Slide Mode and Fuzzy Logic Based Powertrain Controller for the Energy Management and Battery Lifetime Extension of Series Hybrid Electric Vehicles

Abstract

A control strategy was developed to improve fuel economy, enhance engine efficiency as well as extend battery cycle life in the series hybrid electric vehicle (SHEV) powertrain. The controller was based on fuzzy logic, fixed-boundary-layer sliding mode controllers (FBLSMCs) and an optimized battery charge scenario. The fuzzy logic based energy management controller is developed to determine the engine power based on two inputs, battery state-of-charge (SOC) and vehicle power demand. The goal of the fuzzy logic based controller is to enhance the engine and battery operation efficiency and at the mean time, extend battery life. An appropriate battery charge scenario is designed to remove surge charge current, and avoid persistently-high charge power, which are positive factors to the battery lifetime extension. Besides, two robust FBLSMCs against uncertain disturbances are configured in the powertrain control system, responsible for engine speed control and engine torque control, respectively. Simulation results are obtained for comparison between the proposed and conventional powertrain control schemes. Through these simulations, the effectiveness and superiority of the proposed powertrain control strategy are validated. Keywords series hybrid electric vehicle, fuzzy logic, fixed-boundary layer sliding mode controllers, battery charge scenario state of charge, life cycle