Power Loss Reduction of Discontinuous PWM in Two-Level Voltage Source Converters

This paper presents a comparison between Space Vector PWM and Discontinuous PWM with clamping to the negative supply, in terms of power losses of the transistors and diodes in an inverter for AC motor drives. The proposed approach used for the power loss estimation uses an advanced method based on power loss models that are evaluated at each simulation step. The power losses are compared based on results from several simulations using a three-phase inverter with a RL load or three current sources so that the power factor can be controlled. The two modulation methods are used one at a time to measure the power loss in the inverter, the phase voltage and the phase current with its maximum. Based on the simulation results, a comparison between the power loss in the two cases is made, depending on the power factor and the amplitude of the output current.