A Discontinuous Carrier-based PWM Modulation Method for the Control of the Neutral Point Voltage of Three-Phase Three-Level Diode Clamped Converters

The neutral-point voltage of the three-level, three-phase converter is regulated using a hysteresis controller which selects the appropriate expression for the zero sequence voltage signal which augments the modulation signal used in the discontinuous carrier-based PWM modulation scheme for voltage control. The analytical expressions for the zero sequence voltages are generalized to three sets making its DSP implementation very easy. Simulation and experimental results verify the usefulness of the proposed neutral-point regulation technique