Advanced Perturbation and Observation (P&O) based Maximum Power Point Tracking (MPPT) of a Solar Photo-Voltaic System D. K. Sharma
G. Purohit
Department of Electronics and Comm. Engineering, Sir Padampat Singhania University, Bhatewar, Udaipur - 313 601, India e-mail:
[email protected]
Department of Physics, Sir Padampat Singhania University, Bhatewar, Udaipur - 313 601, India e-mail
[email protected]
Abstract- In this paper, a novel algorithm based MPPT has been suggested for extracting maximum possible power from PV module. The proposed algorithm for controlling the MPPT is based upon the mostly used Perturb and Observe (P&O) method. A long with the proposed algorithm, different existing algorithms have been compared in terms of their tracking speed and implementation complexity. The solar module characteristics (I-V and P-V) have been simulated in MATLAB. The simulation results for various parameters of boost converter have also been obtained.
In this
paper, we discuss the results of our study of an improved maximum power point tracker (MPPT) of a PV system. The proposed MPPT algorithm
is
based
on
the
incremental
perturbation
and
observation (IP&O) strategy in which the perturbation steps have
using a power electronic switch operated by an algorithm. The design of MPPT may be based upon Buck converter, Boost con verter [4], Buck-boost converter etc. Due to the more flexibility and better performance, the boost converter has been used in this paper. In the case of buck converter the current is not constantly flowing but in the case of boost converter, the constant flow of current may be achieved. This is one more advantage of boost converter over buck converter. Many types of algorithms are available to control the operation of switch of boost converter like Perturb & Observe (P&O) algorithm [5], [6], Incremental Conductance (INC) algorithm [7], Parasitic Capacitance method [8] etc. II.
been increased to get closer to the maximum power point with
SOLAR Pv SYSTEM DESCRIPTION
minimum possible oscillations. The PV power system, using the proposed MPPT, will be able to optimally track maximum power points with minimum possible oscillation around maximum power points (MPPs).
Consequently the light to electricity conversion
efficiency can be improved significantly. Keywords- Solar Photovoltaic (SPV) system; Maximum Power Point Tracker (MPPT); Boost converter; P&O algorithm; MOSFET; Tracking efficiency.
I.
INTRODUCTION
A.
PV System With MPPT
A typical Photovoltaic (PV) system consists of a PV module and some electrical load. This may also have a Power condition ing unit (PCU) which may comprising of a Inverter (to convert dc into ac), charge controller (to prevent reverse flow of current dur ing dark) and most importantly from the efficiency point of view the Maximum Power Point Tracker (MPPT).In this paper, the MPPT is emphasized for better efficiency of PV system by using improved MPPT with advanced P&O algorithm.
Utilization of renewable energy resources is the demand of today and the necessity of tomorrow. Due to the electric power crisis globally, it is to be thought about the optimized utilization of these resources. In this paper, the efficient extraction of elec trical energy from Solar Photovoltaics (SPV) [1] system is being presented. The efficiency of the SPY system may be substantial ly increased by using Maximum Power Point Tracker (MPPT) [2].MPPT is a power electronic system which tracks the maxi mum power point on the characteristic curve of PV module throughout the day in varying solar insolation. Basically MPPT is a highly efficient DC-DC converter [3] which is controlled by
PVarray
978-1-4673-0934-9/12/$3l.00 ©2012 IEEE
�-
DC-DC converter
::E 3:
p.
MPPT controller Vpv --'---:J algorithm
�
Fig. 1.
The financial support has been provided by Sir Padampat Singhania University, Udaipur (Rajasthan), INDIA
c- --->
Block diagram of PV system with MPPT
Load or other devices
Basically the main problem in tracking the maximwn power points (MPPs) using the Perturb and Observe (P&O) method on the characteristic curves solar PV module or cell is that the oper ating point fluctuates around the MPP as solar insolation varies. By using the advanced Perturb and Observe (adv. P&O), the oscillations of operating point around MPP have been reduced as the perturbation steps have been increased and operating point gets stabilized and as a result of the efficiency is enhanced by using proposed algorithm. B. Simulated PV Characteristic Curves The characteristic curves may be represented as Current voltage (I-V) curve and Power-voltage (P-V) curve which are nonlinear in nature and shown as in figure
