Model Simulation of AC Home Electric Vehicle Chargers Based on Charging Cycle Power Quality Analysis

摘要

This paper presents the development and results of tests on chargers of alternating current (AC) home electric vehicles (EVs) and their model simulation based on measured data. The first tests of the EVs charging system were conducted in steady state and indicators were selected in order to assess the electric grid power quality when an EV is plugged in. When the EV is plugged in, there was no presence of sag, swell, overvoltage or undervoltage. Total Harmonic Voltage Distortion (THDv) and voltage regulation during EV charging were under 5%, which is the legal limit for both of them in Colombia. The second test was conducted in transient state at the beginning of charging. The analysis of voltage and current was done by means of Continuous Wavelet Transform (CWT). The results of the EV charger tests at transient state show that the highest current harmonics were 2nd, 3rd, and 4th; it is also worth mentioning that there were no transient oscillations of frequency. From measurement results, a model of EVs battery charger level I was implemented. In the literature, there are some models of EVs battery charger based on its power electronics, but there are few models based on test assessment of EV charging cycle. The results of this simulation show a maximum error of less than 1 % with respect to the measured values that allow to predict impacts on electric grid when EVs are plugged in or to assess scenarios of EVs massification.