A Carrier-Based Implementation of Virtual Space Vector Modulation for Neutral-Point-Clamped Three-Level Inverter

In this letter, space vector pulse width modulation (SVPWM) and virtual SVPWM (VSVPWM) for the neutral-point-clamped (NPC) three-level inverter (TLI) are reviewed briefly. The relationship between VSVPWM and carrier-based PWM is revealed based on the PWM model of TLI with NP current equation. Then, carrier-based VSVPWM (CB_VSVPWM) is proposed. The CB_VSVPWM is implemented by comparing double modulation waves with a single carrier, and the two modulation waves for each phase are deduced. The CB_VSVPWM can simplify the implementation of VSVPWM to a great extent. Moreover, comparisons between SVPWM and CB_VSVPWM are provided in detail. At last, the simple method proposed in this letter is verified by experiments.