REVIEW PAPER A comprehensive review on energy management strategies of hybrid energy storage system for electric vehicles A. Geetha and C. Subramani * ,† Department of Electrical and Electronics Engineering, SRM University, Kattankulathur, Kancheepuram, Tamil Nadu 603203, India SUMMARY The attention on green and clean technology innovations is highly demanded of a modern era. Transportation has seen a high rate of growth in today’s cities. The conventional internal combustion engine-operated vehicle liberates gasses like carbon dioxide, carbon monoxide, nitrogen oxides, hydrocarbons, and water, which result in the increased surface temper- ature of the earth. One of the optimum solutions to overcome fossil fuel degrading and global warming is electric vehicle. The challenging aspect in electric vehicle is its energy storage system. Many of the researchers mainly concentrate on the field of storage device cost reduction, its age increment, and energy densities’ improvement. This paper explores an over- view of an electric propulsion system composed of energy storage devices, power electronic converters, and electronic con- trol unit. The battery with high-energy density and ultracapacitor with high-power density combination paves a way to overcome the challenges in energy storage system. This study aims at highlighting the various hybrid energy storage sys- tem configurations such as parallel passive, active, battery–UC, and UC–battery topologies. Finally, energy management control strategies, which are categorized in global optimization, are reviewed. Copyright © 2017 John Wiley & Sons, Ltd. KEY WORDS electric vehicle; battery; ultracapacitor; hybrid energy storage system; energy management strategy Correspondence *C. Subramani, Department of Electrical and Electronics Engineering, SRM University, Kattankulathur, Kancheepuram, Tamil Nadu 603203, India. † E-mail: csmsrm@gmail.com Received 24 November 2016; Revised 25 January 2017; Accepted 25 January 2017 1. INTRODUCTION In India, the demand for oil raises more than its growth than any other region in the world. The demand increases from 6.0 to 9.8 million barrels per day by the year 2040. The transport vehicle stock accounts for around 65% of the rise. It is estimated as 260 million cars, 185 million two-wheeled and three-wheeled vehicles, and 30 million trucks, and vans are also required [1]. Hence, the automo- bile industries are looking ahead for a new type of vehicle that is highly efficient than the present one [2,3]. Green- house gas effects are the remarkable concern considered in United Nations Intergovernmental Panel on Climatic Change. To reduce the global average temperature, the council has ended up that minimum of 50% of CO 2 emis- sion at 2000 must be reduced by 2050 [4]. Electric vehicles (EVs) are pollutant free, and it is mostly to rely on renew- able energy sources. Even though there exists a continuous improvement in battery technology, its costs, recharging time, and range capacity are some of the barriers consid- ered in using such vehicles [5]. The behavior of the vehicle in the near future purely de- pends on the quality of the system. Estimation of battery’s life cycle has been considered as a tedious process. Hence, it is tough to design a reliable system model [6]. The primary objective of introducing hybrid energy storage system (HESS) is to limit the stresses in the battery current so as to increase its life time. The author designed a LiFePo 4 battery dynamic degradation model and applied different control strategies. He compared those effects on reducing battery degradation. The outcomes result in the similar performance in the case of rule-based controller (RBC), model predictive control (MPC), and fuzzy logic control (FLC) cycles. Optimization of battery size depends on the minimal mileage and that of supercapacitor (SC) size depends on power demand profile. When the HESS configuration is compared with battery alone configura- tion, about 23% of a life cycle of ESS can be reduced [7]. This paper offers a view of the current scenario of battery/ultracapacitor (UC) technologies, HESS, and en- ergy management systems for an EV drive. First, modern battery/UC cell chemistry will be discussed. It elaborates INTERNATIONAL JOURNAL OF ENERGY RESEARCH Int. J. Energy Res. (2017) Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/er.3730 Copyright © 2017 John Wiley & Sons, Ltd.