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Magnetic resonance technology set a new course in the wireless power transfer (WPT) sector. WPT is derived from inductive power transfer (IPT) which is developed many decades back. After this much time, the transfer efficiency increased from 70% to more than 95% and transfer distance from few centimeters to several meters. A converging pattern in the trade off between transfer efficiency and the air gap distance is visible in every novel designs. This pattern is achieved through the optimum selection and design of compensator, wireless transformer and the battery packs. As the conservation of energy and exploration of renewable energy resources became a common aspect in every novel technological entities, solar power and fuel cells made its debut to wireless charging. A detailed analysis of different types of wireless charger topologies implemented and proposed in plugged in hybrid electric vehicle (PHEV) charging applications are presented in this paper. The recent attempts to integrate the renewable energy sources to the wireless charging is covered. Two winding model is taken for the analysis of the state of art efficiency. For enhancing the performance of wireless charging system, various compensation techniques are validated based on different topologies. Maximum efficiency and charging condition for a given impedance is explained and derived comprehensively. Different winding designs for wireless transformer is described with comparison. Magnetic coupler selection, battery selection and different safety standards for WPT design are mentioned in this paper.

This paper proposes novel current fed converter full bridge isolated DC-DC converter with voltage multiplier and active clamp circuit for fuel cell grid connected applications. The proposed converter is best suited for fuel cells and their interfacing to utility three phase grid. Active clamp concept introduced on the primary side of isolation transformer to reduce the turn-off voltage spikes of full bridge active devices. Innate soft-switching with elongated range can be achieved in the recommended converter by using the parasitic capacitance of MOSFET switches and leakage inductance of the high frequency transformer. Zero Voltage Switching(ZVS) is achieved for all the primary devices which allow greater switching frequency operation and improvement in over-all efficiency of the converter for utility interface. Cost, size and weight of the converter minimizes for the higher switching operation of the converter. Half-wave Cockcroft-Walton Voltage Multiplier (H-W C-W VM) having minimum number of multiplying stages is used on the secondary side of the designed converter in order toget the required DC-link voltage for three phase utility grid connection. The converter's switching frequency is maintained at 100 KHz. This paper is organized as introduction, steady state operation, simulation results with two different cases i.e. full load and half load conditions and finally, test result validation of a 250 Watt experimental setup with the proposed converter.

The transportation field is witnessing a plethora of changes in vehicle electrification sector. One of the revolutionary technologies emerging in this filed is wireless power transmission. Despite various advantages like universal nature, non-physical contact and ease of access, wireless power transmission faces some limitations like flux leakage, non-linear transmitter-receiver relation, etc. This non-linear behavior of wireless power transformer causes a dynamic input-output relation throughout the operation. This leads to the use of multiple sensors which would increase the closed-loop response time. These additional sensing elements and gain determining process will reduce the power transfer efficiency in light power electric vehicles like electric bicycles. To mitigate these non-linear effects of wireless power transmission, a customized linear region is identified and implemented in this work. In this identified region of the transformer, the input-output relation will be linear, which will prevent the use of additional sensing elements. A 250 W electric bicycle is used for this study of linear control of the wireless charger. The overall efficiency of 93% is achieved for a coupling separation of 200 mm even when the primary and secondary coils have much higher misalignments. The linear closed-loop region is designed and represented with analytical equations, and the transformer efficiency obtained through these equations have been validated with the hardware outputs as well as with commercial simulations.

The fundamental dosimetric characteristics of commercially available metal oxide semiconductor field effect transistor (MOSFET) detectors were studied for clinical electron beam irradiations. MOSFET showed excellent linearity against doses measured using an ion chamber in the dose range of 20-630cGy. MOSFET reproducibility is better at high doses compared to low doses. The output factors measured with the MOSFET were within +/-3% when compared with those measured with a parallel plate chamber. From 4 to 12MeV, MOSFETs showed a large angular dependence in the tilt directions and less in the axial directions. MOSFETs do not show any dose-rate dependence between 100 and 600MU/min. However, MOSFETs have shown under-response when the dose per pulse of the beam is decreased. No measurable effect in MOSFET response was observed in the temperature range of 23-40 degrees C. The energy dependence of a MOSFET dosimeter was within +/-3.0% for 6-18MeV electron beams and 5.5% for 4MeV ones. This study shows that MOSFET detectors are suitable for dosimetry of electron beams in the energy range of 4-18MeV.