A maximum power factor of control algorithms of three-level Vienna Rectifier without current distortion at current zero-crossing point

Abstract

Three-level Vienna Rectifier is one of the most popular topologies for three-phase PFC converter which is used in many applications such as telecommunication and wind turbine systems. However, the current distortion resulted from the existence of filter inductor at current zero-crossing point deteriorates the grid current. The traditional injection of zero-sequence component (IZSC) doesn't work well when the modulation index exceeds a certain value. This paper first analyses the mechanism of the current zero-crossing distortion and the application scope of the IZSC, and proposes a novel method which combines the IZSC with the compensation of lagging reactive power. Compared with the IZSC, this approach overcomes the limited application of the modulation index and ensures three-phase current without zero crossing distortion. It also guarantees minimum compensation of reactive power, that is, Vienna Rectifier can achieve the maximum power factor. Simultaneously, this method is extremely simple to be realized by carrier modulation. Finally, the simulation results show the feasibility and effectiveness of the theoretical analysis.