Carrier-based SVPWM through sub-sector identification in multi-level inverters

This paper proposes a simple method for identification of the sub-sectors of the space vector diagram in which the reference phasor tip lies and using that; carrier-based implementation of the Space vector pulse width modulation (SVPWM) is derived for multi-level PWM inverters. This method is based on the line equations of the n-level inverter space vector diagram. Sub-sector identification and thereby a common-mode offset determination for the carrier-based SVPWM can be used to reduce the complexity of implementation of SVPWM as well as modified SVPWM strategies. The logic of the proposed method is implemented for three-level and four-level inverters and can be further extended to higher level voltage-source inverters. The validity of the method is verified in simulation for the three-level and four-level inverters.