混合型MMC的开关频率优化控制算法

混合型MMC每一桥臂由半桥子模块（HBSM）和全桥子模块（FBSM）组成，能够在拥有低损耗、低成本等优点的同时保持故障穿越能力。其中，子模块（SM）电容均压会造成较高开关频率，导致开关损耗较大。为了解决该问题，研究了基于混合型MMC的开关频率优化排序控制策略，将保持因子引入混合型MMC模型，通过数学推导，设计了基于电容电压波动率的保持因子控制器。仿真结果表明，开关频率优化控制算法在保持均压效果的前提下，有效降低了开关频率，在高压直流输电等领域，具有科研理论意义和工程实践价值。

Optimal Switching Frequency Control Algorithm for Hybrid MMC

Each arm of hybrid MMC is composed of half bridge sub modules (HBSMs) and full bridge sub modules (FBSMs), which can maintain the fault ride-through capability while having the advantages of low loss and low cost. Among them, the capacitor voltage sharing of sub modules (SMs) will cause high switching frequency and large switching loss. In order to solve this problem, an optimized switching frequency se-quencing control strategy based on hybrid MMC is studied. The holding factor is introduced into the hybrid MMC model and a holding factor controller based on capacitor voltage fluctuation rate is designed through mathematical derivation. The simulation results show that the optimized switching frequency sequencing control algorithm effectively reduces the switching frequency while maintaining the voltage equalization effect. In the field of HVDC transmission, it has theoretical significance of scientific research and engineering practice value.