| Summary: | 碩士 === 國立高雄科技大學 === 機械工程系 === 107 === This study focuses on the design of DC and AC magnet coils with a bandwidth up to 1 kHz. The key factors affecting the performance of Helmholtz (air core) coil and ferrite-core coil were analyzed by using the ANSYS Maxwell software to simulate the magnetic field distribution in a fixed target area of the coil, and the results were verified by experiment. The simulation results show that the non-uniformity of magnetic field can reach 0.2% in the target region, which is 10% of the outer diameter of Helmholtz coil. The observed optimum non-uniformity was found to be 0.24%. The similar non-uniformity was also achieved for the ferrite-core coil in the region of which the size is 10% of the outer dimension. To generate the alternating field up to 1 kHz, a matrix of capacitors was cascaded with the coil (inductor) to form an inductor-capacitor resonant circuit, which can effectively boost the alternating current. The switchable matrix of parallel capacitors is used to fine-tune the resonant frequency in order to overcome the inductive reactance effect of the coil and increase the bandwidth, allowing virtually continuous adjustment of frequency in the range from 50 Hz to 1 kHz.
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