基于VSG微网储能变流器无缝切换控制策略研究

针对微网储能变流器采用状态跟随控制器进行切换的过程中存在微小电压、电流扰动等问题,本文提出了一种基于线性自抗扰控制器(LADRC)的无缝切换控制策略。在采用P/Q控制和VSG控制相互切换方法的基础上,将电流内环控制器改成线性自抗扰控制器。通过设计一个状态观测器LESO实时在线观测估计输出变量直轴、交轴电流id、iq以及系统的各种扰动;将扰动估计值补偿给P/Q控制器和VSG控制器切换过程中的突变量,从而抑制切换过程中的电压、电流波动。最后,建立基于LADRC的储能变流器无缝切换仿真模型。仿真结果验证了该方法的可行性。

Research on Seamless Switching Control Strategy of Microgrid Power Converter System Based on VSG

A seamless switching control strategy based on linear active disturbance rejection controller(LADRC) is proposed to solve the problems of switching impulse current and voltage fluctuation in the conventional switching process of microgrid power converter system. Based on the switching method of P/Q control and VSG control, the current inner loop PI controller is replaced by a LADRC. A state observer LESO is designed to real time estimate the disturbances of the output variables such as the straight axis current id and the quadrature axis current iq online. The disturbance estimates are compensated to the sudden changes in the switching process of the P/Q controller and the VSG controller, so as to suppress the voltage and current fluctuations in the switching process. Finally, a seamless switching simulation model of power converter system based on LADRC is established. The simulation results verify the feasibility of this method.