Autonomous Series-Connected Micro-Converters for PV Systems
Date Issued
2015
Date
2015
Author(s)
Chen, Cheng-Wei
Abstract
An autonomous series-connected micro-converter (SCMC) photovoltaic (PV) system is proposed in this dissertation. It is the most promising candidate to achieve both low system cost and high efficiency among the distributed maximum power point tracking (DMPPT) PV systems. The proposed SCMC PV system has a two-stage circuit topology, which is composed of a set of SCMCs and a single-phase grid-tied inverter. The four-switch buck-boost converter (FSBBC) with three operation modes and a smooth transition method is adopted to realize the maximum power point tracking (MPPT) function for each PV panel. The single-phase grid-tied inverter with bipolar sinusoidal pulse width modulation (SPWM) control and the AC line current regulation is utilized to control the inverter output current and string voltage. Besides, the autonomous control (AUC) strategy are well-developed for the success of the non-communicating system operation. By adopting the AUC strategy to a PV module which is composed of a PV panel and an FSBBC, a self-contained autonomous PV module (APVM) can be formed. The small-signal AC models, with and without the module interaction considered, are derived to analyze the dynamic behavior and the stability of the APVM. Moreover, the design of controller based on the developed small-signal AC model and the stability analysis of the APVM are presented. Finally, computer simulations and experimental results are presented to verify the accuracy of the small-signal AC model and the performance of the proposed autonomous SCMC PV system.
Subjects
DMPPT
FSBBC
smooth transition
grid-tied inverter
autonomous control strategy
APVM
SDGs
Type
thesis
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