Date of Award

1-1-2012

Document Type

Thesis

Degree Name

M.S.

Department

Electrical Engineering

First Advisor

David Wenzhong Gao

Keywords

Grid-connected VSI, LCL Filter, MPPT strategies, PV array Modeling, Shading Effect

Abstract

To realize the benefits of grid-connected photovoltaic system, it is extremely important to reduce energy losses and improve reliability of grid-connected PV systems with high PV penetration. In this thesis, three different Maximum Power Point Tracking (MPPT) strategies named as Perturbation & Observation MPPT, Incremental Conductance MPPT and Fuzzy Logic Control MPPT have been analyzed, simulated and compared with each other to improve the efficiency of power conversion. A general discussion to counteract partial shading effect in several aspects is also provided in this thesis. In order to improve reliability of the system, an optimum current control loop with suitable control parameters are achieved by comparing three different PI controller parameter design methods, including self-tuning method, trial and error method and mathematical analysis method. Considering the complexity brought by modulation and demodulation process between abc stationary frame and dq0 synchronous frame of PI control loop, P+ Resonant controller, with simple control loop structure and zero steady-state error is also designed in this thesis. At last, LCL filter is analyzed and modeled under both steady state and disturbing condition. The effects of LCL filter for improving disturbance rejection capability and dynamic performance of the system is verified.

Provenance

Recieved from ProQuest

Rights holder

Qing Xia

File size

184 p.

File format

application/pdf

Language

en

Discipline

Electrical engineering

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