基于电压控制的逆变器无互联线并联控制研究

Research on Parallel Operation of Inverters Without Interconnection Based on Voltage Control

针对传统PQ下垂法及其改进方法存在的控制复杂、对功率外环参数设计要求高、动态响应特性差的缺点,对逆变器并联控制条件及传统PQ下垂法进行分析,提出一种基于新型电压控制的逆变器无互联线并联控制策略。该策略跳出传统PQ下垂法的控制思路,提出一种新型电压控制环,通过直接控制逆变器输出电压,达到控制逆变器输出电流相位相同、幅值按各逆变器额定功率成比例的目的,不仅大大简化了控制程序的设计,提高了系统的动态响应特性,而且使电压下垂度能被人为控制。通过模拟负载突变实验验证了该策略的可行性和有效性,选用TMS320F28XXX作为控制核心。

To overcome the shortcomings of conventional and improved PQ droop, such as control complexity, high requirements for setting power loop parameters and poor dynamic response, the parallel control of inverters and the conventional PQ droop are analyzed.Then a strategy for parallel operation of inverters without interconnection based on novel voltage control is proposed.This strategy works beyond the idea of conventional PQ droop and designs a novel voltage control loop.This strategy achieves the purpose that the output current phases become the same and the amplitudes are proportional to the power ratings of inverters by directly controlling the output voltage of inverters, which greatly simplifies the control procedures design, improves dynamic response and enables the droop extent of output voltage to be controlled.The feasibility and effectiveness are verified through experimental results of load sudden change.The control core is TMS320F28XXX.