Harmonic amplification investigation and calculation of electric vehicle charging stations using three-phase uncontrolled rectification chargers

Abstract

In electric vehicle (EV) charging stations equipped with shunt active power filters (APFs), the operation of the shunt APF may amplify the charging current harmonics at the point of power collection (PPC), an effect called “harmonic amplification.” This paper focuses on an EV charging station with three-phase uncontrolled rectification chargers that produce the most serious harmonic pollution. By analyzing the coupling relationship between harmonic current and voltage, as well as by defining the total harmonic current amplification factor (TIF), an analytical method is proposed to quantify the amplification degree of the PPC charging current. Simulations and experiments verify the correctness of the method. Then, the variation trends that the amplification factor changes with key parameters, such as quantity of chargers, compensation rate, and compensation phase difference of APFs, are discussed. The results are beneficial to gaining further understanding on capacity correction and control design of APFs in EV charging stations.