三端口柔性多状态开关多模式平滑切换控制策略

A Control Strategy for Smooth Switching of Three-port Flexible Multi-state Switches

光伏整县推进和电动汽车快速发展造成配电网末端电压偏高等电能质量问题,基于区域柔性互联的柔性多状态开关(flexible multi-state switch,FMSS)技术成为解决方案之一。针对柔性多状态开关PQ模式与VF模式间切换的波动及冲击性问题,提出在状态跟随控制器之后添加惯性环节,并改进相位预同步环节,可实现FMSS并离网工作模式的平滑切换。针对FMSS直流母线控制端的馈线故障导致系统运行崩溃问题,提出一种引入权值调节的控制策略,可实现系统稳定运行情况下,有功控制和直流母线电压控制的平滑切换。在MATLAB/Simulink环境下搭建了三端口FMSS仿真模型,对提出的控制策略进行了仿真验证,仿真结果实现了任意馈线故障下三端口FMSS无缝转供电功能。最后搭建物理实验平台,进一步验证了所提平滑切换策略的有效性。

The rapid development of photovoltaic(PV)and electric vehicle(EV)has caused power quality problems such as high voltage at the end of distribution network,and flexible multi-state switch(FMSS)technology based on regional flexible interconnection has become one of the solutions.Aiming at the fluctuation and impact of switching between PQ mode and VF mode of flexible multi-state switch,the study proposes to add inertia link and and improve phase pre-synchronization link after the state-following controller,which can realize the smooth switching of FMSS parallel and off-grid operating modes.A control strategy with the introduction of weight adjustment is proposed to realize the smooth switching of active control and DC bus voltage control under the stable operation of the system,in respond to potential operation collapse due to feeder failure at the DC bus control terminal of FMSS.A threeport FMSS simulation model was built in MATLAB/Simulink environment to simulate and verify the proposed control strategy,and the simulation results demonstrate the seamless switching function of three-port FMSS under any feeder fault.Finally,a physical experiment platform was built to further validate the effectiveness of the proposed smooth switching strategy.