电动汽车充电站仿真模型及其对电网谐波影响

电动汽车的普及与推广将引致对大功率充电设备的大量需求,采用现代电力电子技术的大功率充电机是高度非线性的用电设备,对电网产生的谐波影响不容忽视。其产生的谐波主要来自充电机的整流装置,基于此,论文从适应于大量电动汽车充电需求的合理充电技术和合理充电规模问题出发,分别建立单台充电机和充电站仿真模型,仿真分析单台和多台充电机工作时对电网电能质量的影响,重点研究各次谐波电流含有率、电流总谐波畸变率和功率因数随电动汽车充电功率的变化规律及其随充电机台数增加的变化规律。仿真结果表明:大功率充电时,随着充电机台数的增加,各次谐波电流含有率呈减小的趋势,小功率充电时,随着充电机台数的增加,各次谐波含有率变化较平缓;电流总谐波畸变率随充电功率的增大和充电机台数的增加呈减小趋势,而功率因数的变化则由充电功率与充电机数目的耦合机制决定。

Simulation Model of Electric Vehicle Charging Station and the Harmonic Analysis on Power Grid

The promotion and popularization of the electric vehicles will lead to the large demand for high-power charging device,and the modern power electronic technique of charger is highly nonlinear electrical equipment.The impacts of a large number of charging station working on the grid cannot be ignored.In present study,considering the reasonable charge technology and charge scale for the large number of the electric vehicles,the models of single charger and charge station are built to analyze the impacts of the power quality.The factors of the harmonic current ratio,the current total harmonic distortion and the power factor varied with the charging power and the number of the chargers are discussed and analyzed.The simulation results show that the harmonic current ratio decreases with the increase of the number of chargers in the high power charging,and it changes relatively flat in the low power charging.Furthermore,the trend of the total harmonic distortion decreased with the increase of the charging power and the number of chargers,and the variation of power factor is determined by the coupling mechanism of the charging power and the number of the chargers.