电动汽车充电站谐波分析

Harmonic Study of Electric Vehicle Chargers

在电力系统中电动汽车充电机为非线性负荷,大型充电站有很多这类充电机,所产生的谐波对电网造成极大的危害,为了抑制谐波以得到较好的电能质量必须对大型充电站产生的谐波进行预测。首先建立单个充电机谐波分析数学模型,利用商用电动汽车充电机收集的数据对谐波电流进行计算,再利用概率统计学大数定律和中心极限定理,建立多谐波源谐波分析数学模型,研究多个电动汽车充电机产生的谐波电流及其概率特性。研究表明,利用概率统计学理论可以预测多谐波源产生的谐波电流。该研究结果同样适用于其他多个非线性负载产生的谐波电流的分析。

Electric vehicle （EV） chargers are highly non-linear load in power systems. They present a potential problem to power system in the forms of excessive harmonic currents and poor power factor. Thus it is important to analyze the effect of EV chargers on power system harmonic current and then to take some measures to improve the loading factor of power systems. Individual EV charger model has been set up on the basis of analyzing actual data from a commercial-available EV charge and battery. By computer simulation we analyzed harmonic current of individual EV charger. Using large number law and central limit theorem, statistics model of harmonic current produced by a cluster of harmonic sources has been built. Research shows that the model can predicte the harmonic currents produced by a group of EV chargers and can also be applied to other types of multiple non-linear loads.