一种半周期SVPWM控制的三相双向双Buck/Boost变流器

Half-cycle SVPWM Controlled Three-phase Bidirectional Dual Buck/Boost Converters

三相AC/DC变流器广泛应用于中高功率场合,传统的三相桥式拓扑上下桥臂功率管直接相连,存在直通问题,需要在驱动信号中加入死区,导致大量低次谐波的产生。三相双Buck/Boost拓扑克服了上下桥臂的直通问题,无需设置死区,大大减小了交流侧的电流谐波。分析三相双Buck/Boost变流器的工作模态,定义半周期冗余开关信号,论证屏蔽冗余开关信号的必要性,讨论整流、逆变双向切换及半周期控制的过零畸变问题,并提出改进的半周期双向空间矢量脉宽调制(space vector pulse width modulation,SVPWM)控制策略,通过仿真与实验验证理论分析的正确性。

Three-phase AC/DC converters are widely used in high power applications. For the traditional three-phase bridge topology, the power switches of bridge arms are directly connected. The dead time should be added to the drive signal to prevent straight-through, which would lead to amount of low frequency harmonics. A three-phase dual Buck/Boost topology overcomes the straight-through problem and there is no need to set the dead time, the AC side current harmonic is greatly reduced. This paper analyzes operation modes of the three-phase Buck/Boost converter. The half cycle redundancy switch signal is defined and the necessity of masking redundancy switch signal is demonstrated. The bidirectional operation and zero crossing distortion caused by the half-cycle control are discussed. An improved method of half-cycle SVPWM is proposed. The simulation and experiment results verify the theoretical analysis.