Interleaved Discontinuous Space-Vector PWM for a Multilevel PWM VSI Using a Three-Phase Split-Wound Coupled Inductor

A multilevel interleaved discontinuous space-vector pulsewidth modulation (DSVPWM) method is presented for a three-level three-phase pulsewidth modulation (PWM) voltage source inverter using a three-phase split-wound coupled inductor. The selection of a suitable PWM switching scheme for this topology is based on the dual requirements for a high-quality multilevel PWM output voltage, together with the need to minimize high-frequency currents and losses in the coupled inductor and the inverter switches. Suitable switching states are described for the DSVPWM method over the full amplitude modulation depth range. The proposed method minimizes the coupled-inductor high-frequency current ripple and also produces three-level PWM output voltage waveforms at twice the inverter switching frequency. The inverter operation is examined using simulation tests. The extensive experimental test results are used to obtain the inverter performance as a variable frequency drive when operated in a steady state and during transient conditions.