Inductive Power Transfer

Since many years ago, kitchen appliances are powered up by cable connected. This create a troublesome case as wire might tangle together and cause kitchen table messy. Due to this, wireless power technology (WPT) is introduced as its ability is to transmit power to load without physical contact. This leads to cordless solution better in safety as the product can be completely seal, highly expandable power range. This work focuses on the design of WPT based on inductive approach to power up multiple kitchen appliances. The selection of inductive approach over its partners capacitive and acoustic is mainly due to high power efficiency. Class E inverter is proposed here to convert the DC to AC current to drive the inductive link. A 1 MHz operating frequency is used. To ensure the circuit is robust with load variations, an LCCL impedance matching is proposed. This solution is table to maintain the output power if there is a slight change in load impedance. Finally, the developed prototype is able to supply 50V utput which can achieve power transmission up to 81.76%. 1. INTRODUCTION Nowadays, wireless power transfer (WPT) technology has become one of the top research areas for reliable applications, especially in low-power technology applications such as cell phone chargers, smart card systems, radio frequency identification (RFID), high-power electric vehicles (EV) and biomedical equipments [1-5]. WPT transfers power or energy from the power source to the power load through the medium without a connection line (physical contact) [1-3]. The WPT system will eliminate existing high-voltage transmission cables, towers and substations between power stations and consumers, as well as facilities interconnected by electrical technology plants worldwide [6]. WPT's advantages in cable elimination and maintenance-free operation are particularly helpful in kitchen applications to put aside the electronic kitchen appliances we use every day. One of the popular WPT technology is based on capacitive coupling between transmitter and receiver. However, existence capacitor required high withstanding voltage along with the high capacitance value for a given output current which means that this kind of supply is only practical for high power applications [7, 8]. On the other hand, acoustic power transfer is comparatively new technology which optimizing sound waves vibration or ultrasonic propagate waves to convey energy wireless for power transmission. Although it is a light-based system but still able to supply a large amount of power. Unfortunately, its diffraction loss directly affects efficiency over far distance [9-11].

This paper overviews theoretical and practical design issues related to inductive power transfer systems and verifies the developed theory using a practical electric vehicle battery charger. The design focuses on the necessary approaches to ensure power transfer over the complete operating range of the system. As such, a new approach to the design of the primary resonant circuit is proposed, whereby deviations from design expectations due to phase or frequency shift are minimized. Of particular interest are systems that are neither loosely nor tightly coupled. The developed solution depends on the selected primary and secondary resonant topologies, the magnetic coupling coefficient, and the secondary quality factor.

In this paper, a high efficiency Gallium nitride (GaN), HEMT (High Electron Mobility Transistor) class-E power amplifier for the wireless power transfer link is designed and simulated on PSpice. A four-coil wireless power transfer link is modeled for maximum power transfer efficiency on ADS (Advanced Design System) and frequency splitting phenomenon is demonstrated, explained and analyzed. Two resonant coupling structures, series & mixed, are presented and compared. The efficiency performance of the link is studied using spiral and helical antennas of different wire make. In addition, techniques for improving efficiency of the wireless power transfer systems with changing coupling coefficient viz. frequency splitting phenomenon of the coils are proposed.

Wireless power transfer (WPT) technologies have been developing rapidly in recent years. Advances in technology
make WPT widely used in many applications. Electric vehicle (EV) contactless charging is an important application
of WPT. Broadly, WPT categorized into radiative and non-radiative power transfer. Radiative power transfer is
transmitting high power density, which is unsafe for humans when it is been used for EVs charging. So, only nonradiative power transfer technologies have been using to charge the batteries. Non-radiative power transfer
includes inductive power transfer (IPT) and capacitive power transfer (CPT). Inductive charging technology is based
on IPT. This paper covers a comprehensive review of an inductive charging system for EVs batteries. Operation
principles, equivalent circuits modelling and power transfer requirements are presented. Some system design
problems are also presented. Several compensation technologies and coil shape designs proposed to enhance
inductive charging performance are also described. However, the air-gap between a charger and an EV, and the
magnetic coupling between them are an area of concern. The stationary and dynamic charging methodologies have
discussed briefly in this research. The most challenges and limitations of contactless EVs charging have been
described in terms of: battery capacity, power level, air-gap, mileage, misalignment tolerance, efficiency, and
interoperability. However, battery capacity can be enhanced by dynamic charging, the power level can be
controlled, while some other limitations can be improved as discussed in this paper.

