Frequency domain harmonic model of electric vehicle charger using three-phase uncontrolled rectifier

The harmonic pollution of electric vehicle (EV) charging station is mainly caused by the former level uncontrolled or thyristor-controlled rectification circuit of charger. In allusion to the charger which adopts three-phase uncontrolled rectifier with passive power factor correction, this paper analyzes the operating principle of charging current in continuous and discontinuous mode. According to the voltage and current balance equations in charging process, the frequency-domain harmonically coupled admittance matrices of charger are derived, and the parameters of the harmonic admittance matrix under different operating modes are gained on the basis of the charging equivalent circuit, therefore the frequency-domain harmonic analytical model of EV charger is established. This model transforms the time-domain nonlinear characteristic of charger into frequency-domain linear admittance matrix to represent the coupling relationship between current harmonic and terminal voltage harmonic of charger. Finally, the accuracy of the model proposed this paper is verified by the simulation analysis and experiment test.