《+++++ Sine Triangle versus Space Vector Modulation for Three Level PWM Voltage Source Inverters》.pdf

500 IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 38, NO. 2, MARCH/APRIL 2002 Sine-Triangle versus Space-Vector Modulation for Three-Level PWM Voltage-Source Inverters Fei Wang, Senior Member, IEEE Abstract— This paper studies the inherent relations between sine-triangle and space-vector pulsewidth modulation schemes for three-level voltage-source inverters. It is shown that the two schemes can function equivalently through proper selection of common-mode injections in the case of sine-triangle modulation, or dwell times in equivalent redundant switching states in the case of space-vector modulation. Simulation and measurement results illustrate that understanding of these relations can lead to a more efficient and flexible three-level modulator with desired or optimal performance. Index Terms—Pulsewidth modulation modulator, three-level voltage-source inverter. Fig. 1. Neutral-point-clamped three-level VSI. I. INTRODUCTION HREE-LEVEL pulsewidth modulation (PWM) Tvoltage-source inverters (VSI) are the converters of choice for many high-power applications such as medium-voltage motor drives [1]–[3]. Fig. 1 shows the most popular type of three-level inverters, the three-phase neutral-point-clamped VSI. Compared with two-level inverters, three-level inverters have half the voltage stress on switching devices for the same dc-link voltage, and generate lower harmonics at the same switching frequency. The performance of a three-level inverter very much depends on its PWM modulator. There have been many three-level mod- ulation techniques developed in the last two decades