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The objective of this work is to discuss the engineering feasibility of high-frequency magnets for the magnetic hyperthermia cancer therapy. For effective induction heating properties of cancer therapy, the target specifications of the high-frequency magnet system are 0.06 T of the peak magnetic flux density with 200 kHz of the operating frequency at the center of used space. The operating time of the system requires 300 seconds. In order to investigate the most optimal design of high-frequency magnet system for magnetic hyperthermia, the authors carry out the design of a small sized high-frequency magnet prototype based on magnetic circuit theorem. In the prototype design, a ferrite core length is limited to 1 m, and copper Litz wires are used for the coil windings. In order to compensate the self-inductance of the magnet, the power supply system requires series resonance circuits using capacitor banks which are directly connected to the coil windings. SiC-MOSFETs will be the feasible solutions for the 200-kHz class high-frequency inverter. The magnet prototype is composed of 16 sets of 5-turns coils and will obtain the target magnetic with an operating current of 65-A. The Litz wires consist of 1800*3 strands is used for the coil windings The diameter of each strand is 0.05 mm. However, from the results of the impedance measurements, the prototype has 2 mH of the self-inductance which value is higher than the designed value. If the magnet is operated with 65-A and 200 kHz, the voltage between each coil winding becomes 10.2 kV. In this case, 5.1 nF of the capacitor banks are required for the series resonance circuit. Addition to this, the resistance of the coil windings is 10 ohm. Therefore, in order to reduce the impedance, further optimization of the magnet design and the Litz wire conductor design is now in progress. In this paper, the authors summarize the final design of the magnet prototype including the conductor design, the cooling method and the capacitor banks.
