无电解电容四象限变频器控制策略分析

Control Strategy Analysis of Four Quadrant Inverter Without Electrolytic Capacitor

针对传统四象限变频器直流母线采用大电解电容带来的缺点,以电梯变频系统为研究对象,对母线电容采用小薄膜电容的可行性进行分析,对电网侧变流器的双环控制策略展开了深入研究。网侧变流器采用了高阶的LCL滤波器,以更好地抑制并网电流的高次谐波。重点讨论了电流环和电压环控制策略,电流环采用PIR控制器,保证并网电流的总谐波满足并网要求,电压环采用PI控制加功率前馈控制,提高小母线电容时系统的稳定性。针对以上控制策略,搭建了离散化的Matlab仿真模型,并进一步搭建了样机,通过仿真和实验验证所提控制策略的正确性。

In view of the shortcomings of the traditional four quadrant inverter DC bus with large electrolytic capacitance,taking the elevator frequency conversion system as the research object,the feasibility of using small film capacitance for bus capacitance was analyzed,and the double loop control strategy of the grid side converter was studied.High-order LCL filter was adopted in the grid side converter to better suppress the high-order harmonics of grid connected current.The control strategies of current loop and voltage loop were mainly discussed.PIR controller was used in current loop to ensure that the total harmonic of grid connected current meets the grid connected requirements.PI control and power feed-forward control were used in voltage loop to improve the stability of the system when the small bus capacitance was applied.In view of the above control strategy,a discrete Matlab simulation model was built,and an experimental platform was further built.The correctness of the proposed control strategy was verified by simulation and experiment.