TITLE:
Research on a New Control Strategy of Three Phase Inverter for Unbalanced Loads
AUTHORS:
Wenhua HU, Weiming Ma, Chunxi LIU
KEYWORDS:
Three-Phase Inverter, Unbalanced Load, the Three-Phase Output Voltage Symmetric, Medium Frequency, P+Resonant Controller
JOURNAL NAME:
Journal of Electromagnetic Analysis and Applications,
Vol.2 No.1,
January
28,
2010
ABSTRACT: One of the very important functions of three-phase inverter is to maintain the symmetric three-phase output voltage when the three-phase loads are unbalanced. Although the traditional symmetrical component decomposing and superimpose theory can keep the voltage balance through compensating the positive-, negative- and zero-sequence components of the output voltage of inverter, however, this method is time-consuming and not suitable for control. Aiming at high power medium frequency inverter source, a P+Resonant (Proportion and Resonant) controller which ensured a balanced three phase output voltage under unbalanced load is proposed in this paper. The regulator was proved to be applicable to both three-phase three-wire system and three-phase four-wire system and developed two methods of realization. The simulation results verified that this method can suppressed effectively the output voltage distorted caused by the unbalanced load and attained a high quality voltage waveforms.