Presentation Details
| Detecting and Quantifying Inverter Clipping and its Thermal Behavior in Hot-Desert PV Systems based on Long-Term Field Measurements Dhanup S.Pillai 1, Carlos D.RodrÃguez-Gallegos2, Oktoviano Gandhi3, Abdelbassat Krama1, Sertac Bayhan1. 1Qatar Environment and Energy Research Institute (QEERI), Hamad Bin Khalifa University (HBKU), Doha, Qatar.2RINA Tech Renewables Australia, RINA Consulting, Victoria, Australia.3Solar Energy Research Institute of Singapore (SERIS), National University of Singapore, Singapore, Singapore |
Abstract
DC/AC oversizing is a widely adopted design strategy in utility-scale photovoltaic (PV) systems to increase inverter utilization and annual energy yield. However, oversizing inevitably leads to frequent and prolonged inverter power clipping in hot-desert climates with sustained high irradiance and elevated ambient temperatures. While clipping losses have been investigated in prior studies, assessments for extreme climates remain limited and are predominantly based on simulations, whereas long-term field measurements are essential for accurate quantification and validation of such losses. This study presents a measurement framework for detecting and quantifying inverter clipping losses using high-resolution operational data from three grid-connected PV systems with DC/AC ratios of 1.07, 1.25, and 1.43 installed in extreme hot desert climate in Qatar. A voltage-ear detection method based on inverter control behavior during clipping periods is first used to identify clipping. Curtailment flags are then defined using the identified power threshold (α = 0.98), and clipped energy is quantified by reconstructing the unclipped power and integrating instantaneous losses. Results show a strong, non-linear increase in clipping severity with DC/AC ratio, with negligible losses at DC/AC = 1.07 and clipping fractions reaching ~1% and ~7% for DC/AC = 1.25 and 1.43, respectively. Module temperature measurements show no statistically significant increase attributable to clipping, nor a systematic dependence on DC/AC ratio. Inverter temperature similarly exhibits no measurable increase directly associated with clipping events, while a clear rise in inverter operating temperature is observed with increasing DC/AC ratio. The proposed field-based methodology enables robust identification of clipping behavior and provides practical guidance for DC/AC ratio selection and inverter thermal management in hot-climate PV systems.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.