配电系统电子电力变压器不对称负载仿真

Simulation research on imbalance loads of electronic power transformer in distribution system

配电系统中经常会出现不对称负载运行的情况,研究不对称负载情况下电子电力变压器的特性和控制策略,对于电子电力变压器在配电系统中应用有重要意义。通过分析原方系统和副方负载的要求,提出了一种简单而有效的控制方案:其输入级在d-q轴系中采用直流电压外环和交流电流内环的双环解耦控制,其输出级采用基于输出电压瞬时值反馈的双环控制。在Matlab/Simulink环境下建立了仿真模型,通过对空载、满载、单相负载、不平衡线负载和非线性负载等条件下的仿真表明,针对三相四线配电系统电子电力变压器所设计的控制方案,无论是在对称负载还是不对称负载条件下,电子电力变压器都能实现原方系统输入电流正弦和负荷侧供电电压恒定,具有良好的负载特性。

A three-phase four-wire distribution system electronic power transformer（EPT） implemented with the input stage, isolation stage and output stage was presented and its load characteristics were analyzed. A simple and appropriate control was developed to obtain good characteristics based on analyzing the demand of the primary system and the loads. In this control scheme the dual-loop decouple control in synchronous rotating d-q frame was adopted in the input stage and the dual-loop control based on voltage instantaneous value was introduced in the output stage. The load characteristics of the electronic power transformer were investigated in detail by simulations under Matlab/Simulink. The results show that the EPT has good performances with the proposed control scheme under balance and imbalance loads, which makes the input current sinusoidal and keeps the load voltage in normal value.