This thesis deals with the modelling and application of magnetic fields in roads. The backbone technology being inductive power transfer (IPT) for electric vehicles. The magnetics for energy transfer in vehicles, can be adapted for heating steel fibres in roads, referred to as self-healing and modelling this is a second aspect of this thesis. The first sections of this thesis is dedicated to an overview of modelling techniques for coil design of IPT systems using both analytical and semi-analytical tools. A detailed literature review of techniques is followed by a comparison highlighting the strengths and weakness of techniques in terms of ease of use, computational efficiency, application to material interfaces etc. Analytical modelling of single and multi-coil configurations of IPT systems is carried out subsequently. The theory of partial inductance is used to model these geometries, to assess the impact of system parameters such as coupling, power transferred and magnetic efficiency with shapes of couplers and misalignment. Next, the problem of misalignment is highlighted by considering a distributed IPT system. The analytical modelling and experimental analysis of misalignment - lateral and longitudinal is performed. Edge effect is observed and experimentally validated. The second part of this thesis is dedicated to a multi-objective optimization based on the results of the developed analytical model. The goal being the development of a prototype IPT system for powering light EVs. The double rectangular (DR) coupler is chosen as the geometry for power transfer. Several geometry parameters - turns, ferrites (number, dimensions), gap between ferrites etc. are considered as design variables. Efficiency, area related power density and weight are considered as the optimization targets. Pareto fronts are developed and a particle is chosen for the development of a prototype. An experimental set-up is built consisting of a 85 kHz inverter, compensated charge-pads, rectifier and resistive load. The inverter is based on SiC MOSFETS and SiC Schottky anti-parallel diodes, the rectifier made from the same diodes. Phase shift control of the inverter legs is used to control power flow. An experimental analysis to validate the magnetic models is also developed. The third part of this thesis deals with system level economic analysis of IPT technology. A case study of bus fleet is considered and a generic methodology is developed to determine driving range as a function of mass and frontal area of the EV. The economic analysis is performed also identifying the trade-offs between road coverage of IPT, efficiency and battery size. Finally, the thesis culminates with a vision toward a future highway. Such a highway is expected to undergo a functional upgrade to handle electrification of transportation. This evolves around the integration of IPT systems, with low maintenance inductive healing asphalt roadways and renewable energy generation. The modelling challenges to such an integration is studied both using simulations and experiments. A case study for sizing renewable energy in a highway (A12) in the Netherlands using IPT is detailed.

For energy, environment, and many other reasons, the electrification for transportation has been carrying out for many years. In railway systems, the electric locomotives have already been well developed for many years. A train runs on a fixed track. It is easy to get electric power from a conductor rail using pantograph sliders. However, for electric vehicles (EVs), the high flexibility makes it not easy to get power in a similar way. The problem for an electric vehicle is nothing else but the electricity stor age technology, which requires a battery which is the bottleneck today due to its unsatisfactory energy density, limited life time and high cost. Wireless power transfer (WPT) using magnetic resonance is the technology which could set human free from the annoying wires. In fact, the WPT adopts the same basic theory which has already been developed for at least 30years with the t erm inductive power transfer. WPT technology is developing rapidly in recent years. The advances make the WPT very attractive to the electric vehicle (EV) charging applications in both stationary and dynamic charging scenarios. Here uses reviews of the technologies in the WPT area applicable to EV wireless charging. By introducing WPT in EVs, the obstacles like charging time, range, and cost can be easily mitigated thus battery technology will no longer be relevant in the mass market penetration of EVs. It is hoped that researchers could be encouraged by the state-of-the-art achievements, and push forward the further development of WPT as well as the expansion of EV.

