对电压电流双闭环反馈控制单相逆变器的输出特性进行了研究,给出了单相逆变器并联系统的等效模型.分析了并联系统中电流环流与逆变器基准信号幅值和相位的关系,并在此基础上提出了一种通过对逆变器输出电流进行有功、无功分解,然后对基准信号的幅值和相位进行解耦控制的逆变器并联控制策略.针对单相逆变器的有功、无功电流分解问题,通过构造三相对称电流,运用瞬时无功理论对输出电流进行有功、无功分解.从而得到输出有功电流、无功电流并给出电流分解的实现框图。基于上述原理研制了实验样机.实现了2台2kV·A逆变器的并联运行控制,实验结果验证了所提出方法的可行性和有效性。
The output characteristics of single- phase inverter with voltage and current closed- loop controls are analyzed and the equivalent model of parallel operating single-phase inverter system is introduced. The relationship between the circulating current and the amplitude and phase of inverter reference is analyzed, based on which the control strategy of parallel operating inverter system is proposed. It decomposes the active and reactive components of inverter output current and then carries out the decoupled control of inverter reference amplitude and phase. A three-phase symmetrical current is constructed according to the instantaneous reactive power theory to decompose the active and reactive components of inverter output current and its implementation block diagram is given. The prototype is developed and the control of two parallel operating 2 kV·A inverters is realized. The experimental results show its feasibility and effectiveness.