Selective Control Algorithm for N-Phase Switching Power Pole of 4-Leg Interlinking Converter in AC/DC Hybrid Microgrid

Abstract

This paper proposes a selective control algorithm to reduce switching losses of N-phase switching pole of 3-phase 4-leg interlinking converter (ILC) in AC/DC hybrid microgrid. Unbalanced load connected to 3-phase 4-leg ILC causes unbalanced voltage condition and this problems can be complemented by N-phase switching pole of 4-leg ILC. However, if the switching pole on N is operated constantly regardless of control decision due to unbalanced load conditions, switching loss on the N-phase switching pole will cause power loss in the entire topology. To compensate this problem, selective control algorithm considering voltage unbalance factor (VUF) for N-phase switching pole in ILC is proposed. Proposed algorithm decides switching operation of N-phase switching pole depending on unbalanced load voltage. When occurring unbalanced load condition, voltage unbalance factor can be reduced by proposed control algorithm. At the same time, the current flowing through the N-phase switch pole and switching losses can be reduced. © 2019 IEEE.