Single-Phase Single-Stage Tri-State Boost Inverter for Grid-Connected PV System

摘要

Single-stage grid-connected photovoltaic inverters have high efficiency,small size,low cost and good reliability.Different single-stage topologies have been proposed.Tri-state boost inverter is one of single-stage topologies.A single-phase single-stage tri-state boost inverter based on grid-connected photovoltaic is researched in this paper.This Tri-state boost inverter utilizes inductor to implement power decoupling and voltage boosting,the electrolytic capacitor in the conventional voltage source inverter (VSI) is eliminated,thus extending the lifetime and improving the reliability of the system.A modified SPWM is proposed to implement independent input-output power control.The MPPT is realized through the control of shootthrough duty cycle based on perturb and observe (P&O) algorithm.The grid current is controlled by using a power feed-forward algorithm.Simulation is carried out to demonstrate the effectiveness of the proposed algorithms,a laboratory prototype is also being constructed.Keyword: Tri-State,Single-Stage,Inductor,Shoot-Through Duty Cycle,Photovoltaic.