Isolated Interleaved Boost Converter Based Single-Phase Grid-Interfaced Photovoltaic System

Abstract

An isolated interleaved boost converter (IIBC) based single-phase grid-interfaced photovoltaic system (SPGIPS) and its control are proposed in this article. The proposed double-stage SPGIPS consists of an IIBC and a single-phase full bridge voltage source converter (SPFBVSC). An IIBC is designed using a high-frequency transformer (HFT), two primary inductors, and two static switches with its emitter shared with photovoltaic (PV) panel ground. Shared emitter terminal reduces the gate control circuit complexity and HFT facilitates a galvanic isolation between PV panels and the utility grid, and thus it mitigates the appearance of leakage current. An IIBC reduces the ripple in PV panel current and voltages and therefore guarantees improved maximum power point operation (MPPO) of the PV system. To ensure the MPPO at PV panel terminals, a sliding mode control is used. The output DC terminals of IIBC are interfaced with self-commutated switches based SPFBVSC. To synchronize SPFBVSC with the utility grid, a new modified fourth-order generalized integrator (mFOGI) is developed. The mFOGI provides stable synchronization signal even under presence of noise, under/over shoot, or DC offset in the AC supply voltage. The proposed SPGIPS control and its performance are validated on Simulink and prototype system.