基于储能单元的级联Buck-Boost变换器及其控制方法

Cascaded Buck-Boost Converter Based on Energy Storage Unit and Its Control Method

随着以风光电为主的分布式电源接入电网,其出力的波动性和不确定性,导致分布式电源发电特性和电网负荷需求特性在时间尺度上不统一,使得配电网的综合负荷特性的复杂度增加。为此,基于储能单元提出一种适用于储能单元的级联Buck-Boost变换器及其控制方法。首先分析了级联Buck-Boost变换器的储能单元结构及变换器的工作原理;其次确定了级联Buck-Boost变换器的三种工作模态;再根据变换器的不同运行模态选取下垂控制作为各储能单元模块的控制方法;最后搭建仿真模型对储能单元和选取的控制策略进行了验证,仿真结果验证了所提的变换器结构及其控制方法能很好地解决配电网因分布式电源接入带来的系统瞬时功率不平衡问题。

With the integration of distributed power sources based on wind and photovoltaic power connect into the grid,due to the fluctuation and uncertainty of its output,the characteristics of distributed power generation and grid load demand characteristics are not uniform on the time scale,which increases the complexity of the comprehensive load characteristics of the distribution network..A cascaded Buck-Boost converter and its control method based on the energy storage unit are proposed.Firstly,the energy storage unit structure of the cascaded Buck-Boost converter and the working principle of the converter are analyzed.Secondly,the three working modes of the cascaded Buck-Boost converter are determined,and then according to the different operating modes of the converter,the droop control is selected as the control method of each energy storage unit module.Finally,a simulation model is built to verify the energy storage unit and the selected control strategy.The simulation results verify that the proposed converter structure and its control method can well solve the instantaneous power imbalance problem of the distribution network caused by distributed power access.