مدل سازي و كنترل واسطه هاي الكترونيكي براي نيروگاه هاي فتوولتايي با قابليت تبادل توان راكتيو

چكيده انگليسي :

106 Modeling and Control of Electronic Interfaces for Photovoltaic Power Plants with Reactive Power Capability Mehrnaz Madadi m madadi@ec iut ac ir Date of Submission 2014 01 22 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Ahmadreza Tabesh Abstract Environmental pollution of fossil fuels along with the rising cost of these finite energy resources are the major reasons for the accelerated growth of renewable energy sources especially wind and solar energy over the past few years In the meantime solar energy an infinite source of clean energy is on the rise as a response to the development of PV technologies and the improvement of PV panels efficiency Significant price reduction for PV panels has provided economic justification for a steep increase in the pace of large scale PV plants installation over the last five years Now in most industrialized countries many utility scale PV power projects are under construction or in operation at a scale of at least 100 MWp Traditionally the main priority of the solar inverter control algorithms is the injection of maximum available active power from the solar arrays to the grid More recently due to the increment of inverters power rating in utility scale PV plants the possibility of controlling reactive power has been provided which results in voltage stability margin improvement and power losses reduction Therefore independent power providers have shown interest in the capability of solar inverters to also control reactive power There are many inverters in a large scale PV power plant which their output power widely varies during a day Especially in cloudy conditions or at night active power output of inverters is much less than their rated power capacity By employing appropriate control methods these surplus capacities of the solar inverters in a PV power plant can be used for reactive power injection to the grid Even in emergency conditions the amount of active power exchange can be reduced to compensate reactive power This thesis proposes a dynamic model for a PV power system based on instantaneous active reactive power components which facilitates control of reactive power in PV inverters Since instantaneous active reactive power components are independent of any qd reference frame thus the designed controller is inherently robust against the system dynamics It is also shown that using power components instead of conventional qd current components as the system state variables in the proposed model reduces the nonlinearities in system dynamics equations Moreover this thesis introduces two control methods based on this model The first method adopts the sequential loop closing technique and the second one uses feedback linearization technique to control the active and reactive power of PV power plant independently The validity and performance of the proposed model and control approaches are investigated through both time domain simulation of a 120 kW grid connected PV system and a low power laboratory prototype of a PV inverter Close match between simulation and experimental results verifies the accuracy of the model It also indicates that this model can successfully control the active and reactive power independently apart from the salient features of controller such as fast response zero tracking error and disturbance rejection capability Keywords Dynamic modelling Control of grid connected PV system Control of instantaneous active and reactive power components Multivariable control of PV system Feedback linearization method PDF created with pdfFactory trial version www pdffactory com

مددي، مهرناز

مدل سازي و كنترل واسطه هاي الكترونيكي براي نيروگاه هاي فتوولتايي با قابليت تبادل توان راكتيو

كنترل سيستم فتوولتايي متصل به شبكه , كنترل توان اكتيو و راكتيو لحظه اي , كنترل چند متغيره سيستم فتو ولتايي , روش خطي سازي با فيدبك