Power optimization for hybrid energy storage system of electric vehicle

Abstract

Hybrid energy storage system of electric vehicles (EVs) has great potential to take full advantages of high power density with supercapacitor and high energy density with battery to improve the dynamic performance and energy efficiency of EVs. However, its energy management becomes much more complicated, in particular, the power distribution between supercapacitor and battery. This article proposes a power optimization method aimed to achieve the objective of minimum battery energy loss. A compound model for power optimization is first established, and a dynamic programming algorithm is used for optimal control. Simulation results show that with the proposed dynamic planning algorithm the battery current is reduced and the energy efficiency is improved, compared to traditional control strategy with logic threshold method.

The Impact of Hybrid Energy Storage System on the Battery Cycle Life of Replaceable Battery Electric Vehicle

“…Wu et al used a lithium iron phosphate (LiFePO 4 ) battery and ultracapacitor to form a hybrid energy storage system, which improves the efficiency of the vehicle energy storage system [5]. Wang et al used the dynamic programming (DP) algorithm to obtain the optimal energy allocation strategy, reducing the peak current of the battery and improving the energy efficiency of the energy system [6]. Zhang et al used model predictive control (MPC) to obtain operating conditions data and optimize HESS energy allocation in the prediction domain through partial historical data and prediction models [7].…”

Loss analysis of hybrid battery-supercapacitor energy storage system in EVs

“…An optimization algorithm is proposed to extend battery life time and simultaneously to improve the energy efficiency of the hybrid battery-supercapacitor energy storage system [2]. A power optimization method is proposed in [3] to have the minimum battery loss. In [4], the topologies of the converters for connecting super-capacitor to battery are analyzed and the current control method for bidirectional non-isolated converters is presented to realize the power flow arrangement.…”

A New Control Strategy of Hybrid Battery/Ultra-capacitor Energy Storage in Electric Vehicle

“…The hybrid energy storage system structure whose battery directly connected to the DC link and ultra-capacitor connected by DC/DC converter is adopted in literature [4], and the corresponding algorithm is proposed to realize the optimal operation of one electric vehicles, but this structure may take high frequency components power into the battery, which leads to frequent charging/discharging and seriously affects its cycling life. Ultra-capacitor is connected to the DC link by a new type DC/DC converter and battery directly incorporated in literature [5], adjustment charging/discharging current based on ultra-capacitor current adjustment rules to realize the distribution of power coordination between them.…”