<p>A compact inverter circuit was developed for driving low-power hysteresis motors. The relatively low efficiency of hysteresis motors and the thermal and spatial constraints of miniaturized circuits highlight the need to ensure and improve system efficiency. Accordingly, this study implemented hardware- and software-based approaches for over-excitation, a technique to enhance the efficiency of hysteresis motors. The system efficiency of each method was evaluated to verify its applicability. In particular, the software-based On-Time control of the drive frequency was shown through comparative analysis with other methods to be a viable and effective alternative for hysteresis motor applications. Considering the importance of noise in compact indoor systems, the acoustic characteristics of each method were compared, and the On-Time control method was confirmed to meet the target noise levels, showing its applicability.</p>