SVG用于单相负荷电能质量综合治理时相电流指令的计算

Phase-current reference calculation for SVG used in comprehensive management of single-phase load power quality

针对三角形级联静止无功发生器(SVG)用于单相负荷电能质量综合治理时指令电流的计算方案进行了研究。将指令电流分为基波电流指令和谐波电流指令两部分。其中,基波电流指令的计算采用基于电纳补偿原理的Steinmetzs理论,谐波电流指令的计算可采用单相谐波全补偿策略、以环流等于0为约束原则的谐波补偿策略、谐波均分补偿策略这3种谐波电流补偿策略,并从SVG每相电流有效值、SVG中开关器件的通态损耗、SVG中开关器件的电流容量3个角度对比了3种谐波补偿策略。在PSCAD中建立了低电压七电平SVG的仿真模型,并搭建了低压实验样机,分别通过仿真和实验验证了所述指令电流计算方案的正确性。

The calculating methods of phase-current reference for the delta-connected SVG（Static Var Generator）used in the single-phase load power quality management are researched. The phase-current reference is divided into the fundamental-current reference and the harmonic-current reference. The fundamental current is calculated based on the Steinmetzs theory while the harmonic current may be obtained by three harmonic compensation strategies：single-phase complete compensation,zero-circulating-current constrained compensation and evenly distributed harmonic compensation. The phase-current RMS,the on-state loss of switching device and the current capacity of switching device are compared among three strategies. A simulation model of low-voltage seven-level SVG is established in PSCAD and a low-voltage prototype is built. The simulative and experimental results validate the correctness of the introduced phase-current reference calculating methods.