<p>The homopolar inductor alternator (HIA) with magnetic modulator ring (MMR) has important applications in flywheel energy storage system, synchronous condenser, capacitor charge power supply (CCPS) and so on. But it has the disadvantage of high non-linearity of magnetic-flux regulation and the no-load iron core losses during idling conditions is not extremely low. In this paper, we propose using the HIA with radial movable permanent magnet (RMPM) to replace the HIA with MMR in the above application scenarios, and compared the HIA with MMR or RMPM in detail. The magnetic circuit model, the magnetic field and flux weakens ability, no-load iron core losses, flux regulation linearity, power density, the electromagnetic force and complexity and reliability of magnetic adjustment actuator (MAA) for HIA with MMR or RMPM are compared. The simulation results show that the HIA with RMPMs has much better magnetic field and flux weakens ability and flux regulation linearity, and also it has much lower no-load iron core loss under idle operating conditions. What’s more, the electromagnetic force of MAA for HIA with RMPMs is much smaller than the HIA with MMR. But the MAA for HIA with RMPMs is more complex than that for the HIA with MMR, so its reliability is relatively lower. The power density of HIA with RMPMs is slightly smaller than the HIA with MMR. The difference of charge voltage between every pulse for CCPS based on HIA with RMPM is much less than that of the HIA with MMR. The research results in this paper are benefit for choosing between HIA with RMPM and HIA with MMR according to different performance requirement. The way of moving PM is also studied, and can guide the operation of HIA with RMPM.</p>