混合型MMC全状态高效电磁暂态仿真方法研究

Research on Hybrid MMC Full-state Efficient Electromagnetic Transient Simulation Method

由半桥子模块和全桥子模块组成的混合型模块化多电平换流器(modular multilevel converter,MMC)兼顾直流故障穿越能力和经济性,具有广阔的工程运用前景。针对混合型MMC电磁暂态模型存在等效复杂、内部节点多、计算效率低的问题,文章分析混合型MMC解闭锁模式的工作状态,提出一种"混合型MMC全状态高效电磁暂态仿真方法":根据混合型MMC中半桥子模块和全桥子模块的闭锁特性,提出一种混合型MMC的闭锁等效方法,提高混合型MMC闭锁模式的仿真效率;根据混合型MMC的调制特性,改进灵活堆排序的电容电压排序算法,提高混合型MMC解锁模式的仿真效率。最后,结合Matlab和PSCAD典型算例进行测试,验证所提高效混合型MMC全状态电磁暂态仿真方法的精确性和快速性。

The hybrid modular multilevel converter(MMC), which composed of half-bridge sub-modules and full-bridge sub-modules, takes into account the DC fault ride-through capability and economy, with broad engineering application prospects. For the problems of complex equivalent,multiple internal nodes and low computational efficiency in the electromagnetic transient simulation model of the hybrid MMC, this paper analyzed the working state of the hybrid MMC in the unlocked and locked modes, and proposed a“efficient electromagnetic transient simulation method for hybrid MMC full-state”. According to the blocked characteristics of the half-bridge sub-modules and the full-bridge sub-modules in the hybrid MMC, the equivalent simulation method was optimized to improve the simulation efficiency in the blocked mode. According to the modulation characteristics of the hybrid MMC in unlocked mode, a flexible capacitor voltage sorting algorithm was proposed to improve the simulation efficiency for unlocked mode. Finally, with typical testing examples in Matlab and PSCAD, the accuracy and rapidity of the hybrid MMC high-efficiency electromagnetic transient simulation method proposed in this paper were verified.