基于改进下垂控制的分布式电源并联运行技术

Parallel Operation Technology of Distributed Generations Based on Improved Droop Control

在多分布式电源(distributed generation,DG)并联运行的系统中,传统的下垂控制受线路阻抗的影响,难以实现无功功率的合理分配,为此提出了改进下垂控制方法。讨论了功率与电压、频率的关系,分析了DG容量对下垂参数选择的影响,并在此基础上采用Q-ΔU(Q为分布式电源输出的无功功率,ΔU为分布式电源输出电压的变化值)下垂控制和ΔU恢复机制相结合的控制方法对DG输出的无功功率和电压进行控制。算例结果验证了该方法的可行性。

In power grid containing multi parallelly operated distribution generations （DG）, due to the impact of line impedance on traditional droop control it is hard to implement rational distribution of reactive power. For this reason, an improved droop control method is proposed. The relationship among power, voltage and frequency is discussed and the impact of capacity of DG on the selection of droop parameters is analyzed. On this basis, a control method combining the Q-AU droop control, in which Q is the reactive power output of DG and AU is the variation of voltage of DG, with restoration mechanism of voltage of DG is used to control both reactive power output and voltage of DG. Simulation results of two parallelly operated inverters show that the proposed method is feasible.