Iterative design method of weakly coupled magnetic elements for inductive power transfer

Author(s):  
Rodolfo Castanho Fernandes ◽  
Azauri Albano de Oliveira
Author(s):  
Jun Xu ◽  
Eugeni L. Doubrovski ◽  
Jo Geraedts ◽  
Yu Song

Abstract The geometric shapes and the relative position of coils influence the performance of a three-dimensional (3D) inductive power transfer system. In this paper, we propose a coil design method for specifying the positions and the shapes of a pair of coils to transmit the desired power in 3D. Given region of interests (ROIs) for designing the transmitter and the receiver coils on two surfaces, the transmitter coil is generated around the center of its ROI first. The center of the receiver coil is estimated as a random seed position in the corresponding 3D surface. At this position, we use the heatmap method with electromagnetic constraints to iteratively extend the coil until the desired power can be transferred via the set of coils. In each step, the shape of the extension, i.e. a new turn of the receiver coil, is found as a spiral curve based on the convex hulls of adjacent turns in the 2D projection plane along their normal direction. Then, the optimal position of the receiver coil is found by maximizing the efficiency of the system. In the next step, the position and the shape of the transmitter coil are optimized based on the fixed receiver coil using the same method. This zig-zag optimization process iterates until an optimum is reached. Simulations and experiments with digitally fabricated prototypes were conducted and the effectiveness of the proposed 3D coil design method was verified. Possible future research directions are highlighted well.


2015 ◽  
Vol 2 (2) ◽  
pp. 107-120
Author(s):  
Rodolfo Castanho Fernandes ◽  
Azauri Albano De Oliveira

The design of magnetic couplers for inductive power transfer has probably become the major challenge for those who wish to enter this promising research field. The number of variables that determine physical dimensions of a coupler is typically too high to allow analytical (exact) solutions in practical time when realistic magnetic materials are to be included. Thus, this paper suggests and describes a series of algorithms based on the finite element method (FEM) able to convert basic inputs (target inductances, primary current, frequency, and mechanical restrictions) into a geometric solution that satisfies user-defined targets for uncompensated power, open-circuit voltage, and short-circuit current. Advantages of these algorithms when compared with other existing design methods are: simplicity in terms of structure at the same time that require minimum user intervention to complete a full design; do not rely in expensive finite element solvers; user does not require previous background in FEM formulation. Experimental results show that the proposed design method based on two-dimensional FEM has errors of <8% when compared with three-dimensional FEM and can perform iterations in seconds. It is expected that the proposed routines encourage and provide design insights for practitioners, enthusiasts, and non-specialized engineers.


2009 ◽  
Vol 69-70 ◽  
pp. 520-524
Author(s):  
Jun Pi ◽  
Xi Peng Xu

Contactless inductive power transfer system with conventional inductive technology was studied and a design method was presented after applying it to ultrasonic vibration machining systems. The compensation techniques are used for piezoelectricity transducer. Nodal plane support of transducer is researched and models of different structures for nodal plane support are got. Influence of rotary precision for different support due to centrifugal force and displacement vibration of nodal plane support to toolholder are analyzed. The system integrated with ultrasonic-vibration toolholder based on contactless inductive power transfer is designed. Power transfer and dynamic tests show that the design procedures and result based on theoretical analysis are comparative.


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