PRESENTED By
Vikrant A.Chaudhari.

---

[attachment=10563]
Automatic Peak Power Tracker using dSPACER
Renewable Energy
Alternate sources of energy
1. Biomass.
2. Solar Energy.
3. Wind Emergy.
4. Geothermal Energy.
5. Microhydel.
6. Fuel cells.
Why Solar Energy.
 Solar energy is the most readily available source of energy.
 It is free.
 It is also the most important of the non-conventional sources of energy because it is non-polluting.
Facts about solar energy.
 Earth surface receives 1.2x1017 W of power from sun.
 Energy supplied by the sun in one hour is almost equal to the amount energy required by the human population in one year.
 Most if the other source on renewable energy have their in sun.
How electricity is generated through Solar Energy
 Solar photo voltaic (SPV). Can be used to generate electricity form the sun.
 Silicon solar cells play an important role in generation of electricity.
Solar cells Characteristics.
 Isc-short circuit current.
 Voc-open circuit voltage.
 Peak power.
How solar cells Generate electricity
 From Cells to Modules
 The open circuit voltage of a single solar solar cell is approx 0.5V.
 Much higher voltage voltage is required for practical application.
 Solar cells are connected in series to increase its open circuit voltage.
Characteristics of a typical Solar Pv Module.
 Variation of characteristics of Solar module with change in the atmospheric conditions
 Variation of characteristics of Solar module with change in the atmospheric conditions
Conclusion from the Characteristics.
 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 isolation level.
 Need to track the peak power in order to maximize the utilizations of the solar module/array.
How Peak Power is tracked.
 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.
Block Diagram
How Peak Power is tracked.
Conclusion.
 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.?
 DC/DC converters
 DC/DC converters
 Duty Cycle
Methods of obtaining Peak Power
 Though Manual tracking is possible but is waste of time.
 Automatic tracking is a better choice.
 Algorithms are used for Automatic Peak Power tracking.
Different Algorithms.
 Perturb & Observe. (P&O).
 Incremental conductance.
 Parasitic Capacitance method.
 Voltage Based Peak Power Tracking.
 Current Based Peak Power Tracking.
Perturb & Observe
 Incremental Conductance
 Parasitic Capacitance
 Account the parasitic capacitances of
 The solar cells in the PV array . Parasitic capacitance uses the switching ripple of the
PPT to perturb the array.
 To account for the parasitic capacitance, the average ripple in the array power and voltage, generated by the switching frequency, are measured.
 The incremental conductance algorithm is then used to determine the direction to move the operating point of the MPPT.
 Voltage Based Peak power Tracker.
 Peak Power point of the module is at 76% of the module open circuit voltage.
 This value is fixed and does not vary much with the changes in the environmental conditions.
 By measuring the open circuit voltage and adjusting the module voltage to about 76% of Voc the peak power can be tracked.
Current Based Peak Power Tracker.
 Peak Power of the module lies at about 95% of its short circuit current.
 Measuring the short circuit current Isc and adjusting the operating the converter at 95% of Isc the module can be made to operate at Peak power.
 Algorithm Used in the Present Report.
Algorithm
 Module Voltage and Current measured at kth instant.
 Power is calculated at kth instant. P(k)
 P(k) stored in the memory.
 Module Voltage and current calculated at k+1th instant.
 Power at k+1th.
 ∆P=P(k+1)-P(k).
 Algorithm
 Also ∆V=V(k+1)-V(k).
 Depending on the sign of the ∆P and ∆V the duty cycle of the module is varied.
 If ∆P>0 and ∆V>0 then D=D- ∆D.
 If ∆P>0 and ∆V<0 then D=D+ ∆D.
 If ∆P<0 and ∆V <0 then D=D+ ∆D.
 If ∆P<0 and ∆ V>0 then D=D- ∆D.
 Were D= duty cycle and ∆D is perturbation.
 Simulation of the Peak Power tracker
 Simulation in Matlab/Simulink.
 Model of solar PV module developed.
 Model of Dc/Dc converter.
 Load.
 Development of PPT algorithm in Simulink.
 Solar PV Module Model.
 Model of PV Module.
 Model of Solar PV Module.
 Simulink Model of the PPT
 Simulink Model of the Algorithm
 Peak Power Tracking.
 Peak Power Tracking.
 dSPACER
 A real time Control solution.
 Control of hardware through Personal computer.
 Works on Matlab/Simulink Platform.
 Automatic C code generation.
 Easy to generate control logic in Matlab/Simulink and downloading to the dSPACE add on card.
 Experimental Setup
 Solar module
 Dc/Dc converter(step up and step down).
 A load (resistive load)
 Personal computer
(installed with dSPACE hardware)
 Experimental Setup.
 Solar Module
 Hardware Setup.
 Schematic
Conclusions
 Power output of the module improves by about 100%( doubles) with the PPT system than it was with out the MPPT system.
 The power delivered to the load in case of step-down and step up converter is almost same. Only difference that was observed was with the output voltage.
 Temperature of the module is an important parameter. The power output of the module changes by about 0.5% for every degree rise in temperature. So a 38W module gives only a power of about 29W peak
 The module placement also plays an important role in power output. Module is kept in south facing. Buts its elevation angle must be adjusted every month to get high power output.