PERFORMANCE ANALYSIS ON DYNAMIC WIRELESS CHARGING FOR ELECTRIC VEHICLE USING FERRITE CORE

The technology of dynamic Wireless Power Transfer (WPT) has been accepted in the Electric Vehicle (EV) industry. Recently, for a stationary EV charging system, the existence of a ferrite core improves power efficiency. However, for dynamic wireless charging, the output power fluctuates when the EV moves. Two main obstacles that must be dealt with is air-gaps and misalignment between the coils. This paper investigates clear design guidelines for fabrication of an efficient Resonant Inductive Power Transfer (RIPT) system for the EV battery charging application using a ferrite core. Two different geometry shapes of ferrite core, U and I cores, will be investigated and tested using simulation and experimental work. The proposed design was simulated in JMAG 14.0, and the prototype was tested in the laboratory. The expected output analysis from these two techniques was that the power efficiency of the ferrite pair should first be calculated. From the analysis and experimental results, it is seen that the pair of ferrite cores that used a U shape at the primary and secondary side provides the most efficient coupling in larger air-gap RIPT application with 94.69% on simulation JMAG 14.0 and 89.7% from conducting an experiment. ABSTRAK: Teknologi Alih Kuasa Wayarles (WPT) dinamik telah diterima pakai dalam Kenderaan Elektrik (EV). Baru-baru ini, kewujudan teras ferit dalam sistem pengecasan pegun EV dapat meningkatkan kecekapan kuasa. Namun, kuasa pengecasan ini akan berubah apabila EV bergerak bagi sistem pengecasan wayarles secara dinamik. Dua halangan utama yang harus ditangani adalah ketidakjajaran dan jarak antara dua gegelung. Kajian ini merupakan garis panduan yang jelas mengenai rekaan fabrikasi dan kecekapan sistem Alih Kuasa Induktif Resonan (RIPT) bagi aplikasi pengecasan bateri EV menggunakan teras ferit. Dua bentuk geometri teras ferit, iaitu teras U dan I telah dikaji dan diuji menggunakan simulasi dan eksperimen. Rekaan ini telah disimulasi menggunakan JMAG 14.0 dan prototaip diuji di dalam makmal. Kedua-dua teknik ini diharapkan dapat menghasilkan kecekapan kuasa yang sama. Dapatan kajian menunjukkan kedua-dua teras ferit pada sisi primer dan sekunder berbentuk U mempunyai gandingan paling efisien bagi jarak paling besar antara 2 gegelung menggunakan aplikasi RIPT dengan 94.69% simulasi JMAG 14.0 dan 89.7% secara eksperimen.

Constant-Current and Constant-Voltage Output for Single-Switch WPT System with Composite Shielding Structure

With the development of wireless power transfer (WPT), the wireless charging has become a research hotspot. This paper proposes a novel single-switch hybrid compensation topology, which can change the compensation network to realize the constant-current (CC) and constant-voltage (CV) output. The zero voltage switching (ZVS) margin can be designed to increase the stability of the system. In addition, the magnetic coupler adopts a composite shielding structure composed of ferrite, nanocrystalline, and aluminium foil. The composite shielding structure has a better shielding effect on magnetic flux leakage, and its weight is lighter. The composite shielding structure is expected to be used in the wireless charging system of electric vehicles (EVs). Finally, an experimental prototype is built to verify the theoretical analysis, and the maximum efficiency can reach 91.4%.

Characterization of a soft magnetic composite for use in road-embedded wireless-charging systems

The ferrite magnetic core is an integral component of road-embedded wireless charging systems for electric vehicles. However, the brittleness of ferrite makes it susceptible to premature fracture due to cyclic wheel loading from vehicles. This has motivated the development of a soft magnetic composite (SMC) composed of a flexible polyurethane and crushed ferrite as an alternative. An experimental investigation was conducted into the trade-offs between mechanical, thermal and magnetic properties at ferrite volume fractions between 45.9[Formula: see text]vol% and 80.6[Formula: see text]vol%. A comparison was made between measured properties and predictions from analytical models in order to further investigate the characteristics of the composite. The investigation showed a trade-off between the increase in magnetic permeability and the reduction in strain-to-failure as ferrite volume fraction increased. In addition, a large increase in flexural modulus and thermal conductivity, along with a slight increase in flexural strength was observed. More importantly, the strain-to-failure of the composite was 20 times higher than that of ferrite even at the highest volume fraction, indicating that the SMC was successful in providing a more ductile and flexible alternative.

Development and Implementation of High Precision Positioning Technology for Electric Vehicle Wireless Charging Coils

This paper mainly studies the development and implementation of the positioning technology of the electric vehicle wireless charging coil, so as to accurately detect the position deviation of the receiving coil, so that the electric vehicle wireless charging system can provide electric energy for electric vehicles more efficiently. Based on the positioning method of electric vehicle based on three detection coils, this paper proposes a calculation method to describe the offset degree of coil based on fuzzy mathematics theory. The algorithm is verified by simulation and experiment, and the influence factors of the error accuracy and the source of the error are analyzed. The work done in this paper has a strong practical significance for the efficient realization of electric vehicle wireless energy transmission.