"Generally, in steel processing systems, steels are heated via induction or combustion furnaces. Natural gas fired furnaces have installation costs advantage
while the induction furnaces have the advantages of less scale formation on the surface of the workpiece as well as less environmental pollutions. The
operation cost of both systems is a vital argument to be solved. In this paper, a natural gas fired and induction heating furnaces of a forging process were
studied. Thermodynamic analysis was performed for the furnaces which heat the steel workpiece up to 1,300 °C. The energy performances of both
systems were analyzed and compared. It is concluded that, instead of a natural gas fired or an induction furnace, a hybrid furnace may save more energy
and cost."

The paper discusses the development status of the inductive power transmission for automotive applications. This technology is, in fact, gaining the interest of electric vehicle manufacturers as an effective strategy to improve the market penetration of electric mobility. Starting from the origin of this technology, the paper presents an overview of the current state-of-the-art as well as the current research and industrial projects. Particular attention is devoted to the description of a prototypal system for the dynamic inductive power transmission whose goal is to extend the battery range by a fast partial recharging during the movement of the vehicle.

In the inductive contactless battery charging, the
power transfer capability and efficiency are mainly depending
on the coupling coefficient (k) between the inductively coupled
coils. In this work, the spiral and square coil configurations were
experimentally made from litz wire as well as another spiral
copper coil. This study investigates the frequency characteristics
of these coil configurations in order to analyze the frequency
characteristics of the self-inductance and equivalent series
resistance of each coil; as well as we measured coefficient k
under different conditions based on the air-gap variation
between the inductively coupled coils and the misalignment
between them. Furthermore, we examined the interoperability
between the spiral and square coils configurations. It has been
found that the litz spiral coil achieved slightly higher selfinductance with compare to litz square coil and spiral copper
coil. Likewise, the square litz coil has slightly high equivalent
series resistance with compare to other coils. On the other hand,
the copper spiral coil has achieved better k than the other
coupling interfaces of the litz wire coils.

A Wireless Power Transfer (WPT) Systems was developed applying the concept of resonance theory. This paper is dedicated to a theoretical study of the series-series capacitive compensation topology, then devoted to the experimental implementation of this study to prove its validity. The experiments are set up to operate in 10-20 kHz frequency ranges at distances of 50 mm by using windings made of Litz wires to test the analytical design consideration. The results showed that the system's efficiency increased until reaching its peak at 80 % with a resonance of 20 kHz. The efficiency increases in accordance with resonance frequency. Although the theoretically calculated efficiency with an ideal transformer is 90.1 %, the actual efficiency obtained from the experiments in the laboratory at a coil distance of 50 mm and with a resonance frequency matching at 20 kHz is 80 %.

A Wireless Power Transfer (WPT) Systems was developed applying the concept of resonance theory. This paper
is dedicated to a theoretical study of the series-series capacitive compensation topology, then devoted to the
experimental implementation of this study to prove its validity. The experiments are set up to operate in 10-20
kHz frequency ranges at distances of 50 mm by using windings made of Litz wires to test the analytical design
consideration. The results showed that the system’s efficiency increased until reaching its peak at 80 % with a
resonance of 20 kHz. The efficiency increases in accordance with resonance frequency. Although the theoretically
calculated efficiency with an ideal transformer is 90.1 %, the actual efficiency obtained from the experiments in
the laboratory at a coil distance of 50 mm and with a resonance frequency matching at 20 kHz is 80 %.

This paper presents a generalised analysis of
a multi-frequency system with two transmitter coils, each
carrying a current of a different frequency and deals with
the frequency decoupling of multi-coil IPT systems. Frequency
decoupling as an alternative to spatial decoupling is suggested
and a design procedure considering the mutual coupling
between all the coils in the IPT system, is elucidated. Simulation
results of a 100 kHz and 30 kHz system are presented and
experimental results that validate this theory are provided.

