DSP based space vector PWM for three-level inverter with DC-link voltage balancing

摘要

The authors describe a novel PWM (pulse width modulation) method for a three-level inverter considering the DC link capacitor balancing problem. Each voltage vector on the space vector plane is classified in relation to the charging/discharging action of DC capacitors, and a novel modulation method is suggested based on the voltage vector selection principle. The algorithm was implemented on the Motorola DSP 56000 and tested with the 7.5 kVA prototype three-level transistor inverter. The effectiveness of the proposed PWM method was verified by the experimental results. It was shown that the proposed PWM techniques are suitable for a high-power GTO (gate turn-off thyristor) three-level inverter satisfying capacitor voltage balancing.