Emerging Technologies for Electric and Hybrid Vehicles

To deal with the energy and environmental crisis, the world's major automotive powers are sparing no effort in the research of electric vehicles (EVs). Electrification, intellectualization, network share have become the new development direction of the automobile industry chain. Promoting technological innovation around this trend is the fundamental means for EVs to break through to the high end.

Classical electric machines, including DC machines, induction or asynchronous machines, and synchronous machines, play a key role in modern electric vehicle (EV) propulsion. Because of the maturity and simplicity, DC machines have been the favorable candidate for early EV traction motors. Due to the disadvantages of carbon brushes and commutators, their reliability and efficiency limit the wide application. Nowadays, AC machines are mainly applied for modern EV propulsion, primarily squirrel-cage induction machines (SCIMs), wound-rotor synchronous machines (WRSMs), and permanent magnet synchronous machines (PMSMs). Especially, SCIMs and PMSMs are becoming the predominant traction motors in the market share for modern EVs recently. In this chapter, the classical electric machines, namely, DC machines, SCIMs, WRSMs, and PMSMs are presented. Their configurations, operating principle, mathematical modeling, and control methods are briefly discussed.

In this chapter, more advanced electric machines for electric and hybrid vehicles are introduced. Even though not all the performance metrics of these advanced electric machines are as good as conventional electric machines, they have some distinct advantages surpassing the conventional counterparts. Hence, these advanced electric machines have been gaining attention. As the rotor permeant magnet (PM) machines suffer from the risk of irreversible demagnetization due to poor thermal dissipation and/or faulty conditions as well as demanding magnet retention, several stator PM machines are introduced including doubly-salient PM machines, flux-switching PM machines, and flux-reversal PM machines. In order to improve the torque density, magnetic gear-based machines are introduced including vernier PM machines and magnetically-geared PM machines. Both the stator PM machines and the magnetic gear-based machines belong to the family of flux-modulated machines, since their original PM flux is modulated by the flux modulator in principle. Furthermore, in order to achieve both high torque density and wide speed range, the concept of flux-controllable/variable-flux machines is introduced including hybrid-excited machines and memory PM machines. The principle, development, and novel topologies of all these aforementioned advanced electric machines will be demonstrated in detail in this chapter. The trends and tradeoffs of these machines for electric and hybrid vehicle applications are highlighted.

The impact of electromagnetic interference (EMI) is an increasingly important aspect of the performance of switching inverters. The challenges of managing EMI continue to grow with the emergence of wide bandgap (WBG) devices, the trend towards ever-greater integration and higher power rating. This paper reviews suppression methods for the conductive common-mode (CM) EMI in inverter fed motor drives. In order to span EMI suppression across the full system design process, the review considers both mitigation from the sources and suppression along the conduction paths. Furthermore, the shortcomings and merits of the reviewed publications are discussed, and their attenuation frequency range and attenuation level are compared. It is demonstrated that the CM EMI at low frequency is mainly determined by the PWM strategies and can be reduced or even theoretically eliminated through zero common-mode control. On the other hand, the CM EMI at high frequency is markedly influenced by the switching transients of the power devices. Thus, various drive circuits are reviewed, which improve the switching behaviour. Finally, the deployment of passive and active filters to suppress or compensate for the EMI is discussed.

Five-phase permanent magnet synchronous motor (PMSM) has been widely studied and applied in many industrial fields because of its high efficiency, high power density, and wide speed range. With the improvement of safety and reliability requirements in these fields, it is of great significance to study the multi-phase motor drive system and its fault-tolerant control. Firstly, this chapter takes five-phase PMSM as the research object and makes a brief introduction to the common fault types and control methods. Then, two different fault-tolerant ideas based on the principle of minimum torque ripple and invariable magnetomotive force respectively are analyzed. Focusing on the latter, two methods of fault-tolerant and reduced-order matrix are derived. Furthermore, model predictive control (MPC), vector control (VC), and direct torque control (DTC) are used to realize fault-tolerant control according to the two different matrices. In order to achieve the optimal running state of the motor, the maximum torque per ampere (MTPA) control method based on the fault-tolerant algorithm is also indispensable. The MTPA control methods based on signal injection have high tracking accuracy and good dynamic performance, but the injected high-frequency signal will bring extra torque fluctuation. Therefore, virtual signal injection (VSI) control is more suitable for fault-tolerant algorithms. Finally, VSI-MTPA is adopted to improve the torque output capacity and operation efficiency of the motor under fault-tolerant operation.

