基于复合滑模控制的MMC串联微电网电压控制策略

Voltagecontrol strategy of MMC series microgrid based on Composite sliding mode control

针对孤岛运行模式下MMC串联结构微电网系统存在的输出电压波动问题,提出了一种复合滑模控制方法实现系统输出电压稳定控制。该方法采用电压外环滑模控制、电流内环PI控制的双闭环结构。为了简化系统控制器的设计,使用逆系统方法对非线性、强耦合的原系统进行反馈线性化实现解耦控制。然后,采用载波移相脉宽调制技术产生调制信号来控制发电单元模块工作。最后,通过搭建仿真模型进行验证。仿真结果表明,与传统的双闭环PI控制相比,复合滑模控制下系统具有较快的动态响应速度和较强的抗负载扰动能力。

Aiming at the problem of output voltage fluctuation of Modular Multilevel Converter series micro grid system in islanded operation mode,a composite sliding mode control method is proposed to realize the output voltage stability control.This method adopts double closed-loop structure of voltage outer loop sliding mode control and current inner loop PI control.In order to simplify the design of the system controller,the inverse system method is used to linearize the nonlinear and strong coupling original system to realize decoupling control.Then,the carrier phase shifted pulse width modulation(CPS-SPWM)technology is used to generate the modulation signal to control the power generation unit module.Finally,it is verified by building a simulation model.The simulation results show that,compared with the traditional double closed-loop PI control,the system under compound sliding mode control has faster dynamic response speed and stronger anti-load disturbance ability.