This paper deals with a generic methodology to evaluate the magnetic parameters 1 of contactless power transfer systems. Neumann's integral has been used to create a matrix 2 method that can model the magnetics of single coils (circle, square, rectangle). The principle 3 of superposition has been utilised to extend the theory to multi-coil geometries such as double 4 circular, double rectangle and double rectangle quadrature. Numerical and experimental validation 5 has been performed to validate the analytical models developed. A rigorous application of the 6 analysis has been carried out to study misalignment and hence the efficacy of various geometries to 7 misalignment tolerance. Comparison of single-coil and multi-coil IPT systems (MCIPT) considering 8 coupling variation with misalignment, power transferred and maximum efficiency is carried out.

—Wearable technologies play a key role in the shift of traditional healthcare services towards eHealth and self-monitoring. Maintenance overheads, such as regular battery recharging, impose a limitation on the applicability of such technologies in some groups of the population. In this paper, we propose an activity monitoring system that is based on wearable sensors that are powered by textile inductive charging surfaces. By strategically positioning these surfaces on pieces of furniture that are routinely used, the system passively charges the wearable sensor whilst the user is present. As a proof-of-concept example, experiments conducted on a prototype implementation of the system suggest that 36 minutes of daily desktop computer usage are on average sufficient to maintain a wearable sensor energy neutral.

The present paper proposes the use of the opposition method to evaluate the performance of a wireless power transfer system. The work is focused on the effect related to the insertion of conductive or ferromagnetic components that are materials typically adopted in the realization of this kind of systems.

An outline and results of decades of research into the claims of excess energy produced from specific devices based on the anomalous unipolar generator.  The anomalies are described in an "American Journal of Physics" article from 1955.  The research has pointed the way to major breakthroughs in the equating of electromagnetic potentials to mechanical energy.  The results show efficiency potentials of orders magnitude higher when utilizing specific inductive geometries.

Ongoing trends in standardized mobile phone charger is charging process with user-friendly wireless power transfer that eliminates the cable connection between the charger and the phone. Wireless power transfer provides convenience in mobile phone battery charging, do not have to hassle with wires and plugs, simply put the phone on the pad. The research design and realize a prototype of a wireless power transfer system for charging mobile phone batteries. This research used high frequency transformer 12 V 25 kHz, the primary coil (20 turns, diameter 9 cm), the secondary coil (36 turns, diameter 9 cm), rectifier and filter and regulator. The result showed that the device and the circuit is designed to perform charging mobile phone batteries with maximum distance required to produce a voltage of 5 volts at the input terminal of mobile phone batteries is as far as 2 cm. In addition, the time required to perform a full battery charge until the phone is 60 minutes with constant charging rate.

The paper proposes the development of a set of rules for the resizing of inductive power transfer systems with particular attention to the ones dedicated to the charge of electric vehicles. These rules aim at the construction of down-scaled prototypes allowing the study and the design with benefits in terms of costs, time consumption and flexibility. The theoretical results are experimentally validated by comparing a 1.1 kW system with its down-scaled version.

This paper presents a comparative analysis of Multi-Coil Inductive Power Transfer (MCIPT) systems. A multi-coil magnetic system can be decomposed into a single system of coils using matrix manipulation when the system is linear. A comparitive analytical study of air-cored coils to estimate the magnetic parameters-L, M, k of several coil shapes-circular, rectangular, square, segmented circular and segmented rectangular (DD) is then carried out. A misalignment shape characteristic is obtained and comparisons brought out. Important criteria to be considered for misalignment tolerant MCIPT is also described. A boundary for performance limits of misaligned multi-coil IPT systems is presented.

This paper overviews theoretical and practical design issues related to inductive power transfer systems and verifies the developed theory using a practical electric vehicle battery charger. The design focuses on the necessary approaches to ensure power transfer over the complete operating range of the system. As such, a new approach to the design of the primary resonant circuit is proposed, whereby deviations from design expectations due to phase or frequency shift are minimized. Of particular interest are systems that are neither loosely nor tightly coupled. The developed solution depends on the selected primary and secondary resonant topologies, the magnetic coupling coefficient, and the secondary quality factor.

