Maximum Power Point Tracking for Photovoltaic (PV) Arrays

CSUN SITE Program 2015 The Short Circuits

Outline

● Introduction● Maximum Power Point Tracking● Modeling and Simulation● Experimental Setup● Conclusion● Questions

Photovoltaic Cells

● PV (PhotoVoltaic) Cell: Converts solar energy into electrical energy

Reference http://www.fsec.ucf.edu/en/consumer/solar_electricity/basics/how_pv_cells_work.htm

Advancements in Efficiency

Approach

● Learn the concepts behind PV power generation

● Understand the individual components of a PV Array system

● Simulate a PV Array using MATLAB’s Simulink

● Analyze optimal conditions for PV Array usage

● Introduce the DC-DC converter

● Utilize the MPPT algorithms and implementation

● Temperature● Irradiance● Shade● PV material

Factors That Affect PV Arrays

Mathematical Model Developed in Simulink

PV Array Electrical Model in Simulink

MPP Change Due to Temperature

Voltage (V)

273 K296 K303 K MPP

Pow

er(W

)

Power(W) vs. Voltage (V)

MPPMPP

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

0.5

2

2.5

Higher cell temperature leads to lower power output.

PV Curves With Different Solar Irradiation

Higher irradiance leads to high power output.

Pow

er (W

)

Voltage (V)0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

0.2

0.4

0.6

0.8

1

1.2

1.4

L = 0.5L = 1L = 2L = 4

MPPT Algorithm Theory

60 Ω

30 Ω

100 Ω

5 Ω

∞Voltage (V)

Pow

er (W

)

Power (W) vs. Voltage (V)

Max power

What is Maximum Power Point Tracking?

● MPPT finds the maximum power of a PV Array and maintains that power output for optimal performance

● Without the MPPT the DC-DC converter would be inefficient

● Maximizes Efficiency of PV Array

http://www.leonics.com/

PV Array System Components

Ipv

Vpv

Ipv

DC/DC Step down Converter (Buck)

� Vo=D*Vin D: Duty Cycle

Finding MPP with variable Duty Cycle

1. Perturb and Observe (P&O)2. Incremental Conductance (IC)3. Three point way comparison4. Short Current Pulse5. Constant Voltage

MPPT Algorithms

Perturb & Observe (P&O)

Voltage (V)

Pow

er (W

)

Power (W) vs. Voltage (V)

Max power

A

BC

D E

1 2 3 6 7 80

0.1

0.6

0.5

Incremental Conductance (IC)�  

Incremental Conductance (IC)

Voltage (V)

Pow

er (W

)

Power (W) vs. Voltage (V)

Max power

A

CB

D

1 2 3 6 7 80

0.1

0.6

0.5

Complete PV model using P&O Algorithm

MPPT for Perturb & Observe MethodDeveloped in Simulink

MPPT for the IC Method developed in Simulink

P&O Method: IC Method:MPPT Power Curve

Experimental Setup

Solar Array8 Volt - 310 mA

Halogen Lamps Decade Resistor Range used: 1 - 1K

Video

Comparison between Methods

Perturb & Observe Condition Incremental ConductanceOscillates around the

maximum power pointOscillations in the graph Doesn’t Oscillate as much

as P&O toward the maximum power point

Oscillates around the maximum power point

Finding the exact maximum point

Able to find the Maximum power and stay at the point

Simpler algorithm Structure of the Algorithm More complex algorithmDoes not adjust as fast as

IC methodRapid changes in

Irradiation Able to find the exact

maximum point rapidly

More efficient with temperatures

Varying Temperature Doesn’t adjust as rapidly as P&O method

Lower irradiation Irradiation and Efficiency Higher irradiationNot as efficient as the IC

modelBuck-Boost Converter Rapidly adjusts to converter

Conclusion

● Learned about parameters influencing energy conversion of Photovoltaic(PV) arrays.

● Recreated the mathematical and electrical model of PV arrays in MATLAB Simulink.

● Learned about the general concept of Maximum Power Tracking (MPPT).

● Successfully redesigned and compared two MPPT algorithms Perturb and Observe

(P&O) and Incremental conductance (IC).

● Understood the concept of DC-DC voltage conversion and its usage in voltage and

power regulation of PV arrays.

● Experimentally acquired data using LabView software and observed and verified the

theoretical concept of MPPT algorithms.

Acknowledgements

● Dr. Kourosh Sedghisigarchi

● Dr. Vibhav Durgesh

● Robert Morris

References

[1] A. Dolara; R. Faranda; S. Leva. “Energy Comparison of Seven MPPT Techniques for PV Systems” in J. Electromagnetic Analysis & Applications, 2009, 3: 152-162

[2] A.P.Yadav, S. Thirumaliah and G. Harith. “Comparison of MPPT Algorithms for DC-DC Converters Based PV Systems” International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering Vol. 1, Issue 1, July 2012

[3] H.N.Zainudin and S. Mekhilef, "Comparison Study of Maximum Power Point Tracker Techniques for PV Systems" Proceedings of the 14th International Middle East Power Systems Conference

(MEPCON’10), Cairo University, Egypt, December 19-21, 2010

[4] R.Faranda and S. Leva, "Energy Comparison of MPPT techniques for PV Systems," WSEASTransaction on Power Systems, vol. 3, pp. 446-455

Questions?