摘要
近年来分布式并网发电受到越来越多关注,抑制直流分量注入电网是并网系统必须解决的首要问题,直流分量可分为共模直流分量和差模直流分量。通常使用工频变压器实现直流分量隔离,然而变压器增加了系统的成本、体积和损耗,在无隔离并网系统中,理论上逆变器通过精确地控制可以使输出电流差模直流分量为零。实际上由于闭环系统中测量误差(包括模数转换误差、传感器测量误差)等原因,逆变器输出电流中包含差模直流分量。本文通过与基于瞬时无功功率理论的谐波检测抑制差模直流分量的方法对比,提出了采用滑动平均滤波器来检测输出电流中差模的直流分量,然后将其反馈到系统中进行闭环控制,从而使得差模直流分量达到允许的范围。搭建了40 kW的仿真和实验平台,证明了该方法的有效性。
With the growing popularity of distributed generation in recent years, the problem of suppressing DC component to inject into the grid connect system must be solved firstly. DC component is divided into common mode and differential mode. The isolation of DC component is normally achieved by the use power frequency transformer. However, the transformer increases the system cost, size and loss. In the Nonisolation grid-connected system, the inverter can in theory keep the differential DC component of output current to zero by way of accurate control. In fact, the differential DC component is included in the output current of inverter due to such reasons as measurement error in the loop system(including modulus transfer error and the measurement error of sensor). In this paper, the use of moving average filter is proposed to detect the differential DC component of the output current by the comparison with the harmonic detection suppression differential DC component method based on instantaneous reactive power theory, then it is fed to the system for loop ring control, thus keeping the differential DC component reach the permitted range.The 40 kW simulation and experimental platform is set up and the effectiveness of the method is proved.
出处
《电力电容器与无功补偿》
北大核心
2018年第1期132-137,共6页
Power Capacitor & Reactive Power Compensation
基金
国家科技部基金项目(矿井爆炸危险性实时监测预警技术研究
2013BAK06B08)
关键词
并网逆变器
无隔离变压器
瞬时无功功率理论
滑动平均滤波
grid-connected inverter
non-isolated transformer
instantaneous reactive power theory
moving average filter
