Research on different carrier phase-shifted angle with output voltage performance of cascade multilevel inverter

The performance of output voltage in cascade multilevel inverter can be improved when carrier phase-shifted PWM technique is applied. However, the performance of output voltage will be different if different carrier phase-shifted angle is taken in PWM technique. Based on this, two different carrier phase-shifted modes of 180deg/N and 360deg/N are analyzed through mathematics illation in this paper. From the mathematics analysis, some conclusion can be gotten, it is that the output waveform performance will be little changed whether the number of cascade unit is odd or even if the carrier phase-shifted angle is 180deg/N, but if the number of cascade unit is even, equivalent carrier frequency, harmonic distributing and the number of output level will be different when the carrier phase-shifted angle is 360deg/N. So the 180deg/N mode is better than 360deg/N mode. Finally, many simulations and experimental result demonstrate the validity of the theory.