A method for five-phase carrier based PWM modulation for balanced and unbalanced reference voltages

The advancement in power electronics has made the use of any number of phases in ac machines possible since with the inverter, any number of phase voltages can be realized as long as the corresponding inverter exists. To supply multiphase drives requires multiphase voltage source inverters (VSIs) whose output voltages depend very much on the methods of generating the pulses to turn on and turn off the inverter devices appropriately. This paper presents analytical technique for the determination of the expressions for the modulation signals used in the carrier-based sinusoidal and generalized discontinuous pulse-width modulation schemes for two-level, five-phase voltage source converters. These expressions can be used for both balanced and unbalanced phase voltages generated by any multi-phase inverter. An example of a five-phase voltage source inverter is presented to illustrate the strategy. Simulation and experimental results are presented in which a close examination shows that both results are similar for both balanced and unbalanced voltage cases.