High-frequency pulsating dc-link inverter has higher power density than the conventional fixed dc-link inverter (FDCLI), and more complicate modulation methods owing to the coupling between the front end and the last stage links. This paper analyzes the zero portion effects on the output voltage of the railway auxiliary inverter with pulsating dc-link based on the approximately independent hybrid modulation technique, and proposes a carrier phase-shift optimization strategy. Average mathematical models of output voltage are built, and Fourier series of the voltage difference is derived for further analysis. The output voltage performances under different conditions are compared in time-domain simulation. The results of simulation and experiments show that the proposed phase-shift approach reduces the zero portion effects and performs as well as that of FDCLI.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.