基于载波移相的MMC电容电压均压控制

Balancing control of capacitance voltage for modular multilevel converter based on carrier phase shifted technique

模块化多电平换流器(Modular Multilevel Converter,MMC)多用在海上风力发电系统中。文章提出一种基于载波移相的闭环控制策略,解决了MMC子模块电容电压的不平衡问题。在基于多个子模块级联的MMC电路系统中,对MMC的每个子模块(Sub-Module,SM)都设置独立的电容电压均压电路。通过控制闭环电路的调制波来控制MMC子模块的投切,从而达到MMC电容电压的均衡。在Matlb/Simulink中搭建了仿真模型,仿真结果验证了所提控制策略能够真实、有效地实现MMC系统中电容电压的均衡控制。

The offshore wind power generation has more prospects,compared with the land one.Aiming at the capacitance voltage dis-equalization of MMC sub-module,this paper presents a closed loop control strategy based on carrier phase-shift to control the MMC capacitor voltage balance of submodule.In MMC circuit based on the cascaded multiple sub-module(SM)system,each module of MMC is set an independent equalizing capacitor voltage circuit.The modulating strategy of the closed-loop circuit can achieve the voltage balance of MMC capacitor,by controlling the switching of MMC module.The corresponding simulation model is set up in Mtalb/Simulink.The simulation results show that the presented control strategy can keep the capacitor voltage balance of the MMC circuit effectively.