Switched reluctance motors (SRMs) offer advantages in efficiency and robustness but suffer from torque ripple and acoustic noise that limit industrial adoption. A new hybrid inverter topology addresses these challenges by strategically combining Silicon Carbide (SiC) and IGBT semiconductor devices to balance performance with cost.
The proposed architecture uses two three-phase inverter stages with 12 total switches—six SiC devices for high-frequency switching during low-inductance rotor positions, and six lower-cost IGBTs during high-inductance phases. This variable-frequency approach exploits the inherent inductance profile of SRM rotors. When inductance is low, the drive activates SiC switches to enable switching frequencies high enough for accurate current tracking via simple hysteresis control. As rotor position transitions to high-inductance zones, the system seamlessly shifts to IGBT operation, reducing switching losses and component costs without compromising torque quality.
Key benefits include significantly reduced torque ripple, lower vibration amplitudes, and decreased acoustic noise emissions—critical for applications such as electric vehicle drivetrains, industrial fans, and pumps where noise is a concern. The architecture also simplifies control logic compared to field-oriented approaches, using straightforward hysteresis-based current regulation.
Validation through multiphysics finite element analysis examined current waveforms, torque ripple, radial force distribution, stator vibration spectra, and radiated acoustic noise. Results confirm that selective SiC deployment maintains performance equivalent to full-SiC inverters while reducing bill-of-materials cost by approximately 30–40% compared to conventional full-SiC solutions.
This hybrid switching strategy represents a practical engineering solution for cost-constrained applications requiring low-noise SRM operation. The methodology is scalable to higher-power industrial drives and offers a design framework for balancing semiconductor costs against performance demands in variable-inductance motor systems.
