MMC module voltage measuring and fault locating method based on state monitoring

Abstract

The invention discloses an MMC module voltage measuring and fault locating method based on state monitoring. Output ports of two adjacent single-capacitor modules in serial connection or a double-capacitor module serve as voltage collecting points, one voltage sensor or measuring circuit can measure the voltages of two modules, the amount of sensors or circuits is greatly reduced, and hardware cost and complexity are reduced. The measuring method can be used for voltage correction, errors caused by difference in parameters as the capacitance are avoided, whether a module has faults can be determined according to the obtained voltage and module state, and the system locates the module according to a fault signal emitted by the fault module. The module voltage measuring and fault locating method is realized in a module controller, the computing load of a main controller is not increased, and the hardware requirement is lowered. The module voltage measuring and fault locating method is suitable for high-voltage large-power occasions in which multiple MMC modules are included, such as the fields including energy Internet and high-tension DC power transmission.

Description

technical field [0001] The invention belongs to the technical field of power electronics application, and particularly designs a state monitoring-based MMC module voltage measurement and fault location method. Background technique [0002] With the rapid development of the economy and the gradual expansion of the scale of social production, the demand for various forms of power continues to grow, and the requirements for power electronic equipment are also getting higher and higher, and power electronics technology is developing rapidly. With the advantages of high output voltage, low harmonic content, small voltage change rate, small voltage stress of power switching devices, and low switching frequency, it is gradually becoming a research hotspot in the field of high-voltage and high-power power applications. With the continuous improvement of the withstand voltage level and capacity of fully-controlled power electronic devices, it is possible to apply a variety of voltage...

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Problems solved by technology

[0004] The existing module voltage measurement method is to directly measure the capacitor voltage of each module. On the one hand, each module must have a corresponding voltage sensor or voltage measurement circuit. The hardware complexity and cost are very large. On the other hand, The voltage of the capacitor in the module is often measured, and the fault of the switching device in the module can only be judged by the change of the capacitor voltage. The existing faulty module location method is also based on this method, so it takes a certain amount of time to find the faulty module. The change of the capacitor voltage in the module, if the time is too long, the impact of the faulty module on the system will become greater

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