A complete class of PWM techniques for voltage source inverter

A propulsion system for hybrid electric vehicles and electric vehicles contains DC voltage supply, DC link capacitor, three phase voltage source inverter and a three phase AC machine. The key role of the inverter is to convert DC voltage to three AC voltages which commands the motor. The electrical machine is chosen to have the phase voltages in star connection and the common node of the phase voltages unconnected to ground. This paper contains a complete class of modulation techniques used to command the voltage source inverter. It consists in variation of potential of common node of electrical machine phases. This class of modulation techniques is simple to be implemented, offers a complete description of all possibilities to command the voltage source inverter and includes all other modulation techniques that could be found in literature. It is demonstrated analytically the inclusion in this class of some modulation techniques which could be found in literature such as sinusoidal pulse width modulation, third harmonic injection, and space vector pulse width modulation with sector selection.