Fundamentals of Inductive Power Transfer

WPT School – Session 1 and 2 – Instructors: Duleepa J. Thrimawithana and Grant A. Covic

Abstract and Session Summary:

Currently, there is a strong drive to electrify the transportation sector as a solution to the environmental and economic impacts of vehicles using internal combustion engines. However, to-date, limitations of battery technologies have hindered the uptake of electric vehicles (EVs). For example, the main drawbacks commonly associated with EVs are the limited range and long charging times, both of which are a direct result of the low energy and power densities of current battery technologies. These issues are further aggravated due to the fact that the EVs need to be plugged-in to refuel, as it can take many hours to fully-charge a depleted EV battery. Although, fast and extreme fast charging systems have been developed and deployed to help EV users refuel in a fraction of an hour, this is achieved at the expense of battery life and user safety. In contrast, wireless charging of stationary and in-motion electric vehicles promises a future where EVs are replenished organically, thus avoiding long charging times, range anxiety and battery degradation. An ubiquitous wireless charging infrastructure, especially one that is bi-directional, can be used to provide grid services, thus not only drastically improving the uptake of EVs, but also supporting grids with high penetration of renewable electricity.

The school will start with a brief discussion on the history of wireless power transfer (WPT) technology. Subsequently, the fundamental operating principles of an inductive power transfer (IPT) system will be presented. Commonly used compensation networks, power electronics converters and magnetic designs will be then reviewed. This will be followed by a discussion on a few applications of IPT technology, with a special focus on wireless electric vehicle (EV) charging. A summary of developments to-date on both stationary and dynamic EV charging will be presented. To conclude the presentation, we will work through a few design examples and validate these designs using LTspice and Ansys Maxwell simulation models.

After completing this theory session, the participants can continue to work on an IPT project to further their understanding. Details about the project and a step-by-step guide is provided and can be accessed via this LINK. To follow this example project, participants can download free software copies – LTspice and Ansys Electronics Desktop Student. During the 2^nd day of the school, the speakers will be available to help with questions relating to the project.