超级电容储能系统中双向DC-DC变换器控制策略研究

城市轨道交通站间距较短、运行密度大,列车需要频繁的启动和制动,列车在启动时需要大量能量,导致直流牵引网电压下降;列车在再生制动时产生大量能量,导致直流牵引网电压升高,严重时还会使再生制动失效。针对这一问题,提出将双向DC-DC变换器应用于超级电容储能系统中,并设计了电压外环、电流内环的双PI控制策略。利用Matlab/Simulink搭建了双向DC-DC变换器和超级电容储能系统的仿真模型,分析了双向DC-DC变换器在Buck模式、Boost模式下的运行情况以及电压外环、电流内环的双PI控制策略的控制效果。仿真结果验证了双向DC-DC变换器能够实现能量的双向传输和控制策略的有效性。

Research on Control Strategy for Bi-Directional DC-DC Converter in Super Capacitor Energy Storage System

The short distance between urban rail transit stations and the high density of railway result in frequent start-ups and brakings of the trains, involving a large consumption of energy when starting, and a drastic drop in DC traction network voltage. A lot of energy is generated during regenerative braking, which leads to an increase of the voltage of DC traction network, and a regenerative braking failure as well. With an aim to solve this problem, a bidirectional DC-DC converter is proposed for the super capacitor energy storage system, and a dual PI control strategy is designed for the voltage outer loop and current inner loop. A simulation model of bidirectional DC-DC converter and super capacitor energy storage system has thus been established based on Matlab/Simulink, and an analysis has been made of the operation of the bi-directional DC-DC converter in Buck mode and Boost mode, and of the control effect of double PI control strategy for the voltage loop and current loop. The simulation results show that the bidirectional DC-DC converter is capable of achieving the bi-directional transmission of energy, thus verifying the effectiveness of the control strategy.