**1. Introduction**

The traction drive of an electric car is an electrical system of considerable power, ranging from 40 to 120 kW. Even higher power levels are found in high‐end models or in other vehicles such as electric buses. These power levels are usually achieved with high currents rather than voltages. Specifically, most commercial vehicles nowadays work with voltage levels below 400 V, which implies currents of the order of hundreds of amperes. This means that these traction drives could generate magnetic fields of considerable strength when compared to other conventional sources.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

At the same time, distances between these magnetic field generators and the passengers are relatively short in most vehicles; for instance, it is usual to place the battery pack as far as possible from the bodywork to minimize the risk of battery damage and its consequences in case of crash; this implies positioning them just under or behind the passenger seats [1]. Consequently, there could be hundreds of amperes circulating some centimeters away from the passengers during strong accelerations or deep regenerative braking.

The combination of high currents and short distances involves some risks due to the presence of strong magnetic fields. These fields can potentially have undesired effects on electric and electronics devices, but also on living beings inside the vehicle, or close to it. The first effects are known as electromagnetic interference (EMI) and are analyzed within the discipline of electromagnetic compatibility (EMC), whose main goal is to ensure proper operation of operational equipment in a common electromagnetic environment. This is usually done by limiting or conditioning the electromagnetic fields (EMFs) emitted by each device, but mostly by immunizing them so that they are not affected by EMI coming from the rest of the devices.

The second effects are named electromagnetic radiation (EMR) and belong to the field known as bioelectromagnetism or bioelectromagnetics, which studies all kinds of interactions between EMFs and biological systems. EMR is usually classified into ionizing and nonionizing radia‐ tion, depending on its capability to ionize atoms and therefore to break chemical bonds. This is only possible if the radiation carries a high amount of energy, and hence ionizing capability is directly associated with wavelength and thus with frequency. The boundary between nonionizing and ionizing EMR is located in the ultraviolet range of the electromagnetic spectrum. In this sense, all the radiation emitted by an electric vehicle is nonionizing.

The relationship between nonionizing EMR and human health has been studied for decades. In 1996, the World Health Organization (WHO) established the *International EMF Project* to assess the scientific evidence of possible health effects of low‐frequency EMR (from 0 to 300 GHz), encouraging focused research to fill important gaps in knowledge and the development of internationally acceptable standards limiting EMF exposure [2]. At present, some possible consequences of low‐frequency EMF exposure are still Unclear. Namely health effects caused by long‐term exposure (such as cancer or neurodegenerative disorders) are mentioned in the literature, although conclusive results have not been obtained. Many long‐term studies have been described as questionable and of low repeatability. Moreover, it could be argued that long‐term effects are impossible to determine with certainty, since they take years or even decades to appear. Hence, long‐term consequences are a source of discussion within the scientific community.

On the other hand, short‐term nonionizing effects are well established, and their mechanisms are well known. These biological effects occur as soon as the exposure begins, and they disappear when it ceases, or shortly after. They are caused by extremely strong low‐frequency (up to a few hundred kHz) and strong medium‐frequency EMFs (radio waves and microwaves up to 300 GHz), and thus they are also known as acute effects. They may be classified into two main groups: electrostimulant effects and thermal effects. The former are a consequence of the coupling between low‐frequency fields and living matter, an example of this would be induced currents in some organic tissues generated by an external magnetic field. The latter are due to energy exchange between medium‐frequency fields and biological tissues, which produces a temperature increase in those body parts affected. Thermal effects are usually negligible for field frequencies below 100 kHz, but become increasingly significant as frequency grows. Current standards, guidelines, and recommendations regarding maximum exposure values are developed considering these acute effects.

This chapter is intended to introduce the reader to the topic of magnetic field exposure in electric vehicles (EVs). For further information, a considerable number of references are provided at the end. The chapter is divided into different sections as follows:

