针对并网逆变器中的电流控制,对比分析了3种典型的线性控制策略。首先介绍了3种不同坐标系下电流控制策略的结构、特点。然后利用频谱搬移理论揭示了dq同步旋转坐标系控制的本质,并推导出了其在αβ静止坐标系下的等效结构;同时,从稳态精度、动态响应和抗电网扰动方面对3种控制策略的性能进行了理论分析。最后在MATLAB中进行仿真验证。理论分析和仿真表明,dq同步旋转坐标系控制和αβ静止坐标系控制在稳态精度、谐波含量、抗电网扰动方面的性能明显优于abc自然坐标系控制,而三者的动态性能差异细微。
Three typical linear current control strategies for grid-connected inverters are compared.Firstly,the structure and characteristics of linear current control strategies with three different reference frames are introduced.Then with spectrum shift theory,the essential of dq synchronous reference frame control is revealed,and its equivalent structure under αβ stationary reference frame is derived.Besides,concern on the steady-state errors,dynamic response and grid disturbance rejection,the performance of three different linear current control strategies are compared theoretically.Finally,the simulation results with MATLAB are presented.Theoretical analysis and simulation prove that the performance of dq synchronous reference frame control and αβ stationary reference frame control are much better than abc natural reference frame control,whereas the dynamic performance of the three are similar.