Test procedures for maximum power point tracking charge controllers characterization

ABSTRACT Photovoltaic stand‐alone systems (PVSAS) are the most widespread technology for rural electrification of off‐grid areas, for communication systems, and for satellite applications. Such applications require high reliability to guarantee an adequate electrical supply. In these systems, charge controllers and inverters are used to fit the PV output power to the load. The power adaptation stage is essential to the proper performance of the PVSAS and to the optimization of the energy management of the system. However, there are no international standards yet approved that cover the quality requirements of this stage. This paper deals with the performance of those charge controllers that use maximum power point tracking algorithms. The aim of this work is to define the specific parameters that describe the real performance of these controllers, paying attention to their static and dynamic efficiency and establishing the acceptable minimum thresholds required for each one. A set of measurements of three commercial controllers was developed. Their behavior in real varying conditions was monitored along 1 year of operation. Results are presented here after being checked with repetitive indoor measurements using a PV array simulator. Main results of the operation in a PVSAS are included in the paper for selected representative days along the year. To perform the daily analysis, we have classified each day according to its weather conditions. The purpose is to analyze the relation between the performance of the controller and the weather variations. Within the conclusions of this work, some guidelines for the definition of test procedures for maximum power point tracking charge controllers are included. Copyright © 2011 John Wiley & Sons, Ltd. The characterization of charge controllers that use maximum power point tracking (MPPT) algorithms is studied in this paper in function of their static and dynamic efficiency under real varying conditions. Results of monitoring along one year of operation are presented within some guidelines for the definition of test procedures for MPPT charge controllers.