级联H桥整流器输出电压平衡控制策略研究

Research on Cascaded H-Bridge Rectifier Output Voltage Balance Control Strategy

对传统的比例式脉冲补偿电压平衡控制策略进行了建模分析,给出了电压平衡比例积分(PI)控制器的参数设计公式。由于级联H桥整流器(CHBR)各级电路输出电压的平方与输入电流成线性关系,因此在比例式脉冲补偿电压平衡控制的基础上,采用输出电压的平方作为控制量,提出了输出电压平方反馈的电压平衡策略,该策略由于引入了可变比例环节,可加快系统的动态响应速度,减小误差,提高负载切换时的动态性能。最后,利用三级CHBR的仿真模型和实验平台对所提策略与传统策略进行了比较测试,测试结果表明所提策略在切载后各级输出电压间的最大压差降低了13 V,调整时间缩短了63 ms,证明了所提策略的正确性和有效性。

The traditional proportional pulse compensation voltage balance control strategy is modeled and analyzed.And the parameter design formula of the voltage balance proportional integral(PI) controller is given.Since the square of the output voltage of cascaded H-bridge rectifier(CHBR) circuits is linear with the input current,based on the proportional pulse compensation voltage balance control,the square of the output voltage is used as the control quantity,and the voltage balance strategy of the output voltage square feedback is proposed.This strategy introduces a variable proportional link,which can speed up the dynamic response speed of the system,reduce the error,and improve the dynamic performance during load switching.Finally,the simulation model and experimental platform of the three-stage CHBR are used to compare the proposed strategy with the traditional strategy.The test results show that after the load is cut,the maximum voltage difference between the output voltages of the proposed strategy is reduced by 13 V and the adjustment time is shortened by 63 ms,which proves the correctness and effectiveness of the proposed strategy.