基于p-q-r理论的UPQC直接控制策略

阐述了p-q-r瞬时功率理论的原理,提出了基于该理论的统一电能质量控制器(UPQC)的直接控制策略,探讨了将其用于三相四线非线性及不平衡系统中的实现方法。着重介绍了p-q-r参考波形的产生方法,以及串联补偿电流和并联补偿电压的计算方法,并将其应用于非线性不平衡负载在电源电压不平衡及电压跌落情况下UPQC直接控制策略中。分析了控制策略的原理,推导出相关运算公式,给出了详细的控制框图。Matlab/Simulink仿真结果表明,采用该方法可以有效地消除非线性及不平衡负载对电网的影响,使电网输入功率因数为1,同时,串联补偿器隔离了电网电压对负载电压的扰动,并联补偿器给负载提供三相平衡及正弦的额定电压,不受电网电压变化的影响。

Direct control strategy of UPQC based on p-q-r theory

The p-q-r instantaneous power theory is introduced,based on which a direct control strategy of UPQC(Unified Power Quality Conditioner) is presented and its implementation in non-linear and unbalanced three-phase four-wire system is discussed.The reference wave generation in p-q-r coordinates and calculation methods of series compensation current and shunt compensation voltage are emphasized,which are used in UPQC direct control for nonlinear and unbalanced system when unbalance and sag occur in source voltage.The principle of control strategy is analyzed,relevant formulas are deduced,and detailed control block diagrams are provided.Simulations with Matlab / Simulink show that,the method eliminates the influence of nonlinearity and unbalanced load on power system and makes the input power factor equal to 1.Furthermore,the series compensator isolates the effect of network voltage variation on load voltage and the shunt compensator provides balanced and sinusoidal rated three-phase voltages to load.