不同电流检测方法对并网逆变器用于电能质量治理的比较分析

现有可再生能源发电并网系统出力具有的间歇性、波动性等特点降低了其设备利用率。兼具电能质量治理和并网功能的复合功能并网逆变器的提出提升了并网设备利用率并改善了并网电能质量。针对其重要环节之一的负荷电流补偿分量检测与提取,本文研究了三相三线制电路在不平衡和非线性负载下两种电流检测方法的差异,并对这两种方法进行运算复杂度进行分析,这两种方法分别是依据p⁃q理论而来的ip⁃iq检测法和基于CPT(conservative power theory)理论的检测法。通过Matlab/Simulink建立的系统模型进行仿真分析。仿真结果表明在不平衡和非线性负载下基于CPT理论的电流检测法可以更灵活地检测出负载电流各分量,但ip⁃iq检测法所需运算量更少。

Comparative Analysis of Different Current Detection Methods for Power Quality Control of Grid-connected Inverters

The intermittent and volatility of the existing renewable energy power generation grid connected system reduces the utilization rate of its equipment. The proposal of multi function grid connected inverter with power quality control and grid connected functions has enhanced the utilization rate of grid connected equipment and improved grid connected power quality. In view of the detection and extraction of load cur rent compensation components, which is one of the important aspects, in this paper the difference between the two current detection methods of three phase three wire system under unbalanced and non linear loads is studied, and the computation complexity of these two methods is analyzed. The two methods are the ip iq detection method based on the p q theory and the detection method based on the CPT( conservative power theory) theory. The simulation model was carried out by the system model established by Matlab/Simulink. It is shown by the simulation result that the current detection method based on CPT theory can detect the components of the load current more flexibly under unbalanced and non linear loads, but the computation needed by the ip iq detection method is less.