逆变器无连线并联系统的统一小信号模型及应用

Generalized small-signal model and its application for wireless-parallel inverter systems

为分析逆变器无连线并联系统的稳定性,建立了一种以下垂法作为均流控制方法的并联系统的统一小信号模型,并给出了下垂系数的设计方法.该小信号模型可适用于传统下垂法及改进下垂法控制的并联系统.基于小信号模型建立了由2台1 kVA逆变器构成的无连线并联系统,使用Matlab绘制了该并联系统的根轨迹图,分析了下垂系数变化对系统稳定性和动态响应性能的影响,并在此基础上选取了适当的下垂系数,使系统能稳定运行,实现较好的均流效果.实验结果证实了该小信号模型及下垂系数设计方法的正确性和可行性.

A generalized small-signal model for wireless-parallel inverter systems based on the droop-method was presented to analyse the stability of parallel inverter systems, and a method to design droop coefficients was proposed. The small-signal model is fit for parallel inverter systems based on both the traditional droop-method and the improved droop-method. As an application of the small-signal model, a parallel inverter system which consists of two 1 kVA inverters was built. The root locus plots of the system were shown by the software of Matlab. Influences of the coefficients＇ variation on the stability and dynamic response were studied. Optimum droop coefficients were obtained, which makes the system distribute current equally and work stably. Experimental results verified the correctness and feasibility of the small-signal model and the coefficient design method.