See this study:

https://www.academia.edu/4344956/Design_and_Implementation_of_Maximum_Power_Point_Tracking_MPPT_Algorithm_for_a_Standalone_PV_System

See also this link:

https://en.wikipedia.org/wiki/Maximum_power_point_tracking

You can see this paper:

I hope that these studies would be helpful for you.

Dear Ahmad,

This is the second time that i share a question with you. I wish you success.

For maximum power point tracking you need two major processes:

You have to determine  the maximum power point of the I-V array at the the input insulation and temperature. You need for this to scan the illuminated I-V CURVE OF THE ARRAY , CALCULATE THE POWER P=IV and determine its maximum value Pm..

This process can be made by analog or digital processors.. 

The second major step is to vary the duty ratio of the inverter,  assuming that we input to it the maximum voltage Vm of the maximum operating voltage of the module, such that it withdraws an input current equals the current Im, the operating current of the module at the maximum power point. This can be also made by an analog processor,

So. one can use analog processor to operate the photovotaic system at the maximum operating point. Digital control is more easier as the calculations can be done easily in the digital domain. In addition, it is easily alterable through software. The parameters can be easily changed through software.

The maximum power point tracking is a hot topic and there are fairly  recent research paper. I woud like that you see the papers in the LINKS;https://www.researchgate.net/publication/264897184_Enhancing_the_maximum_power_point_tracking_techniques_for_photovoltaic_systems

https://www.researchgate.net/publication/290436504_Enhancing_the_design_of_battery_charging_controllers_for_photovoltaic_systems

Article Enhancing the maximum power point tracking techniques for ph...

Article Enhancing the design of battery charging controllers for pho...

see the attached paper

Hello Mr. Ahmad

On line methods: P&O, Hill Climbing, IncCond, Constant Voltage,...

Off line methods: you require PV array model and measurement of temperature and solar irradiance. 

However, if PV system will be installed in isolated location (stand alone configurations) then MPPT controller must be very simple, low cost and effective: current feedback strategy or simple circuit array(*).

Please review:

Maximum Power Point Tracking Techniques for Photovoltaic Systems. Marcelo C. et al.

Development of Microcontroller-based, photovoltaic MPPT control system. Koutroulis et al.

(*) Simple maximum power point tracker for photovoltaic arrays. Yan Hong and D.C. Hamill. 

Best regards

Herman

Maximum Power point tracking system can be implemented using four methods mainly (using Micro controllers, IC, Artificial intelligence/neural network and PLC).

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=7050144&newsearch=true&queryText=MPPT%20system%20with%20artificial%20intelligence