Title: Minimising current ripple in electric vehicle batteries by proper pulse width modulation techniques
Authors: Onur Satilmis; Erkan Mese
Addresses: Aselsan Company, Radar & Electronic Warfare Systems Business Sector, Konya Yolu 8. km Oğulbey Mh. 3051, Sk. No:3 06830 Gölbaşı, Ankara, Turkey ' Department of Electrical and Electronics Engineering, Ege University, Bornova, 35100, Izmir, Turkey
Abstract: Batteries are one of the key components of electric vehicles (EVs). Batteries supply energy to output in normal working mode by converting internal chemical energy to electric energy (discharging), and they restore energy in regenerative working mode as opposed to discharging (charging). During each mode, battery current contains ripple which influences battery lifetime negatively. Simulations which include ideal models for battery and DC bus capacitors do not give realistic results in terms of battery ripple current. This paper presents comparative investigations and evaluations with regard to battery current waveform, battery current harmonic spectrum and the ratio of battery current harmonic components to battery average current. Various modulation methods and operating conditions (i.e., a different modulation index and load power factor for an open loop scheme, and a different speed and torque for a closed loop scheme) are considered with high-frequency models of battery and DC bus capacitors.
Keywords: electric vehicles; EV batteries; DC bus capacitors; power electronics; current ripple; pulse width modulation; PWM; battery lifetime; simulation; current waveform; current harmonic spectrum.
International Journal of Vehicle Design, 2017 Vol.73 No.4, pp.219 - 243
Received: 13 Oct 2014
Accepted: 23 Jun 2015
Published online: 29 Mar 2017 *