Single Phase Grid Connected Inverter Controls using Three-Pole Three-Zero Compensator

Author: Md Shamimul Islam, Department of Electrical Engineering

Mentor: Dr. Sayan Roy, Department of Electrical Engineering

In this thesis, a single-phase dual stage grid-connected solar inverter is presented. The dual-stage converter comprises of a DC-DC boost converter and a DC-AC inverter connected to the grid through an LCL filter. A complex pole-zero pair based three-pole three zero (3P3Z) compensator and a PI controller is proposed to control the grid current and DC bus voltage, respectively. The 3P3Z compensator is a good candidate to track the current reference and control the resonance peak introduced by the LCL filter without the need for active or passive damping. Moreover, this compensator efficiently supports the grid under various fault scenarios such as grid voltage variation, frequency fluctuation, and grid voltage with DC offset. A detailed analysis of the proposed control design is presented and validated for various grid fault scenarios through simulation studies in PSIM.