模块化多电平换流阀运行试验回路电流闭环控制方法研究

Research on Close-Loop Current Control Method of Operational Test Circuit for MMC Valves

模块化多电平换流器在投运前必须通过运行试验来考核其设计是否满足工程要求。根据IEC标准,运行试验需定性和定量地产生实际工况下的电流应力。传统方法主要采用开环控制方式对试验回路电流进行控制,其控制精度和等效性均有待提高。为此,针对H型运行试验拓扑,提出了一种回路中直流电流、基频电流、二倍频电流的闭环控制方法。采用该方法可使上述各电流分量精准快速地跟踪其参考值,从而使运行试验产生的电流应力与实际工况下的电流应力等效。最后,通过仿真与试验验证了所提控制方法的正确性和有效性。

Modular multilevel converter（MMC） must pass operational test before field operation to check whether its design meets engineering requirements.According to IEC standards,in operational test,the same current stress as the counterpart under actual operation condition need to be generated qualitatively and quantitatively.In traditional ways,open-loop control method is commonly used to control the current in test circuit and its control accuracy and equivalence both need to be improved.For this purpose,close-loop control methods for direct current,fundamental current and second harmonic current in H-model operational test topology are proposed in this paper.By adopting the methods,above mentioned current components can track their reference values accurately and rapidly,so that the current stress generated in the test is equivalent to the counterpart under actual operation condition.Finally,simulation and experiment verify correctness and effectiveness of the proposed control methods.