svg main circuit switch device open circuit fault location method

Abstract

The invention relates to a method for locating an open circuit fault of an SVG main circuit switching device, which is: x Phase output current, AC side grid of SVG x The phase voltage is sampled to obtain the sampled current and N a sampled voltage; calculate x The reactive power corresponding to the positive half-wave and the reactive power corresponding to the negative half-wave of the phase; calculation x Open-circuit fault characteristic value of the phase; according to x The relationship between the open-circuit fault characteristic value of the phase and a plurality of preset thresholds is used to determine the location of the open-circuit fault. The invention can accurately and reliably locate the open circuit fault of the SVG main circuit switching device, and is not affected by the load fluctuation, and solves the problem that the existing diagnosis method cannot distinguish the open circuit fault of the IGBT and the freewheeling diode.

Description

technical field [0001] The invention belongs to the field of inverter fault diagnosis, and in particular relates to a method for locating an open circuit fault of an SVG main circuit switching device. Background technique [0002] Inverters are more and more widely used in industrial production. Inverters must use power switching devices with high switching frequencies. According to the statistics of more than 200 surveys from 80 companies, power device failures account for more than 60% of inverter failures. Therefore, it is very important for inverters to quickly locate faulty power devices. [0003] At present, there are many fault diagnosis methods for inverter power devices, and current detection is the most commonly used method, such as PARK vector method and current vector trajectory method. However, these methods are only suitable for variable frequency speed regulation systems, not for SVG, because the AC side of the variable frequency speed regulation system is c...

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Problems solved by technology

However, these methods are only applicable to frequency conversion speed control systems, not SVG, because the AC side of the frequency conversion speed control system is connected to the motor, which is an inductive load

However, for SVG, it is necessary to work under both perceptual and capacitive working conditions, so the reliability of these judgment methods is difficult to guarantee

[0004] Open-circuit faults of power switching devices include IGBT open-circuit and free-wheeling diode open-circuit. Since the current direction of the upper-side IGBT and the lower-side diode is always the same, the above-mentioned diagnosis method based on the amount of current cannot further distinguish the open-circuit fault of the IGBT and the diode.

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