Hybrid energy storage unit fed motoring and regenerative braking control of electric vehicle drivetrain

Abstract

Nowadays, adoption of supercapacitors (SC) as secondary power reservoir is a growing trend in electric vehicles (EVs). This paper delineates motoring and regenerative braking control of a hybrid energy storage unit (HESU) fed brushless direct current motor (BLDCM) based EV drivetrain. The topology comprises SC-battery with an inductor in series at input side to resist current transients in battery diverting to SC. As both exhibit limitations in terms of power and energy density respectively, the composite combination offers an optimized energy storage solution. SC helps in prolonging battery lifespan by managing frequent charging/discharging phenomenon. Additionally, SC contributes efficiently handling power during regenerative braking and acceleration phases. The regenerative braking capability of BLDCM is utilized to harness power and replenish the stored energy of battery/SC. The effectiveness of the EV drivetrain is verified through simulation in MATLAB/Simulink under different operating scenarios, showcasing its potential for low-voltage EVs during heavy traffic that requires frequent starts and stops or hilly terrain. Furthermore, a laboratory test-bed of the same architecture is developed to verify controller performance under different loading as well as speeds of BLDCM showcasing efficient operation. This research showcases immense potential as a future outlook for evolution of EV technology.