Performance comparison of electromagnetic generators based on different circular magnet arrangements

In this study, we originally investigated the influence of different magnets arranged circularly on the output performance of an electromagnetic generator. Three cases are studied: an alternating magnet arrangement, a Halbach arrangement and a separate arrangement. We established a theoretical analysis model and simulated the induced electromotive force of the generator via MATLAB. The experimental results indicate that the alternating magnet arrangement yields the highest power (about 2.55 mW) with an energy conversion efficiency of about 0.6% under the low-frequency condition (the excitation speed is 60 rpm) with a load resistance of 1 kΩ among the three arrangements. Besides, we compared the charging performance of generators based on different arrangements regarding charging rate described as charging power on a 10 μF capacitor. The generator with the alternating magnet configuration charged a 10 μF capacitor about 0.68 V in 400 s, whereas in the Halbach and the separate scenarios, the ending voltages were 0.51 V and 0.38 V, respectively. The charging power was about 28.9 × 10−6 mW while they were 9.4 × 10−6 mW and 5.6 × 10−6 mW in the other two cases, respectively, which highlights the desirable charging performance of the generator with the alternating magnet arrangement. This paper can be of great significance for designing high-performance generators and further development of the magnet configuration inside the electromagnetic generator.