Common-Mode Voltage Reduction in Three-Level T-Type Converters Using a Quadruple Reference Voltage-Based PWM Technique

This paper introduces a novel Quadruple Reference Voltage-Based Pulse Width Modulation (QRVPWM) technique for mitigating common-mode voltage (CMV) in three-phase, three-level T-type converters. In contrast to conventional carrier-based PWM (CBPWM) methods, the proposed approach utilizes four phase-shifted reference voltages, enabling significant attenuation of CMV ripple without increasing control complexity or requiring additional hardware. Both simulation and experimental results, conducted under various load conditions and modulation indices, demonstrate up to a 50% reduction in CMV magnitude while maintaining balanced DC-link capacitor voltages. Although a marginal increase in total harmonic distortion (THD) is observed in one phase, the average THD across all three phases remains within acceptable IEEE 519-2022 standard. Furthermore, Fast Fourier Transform (FFT) analysis verifies the effective suppression of dominant CMV spectral components. These results confirm the suitability of the proposed QRVPWM technique for electromagnetic interference (EMI)-sensitive applications such as electric vehicles, motor drives, and grid-connected renewable energy systems.