Ultracapacitor/battery hybrid energy storage system with real-time power-mix control validated experimentally in a custom electric vehicle

Abstract

This paper experimentally demonstrates the benefits of integrating ultracapacitors (u-cap) into a custom electric vehicle. The new hybrid energy storage system (HESS) includes a 25 kW four-phase dc-dc converter connected in between the 33.8 kWh lithium phosphate battery pack and the u-caps. By combining the high energy-density of the battery and the high power-density and cycle-life of u-caps, the HESS delivers high power while minimizing peak battery current during acceleration and regenerative braking. Real-time power-mix control within the HESS using the dc-dc converter is the main challenge addressed in this project. In one experimental test-drive, the HESS not only improves the maximum power of the EV from 38 kW (50 hp) to 52 kW (70 hp), but also captures the majority of the regenerative braking energy, greatly reducing the stress on the battery pack.978-1-4799-6735-3/15/$31.00 ©2015 IEEE

A Review on the Selected Applications of Battery-Supercapacitor Hybrid Energy Storage Systems for Microgrids

“…Considering this topology, the capabilities of SCSS effectively utilized in regenerative braking and BESS protection with an improvement in the driving ability of the vehicle at low temperatures. Correspondingly in [197], experimental quantification is presented to assess the increment in the recuperation of regenerative braking by hybridization of BESS with SCSS. In this work, a rule-based algorithm is implemented to offload the current peaks from BESS and set a power-mix between HESS based on load power prediction.…”

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. However, controlling role of the battery is too weak under this method, which cannot achieve a good control of the battery charging/discharging current.…”