MPPT Solar Power Controller

To develop a small scale solar powered system that will power a DC load, which incorporates power management techniques, DC-DC conversion and a user interface using the microcontroller.

SolarPanel

DC-DC Converter Load

microcontroller Back-upBattery

Variation due to irradiation changes

• Power of the module has only single maxima.• Peak Power of the module changes with the change in temperature.• Peak power of the module changes with the change in irradiation level.• Need to track the peak power in order to maximize the utilizations of the solar module/array.

• The photovoltaic system displays an inherently nonlinear current-voltage (I-V) relationship, requiring an online search and identification of the optimal maximum operating power point.• MPPT controller is a power electronic DC/DC chopper or DC/AC inverter system inserted between the PV array and its electric load to achieve the optimum characteristic matching• PV array is able to deliver maximum available power that is also necessary to maximize the photovoltaic energy utilization

Nonlinear (I-V) and (P-V) characteristics of a typical PV array at a fixed ambient temperature and solar irradiation condition

• Peak Power is tracked by adjusting the impedance of the load.• This is obtained by using an interface between the load and the solar module.• A Dc/Dc converter can act as a interface between the load and the module.

• Dc/Dc converter is must in tracking peak power.• Duty cycle of the converter needs to be changed for adjusting the peak power.• How to adjust the duty cycle?• Manual or Automatic?

• Though Manual tracking is possible but is waste of time.• Automatic tracking is a better choice.• Algorithms are used for Automatic Peak Power tracking.

• Perturb & Observe (P&O).• Modified Perturb & Observe (MP&O)• Estimate Perturb-Perturb (EPP)• Incremental conductance.• Parasitic Capacitance method.• Voltage Based Peak Power Tracking.• Current Based Peak Power Tracking.

• To design an algorithm for MPPT• To simulate the algorithm using LabVIEW or MATLAB • To design a ZVS based DC-DC converter • Using Freescale microcontroller, to design a hardware interface and to port firmware based on simulation result which meets Indian weather conditions• Same microcontroller will be used for remote communication, control & troubleshooting, since, the power plants are located in remote areas