Two-triangle carrier SPWM modulation for a five-level diode-clamped PWM inverter

Abstract

This paper describes two-triangle carrier sinusoidal pulse-width-modulation (SPWM) for a five-level diode-clamped PWM inverter and compares it to the SPWM-based neutral-point-clamped (NPC) PWM inverter and the original SPWM-based five-level diode-clamped PWM inverter for use in medium-voltage motor drives. The characteristics of the three techniques are compared by analysis and experiment for an adjustable-speed motor drive for pumps and blowers without a transformer. The experimental systems are 380-V 5.5-kW downscale models. The experimental systems were designed, constructed, and tested for the comparison study and were based on a 16-bit digital signal processor with the use of insulated gate bipolar transistors as switching devices. A 5.5-kW four-pole induction motor coupled with a permanent-magnet synchronous generator was used as the electrical load. © 2015 The Institute of Electrical Engineers of Japan.