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Transcript of Solar Power Generation with Maximum Power Point Tracking...
Solar Power Generation with Maximum Power Point Tracking
(MPPT) Control Technique Abdul Majeed
3/10/2015
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Overview
u Introduction
u Effect of irradiance and temperature
u MPPT
u MPPT techniques
u Offline methods
u Online methods
u Hybrid methods
u Charge controller
u Conclusion
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Introduction
u Solar Energy rapidly growing market
u Huge potential for innovations
u Low power conversion efficiency
u Influenced by weather conditions
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Solar Radiation in the US
4
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Operating point1
1
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Effect of Irradiance on Solar cells2
2
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Effect of Temperature on Solar cells3
3
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Maximum Power Point (MPP)
u Corresponds to the peak of the P-V curve
u Or the knee of the I-V curve
u Maximum power is delivered at the MPP 1
1
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Need for MPPT
u Atmospheric conditions cause change in operating point
u MPP keeps varying
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Maximum Power Point Tracking (MPPT)
u Tracks the MPP at all times1
u Is not affected by changing weather conditions
u Maximum power is delivered at all times 1
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
MPPT Techniques
u Offline Methods
u Constant Voltage (CV) method
u Open Circuit Voltage (OCV) method
u Short Circuit Current (SCC) method
u Online Methods
u Perturb & Observe (P&O) Method
u Incremental Conductance (IncCond) method
u Hybrid methods
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Constant Voltage (CV) method
u Operating point is made to match with a Vref
u Vref is made equal to MPP voltage
u Assumptions of irradiance and temperature
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Open Circuit Voltage (OCV) method
u MPP can be measured by Open Circuit Voltage
u VMPP = VOC x k
u k = 0.7-0.8 for crystalline silicon
u Loss of power due to disconnection
u Use of pilot cells
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Short Circuit Current (SCC) method
u Similar to OCV method
u MPP can be measured by Short Circuit Current
u IMPP = ISCC x k
u k = 0.8-0.9 for crystalline silicon
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Drawbacks of Offline methods
u Interruption of power due to disconnection
u K is an estimated value
u True MPP can never be tracked constantly
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Perturb & Observe (P&O) method
u Increase in voltage causes increase or decrease in power
u The operating point is shifted left or right
u Never converges on the MPP
u Usage of small perturbation steps4 4
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Incremental Conductance (IncCond) method
u At MPP, slope of P-V is zero
u The operating point is shifted left or right
u Converges on the MPP
u Better accuracy than P&O
u Difficult hardware implementation5
5
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Hybrid Methods
u Combination of offline and online methods
u Estimates a value by offline method
u Tracks using perturbations towards MPP using online methods
u Faster convergence rate
u Variable amplitudes of perturbation
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
MPPT Charge Controllers u Devices that control the voltage
delivered to the battery
u Most modern charge controllers have MPPT
u Uses the extra voltage from PV array5
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Conclusions
u MPPT can improve the power conversion efficiency of PV panels
u Produces maximum power at all times
u High cost of MPPT controllers but no change in LCOE
Solar Power Generation with Maximum Power Point Tracking (MPPT) Control Technique – Abdul Majeed
Questions?
Bibliography u 1Texas Instruments
u 2Victron Energy
u 3Comparison Between Fuzzy and P&O Control for MPPT for Photovoltaic System Using Boost Converter
u 4 www.rs-online.com
u 5 electronics.stackexchange.com