Modeling method for harmonic model of three-phase charger of electric vehicle

Abstract

The invention discloses a modeling method for a harmonic model of a three-phase charger of an electric vehicle. The modeling method comprises the following steps: deducing a time-domain expression of an alternating current of the charger of the electric vehicle according to a three-phase uncontrollable bridge type rectification equivalent circuit; creating a three-phase charger harmonic coupling admittance matrix according to obtained charging currents in two work modes; combining the time-domain alternating current with a voltage of the charger, and proposing a model parameter determination method, wherein a coupling effect of the charger-terminal voltage and a harmonic current is considered in the model and matrix elements are not changed along with a harmonic voltage of the charger; creating the harmonic model of the three-phase charger of the electric vehicle in combination with the created coupling admittance matrix according to an admittance matrix parameter calculation method, wherein the harmonic model is used for providing a good theoretical basis for analyzing the characteristics that the harmonic current of a charging station with a plurality of chargers is changed along with the number of the chargers and the charging power. The modeling method can be used for directly and effectively calculating the harmonic current of the three-phase charger of the electric vehicle.

Description

technical field [0001] The invention relates to the field of electric vehicles, in particular to a modeling method for a harmonic model of a three-phase charger of an electric vehicle. Background technique [0002] With the promotion and application of electric vehicles, the scale of nonlinear high-power chargers connected to the grid is gradually increasing, which will bring load impacts to the grid, and have a non-negligible impact on the power quality, network loss, and equipment utilization of the grid. influences. [0003] Electric vehicle chargers usually use single-phase or three-phase rectifier circuits, which are divided into three levels in the Society of Automotive Engineers (SAE) charging interface standard SAE J1772. The first level is single-phase uncontrollable Slow charging of the rectifier circuit; while the other two stages are conventional (vehicle) and fast (non-vehicle) charging using three-phase rectification, and the charging time corresponding to dif...

AI Technical Summary

Problems solved by technology

However, these methods are computationally intensive and difficult to analyze and calculate

At present, the literature has studied the frequency-domain analytical models of single-phase controllable rectification circuits and uncontrollable rectification circuits, but considering that the three-phase rectification circuit is different from single-phase rectification, each diode has two conduction processes within half a cycle. , Affected by the DC load, the charging current may be continuous and intermittent during the conduction process

This makes the harmonic model of three-phase rectification more complicated, and the modeling method of single-phase rectification cannot be applied to electric vehicle three-phase rectification chargers

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