在逆变电源并联系统中普遍采用外特性下垂控制技术,即依据有功功率和无功功率分别调节输出电压的相位和幅度。但是,对于电压电流双闭环反馈的单相逆变电源,输出有功功率和无功功率与输出电压相位和幅度均有耦合关系。针对这一问题,该文推导了单相逆变电源的等效输出阻抗,研究了有功功率和无功功率与输出电压相位和幅度间的定量关系;并在此基础上提出了一种外同步幅度下垂的并联控制策略,即逆变电源输出的相位通过外部总线来同步,而幅度则根据有功功率和无功功率的大小进行调节。建立了并联系统模型。实验结果表明了该方法的有效性。
The conventional droop-control strategy which is adopted generally for parallel inverter regulates the phase and the amplitude of the output voltage according to output active power and reactive power, respectively However, active power and reactive power are related to both output amplitude and output phase for double closed-loop feedback voltage-source inverter. This paper deduces the equivalent output impedance of the inverter and discusses the quantitative relationship between active/reactive power and amplitude/phase of output voltage. Then a parallel control strategy based on synchronization bus and output amplitude regulated by the couple connection beween the output active power and the reactive power is proposed and the model of parallel system is established. Experimental results show the effectiveness of the control strategy.