基于纹波电压前馈的级联H桥整流器输出电压平衡策略

Output voltage balance strategy based on ripple voltage feedforward for cascaded H-bridge rectifier

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。通过分析发现大范围投切载时输出电流扰动对平衡控制的影响不可忽略。在此基础上给出了投切载时系统调整时间、输出电压跌落值与系统特征参数之间的关系曲面。针对投切载时比例式脉冲补偿电压平衡控制下CHBR动态性能差的问题,结合输出电流与输出电压纹波峰值之间的关系,通过将输出电压纹波峰值引入电压平衡环节,提出了纹波电压前馈电压平衡控制策略,并给出了纹波电压峰值的检测方法。最后,利用三级CHBR的仿真模型和实验平台对所提策略与比例式脉冲补偿电压平衡控制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不平衡电压减小了12 V,调整时间缩短了43 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.It is found that the influence of output current disturbance on the balance control can not be neglected when a wide range of load is switched on or off.On this basis,the relational surfaces between the system adjustment time,the output voltage drop value and the system characteristic parameters are given.Aiming at the problem of poor CHBR dynamic performance under proportional pulse compensation voltage balance control during load switching,combining the relationship between output current and output voltage ripple peak,a ripple voltage feedforward voltage balance control strategy is proposed by introducing the output voltage ripple peak into voltage balance link,and the detection method of ripple voltage peak is given.Finally,the simulation model and experimental platform of three-stage CHBR are used to compare the proposed strategy with the proportional pulse compensation voltage balance control strategy.The test results show that the maximum unbalance voltage between the output voltages of the proposed strategy is reduced by 12 V and the adjustment time is shortened by 43 ms.The correctness and effectiveness of the proposed strategy are proved.