الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 155 |  |  |
| | | from | 155 | | |
Abstract
his thesis proposes modeling, analysis, and control of non-isolated boost three-port DC to DC converter for a standalone photovoltaic (PV) system application. Models of various components of the system such as PV array, storage batteries are presented.The converter is controlled such that it regulates the flow of power from the PV array to the
load and the batteries, provides load voltage regulation, and extracts maximum power from the PV array. Depending on the power generated from the PV array, there are four operating modes of operation of the converter. These modes are dual output mode (DOM), dual input
mode (DIM), PV to load mode, and battery to load mode. The analysis, modeling and
simulation of these modes are presented at steady-state conditions. In addition, the design and selection of the converter components, suitable for all operating modes, is carried out.
Dynamic models of the converter operation in various modes of operation, are obtained using state-space averaging technique, perturbation, and small-signal approximation. The open
loop transfer functions for each mode are found, then their orders are reduced for simplicity of analysis, these transfer functions are then used to design the required controllers.
The controllers of the closed-loop scheme are selected to achieve output voltage regulation,and to extract maximum power from the PV array under different operating conditions. PIcontroller is used to ensure stability, and eliminate the steady-state error, but the phase and
gain margins are not acceptable for the closed-loop operation of the system. Therefore,phase-lead compensator is cascaded with the PI-controller to improve the transient response,
it is found that the phase and gain margins are improved to give less maximum overshoot, faster settling, and lower steady-state error.
Detailed design of the closed-loop controller is outlined to ensure good stability measures (gain and phase margins) and maintain acceptable steady-state error. Closed-loop
MATLAB/Simulation is used to verify the operation of the converter in different modes with the designed controllers, the transition between modes is reported with solar radiation variation, and the operation when load is changed is also simulated. Experimental verification of the open-loop control system at different modes of operation is reported. The experimental and simulation results with the same operating conditions are in good
agreement.