六相子模块混合型MMC风电机组的全频域控制

Full Frequency Control of Six-phase Submodule Hybrid MMC Wind Turbine

针对深远海、中高压及大容量海上风电的应用场景,提出六相子模块混合型模块化多电平变流器(MMC)拓扑结构,研究其全频域的控制。在N个半桥子模块(HBSM)的基础上,增加一个全桥子模块(FBSM),增加等效输出电压电平数。针对其混合模块结构采用最近电平-脉宽调制的混合调制方式,达到降低开关损耗的作用,实现高效的电能变换。在全频域运行时,采用随机端电压频率变化的环流控制方法,将控制信号叠加在FBSM调制信号中,可减小子模块电容电压波动。通过仿真和实验验证该拓扑及控制的有效性。

A six-phase submodule hybrid modular multilevel converter(MMC)topology is proposed,its control in full frequency domain are studied,with the goal of addressing offshore wind power application scenarios in deep sea,medium and high voltage,and large capacity.To increase the number of equivalent output voltage levels,a full-bridge submodule(FBSM)is added on top of N half-bridge submodule(HBSM).For the hybrid module structure,hybrid modulation mode of nearest level pulse width modulation is used to reduce switching loss and realize efficient power conversion.In the full frequency domain,the circulation control method suppression with random terminal voltage and frequency change is adopted to superpose the control signal in the FBSM modulation signal,which can reduce the voltage fluctuation.The effectiveness of topology and control is verified by simulation and experiment.