DESIGN AND SIMULATION OF GRID CONNECTED PV SYSTEM USING MPPT

Abstract: A photovoltaic solar panel exhibits non-linear current–voltage characteristics. According to the maximum power transform theory, it can produce maximum power at only one particular operating point i.e, when the source impedance matches with the load impedance. Furthermore the maximum power point changes with temperature and light intensity variations. Therefore, different algorithms have been developed for maximum power point tracking based on offline and online methods. Evaluating the performance of these algorithms for various PV systems operating under highly dynamic environments are essentials to ensure a reliable, efficient, cost-effective, and high performance systems.

Problem identification: The development of renewable energy has been an increasingly critical topic, due to the tremendous growth in energy demand that is expected to climb 35% by 2030 in comparison with current energy consumption. As a result of that an enormous pressure on existing conventional energy resources, in particular, fossil fuels such as oil and natural gas. Where they are currently providing more than 98% of the energy consumed worldwide . Dependence on fossil fuel present a number of challenges, including: high cost, environmental damage, and lack of sustainability. Less efficiency of pv module because of uncontrollability in varying environmental conditions. Efficiency of battery is less

Problem solution: The most obvious source of renewable energy is the solar energy. Use of maximum power point tracking for photovoltaic systems using perturb and observe algorithm. To increase the efficiency of a battery MPPT should be used. Maximum power point tracking plays an important role in photovoltaic system because it maximize the power output from a PV system for a given set of conditions, and therefore maximize the array efficiency and minimize the overall system cost.

What is mppt: It is not an mechanical system which physically orients the panel straight to the sun. Mppt system is basically electronically controlled system . it can change the electrical operating point of the panel in accordance with changes in environmental conditions . Mppt plays the important role of impedance matching adapter i.e it forces the impedance at the terminals of the pv panel to the value that produces maximum power out of the panel.

Equivalent model of pv cell:

Physical structure of pv cell:

Characteristic I–V curve of the PV cell:

Existing Diagram:

Reference voltage control:

Perturb and Observe MPPT Algorithm Flowchart:

P-V characteristics:

MPPT Curves : A . I and V curve without MPPT: Fig : shows V-I curve with different solar insolation and constant temperature 25deg cel.

  B. P-V curve with MPPT: Fig: shows p-v curve with different solar insolation and constant temperature 25deg cel

C. I-V curve with constant insolation and different temperature: Fig. : I-V curve for different temperature and constant insolation .

D . I and V curve with MPPT: Fig.: shows V-I curve with different solar insolation and constant temperature 25deg cel

Block diagram of proposed system: BI-Directional converter

Simulink Models: 1. V System:

2. Simulation diagram of MPPT:

3. DC-DC Boost Converter:

4. BI-Directional converter:

5. Existing diagram:

6. Proposed Diagram:

Simulation results of Grid connected PV system: 1. Output voltage of PV system:

2. Inverter boost output waveform:

3. Simulation results of three phase grid Voltages during synchronization:

4. Simulation results of three phase currents of grid:

5. Simulation results during grid connected mode shows power factor improvement:

Advantages: Maximum power can be extracted by using this system. It is pollution free source of energy. Easily available source of energy worldwide . This system has reduced size. As short circuit current as well as power increases with increase in insulation level, while a very little change in open circuit voltage is observed.

Used for water pumping in rural area Used for water heaters Applications: Used for water pumping in rural area Used for water heaters Street lights Traffic signals For high power applications PV system is directly connected to grid

Conclusion: Grid connected PV system is modeled with MPPT under various climatic conditions. With the help of MPPT Algorithm the maximum available power with PV system can be fed to grid. When grid is operating under stresses at that time the pv power can be fed to grid to reduce the under voltages conditions . Also by using this system the dependence on non- renewable energy resource can reduced there , by using this system the clean and pollution free environment can be maintained . Many other parameters can be modeled and investigated using the same model which all left for future research.

References: C. Hua and C. Shen, “Implementation of a DSP-controlled photovoltaic system with peak power tracking”, IEEE Transactions on Industrial Electronics, Vol. 45, Issue, 1, pp. 99-107, February 1998. Samer Alsadi, Basim Alsayid, “Maximum Power Point Tracking Simulation for Photovoltaic Systems Using Perturb and Observe Algorithm”, International Journal of Engineering and Innovative Technology (IJEIT), Vol. 2, Issue 6, pp. 80-85, December 2012. R. A.Cullen, “What is Maximum Power Point Tracking (MPPT) and How Does it Work?” Blue Sky Energy, www.blueskyenergyinc.com, July 2000. MATLAB, www.mathworks.com/products/matlab.

Thank you