Distributed Maximum Power Point Tracking in Solar ......Distributed Maximum Power Point Tracking in...

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Distributed Maximum Power Point Tracking in Solar Photovoltaic Applications Using

Multiphase Switching Converters

Marcel Schuck, Robert C. N. Pilawa-Podgurski mschuck2@illinois.edu

Power Affiliates Program 2013

16.06.2015 | Distributed MPPT in Solar Photovoltaic Applications Using Multiphase Switching Converters | Marcel Schuck | 2

Table of contents

• Maximum Power Point (MPP) Tracking in Solar Photovoltaic

(PV) Applications

• Multiphase dc-dc Converters and Interleaved Operation

• Derivation of a New Control Strategy

• Performance Verification by Simulation

• Experimental Results

• Conclusions

• Questions/Discussion

MPP Tracking in PV Applications • Different PV curves for variations in irradiation and temperature.

MPP Tracking in PV Applications • System architecture determines the level at which MPP tracking

is performed. • Trade-off between efficiency, reliability and cost.

MPP Tracking in PV Applications

MPP Tracking in PV Applications • Shaded sub-module is bypassed and does not contribute to

energy production. • MPP tracking at the sub-module level increases power yield.

MPP Tracking in PV Applications

• Dc-optimizer solution • No need to perform voltage step-up at the sub-module level • High efficiency, low cost implementation is possible • Can be used with a central inverter

Multiphase dc-dc Converters and Interleaved Operation

• Parallel multiphase converters are used in high power applications.

Multiphase dc-dc Converters and Interleaved Operation • Interleaved operation enables significant ripple reduction.

Multiphase dc-dc Converters and Interleaved Operation • Different input voltages in MPPT application

Multiphase dc-dc Converters and Interleaved Operation • Different current ripple magnitude in each phase

Derivation of a New Control Strategy • Output low-pass filter attenuates high frequency components. • Control needs to effectively minimize low frequency ripple.

Derivation of a New Control Strategy • Inductor current waveforms with different ripple magnitudes

Derivation of a New Control Strategy

time domain frequency domain

Performance Verification by Simulation

• Relative improvement of 43%

Experimental Results

Conclusions

• MPP tracking on the sub-module level increases power yield under mismatched conditions.

• Converters can efficiently be implemented with a multiphase topology.

• Control strategy that enables improved ripple cancellation for multiphase converters with asymmetric operating conditions has been presented.

• Its performance was verified by simulations and experimantal results.

• Calculation of uneven phase angles based on the frequency domain representation of the current waveforms goes beyond the previous works in the field.

Thank you !

Questions / Discussion

Mathematical Derivations – for N phases

• Shift phasors with similar magnitudes by 180° • Apply for N-2 phasors with the largest magnitudes • Apply proposed technique with the summed and the remaining

phasors

Mathematical Derivations • Adjust time/phase shift accordingly • Waveform is represented in the frequency domain

Formulation of minimization problem

Other applications

buck converter input current waveforms buck converter output current waveforms

Other applications

boost converter input current waveforms boost converter output current waveforms

MPPT Algorithm

Automatic bypass mode detection

Circuits

Level Shifting

Bypass MOSFET Driver

Efficiency Measurements

Field Measurements

Distributed Maximum Power Point Tracking in Solar ......Distributed Maximum Power Point Tracking in...

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