A Control Method for THD Minimization in High Power Density Vienna-type Rectifier

Among many existing converter topologies for active power factor correction, Vienna-type rectifiers are widely used in high-power three-phase applications such as electric vehicle chargers, uninterruptible power supplies and telecommunication power supplies. The Vienna rectifier offers many advantages compared to the traditional two-level rectifier, which include: three-level switching, reduced switching losses, shoot-through immunity and lower conducted common-mode EMI. However, distortion of input currents is an inherent drawback of this topology due to the discontinuity of the switching current around zero-crossing. This issue can be resolved by oversizing the filter inductors or increasing the switching frequency. However, these approaches reduce power density, increase cost and switching losses of the converter. In this paper, we propose a control method that can reduce the total harmonic distortion (THD) of the input currents without adding to the costs or losses of the converter. The proposed control architecture is verified on a three-phase 12 kW SiC-based Vienna rectifier.