IP Library › Granted Patent US 12699150
Granted Patent B2
US 12699150 · App. 18/810,787 · Granted Aug 4, 2026

Fault detection method and fault protection method for power conversion system, and power conversion system

Inventors: Feiyang Zheng (Hefei, CN); Kai Deng (Hefei, CN); Le Li (Hefei, CN)
Assignee: Sungrow Power Supply Co., Ltd.
G01R31/52H02M5/04
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Quick Facts
Patent No.
US 12699150
App. No.
18/810,787
Granted
Aug 4, 2026
Kind
B2
Abstract

A fault detection method and a fault protection method for a power conversion system, and a power conversion system are provided, which relate to the technical field of fault detection for circuits. The fault detection method includes: controlling, when the power conversion system operates in a reactive mode, an alternating current pre-charge power supply to operate to charge a bus capacitor of the power conversion system, where the bus capacitor supplies power to a digital signal processor (DSP) through a first switch power supply (SPS), determining whether the DSP is energized to obtain a first determination result, and determining that the bus capacitor is short-circuited if the first determination result indicates that the DSP is de-energized. According to the present disclosure, when the bus capacitor of the power conversion system is short-circuited, the short-circuit fault of the bus capacitor can be detected.

Claims (42)

1 . A fault detection method for a power conversion system, comprising:

controlling, when the power conversion system operates in a reactive mode, an alternating current pre-charge power supply to operate to charge a bus capacitor of the power conversion system, wherein the bus capacitor supplies power to a digital signal processor (DSP) through a first switch power supply (SPS);

determining whether the DSP is energized to obtain a first determination result; and

determining that the bus capacitor is short-circuited, if the first determination result indicates that the DSP is de-energized.

2 . The fault detection method for a power conversion system according to claim 1 , wherein after the determining whether the DSP is energized to obtain a first determination result, the method further comprises:

controlling a first preset power supply to supply power to the DSP through the first SPS, if the first determination result indicates that the DSP is de-energized;

re-determining whether the DSP is energized to obtain a second determination result; and

determining that the bus capacitor is short-circuited, if the second determination result indicates that the DSP is energized.

3 . The fault detection method for a power conversion system according to claim 2 , further comprising:

determining that the first SPS fails, if the second determination result indicates that the DSP is de-energized.

4 . The fault detection method for a power conversion system according to claim 2 , wherein after the re-determining whether the DSP is energized to obtain a second determination result, the method further comprises:

controlling a second preset power supply to charge the bus capacitor, if the second determination result indicates that the DSP is energized;

determining whether there is a voltage on a direct current bus of the power conversion system to obtain a third determination result; and

determining that the bus capacitor is short-circuited, if the third determination result indicates that there is no voltage on the direct current bus.

5 . The fault detection method for a power conversion system according to claim 4 , further comprising:

determining that the alternating current pre-charge power supply fails, if the third determination result indicates that there is a voltage on the direct current bus.

6 . The fault detection method for a power conversion system according to claim 1 , wherein before the controlling an alternating current pre-charge power supply to operate, the method further comprises:

determining whether a processor of the power conversion system is communicatively connected to a battery management system (BMS); and

controlling the alternating current pre-charge power supply to operate, in a case of determining that the processor is communicatively connected to the BMS.

7 . The fault detection method for a power conversion system according to claim 6 , wherein after the determining whether a processor of the power conversion system is communicatively connected to a BMS, the method further comprises:

determining that there is a communication failure between the processor and the BMS, in a case of determining that the processor fails to be communicatively connected to the BMS.

8 . The fault detection method for a power conversion system according to claim 1 , wherein the determining whether the DSP is energized comprises:

determining whether the DSP is communicatively connected to a processor of the power conversion system;

determining that the DSP is energized, in a case of determining that the DSP is communicatively connected to the processor of the power conversion system; and

determining that the DSP is de-energized, in a case of determining that the DSP fails to be communicatively connected to the processor of the power conversion system.

9 . A fault protection method for a power conversion system, comprising:

controlling, during fault detection on the power conversion system with the fault detection method for a power conversion system according to claim 1 , the alternating current pre-charge power supply to stop operating when it is determined that the DSP is de-energized for a first time.

10 . The fault protection method for a power conversion system according to claim 9 , further comprising:

controlling the power conversion system to stop operating when it is determined that the bus capacitor of the power conversion system is short-circuited, when it is determined that the alternating current pre-charge power supply fails, or when it is determined that the first SPS fails.

11 . A power conversion system, comprising:

a DSP;

a first SPS, configured to supply power to the DSP;

a main circuit, wherein a bus capacitor is connected between a positive electrode and a negative electrode of a battery side of the main circuit, and the bus capacitor is connected to an input end of the first SPS;

an alternating current pre-charge power supply, wherein an output end of the alternating current pre-charge power supply is connected to the bus capacitor, and the alternating current pre-charge power supply is controlled by the processor; and

a processor, wherein the processor is communicatively connected to the DSP and a BMS, and the processor is configured to: control a first preset power supply through the BMS to supply power to the first SPS; and perform the fault detection method for a power conversion system according to claim 1 , to implement fault detection on the power conversion system.

12 . The power conversion system according to claim 11 , wherein the BMS is powered by an external second SPS and configured to supply power to the processor.

13 . The power conversion system according to claim 11 , wherein

a positive electrode of the bus capacitor is connected to a positive electrode of the input end of the first SPS through a first diode; and

the first preset power supply is configured to supply power to the first SPS through a second diode.

14 . The power conversion system according to claim 11 , wherein

a negative electrode of the input end of the first SPS is connected to a negative electrode of the output end of the alternating current pre-charge power supply through a third diode; and

a negative electrode of the bus capacitor is connected to the negative electrode of the output end of the alternating current pre-charge power supply through a fourth diode.