基于V2G的双向AC/DC变换器控制技术及电流畸变问题的研究

Research on Control Technology and Current Distortion of Bidirectional AC/DC Converter Based on V2G

随着智能电网和电动汽车技术的发展,V2G(vehicle-to-grid)概念受到越来越多的关注,其核心思想在于电动汽车和电网的双向互动,通过调度实现电动汽车的有序充放电,缓和新能源发电接入电网带来的波动,优化电网运行。双向变换器是实现V2G技术的核心装置,其不仅需要实现能量的双向流动,还要能够控制输入输出的电能质量,这便对变换器的控制提出了更高的要求。针对双向变换器的关键控制技术进行了分析、比较,选取了单极性PWM调制和平均电流控制作为本文所提双向变换器的控制策略;同时就单极性调制下电流过零点畸变的问题进行了理论分析,并且提出了一种改进的过零点控制策略。最后通过一个3 k W的双向AC/DC变换器实验平台证实了所提方法的有效性和可行性。

With the development of smart grid and electric vehicle(EV)technology,the concept of vehicle-to-grid(V2G)has attracted more and more attention.Its core idea is the interaction between EVs and power grid,in which orderly charging and discharging of EVs is realized through scheduling,and the fluctuations brought by the connection of new energy power generation to power grid is alleviated.In this way,the operation of power grid is optimized.Bidirectional converter is a core device to realize the V2G technology,which not only needs to realize the bidirectional flow of energy but also needs to control the power quality of input and output,thus leading to higher control requirements for the converter.In this paper,the key control techniques of a bidirectional converter are analyzed and compared,and the control strategies of unipolar PWM modulation and average current control are selected for the bidirectional converter.Meanwhile,the problem of current zero-crossing distortion under unipolar modulation is theoretically analyzed,and an improved zero-crossing control strategy is proposed to solve this problem.At last,the validity and feasibility of the proposed method was proved through tests on a 3 kW bidirectional AC/DC converter platform.