Analytical study and evaluation results of power optimizers for distributed power conditioning in photovoltaic arrays

• Published in: Progress in photovoltaics 2013-05, Vol.21 (3), p.359-373
• Main Authors: Orduz, Ricardo, Solórzano, Jorge, Egido, Miguel Ángel, Román, Eduardo
• Format: Article
• Language: English
• Subjects: Applied sciences; Arrays; BIPV; Converters; DC-DC converters; different tilt and orientation; Energy; Equipments, installations and applications; Exact sciences and technology; Mathematical analysis; Maximum power; mismatch; Modules; MPPT; Natural energy; Photovoltaic cells; Photovoltaic conversion; power optimizers; shading; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Tracking
• ISSN: 1062-7995; 1099-159X
• DOI: 10.1002/pip.1188

ABSTRACT The use of modular or ‘micro’ maximum power point tracking (MPPT) converters at module level in series association, commercially known as “power optimizers”, allows the individual adaptation of each panel to the load, solving part of the problems related to partial shadows and different tilt and/or orientation angles of the photovoltaic (PV) modules. This is particularly relevant in building integrated PV systems. This paper presents useful behavioural analytical studies of cascade MPPT converters and evaluation test results of a prototype developed under a Spanish national research project. On the one hand, this work focuses on the development of new useful expressions which can be used to identify the behaviour of individual MPPT converters applied to each module and connected in series, in a typical grid‐connected PV system. On the other hand, a novel characterization method of MPPT converters is developed, and experimental results of the prototype are obtained: when individual partial shading is applied, and they are connected in a typical grid connected PV array. Copyright © 2011 John Wiley & Sons, Ltd. The analytical methods and new expressions set out in this paper provide useful information on the behavior of cascade maximum power point tracking (MPPT) converters applied to each photovoltaic (PV) module in a typical grid‐connected PV system. A novel characterization method allows to verify on site, and at the same time, associate the PV module and its MPPT converter. The progressive shadow profile test provides important information on the tracking of the MPP and the conversion ratio limits. Also, the correlation between punctual shading levels and the power improvement factor allow to identify when to reach the input power maximization using MPPT strategy.