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.
Three-Phase Inverter, Unbalanced Load, the Three-Phase Output Voltage Symmetric, Medium Frequency, P+Resonant Controller
nullW. HU, W. Ma and C. LIU, "Research on a New Control Strategy of Three Phase Inverter for Unbalanced Loads," Journal of Electromagnetic Analysis and Applications, Vol. 2 No. 1, 2010, pp. 39-44. doi: 10.4236/jemaa.2010.21006.
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