**1.3. Objectives and contents' overview**

to innovate the automobile industry. For instance, in the United States, the sales volume of battery electric vehicles (BEVs) is expected to account for 12% of that of all registered vehicles in 2025. As an energy-efficient, low-carbon and environment friendly traffic tool, AFVs are

Most national research institutions and automobile manufacturers have increased R&D investment in the AFV technology to replace traditional vehicles, forming the trend of different technologies developed in parallel. Some of the technologies have achieved significant success in commercial fields [2], [3]. In the United States, Germany, and Japan, GM, Ford, Volkswagen, BMW, Toyota, Honda, and other major automobile manufacturers have adopted different new technology development strategies, based on the situation of the nation and the company, and successfully developed a number of concept AFVs and utility vehicles. AFVs are usually classified into hybrid electric vehicles (HEVs), electric vehicles (EVs), fuel cell electric vehicles

Some countries, e.g., Japan, have been committed to the hybrid vehicles and have developed a lot of well-known models, e.g., the Toyota "Prius." Some other countries, e.g., Germany, have unique technology in the pure electric vehicles, fuel cell electric vehicles, and so on. BMW i3

The world's major automobile production countries have policies to promote the development of AFVs to cope with difficulties and opportunities. By 2015, the United States raised the goal to one million plug-in hybrid electric vehicles (PHEVs). Tax incentives have been implement‐ ed. The EU will issue €7 billion loan to support energy-efficient vehicles. The German gov‐ ernment raised million BEV and PHEV goals by 2020. Japan in 2009 proposed a "carbon revolution" program, in which development of electric vehicles is one of the core. In China, basic research and the establishment of public service platform are listed as the focus of development. "Three vertical and three horizontal" development layout is presented to

AFV electric drive systems include the energy storage systems (battery and/or ultracapacitor), electronic controller, power converters, motors, and so on. The electronic controller is divided into three functional units: sensors, circuits, and processors. In driving and regenerative processes, the energy flow between the energy source and the motor is adjusted by the power

The electric drive system itself as a whole is closely linked with the energy subsystem, which is the core technology of electric vehicles. The main function of electric drive system is to transfer energy from storage system to wheels, which is used for overcoming rolling resistance, air resistance, acceleration resistance, and climbing resistance. When braking, the mechanical energy is converted to electrical energy back to the energy storage system. AFVs can choose single or dual motor drives. AFVs can also employ in-wheel motors. Now, low-power electric vehicles on the market almost all employ single-motor power systems with simple structure.

**1.2. Current research situation and new challenges for electric drives in AFVs**

expected to become increasingly popular in the future.

with carbon fiber body is the lightest electric car on the market.

(FCEVs).

2 New Applications of Electric Drives

promote the AFV industries.

converter.

The objectives of this chapter are to analyse some new electric drive design requirements raised by dynamic driving cycles of AFVs; to introduce some novel ideas about integration modeling from the energy storage system (ESS) to motor and power electronic device design for ESS lifetime extension and to delineate a few latest control strategies of AFV traction motors related to sensorless drives and flux weakening control. The rest of this chapter is organized as follows. Section 2 describes the basic concepts of structure and main components of electric drives in AFVs. Integration of modeling and novel design of the DC active power filter for ESS lifetime extension are given in section 3. In section 4, advanced motor control strategies with respect to sensorless drives and flux-weakening regions are explained. Finally conclusions of this chapter are drawn in section 5.
