This paper analyzes the switching sequence of an improved interleaved discontinuous pulse width modulation (IIDPWM). An interleaved PWM is used
to improve the output current quality of parallel inverters. However, the carrier phase difference caused by the interleaved PWM inevitably generates
zero-sequence circulating current (ZSCC). The IIDPWM is the interleaved DPWM applied the carrier phase shift algorithm to suppress ZSCC and has
been proposed only in parallel two-level inverters. This paper proposes the IIDPWM applied to parallel three-level inverters for higher power capacity
and better output current quality. The switching sequence analysis of the proposed method proves that it has significant ZSCC suppression
performance even at high modulation index
(MI). The effectiveness of the proposed modulation method is
verified by the simulation results.