Electric and Hybrid Vehicles: Technologies, Modeling and Control - A Mechatronic Approach

8Energy/Power Allocation and Management

8.1 Introduction

As the electrical and electronic content in vehicles increases, the on-board electric power requirement for non-propulsion loads will increase from about 1 kW to 5 kW, and vehicle propulsion loads will exceed 100 kW. This increase in power demand is primarily a result of electric and hybrid drivetrains, however, other automotive technologies for internal combustion engine vehicles contribute to this trend, such as variable engine valve and active suspension [1]. The huge amount of required power complicates the issue of appropriate power management and distribution. In conventional ICE vehicles, an alternator and voltage regulator manage electric power. In early electric and hybrid vehicles, the on-board power management strategy controlled the state of charge of the battery. However, in modern EVs and HEVs, the purpose of a strategic power and energy management system is to control and coordinate the power generation, energy storage, and power flow within subsystems to achieve maximum overall system efficiency. In addition, it must prioritize real-time power requests from loads and allocate the available power resources from generation and storage devices to maximize the vehicle's efficiency and performance. The use of energy storage devices in vehicles has altered the paradigm of power management to include energy management as well. Managing power and energy improves vehicle performance and system reliability, and ...