模块化多电平换流器交流故障穿越试验研究

Experimental Research on the Fault-ride-through Control of Modular Multilevel Converter Under Alternating Current Grid Faults

针对模块化多电平换流器(MMC),研究了基于a,b,c坐标系的三相瞬时电流直接控制策略,建立了MMC瞬时电流直接控制方法。通过基于MMC的直流输电小容量试验样机,对MMC在各种交流电网故障情况下动态电流控制特性和故障穿越特性进行试验研究。结果表明,采用三相瞬时电流直接控制方法时,MMC在暂态过程中对电流控制性能良好,能顺利穿越交流电网故障,在故障期间维持有功功率传输,并提供动态无功支撑。

The dynamic current control strategy of modular multilevel converter （MMC） based on three phase instantaneous currents is discussed.A direct instantaneous current controller for MMC is developed under three-phase a, b ,c coordinates.A prototype of MMC-based HVDC system is built to verify the direct instantaneous current controller.The dynamic response and fault-ride-through capability under various alternating current grid faults are verified using experimental results.The experimental results show that the MMC have a good control performance during the transients,and can ride through the alternating current grid faults successfully.Besides,the MMC can also provide dynamic reactive power during the faults.