一种用于无互连线逆变器并联的多环控制方法

An Improved Wireless Control Strategy for Parallel Operation of Distributed Generation Inverters

针对传统逆变器无线并联系统稳态均流精度低和动态响应差等缺点,提出基于传统无线并联下垂法的新型多环控制结构,分析了逆变器并联系统有功和无功功率的环流模型。在传统的双环控制结构中增加了负载电流和输出电压补偿环,提高了单台逆变器的性能;基于PQ下垂系数法增加了瞬时电压基准补偿环和输出阻抗调节环,提高了系统的动态均流能力和对线阻抗等参数不平衡的调节能力。仿真和实验结果均验证了该方案的良好性能。

In this paper, a novel control scheme is presented, which is able to improve the transient response and power sharing accuracy of parallel-connected inverters with no control interconnections, and the active and reactive circulating current of the parallel system model are analyzed. A multiple-loop controller is developed based on the traditional droop method. The output voltage and load current compensation loops are added in the scheme to improve the performance and robust of single inverter. The instantaneous reference adjustment loop and variable impedance adjustment loop are added to enhance dynamic performance of parallel inverters, as well as reduce the circulating current at the parallel inverter＇s startup and running. The proposed controller provides both steady-state objectives and a good transient performance. Simulation and experimental results are reported, confirming the validity of the proposed control technique.