基于IHPWM的三电平VIENNA整流器中点电位平衡策略

IHPWM Based Neutral-point Voltage Balance Strategy for Three-level VIENNA Rectifier

针对三电平VIENNA整流器固有的中点电位波动问题,详细分析了中点电位平衡控制的可控和不可控区域,提出了一种改进型混合调制IHPWM(improved hybrid pulse width modulation)策略,即在可控区域采用空间矢量脉宽调制SVPWM(space vector pulse width modulation)策略,在不可控区域采用虚拟空间矢量脉宽调制VSVPWM(virtual SVPWM)策略。仿真实验表明,改进型混合调制方法能够有效地降低低频脉动,更好地平衡中点电位。

Considering the inherent fluctuation problem of neutral-point in the three-level VIENNA rectifier, the controllable and uncontrollable regions under neutral-point voltage balance control strategy are analyzed in detail, and an improved hybrid pulse width modulation（IHPWM） strategy is proposed, i.e., space vector pulse width modulation（SVPWM） is used in the controllable region, while virtual space vector pulse width modulation （VSVPWM） is used in the uncontro-llable region. Simulation results show that the improved hybrid modulation strategy can reduce the low-frequency ripple effectively and balance the neutral-point voltage better.