一种直流充电桩电能计量精确算法

An Accurate Algorithm for Energy Metering of DC Charging Pile

阐述直流充电桩现场环境复杂,有直流、谐波和非稳态信号,使得传统的电能计算方法产生较大误差。提出一种结合经验小波变换(EWT)和互卷积窗(Kaiser与Rife-Vincent,K-RV)的电能计算方法,该方法通过EWT和希尔伯特(Hilbert)变换分解出直流信号和非稳态信号,K-RV互卷积窗FFT计算,分解出各次谐波信号;然后计算直流、谐波及非稳态电能。实例验证,此方法具有很高的计算精度,为直流充电桩现场电能计算提供了一种精确方法。

Due to the existence of DC signals, harmonic and unsteady signals, the electromagnetic field environment of DC charging pile becomes complex, which leads to fairly great error when using traditional electric energy calculation methods.Therefore, an electric energy calculation method combining EWT(empirical wavelet transform) and K-RV(Kaiser and Reaction-Vincent convolution window) is proposed in this paper. Firstly, the DC signal and unsteady signal are decomposed by EWT and Hilbert transform. Each harmonic signal is decomposed by calculating K-RV convolution window FFT. Then the DC electric energy, harmonic electric energy and unsteady electric energy are calculated respectively. Finally, it is verified by example that the proposed method has high calculation accuracy and can reduce the calculation error of electric energy, which provides an effective method for on-site electric energy calculation of DC charging pile.