基于有功电流峰值反馈的级联型PWM整流器电容电压平衡的研究

Research on Capacitor Voltage Balance of a Cascaded PWM Rectifier Based on Active Current Peak Feedback

根据能量守恒原理,对级联型PWM整流器(cascaded H-bridge rectifier,CHBR)进行串并联等效,提出一种基于有功电流峰值反馈的电容电压平衡算法。建立了CHBR的时间平均模型,得出调制比和各级单元有功电流峰值之间的数学关系,由此推出相应的控制算法。在MATLAB/Simulink中建立3单元的仿真模型,仿真结果表明所采用的基于有功电流峰值反馈的电容电压平衡控制是有效的,且易于实现。

In the principle of energy conservation, a capacitor vohage balance algorithm is proposed on the basis of series-parallel equivalence of the cascaded PWM rectifier. A time average model of the rectifier is established, the mathematical relationship between modulation ratio and active current peaks of units at various levels is obtained, and corresponding control algorithms are deduced. A 3-unit simulation model is built up in Matlab/Simulink. Simulation resuhs show that the capacitor voltage balance control based on active current peak feedback is effective and is easy to implement.