基于下垂特性控制的无互联线逆变器并联动态性能分析

Analysis of Dynamic Performance for Parallel Operation of Inverters Without Wire Interconnections

对于无互联信号线逆变器并联系统,采用传统有功和无功功率下垂控制法往往会引起动态性能的问题。该文在传统下垂法中额外加入瞬态下垂分量,并且稳态下垂分量采用了旨在减小连线阻抗影响的并联控制策略,使多逆变器模块的电流均分能快速达到稳定。运用小信号建模分析表明控制方程系数的匹配能较大的影响瞬态响应,合理的参数设计有利于动态性能的提高。采用数字信号处理器(digital signal processor,DSP)实现全数字化逆变器并联系统设计,实验结果表明所提出的方案能有效提高无互联信号线逆变器并联系统的动态性能。

For system of parallel connected inverters without wire interconnections, using conventional PQ droop control method always results in the problems in dynamic performance. A supplemental transient droop was put in conventional droop method. A control strategy to alleviate the influence caused by link impedance was used in static droop. Thus the current distribution of multi-inverters parallel systems can reach the stable state rapidly. The small-signal model analysis verifies that matched parameters can greatly influence the transient response, and appropriate design of parameters is good for the improvement of dynamic performance. The DSP was adopted to realize fully digitized control in this inverter parallel system. The experimental results demonstrate that the improvement of dynamic performance in system of parallel connected inverters without using communication signals can be realized effectively by these schemes.