Harmonic Resonance Suppression Strategy of the Front-End Vienna Rectifier in EV Charging Piles

Owing to the distributed installation position, the electric vehicle (EV) charging pile is usually connected to the grid via transmission cables of different lengths. The resonance of parasitic inductance and parasitic capacitance on the transmission cables might amplify the background harmonics, which result in a serious distortion of the grid-connected current of the front-end Vienna rectifier of EV charging piles. To overcome the resonance issue, this article proposes a harmonic resonance suppression strategy of the Vienna rectifier, which reshapes the closed-loop input harmonic impedance of the Vienna rectifier to be close to the characteristic impedance of the transmission cable by optimizing the traditional dual closed-loop control strategy of the Vienna rectifier based on the dq coordinate frame. The proposed suppression strategy can not only ensure the low ripple output voltage of the Vienna rectifier, but also suppress the background harmonic resonance amplification; thus, the power quality of the Vienna rectifier grid-connected current and the voltage at the point of common coupling will be improved effectively. Both the simulation and experimental results verify the effectiveness and correctness of the proposed strategy.