This chapter introduces basic procedures for designing and optimizing an electric motor for electric vehicle applications using the example of an axial flux induction motor. The analytical model for the motor is derived firstly, which can provide output values close to that provided by finite element analysis in ANSYS Maxwell with a much shorter simulation time. Then, based on the developed analytical model, the corresponding optimization and solution will be formulated to help optimize the motor to meet all design requirements and achieve excellent performance. Finally, the optimized motor design will be validated by ANSYS Maxwell.

With the ever-growing concerns on the impact of climate change, the world has stepped up efforts to reduce carbon emission by implementing policies in several key areas. One of the main strategies is to phase out the internal combustion engine vehicles (ICEVs) that have contributed significantly to greenhouse gases and replace them with electric and hybrid vehicles (EVs and HEVs) that run on cleaner energy alternatives. This chapter focuses on three different electrochemical energy sources employed in EVs and HEVs: batteries, supercapacitors, and fuel cells. We will discuss the capabilities and development of the state-of-art electrochemical energy sources, outlining their key challenges and providing the outlook toward realizing a safer, greener, and efficient urban transportation system.

Hybrid electric vehicles (HEVs) and electric vehicles (EVs) have been advocated by global governments’ policies in recent decades. Besides combating the climate crisis and urban air pollution, great contributions of developing the HEVs and EVs have been identified to accelerate the process of green transportation and smart city. Battery management is one of the most crucial functions for HEVs and EVs. It can ensure safe operation and optimize the performance of EV batteries. This chapter discusses the mainstream technologies of battery management in HEVs and EVs. Wherein, battery management technologies, including battery modeling, battery state estimation, safety prognostic (such as thermal management), and fault diagnosis, are elaborated in detail. Among them, the data-driven method is most effective and promising for battery state estimation (such as for state of charge and state of temperature) and health diagnosis or prognostics with impressive accuracy. Besides, some emerging management technologies, including multi-model co-estimation, artificial intelligence, cloud computing technology, and blockchain technology, are briefed, which can play a significant role in coordinating the information and energy flows in a vehicular information and energy internet.

This chapter introduces the technical background of fast chargers for plug-in electric and hybrid vehicles, including technique development for on-board chargers and fast charging stations, standard, regulations, and future trends. The development of wide-bandgap (WBG) devices is the basic technology and the biggest driving force for innovation of fast chargers. The fundamentals of WBG devices and the unipolar and bipolar WBG power semiconductors commonly used in fast chargers are introduced. To take advantages of WBG devices, state-of-the-art topologies for on-board chargers and fast-charging stations are presented. The medium frequency transformers and the control strategies for modular SST-based fast charging stations are also introduced.

European countries have agreed to accelerate the development of low-emission transport technologies to meet targets set during the Paris climate summit.

Electric vehicles (EVs) will become prevalent in this decade. An EV is equipped with a battery, which enables its interaction with the power grid in many interesting ways. An EV not only gets charged from but also discharges its energy back to the grid. Due to their mobility, an aggregation of EVs turns into a significant energy resource with high flexibility and convenience, constituting the vehicle-to-grid (V2G) system. In this chapter, we investigate some advanced V2G technologies in terms of architecture, applications, and smart city integration. We first introduce various system components and discuss a hierarchal structure, which is generalized to most V2G architecture. Then several innovative applications are reviewed, including frequency regulation, voltage regulation, unit commitment, and energy trading. After that, we study how V2G can be enhanced with new vehicular technologies and integrated into a smart city. EVs with self-driving capability allow us to drive a fleet of vehicles to strive for various V2G objectives. With the support of dynamic wireless power transfer, we can turn a road network into a big energy buffer, which can function like V2G. It can be seen that V2G technologies continue to evolve, become smarter, and cultivate new applications which are impossible before.

With the increasing concern of environmental protection and energy sustainability, as well as the rapid advancement of high-performance electric motors, power electronic converters, and energy storage technology, electric and hybrid electric vehicles (EV/HEVs) are perceived as the viable substitution for conventional gas-fueled automobiles. EVs were attracting wide attention in the early 1900s but failed in the competition with gas-powered cars during the following decades. The 1973 gasoline crisis sparked new interest in EVs. Later in 1976, the US Congress recommended EVs as a solution to reduce oil dependency. However, electric vehicles didn’t attract worldwide attention until the appearance of the Toyota Prius in 1997. Afterward, famous car manufacturers including Honda, Ford, Nissan, GM, BMW, Mercedes, Land Rover, and Audi made great efforts in improving the performance of EVs. Among them, Tesla is the pioneer pushing the frontiers of innovation in this area. Fueled by the continuous advancement in electric motor, power electronics, and battery technology, the sales of EVs in 2021 reached a new record (U.S. Department of Energy, Energy Vehicle Technologies Office in Transportation Energy Data Book. Oak Ridge National Laboratory, https://​tedb.​ornl.​gov/​data/​, 2022), as shown in Fig. 1.