Harmonic Suppression Method of PWM Charger under Unbalanced Conditions

With the rapid development of the electric vehicle industry, the application prospects of PWM-type chargers can not be underestimated because of its unit power factor operation and low grid harmonic pollution. This paper analyzes the grid-side harmonic generation mechanism of PWM chargers under unbalanced conditions, and derives the coupling mechanism between the DC-side voltage ripple and grid-side current harmonics, and then an improved reduced order generalized integrator is proposed to suppress grid-side current harmonics. Finally, a simulation model is built in PSCAD to verify the effectiveness of the proposed control strategy.