Dual Three-Phase Sparse Inverter: Topology Analysis, PWM Scheme, and Common Mode Voltage Elimination

Dual three-phase drives offer significant advantages for medium and high-power applications, including reduced current ratings for power switches, lower torque ripple, and enhanced fault tolerance compared to conventional three-phase drives. However, traditional three-level inverters used to drive these motors often escalate system costs due to their large number of power switches. This article introduces a dual three-phase sparse inverter designed to address these limitations. The proposed inverter utilizes only 16 power switches, a substantial reduction compared to conventional three-level inverters. This article also propose a carrier-based pulsewidth modulation (PWM) scheme that uniquely imposes no computational burden on the microcontroller. This PWM strategy incorporates a 180° phase shift between carriers of two three-phase systems, effectively eliminating common-mode voltage and xy harmonics. A comprehensive comparative study was conducted, assessing the proposed inverter against both two-level and conventional three-level inverters based on total harmonic distortion and efficiency. To validate its performance, experimental results are provided for the proposed dual three-phase inverter driving a 746 W induction motor using a constant volt/Hz open-loop control method.