D.C.J. Krop

Optimal design of a pot core rotating transformer

This paper discusses the optimal design of a pot core rotating transformer to replace wires and slip rings in mechatronic systems by means of contactless energy transfer. Analytic models of the transformer are derived in the electromagnetic and thermal discipline. The models are compared with both 2D/3D FEM simulations and measurements. The analytical models are combined and used in a multi-objective sequential quadratic programming algorithm to find the minimal Pareto front in terms of volume and power loss for comparison of the adjacent and coaxial winding topologies. Finally, the optimization algorithm is used for the design of two prototype rotating transformers for a power transfer of 1kW peak, rotating at 4000 rpm. The prototypes are manufactured and tested in an experimental setup.

Contactless power transfer to a rotating disk

This paper discusses a power transfer system from the stationary to the rotating part of a device, by means of contactless energy transfer. A rotating transformer is proposed as a replacement for wires and slip rings. A pot core geometry is used for the rotating transformer and two different winding topologies are compared. The transformer is analyzed in the electromagnetic and thermal domain. An analytic model for each domain is derived. The validity of the analytical models is confirmed with both 2D and 3D FEM simulations and measurements. Two prototype rotating transformers are designed for the transfer of 1 kW peak, rotating at 6000 rpm. The prototypes are manufactured using commercially available pot cores and tested in an experimental setup.

A study on the integration of contactless energy transfer in the end teeth of a PM synchronous linear motor

Linear motors find their utilization in an increasing number of industrial applications. Permanent magnet linear synchronous motors (PMLSMs) are favorable in many applications due to their servo characteristics, robustness, and high force density. The major disadvantage of moving coil type PMLSMs is the cable slab that energizes the coils from the fixed world to the moving parts of the machine. These cable slabs introduce extra wear and dynamical distortions. Moreover, in precision application the cable slab is supported by additional linear drives. These disadvantages can be eliminated if the coils could be powered wirelessly. In this paper two topologies are proposed that are capable of transferring 1 kW of power at most. The transformer part of the CET is characterized by means of two dimensional finite element analysis, and the influence of using additional capacitors to boost the output power is examined. Furthermore, an analysis of the core losses is conducted. Conclusions are drawn from the results.

Decoupled Modeling in a Multifrequency Domain: Integration of Actuation and Power Transfer in One Device

A novel topology of a moving-coil, tubular permanent magnet linear motor with an integrated coaxial transformer is introduced in this paper. The topology is able to continuously transfer 800 W of power and generate at least 250 N of force. The isotropic, soft-magnetic composite core of the topology simultaneously functions as the flux guide of a high-frequency (5–10 kHz) transformer core and the low-frequency (

Analytical modelling techniques for thrust force calculation of a permanent magnet linear motor

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Analysis and design of a tubular linear PM motor with integrated contactless energy transfer

100 Hz) motor core. The magnetic fields of the motor and the transformer have an orthogonal mutual orientation to minimize cross-coupling effects between both functionalities. The magnetic behavior of the complex, 3-D, electromagnetic problem, that simultaneously operates in two frequency domains, is analyzed by means of decoupled Fourier models. The Fourier models are, first, applied to identify the electromagnetical implications that originate from the integration of the two functionalities, and, second, applied within an optimization routine to obtain a final design. The optimal design is then compared to 3-D finite element analysis simulations.

Linear motor with contactless energy transfer

This paper presents a comparative study on two analytical modelling techniques (i.e. Fourier analysis and Tooth Contour Method), applied to a benchmark topology of a linear permanent magnet synchronous motor (LPMSM). The investigated methods are used for obtaining the thrust force of a LPMSM with significantly reduced computation time (from the order of seconds to the order of milliseconds), compared to traditional numerical modelling techniques (i.e. Finite elements method). Despite the reduced computation time, the analytical modelling techniques accuracy is kept high, having less than 5.0% discrepancy, in comparison to the finite elements method.

Development of a linear position independent Inductive Energy Transfer system

A novel tubular permanent magnet motor topology with integrated contactless energy transfer is proposed in this paper. The high-frequency transformer of the contactless energy transfer, that is able to transfer 800 W of power continuously, is fully integrated in the design of the linear motor. The energy can be delivered to the mover while the motor is moving. The magnetic field orientation inside the soft-magnetic composite material is such that cross coupling effects between the motor and the transformer are minimal. Two 2D Fourier models are created to predict the transformer and motor behavior of the system separately. The models are applied in a design routine to determine the optimal geometries for different design objectives. The performance analysis of one of the optimized designs is analyzed with 3D finite element software.