电力电子变压器输入级LCL滤波研究

Research on Power Electronic Transformer Based on LCL-filter

提出了一种改进的电力电子变压器,输入级采用LCL滤波.LCL滤波器是3阶系统,自身存在谐振的可能,在获得较好滤波效果的同时,也降低了系统稳定性.因此提出了原边侧采用直流电压外环、网侧电流中环、电容电流内环的三闭环控制策略.另外,详细介绍了所提出的三闭环控制策略的电力电子变压器系统各部分工作原理,并基于Matlab/Simulink建立了仿真模型.仿真结果验证了该方案的有效性.

A research is presented on an improved power electronic transformer（PET） based on the LCL-filter, which can get better filtering effect. However, the character of three-step system makes the system unstable. In order to solve this problem, a control strategy of multiloop closed- loop - the primary side using the outer side loop of DC voltage,the grid side using middle loop of current,the inner loop using the capacitive current is proposed. The working principle of each component of the proposed PET system is explained in detail and the simulation model is established based on Matlab/Simulink. The simulation results verify the validity of the scheme.