In this paper, a high efficiency Gallium nitride (GaN), HEMT (High Electron Mobility Transistor) class-E power amplifier for the wireless power transfer link is designed and simulated on PSpice. A four-coil wireless power transfer link is modeled for maximum power transfer efficiency on ADS (Advanced Design System) and frequency splitting phenomenon is demonstrated, explained and analyzed. Two resonant coupling structures, series & mixed, are presented and compared. The efficiency performance of the link is studied using spiral and helical antennas of different wire make. In addition, techniques for improving efficiency of the wireless power transfer systems with changing coupling coefficient viz. frequency splitting phenomenon of the coils are proposed.

Wireless power transfer system (WPT) is a technology that transports electric energy to another location without physical wires. It is a good idea to wirelessly transmit electricity especially where it is inconvenient, impractical, hazardous, or impossible to reach, but the method at which the electric power is being transmitted is most important factor of wireless power transmission. Energy should be transmitted with power losses and interference with other electronic devices which required a Pulse duration modulation. Pulse duration modulation (PDM) based inductive links for wireless power transfer system is a novel innovation in wireless power transmission. Several techniques and technologies has been used in the past for wireless power transfer but none of the techniques uses PDM or pulse width modulation (PWM) which offer a fast switching that can easily be controlled or manipulated via feedback networks. The longer the switch rate of PDM compared to the off periods can determine the efficiency and total power supplied to an inductive link. PDM as one of the principal algorithms used in power inverters and photovoltaic system for maximum power point tracking and here it offers the best technique for adequate power output at the receiver end of wireless power transmission system. Since efficiency plays an important role in the design of wireless power transfer so the introduction of PDM makes a significant contribution to knowledge for eliminating power loss in WPT switching techniques.--Introduction:

We present a novel solution for vacuum inductive heating of a gradual crucible. A numerical model was built to estimate the temperature gradient in the crucible. The method was validated with an experimental inductive furnace setup. The solution was shown enable to use in gradual diameter crucible. g r a p h i c a l a b s t r a c t Stepped diameter crucible with SHC. On the right, a section of the SHC is shown with current flow. a b s t r a c t Induced heating in a vacuum environment is the most common method for high precision and purity casting. A significant disadvantage in this process is that it is designed for heating in a crucible of uniform diameter. However, it is not suited for the heating of a crucible with stepped diameter. The use of a variable diameter crucible enables to place a larger amount of raw material into the wider diameter section of the crucible. After the material melts, the liquid fills the narrow part of the crucible and enables better control of liquid flow into the casting mold. Hence, in this research we present a novel solution for vacuum inductive heating in a stepped diameter crucible by using a secondary heating coil (SHC). In order to examine the SHC solution, numerical models were developed to describe the temperature distribution and the heat generation in the crucible. Experiments on a vacuum induction furnace were conducted to validate the numerical models of the SHC. A good match was acquired between the numerical and experimental results. The results of the simulations and experiments have shown great improvement in the capability of heating a stepped diameter crucible with an SHC.

In today’s rapidly growing industries power source is a major aspect of any field. The use of wires is becoming redundant day by day. Considering this as a major issue, the fundamental idea here is to wipe out the utilisation of wires. This may be achieved by implementing wireless power transmission techniques which are far better than the standardised methods of transfer of power. Using close range and far range methods is dependent on the medium of its application.

The latest technological advances in battery and converter technology, along with government mandates on energy independence and resilience, are expected to pave the way for higher deployment of plug-in electric vehicles (PEV) in the transportation fleet. These vehicles, when equipped with bidirectional energy transfer capabilities, can function as mobile energy resources and can be utilized in a Vehicle-to-Grid (V2G) scheme in order to temporarily inject energy back into the power grid, thereby functioning as energy storage systems. The forecasted increase in the number of these dispersed vehicles can potentially turn them into a significant energy resource that can be used by the utilities for ancillary services or even for long-term integration with the power system. The notion of energy injection through V2G schemes has been conceptually investigated in the literature for charging stations or single residential charging devices. In all these case studies, the vehicle needs to be parked, and a connection be established by the driver, for the duration of the battery charge or discharge. This paper looks into V2G through the employment of contactless means for energy transfer, namely inductive power transfer (IPT). IPT adds flexibility to V2G schemes by allowing energy exchange with vehicles in motion or when the driver is not physically present to establish a connection. The performance of IPT for bidirectional power flow has been shown through simulation as well as experimental results. Also, statistical analysis are provided that demonstrate the large scale integration of these vehicles into the grid.

