Diagnosis method considering fault of inverter current sensor and open-circuit fault of power tube

Abstract

The invention discloses a diagnosis method considering a fault of an inverter current sensor and an open-circuit fault of a power tube. The method comprises the steps of acquiring a signal for diagnosis from an inverter; calculating an expected value and an actual value of a line voltage between bridge arms; calculating a deviation value of the line voltage between the bridge arms to serve as a first diagnosis variable; calculating a deviation value of a sum of inductive currents to serve as a second diagnosis variable; setting a threshold value of the first diagnosis variable; setting a threshold value of the second diagnosis variable; calculating the polarity of the first diagnosis variable and the polarity of the second diagnosis variable, and then comprehensively diagnosing the fault of the inverter current sensor and the open-circuit fault of the power tube according to a fault diagnosis table; and if the fault of the current sensor of a certain phase is diagnosed, performing fault tolerance of the current sensor. The diagnosis method provided by the invention has comprehensiveness, quickness and robustness, does not need extra hardware circuit, can be suitable for inverter systems of different control methods, and is low in sampling frequency and small in calculation amount.

Description

technical field [0001] The invention belongs to the technical field of fault diagnosis of power electronic equipment, and in particular relates to a diagnosis method that takes into account both inverter circuit sensor faults and power tube open circuit faults. Background technique [0002] Inverter reliability is important for applications such as renewable energy systems, microgrids and electric drivetrains. In order to meet the requirements of safety, cost and practicability in these application fields, more and more attention has been paid to the research of inverter fault diagnosis technology in recent years. [0003] The current sensor in the high-power inverter is prone to failure due to the influence of noise, vibration, aging and other factors. The failure of the sensor will cause the feedback current value to be wrong and cause the entire system to be disordered. The semiconductor power tube is the component with the highest failure rate in the power electronic co...

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Problems solved by technology

[0006] At present, there are many research methods for current sensor fault diagnosis and power tube open-circuit fault diagnosis. However, these diagnostic methods only consider one of the fault types, and do not consider the current sensor fault and power tube fault as a whole, whic...

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