Cumulative current‐magnetizing method for a capacitor‐discharged impulse magnetizer

Abstract

This paper presents a cumulative current-magnetizing method for magnetization of permanent magnet, aimed at alleviating the bulky capacitor problem of traditional capacitor-discharged impulse magnetizers. The method employs circuit resonance to boost the output voltage. The resonant alternative current (ac) voltage is then directly discharged to the magnetizing coil without using any rectifier. The proposed resonant ac discharge repeats a number of times over several milliseconds. This allows the magnetizing current to increase incrementally until it reaches the peak that is sufficient to fully magnetize the permanent magnet. With this design, the energy for magnetization is accumulated by small steps, and each increment would require much lower energy. This results in smaller capacitors needed compared to traditional designs. To validate the effectiveness of the proposed scheme, several pieces of ferrite magnet without being pre-magnetized were tested using the developed magnetizer. The test results support the feasibility and practicability of the scheme for potential applications.