carrier phase-shifted pulse width modulation(CPS-PWM)is preferred due to its high equivalent frequency and power balance across cascaded units. However
the issue of narrow pulse cannot be overlooked
which can cause significant voltage spikes and oscillations in power devices
thereby affecting the safe operation of power electronic equipment. To address this
a novel modulation strategy without narrow pulse was proposed
which can completely eliminate narrow pulse in the CHB inverter while maintaining high waveform quality. First
considering dead-time and dead-time compensation mechanisms
the relationship between the inverter operating parameters and the switching functions of the power devices was derived. On this basis
the generation mechanism and distribution characteristics of narrow pulse under the CPS-PWM strategy were analyzed. Then
by comparing the occurrence conditions of narrow pulse before and after dead-time insertion
the relationship between the original driving signal width and narrow pulse was evaluated
and the method for selecting the original signal width to avoid narrow pulse issue was proposed. Further research is conducted on the dynamic change of modulation waveform and carrier that can effectively reduce the output harmonic content. Finally
the digital implementation of the proposed strategy was discussed. The experimental results verify the effectiveness of the proposed strategy.