Space Vector Analysis of Dead-Time Voltage Distortion in Multiphase Inverters

Inverter dead-time effects have been widely investigated in past for three-phase voltage source inverters (VSIs). Recently, a great deal of research has concentrated on PWM methods suitable for multi-phase VSIs (with more than three phases). All PWM methods theoretically produce sinusoidal output voltages without low-order harmonics. This paper analyzes the dead-time effects on output variables of multi-phase VSIs in the case of carrier-based PWM techniques if no any compensation technique is applied. In particular, a generalized analysis for n-phase inverters is introduced first, and numerical verification for three-, five- and seven-phase inverters are performed to verify the analytical developments. The dead-time effect on load voltage is also represented in terms of multiple space vectors, and analysis of harmonics content for each alfa-beta plane is given.