单相三电平PWM整流器双环控制系统的研究

Study of Dual Loop Control Technology of Single-phase Diode-clamp PWM Rectifier

为了得到单位功率因数、较低的电流谐波和较小的电压开关应力,对单相二极管箝位型三电平PWM整流器的双环控制系统进行了研究。中点电压平衡问题是三电平变换器的一个固有问题,因此针对单相三电平变换器进行了深入分析,并提出了一种中点电压平衡的Bang-Bang控制方法。仿效直流电机的转速电流双闭环控制,建立了三电平PWM整流器的双环控制模型,通过工程设计获得了良好的稳态和动态性能,保证了输入电流正弦化和单位功率因数。实验结果验证了控制方案的正确性和可行性。

A single-phase high power factor rectifier based on neutral-clamped converter （NPC） is proposed to achieve high power factor,lower current distortion and low voltage stress of power semiconductors.The principle of single-phase three-level PWM rectifier is introduced and mathematically modeled.Neutral-point balance is an inherent problem of threelevel converter,so a Bang-Bang control method is schemed to controi the capacities＇voltage.A dual close-loop control is used to make the rectifier have favorable dynamic and steady state performance,sinusoidal input current and unity power factor.Finally ,the feasibility and validity of the proposed control scheme are verified by the experiment.