Carrier-Based Discontinuous PWM Method for Five-Leg Inverter

Abstract

This paper proposes a rotation carrier-based discontinuous pulse width modulation (CB-DPWM) method for the five-leg inverter (FLI). The FLI based on two-level topology consists of 10 switching devices for driving dual motors. Therefore, two switching devices can be reduced to compare the configuration using two three-leg inverters for driving dual motors. The proposed pulse width modulation (PWM) method is based on the reference signals which are used in existing carrier-based continuous pulse width modulation (CB-CPWM) method for FLI. In the proposed rotation CB-DPWM method, one of five-leg is periodically clamped to Vdc/2 or - Vdc/2 by adding the offset voltage to the reference voltages of the existing CB-CPWM method. The five reference voltages for all legs are considered to calculate the offset voltage of the proposed rotation CB-DPWM method. Consequently, since the proposed rotation CB-DPWM method has less switching than the existing CB-CPWM, the switching loss can be reduced and it results in the efficiency improvement. Simulation and experimental results confirm the effectiveness and feasibility of the proposed method.

Keywords

• Five-leg inverter (FLI)
• modulation
• rotation carrier-based discontinuous pulse width modulation (CB-DPWM)
• dual-motor driving system