Design And Fabrication of Regenerative Braking System

Abstract

In this thesis, series-parallel hybrid electric vehicle (Toyota, Prius THS II) is studied. The energy storage system of this vehicle is batteries. It is not good to use batteries or ultra-capacitor alone. In this thesis, two energy storage devices are used together to form the hybrid energy storage system. The advantages of this hybrid energy storage system are the combined advantages of the two energy storage devices. The two devices compensate the drawbacks of each device. A performance of series-parallel hybrid electric vehicles (Toyota, Prius ths II) using hybrid energy storage system are presented. The hybrid energy storage system consists of nickel-metal hydride batteries and ultra-capacitors. The hybrid storage system is designed to reduce the total weight of the energy storage system and in turn increase the overall efficiency. The ultra-capacitor contributes to the rapid energy recovery associated with regenerative braking and to the rapid energy consumption associated with acceleration in electric vehicles. This Ultracapacitor allows acceleration and deceleration of the vehicle with minimal loss of energy and minimizes the stress of the main batteries by reducing high power demands away from it. It also leads to longer battery life by extracting energy at a slower average rate. This paper analyzes and compares between the performances of the series-parallel hybrid electric vehicles with the proposed hybrid storage system (batteries/ultra-capacitors) and with the conventional storage system (batteries only). Simulation works are carried out to evaluate the performance of the two storage systems under different operating conditions such as acceleration, constant speed and deceleration.