Research on Modelling Inductive Power Transfer for Electric Vehicles

The environmental pollution caused by fossil fuels is a hot issue around the world in recent years. The gases lead to poor air quality, in particular in large cities, and the global warming that can cause ecological calamity such as tropical cyclones, heatwaves, drought, and extreme tides. International Energy Agency clearly states that the current energy trend is not sustainable environmentally, economically, and socially. Therefore, it must devise solutions to achieve the future economic growth without adverse environmental effects. The increasing diffusion of electric vehicles is driving academic and institutional research towards exploring different possible ways of charging vehicles in a fast, reliable, and safe way. For this reason, wireless power transfer systems have recently been receiving a lot of attention in the academic literature. This chapter reviews the main analytic and computational tools that are typically used to perform analyses in the context of inductive power transfer systems (IPTSs).

An Inductive Power Transfer System for the Wireless Charging of Electric Vehicles

This chapter describes two methods whose purpose is to estimate the coupling factor k for the inductive coupling of an experimental prototype designed for the contactless battery charging of electric vehicles. The air gap that separates the two square-shaped coils of the inductive coupling is 150 mm. The first method is analytical and provides an expression with which to calculate the mutual inductance between both coils by solving Neumann's formula, from which k readily follows. The second approach is empirical and combines data from waveforms of currents that were obtained both experimentally and from PSpice simulations, where k is a model parameter, under different loading conditions. The agreement between the analytical and the empirical method is good, as they both yield coupling factor figures that are equal to 0.197 and 0.200, respectively. Both techniques could, therefore, be applied in order to determine the coupling factor of the constructed inductive coupling for other air gaps near to 150 mm, which are also of practical interest in electric vehicle charging.

Radio-Frequency Identification (RFID)

RFID technology has been widely adapted in industries for uses in logistical tracking, highway tolling, building access, and transportation ticketing. These applications have generally been limited to the original intended use of RFID, that is identification and a replacement for bar codes. Research in this area focuses on increasing the read rate, range, and reliability of their RF tags. The WPT is the enabling technology for realizing a true internet of things. Broad sensor networks capable of monitoring environmental pollutants, health-related biological data, and building utility usage are just a small fraction of the applications which are part of an ever-evolving ubiquitous lifestyle. Realizing these systems requires a means of powering their electronics sans batteries. Removing the batteries from the trillions of these envisioned devices not only reduces their size and lowers their cost, but also avoids an ecological catastrophe. This chapter discusses new theoretical models of RFID, communication standards, radio channel characteristics, RFID readers and tags.

Rectennas for Microwave-Based Wireless Power Transfer (WPT)

Electromagnetics has an important role in power and energy industry. In this chapter, the concept of rectenna is reviewed. The history of rectenna for wireless energy harvesting and transmission is discussed. Finally, examples are employed to illustrate some rectenna design and measurement issues such as rectenna impedance matching and its conversion efficiency. It is also shown that rectennas can harvest wireless energy efficiently under certain conditions and have the potential to become a power supplier for some special applications.

Control for the Contactless Series Resonant Energy Converter

This chapter presents control methods applied in the operation of the series loaded series resonant (SLSR) power converters in a most efficient operation zone. The choice of the control method is affected by the objective to guarantee suitably the efficiency, being this method in the same time, relatively easy to apply. The first part of the chapter compares three basic principles of regulation: frequency mode (FM), pulse width mode (PWM), and their combination (PWM/FM). Finally, a new method for instantaneous regulation is developed. The proposed technique consists of a simplified observation of a state variable value to limit each portion of supplied energy, depending on the requirement for power in each half period. The result of this regulation is comparable to the current mode (CM) control applied to the hard-switching power converters. The viability of this new regulation method is demonstrated by simulations of its analogue circuit implementations and experimentally proved. The circuit is also prepared for the changes in the magnetic coupling (contactless energy transfer).

Analysis of the Strongly Coupled Magnetic Resonant Technology for Wireless Power Transfer

Wireless power transfer (WPT) systems are involved in multiple and heterogeneous applications. This diversity is reflected in several factors such as the amount of power that is transferred or the distance separating the energy source and the receiver. In the current research work, the authors find several groups of technologies that try to adapt the process to the particularities of the application. In this way, wireless power transfer can be achieved with an inductive technology, with a resonant-inductive approach, or with a strongly coupled magnetic resonant configuration. This chapter focuses on strongly coupled magnetic resonant technology, which is appropriate for home applications.

Dynamic Pivoting Antenna-Module-Based Flexural Wireless Power Charger for Various Wireless Sensor

IoT is one of the popular topics for the past few years. The study achieves the data in the internet collecting and sharing by data transmission wired or wireless from information carriers. In most of IoT application, the main information devices are embedded systems and micro sensors. Due to the hardware limitations, most of information devices use the wireless transmission to do the data exchange like Wi-Fi, NFC, and Bluetooth. However, most of these devices are powered by batteries. In the other words, there are some problems that the user has to face: time limit, hard to replace batteries, and different specifications. In order to solve these problems, a dynamic antenna-based wireless power charger based on electromagnetic coupling of coil is proposed to replace traditional batteries in this chapter. Flexible printed circuit can allow the user changes in the circuit into a suitable shape by cutting, reversing, and coiling. In this way, the user can improve the electricity supply effect by adjusting the power of wireless transmission.

Wireless Power Transfer to Implantable Medical Devices With Multi-Layer Planar Spiral Coils

Implantable medical devices such as pacemakers, implantable cardioverter defibrillators, deep brain stimulators, retinal and cochlear implants are gaining significant attraction and growth due to their capability to monitor the health condition in real time, diagnose a particular disease, or provide treatment for a particular disease. In order to charge these devices, wireless power transfer technology is considered as a powerful means. This eliminates the need for extra surgery to replace the battery. In this chapter, some of the major implanted medical devices are reviewed. Then, various wireless power transfer configurations are reviewed briefly for charging such devices. The chapter continues with reviewing wireless power transfer configurations based on the multi-layer printed or non-printed planar spiral coils. At the end, some of the recent works related to using multi-layer planar spiral coils for safe and efficient powering of IMDs will be discussed.

Resonant Compensations in Inductive Wireless Power System

A resonant wireless power system uses capacitors to create resonance between primary and secondary coil at a specific resonant frequency. Thereby, they reduce the reactive power and produce the required transmitted real power over a long range of separation and at higher efficiencies. Depending on the connection between the capacitors and coils, four main topologies can be identified: series-series, series-parallel, parallel-series, and parallel-parallel. In this chapter, these resonance compensations schemes are analyzed, and the advantages and disadvantages of each topology are highlighted.

Efficiency Improvement in Wireless Power System

This chapter focuses on mid-range wireless power transfer (WPT) systems applied to electric vehicle (EV) battery chargers. The WPT is recently considered as an efficient electric energy transfer process between two or more points in space, without wiring. The technology associated with each specific process of WPT differs from case to case depending on the distance between those points and the power to be transferred between them. The widely adopted distance categories are named short-range, mid-range, and long-range. The short-range is normally defined as up to a few millimeters range. The mid-range is between a few millimeters and a few meters. The long-range distance is defined as a longer than that of the previous category, stretching up to a few kilometers.