级联H桥整流器输出电压均衡控制及稳定分析

Output Voltage Balancing Control and Stability Region Analysis of Cascaded H-bridge Rectifier

级联H桥整流器(CHBR)体积重量小,可成倍提高等效开关频率,适用于航空、车载等对供电电源具有高功率密度技术要求的场合。实现输出直流侧电容电压均衡控制是CHBR实际应用的技术难点,此处以单相两单元CHBR为例,分别结合单极性倍频调制与载波移相正弦脉宽调制(SPWM)控制技术,提出了一种输出直流电容电压均衡改进控制策略,并通过相量图定量分析了系统稳定域,给出了输出直流负载不平衡度的定量表达式。最后通过系统仿真和原理样机实验验证了理论分析的正确性。

The cascaded H-bridge rectifier(CHBR)has a small volume and weight,and can multiply the equivalent switching frequency.It is suitable for aviation,vehicle and other occasions where the power supply has high power density technical requirements.The realization of voltage balancing control of output DC side capacitor is the technical difficulty in the practical application of CHBR.A single-phase two-unit CHBR is taken as an example,combined with unipolar frequency doubling modulation and carrier phase-shifting sinusoidal pulse width modulation(SPWM)control technology respectively,an improved control strategy of output DC capacitance voltage balancing is proposed,and the stability region of the system is quantitatively analyzed by phasor diagram,and the quantitative expression of output DC load unbalance degree is given.Finally,the correctness of the theoretical analysis is verified by system simulation and prototype experiment.