MPC-Based Harmonic Injection Techniques for Reconfigurable Single/Three-Phase Inverters with Grid Neutral Point Connection

This paper proposed the harmonic injection techniques for the single/three-phase inverters with grid neutral point connections. The harmonic injection methods are based on model predictive control to regulate the injected harmonic components with higher reliability. An extra phase leg is connected to the split single-phase/three-phase grid through an inductor to handle the neutral current with less leakage current. The advantages can be concluded as follows: (1) The harmonic injection techniques improved the DC bus utilization with less required DC capacitance; (2) The injected harmonics have been regulated by the MPC before added to the output side which improved the robustness; (3) The grid neutral points are connected to the extra phase leg with the corresponding neutral current control which reduced the leakage current and improved the unbalanced handling capability. The experimental results verified the proposed methods.