Finite Element Modeling and Analysis of High Power, Low-loss Flux-Pipe Resonant Coils for Static Bidirectional Wireless Power Transfer

This paper presents the optimal modeling and finite element analysis of strong-coupled, high-power and low-loss flux-pipe resonant coils for bidirectional wireless power transfer (WPT), applicable to electric vehicles (EVs) using series-series compensation topology. The initial design involves the modeling of strong-coupled flux-pipe coils with a fixed number of wire-turns. The ohmic and core loss reduction for the optimized coil model was implemented by creating two separate coils that are electrically parallel but magnetically coupled in order to achieve maximum flux linkage between the secondary and primary coils. Reduction in the magnitude of eddy current losses was realized by design modification of the ferrite core geometry and optimized selection of shielding material. The ferrite core geometry was modified to create a C-shape that enabled the boosting and linkage of useful magnetic flux. In addition, an alternative copper shielding methodology was selected with the advantage of having fewer eddy current power losses per unit mass when compared with aluminum of the same physical dimension. From the simulation results obtained, the proposed flux-pipe model offers higher coil-to-coil efficiency and a significant increase in power level when compared with equivalent circular, rectangular and traditional flux-pipe models over a range of load resistance. The proposed model design is capable of transferring over 11 kW of power across an airgap of 200 mm with a coil-to-coil efficiency of over 99% at a load resistance of 60 Ω

Control of wireless power transfer system for dynamic charging of electric vehicles

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Linear actuator for a submersible water pump for use in boreholes

Both the theory and the test results show that the E-core electromagnet linear actuator, which is based on the variable reluctance principle, can generate a normal force in excess of 400kNm(^-2) when there is a flux density of IT within the airgap. When the actuator is used as a driver in a submersible water pump for use in boreholes the results show that the pump is capable of pumping up to 90% of the expected value. Pressures in excess of 10 Bar have been achieved, whilst the pump was operating at frequencies up to 30Hz. The flow rate was less than 0.21s ', however improvements to the pumping system are given, and the desired 1ls ' flow rate is achievable at a delivery head of 100m.The use of linear actuators for use in submersible water pumps is a relatively new technology, and as the demand for safe clean water increases, it provides for sustainable development. The actuator utilises a D C. supply with solar panels as the source, giving the potential for global use, particularly in developing countries (the South).The design of the driver can be optimised for selected parameters. However, the development of such drivers does have limitations, the overall diameter of the pump is restricted to that of the bore-hole size, 4 or 6 inches; further the length of the pump is dictated by the straightness of the bore-hole. Consequently, design tools, for the design of E-core Variable Reluctance Linear Actuators, (VRLA), are given