Active & reactive power control in a 3-phase grid connected solar pv system by employing decoupled control scheme
Loading...
Date
2020-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The proposed control scheme is efficient in controlling the flow of Active and Reactive power to the grid independently by maintaining the DC link voltage at a fixed value, irrespective of the source intermittency and ambient temperature conditions. The “Decoupled control scheme” employs two control loops to control the operation independently. So, by using the inner control loop it controls the power flow whereas, by using external control loop it maintains the DC link voltage at a constant level. Depending upon the converter topology and switching scheme the 3-phase power can be delivered to the grid with a THD value lower than specified value according to the IEEE standard. In the proposed scheme the triangular comparison based SPWM switching scheme is compared with the SVPWM switching scheme and also three-level multi-level DC/AC invertor topology (Diode Neutral Clamped invertor) is compared with the conventional two-level DC/AC convertor topology. The SVPWM switching scheme is efficient in generating 3- phase output with very low harmonic content and operates both in linear as well as overmodulation region as opposed to its SPWM switching scheme which operates only in linear modulation region i.e. m<1. Since, by using the proposed converter topology and switching scheme the majority of the low order harmonics would be be eliminated, the rest of the higher order harmonics can attenuated by inserting LCL passive filter between the three-phase grid and three phase invertor which consequently lead the output waveform very closer to the sinonosuidal waveform and consequently making the THD value as par IEEE standard. The proposed thesis work on the operation of the Decoupled Control scheme using MATLAB/Simulink software is performed under various temperature as well as irradiance conditions and also under varying conditions.