DOUBLE-DELTA-WINDING SYSTEM WITH NEUTRAL-POINT-CLAMPED CONVERTERS CONTROLLED BY SYNCHRONOUS MULTI-ZONE PWM

Abstract

In this paper, algorithms of the universal scheme of synchronous multi-zone modulation have been developed and dis-seminated for adjustment of two neutral-clamped inverters of double-delta-winding system (which is perspective for ap-plication in high power variable speed ac drives), providing synchronization and symmetry of waveforms of inverter-side voltage of power transformer for any control modes of operation including regimes with fractional relationship be-tween the switching frequency of inverters and fundamental frequency of system. In this case inverter-side winding voltage of double-delta-winding system has quarter-wave symmetry, and its spectra do not contain even harmonics and undesirable subharmonics. Simulation results show behavior of system with two neutral-clamped inverters con-trolled by three basic versions of synchronous multi-zone modulation. References 9, figures 5, table.

Keywords

• inverter
• ac drive
• pulsewidth modulation