Modeling and Analysis of Voltage Harmonic for Active Neutral-point-Clamped Five-Level H-Bridge Inverter in Consideration of Dead-time

The active neutral-point-clamp five-level (ANPC-5L) multi-phase H-bridge inverter has the advantages of a simple interface to the ship's medium voltage DC network, the single H-bridge topology with nine levels of output voltage and switching frequency multiplication, etc. To prevent the bridge leg from passing through, dead time needs to be set for inverters. However, for the medium and high voltage inverter, the dead time is up to 10μs, which has a prominent impact on the output harmonics. To accurately analyze the influence of the dead time of the ANPC-5L H-bridge inverter on the output harmonics, it is necessary to analytically model and verifies the output voltage harmonics considering the dead time. In this paper, the principle of the phase-shifted PWM(PS-PWM) method of ANPC-5L H-bridge inverters were firstly introduced. Then, the analytical models of output voltage harmonics with and without considering the dead time were established based on the double Fourier series approach and the harmonic distribution of the dead-time effect was accurately characterized. Based on the above, the theoretical calculation results of output harmonic analysis modeling of ANPC-5L H -bridge topology considering dead-time are verified by offline simulation and experiment, and the correctness and feasibility of the theoretical modeling are verified. The results of this study can be used as a reference for quantitative analysis of output harmonics of ANPC-5L H-bridge inverter considering dead-time and extended to other multi-level inverters for harmonic analysis and modeling.