Abstract: In order to reduce the cost of three-phase Vienna-type rectifiers and improve the efficiency of corresponding control algorithms，a single closed-loop strategy without current sensor is designed． Aiming at the problems of the neutral point voltage unbalance and the complex calculation of the space vector pulse width modulation(SVPWM) topology of Vienna-type rectifiers，a simplified equivalent SVPWM technology is proposed based on carrier modulation，which controls the neutral-point potential balance mainly by adding the balance factor into the zero-sequence component． The combination of the single closed-loop control algorithm with the equivalent SVPWM simplifies the design process of the control system，and improves the efficiency of the whole control system． Finally，the correctness and effectiveness of the proposed algorithm are verified by an experiment．

Key words: vienna-type rectifier, single closed-loop strategy, neutral-point potential balance, space vector modulation, carrier modulation, zero-sequence component, pulse width modulation