Abstract

Contactless energy transfer 1 has indubitable advantages in modern technique given by the lack of electro-mechanical contacts predisposed to pitting and failure: use in aggressive or explosive (no sparks) environments, application to mechanisms with translation or rotation move-ments (robotics), high efficiency on relatively short distances a.s.o. Recent researches carried out in Romania demonstrate the feasibility of these systems for a wide power range, from a few watts up to tens of kW, suitable for the expansion of the electro-mobility and proliferation of multimedia and mobile communication devices. Such systems impose storing the energy in batteries requiring frequent charging. The concept of high frequency transformer with separable windings, as well as a capacitor with separable electrodes working in near field regime, the use of resonance and magnetic flux concentrators for increasing the transfer efficiency, some practical achievements and also maintaining of electromagnetic compatibility within well-defined limits are presented. The paper aims to draw the attention of users and also of prospective investors on the applications and advantages of these systems and to encourage national partnerships for developing theoretical and applied research in this field.

Abstract

Wireless power transfer systems (WPTS) can be made more efficient from the emitter-receiver and from the active power transfer efficiency point of view by using the scattering parameters S. Using electrical circuit theory and starting from the correct formulation of scattering parame-ters, S parameters are computed in an automated manner based on modified nodal equations corresponding to WPTS. Advanced computation software (ADS, Ansoft Extractor Q3D, Cadence, etc.) is used to compute the parameters cor-responding to the magnetically coupled coils. The magneti-cally coupled coils can be described by the parameters of the resulting equivalent circuit, such as: impedance and admit-tance matrices, transfer coefficients matrix and the scatter-ing parameters matrix. This paper presents on one hand the correct formulation of S parameters and on the other hand the practical use of these parameters to streamline the wire-less energy transfer. To generate the analyzed parameters, dedicated function were developed in MATLAB and exist-ing routines from the Microwave toolbox (MATLAB) have been used. The frequency variation of S has been studied using graphical representation and Smith diagram. The accuracy in defining the scattering parameters S, based on analog circuit theory in harmonic state, in complex domain, is confirmed by the results obtained using the program ADS, that contains routines specific for generating S parameters.

Abstract

This paper describes the use of WEBENCH Coil Designer for generating wireless power transfer PCB induc-tors for low and medium power portable systems without the need of complex calculations or complex layout design. This tool is also used to generate the design files that engi-neers can include in their final designs. These results are of great importance in the wireless charging domain, with ap-plicability from mobile phones to industrial equipment charging. The designed coil inductors can also be used in medical equipment by printing them on flexible materials. To minimize the cost and design time for new products, the use of a specialized tool, like WEBENCH Coil Designer, is recommended for new and experienced engineers. Switching to PCB inductors is more cost effective and creates more stable inductors with precise electrical parameters and good repeatability.

Abstract

This paper presents a set of diagrams for wireless power transfer systems (WPTS) with applications in key domains such as: medical, electrical engineering, military, etc. Our research is based on original circuits working as WPTS. All the circuits are using sets of two magnetically coupled coils whose parameters were extracted by simula-tions using the specialized software ANSOFT Q3D Extrac-tor. The simulations of the circuits were performed using TINA, PSpice and Simulink in MATLAB. We used existing parts libraries from Texas Instruments. The circuits were also physically built and tested and the results were very close to the numerical ones. We also compared the results with data in existing literature and we obtained an accept-able computation error. We also studied the efficiency of the power transfer and presented some practical applications for these systems such as low power battery chargers.

Abstract

Function of the alignment of the two magnetic coupled coils, a procedure, to choose the proper structure of the two coils used in the wireless power transfer systems (WPTS’s), is presented. The deviation in the alignment of coils can be made in two ways – the angular displacement and the lateral displacement. For the lateral displacement, the two coils are located in parallel planes with their centres misaligned, respectively in the case of angular displacement there is an angular deviation between the receiver and transmitter coils having aligned centres. The main target is to compare the obtained results and select the best solution with the great value for mutual inductance. The main focus was on the influence of lateral displacement of two coils, for two configurations: transmitter and receiver coils are circu-lar type; transmitter coil is pancake type and receiver coil is circular type. After the simulations, we shown that there is a smaller deviation from initial value of the mutual induc-tance for the second case (transmitter coil is pancake type and receiver coil is circular type). Combining the two effects (angular and offset side) we get a surface where if the re-ceiving coil is located on it, the coupling factor of the wire-less system has the same value

Abstract

With the increase of the number of devices pow-ered and using wireless systems, the optimal design of such systems is necessary. The present study aims at determining the influence of parameters like distance between inductors and the placement of ferrite layers on the phenomena re-garding the spiral inductors through their numerical model-ling. A simple wireless power system constructed from an emitter and a receiver spiral inductor is considered in the present study. The numerical modelling of the system is made using the software program Ansys Maxwell 3D Field Simulator. Also, a comparison of the results obtained from the modelling and simulation of this wireless power system and from a practical model made in the laboratory is pre-sented. As the modelled structure, the practical model is constructed from two spiral inductors. The importance of numerical modelling of the structure in order to determine an optimum is highlighted. The parameters obtained and analysed from the 3D model are magnetic field intensity, magnetic induction and mutual inductance, while for the constructed model the voltage is studied. For the modelled structure, the distance between the receiver and the emitter is varied between 0.05 mm and 5 mm, considering the struc-tures with and without the ferrite layers in order to reach a conclusion.

Abstract

This research work deals with the challenges and issues facing the misalignment contactless inductive power charging of electric vehicles (EVs). The focus is on analysis and design of the inductive power transfer (IPT) for dynamic (in-motion) charging systems. The computational electromagnetics approach is used here, and a graphical and programming platform is developed capable to link and co-simulate the models of the coupled coils with the models of the external circuitry of the overall IPT system consisting of: high frequency power inverter on the primary coil side, resonant tuning capacitors, diode bridge rectifier on the secondary coil side, DC filtering capacitor and the vehicle battery load.

Contactless Power Transfer – Theoretical Principles and Fields of Applications – Andrei Marinescu, Mihai Iordache, Lucian Mandache

Inductive Power Charging forElectric Vehicles in Misalignment Conditions – Constantin M. Apostoaia, Mihai Cernat

Design of Wireless Electromagnetic Energy Transfer Systems – Mihai Iordache, Victor Bucată, Dragoş Niculae, Marilena Stănculescu, Maria-Lavinia Bobaru

An Analysis on Efficiency of Wireless Transfer Energy Due to a Misalignment of Two Coils – Dragoş Niculae, Marilena Stănculescu, Mihai Iordache and Maria-Lavinia Bobaru

Wireless Power Transfer AnalysisUsing Scattering Parameters – Marilena Stănculescu, Lavinia Bobaru, Mihai Iordache, Dragoş Niculae and Victor Bucată

Easy Design Procedure of PCB Inductors Using WEBENCH Coil Designer – Catalin Bibirica, Sandu Cristian, Lucian Ene, Mihai Iordache Iordache

Modeling, Simulation and Practical Realization of the Spiral Inductors Used in Wireless Power Systems – Claudia Păcurar, Adina Răcăşan, Vasile Ţopa, Călin Munteanu, Claudia Constantinescu