UPQC并联变流器频域无源控制策略研究

Study on passivity-based control strategy in frequency domain for the shunt converter of UPQC

为了提高统一电能质量控制器(UPQC)中并联变流器的频域补偿性能,本文提出在频域中设计一种多频无源控制策略.采用傅里叶变换技术对其交流数学模型进行频谱分解及多频直流建模,在被指定频率的直流模型上实施所提的控制器设计,理论分析表明该控制策略能够实现对并联变流器的指定频率控制,而且除了适用于三相系统外也适用于单相系统,可实现分相控制.该策略改善了传统在基频模型上设计的无源控制策略在跟踪多频指令信号时控制性能下降的现象.实验结果表明所提的控制策略可将谐波补偿率提高到95%.

In order to improve the compensation performance of shunt converter of unified power quality controller （UPQC） in frequency domain,this paper proposes a multi-frequency passivity- based control （PBC） strategy implemented in frequency domain. Firstly,with the Fourier trans-form technique,spectral decomposition on the mathematical model of AC shunt converter is con-ducted ,its multi-frequency DC model established. Then the proposed PBC controller is designed based on the DC model at asigned frequency. According to theoretical analysis, the strategy can not only realize asigned frequency control for the shunt converter but also achieve individual phasecontrol applicable to three phases and single phase system. Besides,the strategy can surmountthe deficiencies that the significant performance degradation of traditional PBC designed at the fundamental frequency model when tracking multi-frequency control signal. Finally, experimental results verify that the proposed control strategy coaid improve the harmonic compensation rede to 95%.