnosing that a fault has occurred in a phase corresponding to a winding where a phase current, with the error exceeding the predetermined tolerance, flows.
18. 18 . The method of claim 11 , wherein the driving unit further includes multiple changeover switches, each multiple changeover switch has a first end connected to the second end of a corresponding winding among the multiple windings, each changeover switch having a second end, wherein the second ends of the changeover switches are interconnected to form a node, and wherein the method further includes controlling switching states of the multiple changeover switches to electrically connect or disconnect the motor and the second inverter.
19. 19 . The method of claim 18 , wherein the controlling of the outputs includes controlling the outputs of the first inverter and the second inverter based on the zero-sequence current command with the second inverter electrically connected to the multiple windings.
20. 20 . The method of claim 11 , further comprising stopping the driving of the motor when a fault is diagnosed to have occurred in the driving unit.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This application claims priority under 35 U.S.C. 119 to Korean Patent Application No. 10-2024-0156396, filed on Nov. 6, 2024, in the Korean Intellectual Property Office, the disclosure of which is herein incorporated by reference in its entirety. TECHNICAL FIELD The present disclosure relates to a motor driving system for diagnosing a fault by using a zero-sequence current command and a method for diagnosing a fault thereof. BACKGROUND In the case of windings of phases in a 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 driving of the motor, switching elements in the inverter are turned on and off by pulse width modulation control to apply a line-to-line voltage to the Y-connected windings of the motor, thereby generating alternating current and producing torque. Furthermore, instead of forming a Y-connection with the other end of the motor, two inverters may be connected to opposite ends of the motor, respectively, and the output of the motor may be increased by driving the motor through the two inverters. Diagnosis of a fault in a motor-driven system including the motor and the inverter may be performed by applying a current command for fault diagnosis and identifying the value of a phase current (e.g., actually) flowing in each winding in response to the current command. The foregoing is intended to aid in providing background of the present disclosure, and is not intended to provide that the present disclosure is prior art. SUMMARY The present disclosure provides a motor driving system capable of diagnosing a fault while (e.g., substantially) preventing vibration and noise caused by (e.g., instantaneous) torque, and a method for diagnosing a fault thereof. The present disclosure may not be limited to the technical subjects provided herein, as other technical subjects which are not mentioned may be understood from the following descriptions. In an example embodiment, a motor driving system includes a driving unit including a motor having multiple windings corresponding to multiple phases, a first inverter connected to one end (e.g., a first end) of each of the multiple windings, and a second inverter connected to the other end (e.g., a second end) of each of the multiple windings, and a control unit configured to control 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 multiple windings, and diagnose a fault in the driving unit based on the phase currents flowing in the multiple windings as a result of the control. In an example embodiment, a method for controlling a motor driving system is provided. The method for diagnosing a fault in a driving unit includes a motor having multiple windings corresponding to multiple phases, a first inverter connected to one end of each of the multiple windings, and a second inverter connected to the other end of each of the multiple windings. The method also includes controlling outputs of the first inverter and the second inverter based on a zero-sequence current command, which causes phase currents having the same magnitude and phase to flow in the multiple windings, and diagnosing a fault in the driving unit based on the phase currents flowing in the multiple windings as a result of the control. According to example embodiments of the present disclosure, it may be possible to diagnose whether a fault has occurred in the motor driving system, even while the motor is being driven, and furthermore, it may be possible to identify (e.g., specify) a phase in which the fault has occurred among phases of the motor. Furthermore, according to an example embodiment, by diagnosing, based on the zero-sequence current command, whether a fault has occurred in the motor driving system, it is possible to (e.g., substantially) prevent vibration and noise caused by instantaneous torque during the fault diagnosis process. The present disclosure may not be limited to the above-mentioned improvements, and other improvements which are not mentioned may be understood from the descriptions herein. BRIEF DESCRIPTION OF THE DRAWINGS The aspects and features the present disclosure may be provided from the description and accompanying drawings herein, in which: FIGS. 1 and 2 provide a configuration of a motor driving system according to an example embodiment of the present disclosure. FIG. 3 provides a configuration of a control unit according to an example embodiment of the present disclosure. FIG. 4 provides a graph of a phase current and torque resulting from the fault diagnosis of a motor driving system according to an example embodiment of the present disclosure. FIG. 5 is a flowchart providing a method for diagnosing a fault in a motor drive system according to an example embodiment of the present disclosure. DETAILED DESC