Hi All,

Recently, I'm doing a research on the PV Grid Connected System and try to model out for further understanding. I found a model to refer to. However, I came across this MPPT (Maximum Power Point Tracking) which is part of the system that I totally have no idea in it. Could anyone possibly explain or refer me to any websites or links that provide explanation on why the block elements were used in the model and how it works?There's an attachment on the PV grid model used in Simulink as my reference. Your time and efforts are much appreciated. Many thanks.


Attached File(s)
 PV_System_MPPT_Grid.zip ( 13.69k ) Number of downloads: 28

In your proposed research, if generating optimum electrical power is NOT your primary interest, you can omit the MPPT part from the your research. See explanation below.

In solar engineering, Maximum Power Point Tracking refers to an automatic control system to track the sun for the change in solar angle of incidence. This enables the photovoltaic solar panels to effectively convert the maximum solar photon flux density to yield optimum electrical power generation. It can be shown that in terms of the relative power output, a dual-axes solar tracker (Nur Mohammad and Tarequl Karim doi:10.1115/1.4007295) is the most efficient system available.



However, if we take the complexity and the cost–benefit analysis into consideration, the system is usually equipped with a manual North–South Rotation instead of an automated rotation. Moreover, near the Equator the temperatures are usually high year-round and lowlands around the Equator generally have a tropical rainforest climate. Thus, most tracking systems at the tropical regions have one automated East–West tracking mechanism and a provision for manually adjusting the North South inclination across the year. This mechanism is shown in the simplified block diagram below.



How It Works

Ve = Vi − ΔV

where ΔV = VE − VW is the potential difference between photoresistor LDR@East and LDR@West.

A positive +Ve will produce an electromotive force (emf) to drive the servomotor to rotate to the West. A negative −Ve will produce an emf to drive the servomotor to rotate to the East, usually during sunrise.

Because the reference input Vi = 0 V, to produce a positive +Ve, then ΔV must be a negative value. That means LDR@West (VW) has received a higher intensity of light than the LDR@East (VE). It is based on the principle of photoconductivity where a photoresistor or light dependent resistor (LDR), whose resistance decreases with increasing incident light intensity. The photoresistors are positioned at a “v” angle with one faces the east and the other faces the west, so that as the sun rises into the sky, LDR@West will receive more effective light since the sun is closer to being perpendicular to its surface while LDR@East will receive less.



This post has been edited by Critical_Fallacy: Aug 25 2013, 03:06 AM

Hi Critical_Fallacy,

Thank you very much for sharing the MPPT informations with me. However, I still have difficulties in understanding the subsystem and MPPT present in the model. Can you please show me some guidance on it? Many thanks.

It’s too early to say thanks. If you really want to excel in the research of Solar Energy, you must have strong foundations of the underlying physics. A good starting point would be reading and understanding the concepts and mathematics from the Photovoltaics books. They are many good books on Photovoltaics around but I can only keep a few ones close to me. Handbooks are used as references, can be borrowed from the library.

Planning and Installing Photovoltaic Systems: A Guide for Installers, Architects and Engineers, 3rd Edition



Applied Photovoltaics, 3rd Edition (used as a textbook in UNSW B.Eng in Photovoltaics & Solar Energy). Moreover, Stuart R. Wenham & Martin A. Green are some of the famous inventors in this field.



Modelling Photovoltaic Systems Using PSpice



Power Electronics and Control Techniques for Maximum Energy Harvesting in Photovoltaic Systems (The book discusses several ways to achieve the best maximum power point tracking performance.)



Practical Handbook of Photovoltaics: Fundamentals and Applications, 2nd Edition



Handbook of Photovoltaic Science and Engineering, 2nd Edition