基于虚拟阻抗的多逆变器并联运行控制策略研究

Research on Strategy of Multi-Inverter Parallel Operation Control Based on Virtual Impedance

考虑到低压微电网中多逆变器并联运行时功率合理分配和环流抑制的问题,提出了一种基于虚拟阻抗的多逆变器并联运行控制策略。由于逆变器的等效输出阻抗存在较大的差异,通过引入虚拟阻抗使得逆变器的系统输出阻抗呈可调节的感性,降低了线路电阻引起的功率耦合,并改善了各逆变器输出电压质量。在此基础上通过改进逆变器的功率下垂控制策略,实现了并联逆变器之间较高的功率分配精度和良好的动态响应能力,抑制了并联逆变器之间的环流。最后,在Matlab/Simulink环境下构建多逆变器并联系统模型,分析了多逆变器并联运行特性,仿真结果验证了所提控制策略的正确性和有效性。

Taking the problem of the power reasonable distribution and circulation of the current prevention problem in the low-voltage micro-grid during multi-inverters parallel operation,a multi-inverter parallel operation control strategy based on virtual impedance is proposed.As a huge difference in the equivalent output impedance of the inverter,a virtual impedance is introduced to achieve the system output impedance of the inverter to be regulated inductively,as well as reducing the power coupling due to line resistance and improving each inverter outputs voltage quality.On this basis,the power droop control strategy of the inverter is improved to achieve the high power distribution accuracy and good dynamic response capability,as well as reduced the circulation between the parallel inverters.Finally,the model of multi-inverter parallel system is established in Matlab/Simulink environment.It analyzes the parallel operation characteristics of multi-inverter.The simulation results verify the properness and effectiveness of the proposed control strategy.