应用于智能微网的SVPWM固态变压器研究

Research on the SVPWM Solid State Transformer Applied in Smart Micro-Grid

固态变压器(SST)是美国北卡大学所兴建的新型智能微网示范工程FREEDM的核心设备。本文以FREEDM的先进理念为背景,对SST的工作原理、主要创新功能和拓扑结构进行了分析,建立一个基于我国电力系统参数的三相交-直-交型SST模型,探讨该模型输入AC-DC整流单元、中间DC-DC变换单元和输出DC-AC逆变单元各部分的实现方式和控制策略,并引入空间电压矢量PWM(SVPWM)控制技术,提高SST的性能。通过Matlab/Simulink仿真分析表明,该SST模型能够实现单位输入功率因数和电能双向流动,输出三相工频正弦交流电压,具有良好的抗干扰性能,对FREEDM中国化具有重要意义。

SST is the fundamental component of the innovative smart micro-grid future renewable electric energy delivery and managementl（FREEDM） proposed by NC State University.In this paper,the operating mode,system function and topology of SST are analyzed from the FREEDM＇s overall system objectives.A three phase SST model based on Chinese power system parameters is built.The control strategies of input AC-DC rectifier,DC-DC converter and output DC-AC inverter are illustrated respectively,and SVPWM control technique is adopted to strengthen SST＇s performance.Simulation results demonstrate that the SST can exchange energy with grid smoothly while operating under a unit power factor condition.The low voltage wave is a perfect sine curve.The SST has good stability when heavy disturbances occur.This paper will play a constructive role in promoting the FREEDM research in China.