A novel SVPWM scheme for Vienna rectifier without current distortion at current zero-crossing point

Abstract

Vienna rectifier is one of the most popular topologies for three-phase PFC converter. DC voltage, grid current double loop controller and three-level SVPWM are normally used to control the Vienna rectifier. Accurately detecting the current zero-crossing point is required to achieve the correct SVPWM signals since the output level of Vienna rectifier is also decided by the direction of the phase current. The error of the duty ratio is decided by the error time of the current zero-crossing point detecting and the duty ratio before and after the current zero-crossing point. It can be concluded that the impact of current zero-crossing will be eliminated if the switches near current zero-crossing point are kept “on”. To achieve this goal, a novel SVPWM scheme is proposed by using the certain state combinations of short vectors in each sector. In this method, the calculation of duty ratio will not be affected by the direction of phase current near the zero-crossing point, and therefore the distortion of current caused by current zero-crossing detection error will be eliminated. Simulations and experiments are conducted to verify the presented method.