Dynamic Modeling of Load Demand in Electrified Highways Based on the EV Composition

TL;DR

This paper models the dynamic load behavior of electric vehicles on electrified highways with wireless power transfer, analyzing how EV composition affects load harmonics and providing insights for power system design.

Contribution

It introduces a novel dynamic load model for EVs on electrified highways, including stochastic analysis of total load and effects of EV composition on harmonics.

Findings

Harmonics decrease with longer Rx coils in individual EVs.

Nonlinear control schemes produce milder harmonics than linear ones.

EV composition influences the frequency spectrum of the total load.

Abstract

Electrified roadways (ERs) equipped with the dynamic wireless power transfer (DWPT) technology can achieve longer driving range and reduce on-board battery requirements for electric vehicles (EVs). Due to the spatial arrangement of transmitter (Tx) coils embedded into the ER pavement, the power drawn by the EV's receiver (Rx) coil is oscillatory in nature. Therefore, understanding the dynamic behavior of the total DWPT load is important for power system dynamic studies. To this end, we model the load of individual EVs in the time and frequency domains for constant EV speed. We establish that a nonlinear control scheme implemented in existing DWPT-enabled EVs exhibits milder frequency harmonics compared to its linear alternative. According to this model, the harmonics of an EV load decrease in amplitude with the Rx coil length. We further propose and analyze stochastic models for the total DWPT load served by an ER segment. Our models explain how the EV composition on the ER affects its frequency spectrum. Interestingly, we show that serving more EVs with longer Rx coils (trucks) does not necessarily entail milder harmonics. Our analytical findings are corroborated using realistic flows from a traffic simulator and offer valuable insights to grid operators and ER designers.