To address the challenges of global warming resulting worldwide climate change leading to devastating calamities and posing basic threat to all living things on earth, modern day research is rightfully directed towards clean sources of green energy. Wind Power is the fastest growing environmental friendly emission free green source of energy. Effective long distance power transfer capability of the system is warranted due to locational disadvantages of availability of some Wind Power sites situated in remote areas away from load centre and even some best sites available offshore. This paper presents the study of doubly fed induction generators (DFIG) converter controllers integrated to flexible alternating current transmission system (FACTS) to improve power transfer capability of Wind farms over long distances. I. INTRODUCTION In the modern world, the gradually increasing electric power demand arising out of our power dependent life style in every sphere is necessitating generation of more electric power throughout the globe. To meet the requirement of ever increasing power demand, new power plants are being established in a very fast pace and in some cases the capacity of the existing plants are increased. It is however scientifically established that power sector is significantly contributing towards global warming which is directly impacting climate change throughout the world due to burning of fossil fuels for generation of electricity and polluting the atmosphere by emission of greenhouse gases. Therefore there is a definite need to look into various sources of clean green energy. Wind source has a distinct edge over other available renewable sources of clean energy such as solar power, hydro power, ocean wave power and so on. With the development of technology, electricity generation using wind source has drawn an increased attention throughout the world. More wind power integrated into the system causes power quality and stability problems. Therefore power utilities are developing strict grid codes which are to be satisfied by the producers of wind power. Voltage control and reactive range potential, frequency control capability and fault ride through ability are among the major requirements specified in the grid codes [1]. Due to the intermittent feature of the wind, power quality and stability problems are faced. This problem becomes noticeable, especially, when the amount of wind power integrated to the system is sufficiently large. In view of the variable speed operation potential, DFIG is becoming popular generation of wind power. Control of the voltage of the DFIG wind farm has been identified as the latest challenge with the present requirements of grid code. Variations of output voltage of a wind farm occur due to the wind gusts and frequent gradual wind speed variations. Also wind power plants are vulnerable during some transient states as well. Sub synchronous resonance (SSR) is a major challenge in long distance power transfer in wind farms and its damping is essential for effective system stability and power transfer. The wide use of wind generation warrants that the wind farms should be able to contribute to network support like the conventional synchronous generators. DFIG is a wound rotor induction motor with rotor insertion. The speed of the DFIG can be controlled by inserting changeable voltage of slip frequency to the machine rotor. It has become popular in wind farms, since it enables maximum energy due to its ability of operation in variable speed.

This paper investigates different approaches to improve the power transfer capability (PTC) of transmission lines. Study was performed on the Eastern Gold Fields (EGF) area of the Western Power network in Western Australia where power transfer to this area is currently enhanced using four saturable reactor types static var Compensators (SR SVCs) installed in this region. These SR SVCs have reached to the end of operational life and they are scheduled for replacement by different dynamic reactive power devices such as Static Synchronous Compensators (STATCOMs) or Thyristor Controlled SVCs (TSVCs). Another proposed option to enhance the PTC to this area is by upgrading the 220 kV transmission line to 275 kV transmission line and / or using series capacitor compensation. This paper introduces technical and economical study for the aforementioned options and suggests a reliable and cost effective approach to improve the PTC to EGF area.

Wireless charging by transferring energy between two objects using electromagnetic fields commonly called Wireless power transfer is an alternative technology that is physically installed in an electric vehicle (EV) to charge. Parking alignment is a very important factor in driver behavior that affects power transfer efficiency (PTE). The proposed hexagonal coil array design in this experiment is to optimize PTE and receiver coil size. The experimental results show that PTE in the tangential boundary plane Misalignment increases by 5-10% when compared to coil array circles and increases by 82% when compared to single coil circles.

