基于组合三相逆变器的孤岛微电网电压平衡控制策略

针对微电网孤岛运行时,微电网三相功率不平衡以及输出阻抗不同,导致三相电压不平衡的问题,本文提出了基于组合三相逆变器的孤岛微电网电压平衡控制策略。一方面,以组合式三相逆变器作为分布式电源的接口电路,从而实现对各桥的独立控制;另一方面,通过调整P~f和Q~U下垂曲线对传统下垂控制进行改进,得到三相平衡参考电压。此外,本文通过引进阻抗压降补偿控制,进一步改善输出阻抗不同引起的电压不对称问题。最后,在负载平衡和不平衡的情况下分别进行模拟与实验,结果表明本文所提电压综合控制策略的可行性及有效性。

Voltage Balance Control Strategy of Islanded Microgrid Based on Combined Three-Phase Inverter

In view of the issue of three-phase voltage imbalance due to imbalance of three phase power and different output impedance during the operation of islanded microgrid,the voltage balance control strategy of islanded microgrid based on combined three-phase inverter is proposed in this paper.On one hand,the combined three-phase inverter is used as the interface circuit of the distributed power supply so to achieve the independent control of each bridge.On the other hand,the traditional droop control is improved by adjusting the P~F and Q~U droop curves to obtain three-phase balance reference voltage.In addition,the issue of voltage asymmetry due to different output impedance is improved further by way of introducing impedance voltage drop compensation control in this paper.Finally,the simulation and experiment are carried out at load balance and unbalance conditions respectively.It is shown by the result that the proposed integrated voltage control strategy is feasible and effective.