电压源型虚拟同步机并联系统均流控制方法

Current Sharing Control Method for Parallel System of Voltage Source Type Virtual Synchronous Generation

分析了逆变器并联系统的环流产生机理,指出在线路阻抗呈感性时,并联单元间线路阻抗差异和输出电压偏差对系统无功功率均分具有较大影响。为此,提出一种电压源型虚拟同步机(VSG)并联系统均流控制方法,通过在VSG无功电压控制环路上叠加一个根据当前无功功率自适应变化的电压补偿值,可以有效改善由于线路阻抗不一致和电压偏差导致的无功功率不均分,实现并联系统的均流控制。仿真和实验结果验证了该控制策略可以显著抑制功率环流,实现不同线路参数下各台逆变器输出功率的平均分配。

The circulation mechanism of the parallel inverter system is firstly analyzed.It reveals that the difference of the line impedance and the deviation of the output voltages between two parallel units both have significant effects on the power sharing accuracy of reactive power under the condition of the inductive line impedance.A current sharing control method for parallel system of voltage source type virtual synchronous generation(VSG)is proposed.By superimposing voltage compensation according to the adaptive reactive power change on the reactive voltage control loop of VSG,the reactive power unevenness due to line impedance inconsistency and voltage deviation can be effectively improved and the current sharing control of the parallel system can be realized.The simulation and experimental results verify that the control strategy can significantly suppress the power circulation and achieve the average distribution of the output power of each inverter under different line parameters.