The use of renewable energy source (RES) in meet the demand of electrical energy is getting into attention as solution of the problem a deficit of electrical energy. Application of RES in electricity generation system is done in a variety of configurations, among others in microgrid system. Implementation of microgrid systems provide many advantages both from the user and from the electric utility provider. Many microgrid development carried out in several countries, because microgrid offers many advantages, including better power quality and more environmentally friendly. Microgrid development concern in technology generation, microgrid architecture, power electronics, control systems, protection systems. This paper reviewing various technological developments related to microgrid system and case study about microgrid system development using grid tie inverter (GTI). Microgrid system can implemented using GTI, power transfer can occur from GTI to grid when GTI has power excess and grid supplying power to GTI when GTI power shortage.

The imperfect coupling (or misalignment)
between the inductively coupled coils in an inductive power
transfer (IPT) system is a major problem of the wireless battery
charging. This problem causes decreasing and fluctuations of
the system efficiency and load power (or load voltage). In this
paper, a new approach was introduced to deals with such a
problem. The proposed approach based on the maximum power
point tracking (MPPT) and load power/voltage regulation
(PR/VR). The MPPT technology based on the impedance
matching (IM), where the tuning capacitances are still varying
to keep the resonant frequencies of the coils equal to the inverter
switching frequency (fs). The proposed PR/VR was achieved
based on the duty cycle control of the inverter; the fuzzy logic
controller (FLC) was used to achieve that.

In this paper, starting from the experimental experience of the road embedment of a transmitting coil for wireless power transfer, a numerical model of such device is constructed. The model is then used to perform several parametric analyses which aim at investigating the influence of the main electromagnetic parameters of the concrete and the geometrical parameters of the wireless power transfer on the overall behavior of the device. The results of such study allow for providing guidelines for the design of the coil and the choice of the materials for the embedment. Moreover, as a secondary result of the adopted methodology, the electromagnetic characterization of the concrete adopted for the road embedment is obtained.

The power transferred between the human body and the environment at any time and the work performed are important quantities to be estimated when evaluating and optimizing the physical interaction between the human body and the environment in sports, physical labor, and rehabilitation. It is the objective of the current paper to present a concept for estimating power transfer between the human body and the environment during free motions and using sensors at the interface, not requiring measurement systems in the environment, and to experimentally demonstrate this principle. Mass and spring loads were moved by hand over a fixed height difference via varying free movement trajectories. Kinematic and kinetic quantities were measured in the handle between the hand and the load. 3-D force and moments were measured using a 6 DOF force/moment sensor module, 3-D movement was measured using 3-D accelerometers and angular velocity sensors. The orientation was estimated from the angular velocity, using the initial orientation as a begin condition. The accelerometer signals were expressed in global coordinates using this orientation information. Velocity was estimated by integrating acceleration in global coordinates, obtained by adding gravitational acceleration to the accelerometer signals. Zero start and end velocities were used as begin and end conditions. Power was calculated as the sum of the inner products of velocity and force and of angular velocity and moment, and work was estimated by integrating power over time. The estimated performed work was compared to the potential energy difference corresponding to the change in height of the loads and appeared to be accurate within 4% for varying movements with net displacements and varying loads (mass and spring). The principle of estimating power transfer demonstrated in this paper can be used in future interfaces between the human body and the environment instrumented with body-mounted miniature 3-D force and acceleration sensors.

Wireless power transfer system (WPT) is a technology that transports electric energy to another location without physical wires. It is a good idea to wirelessly transmit electricity especially where it is inconvenient, impractical, hazardous, or impossible to reach, but the method at which the electric power is being transmitted is most important factor of wireless power transmission. Energy should be transmitted with power losses and interference with other electronic devices which required a Pulse duration modulation. Pulse duration modulation (PDM) based inductive links for wireless power transfer system is a novel innovation in wireless power transmission. Several techniques and technologies has been used in the past for wireless power transfer but none of the techniques uses PDM or pulse width modulation (PWM) which offer a fast switching that can easily be controlled or manipulated via feedback networks. The longer the switch rate of PDM compared to the off periods can determi...