Sistema fotovoltaico de conexão direta em aplicação multimotores para setores para o setor rural

Abstract

Variable-speed drive pumping system (PVPS-VSD) are generally used in conditions where there is no water supply and conventional energy service. Because it is a direct-coupled photovoltaic system, it is common two operating situations: available energy and the full storage tank or available energy and insufficient to perform water pumping. In these scenarios, the photovoltaic generator will be underused. Therefore, the proposal of this work was to evaluate the shared use of the photovoltaic generator of PVPS-VSD in a multi-motor application, i.e. a motorpump and a three-phase induction motor of an agricultural equipment connected to the same variable-speed drive. The study site was the renewable energy laboratory of the Federal University of Amapá and an agricultural property located in the county of Itaubal-AP. The motor load selected to integrate the PVPS-VSD was the Cassava grater, being a prototype built with a 0.5 HP motor for the laboratory tests and a Cassava grater reformed in the agricultural property for the field study, the reform consisted in the substitution of a petrol engine 5.42 HP by a three-phase electric motor 1 HP. Then, there was the programming in the variable-speed drive that proved to be compatible with the motorpump of the PVPS-VSD and the two motors used in the graters. The laboratory test was performed using the equipament every two hours, while the field study were carried out continuously, simulating the use of the farmer. During the tests, it was possible to tune the system PID controller and the scalar control to the 0.5 HP motor. The results indicate that there is only water pumping at frequencies above 32 Hz in the motorpump, which were obtained in irradiance values from 375 W/m². The field tests of the motors were carried out in a rainy season with a maximum irradiance of 351.83 W/m², under these meteorological conditions the grater with a 0.5 HP motor operated at rated speed in all periods tested and the 1 HP operated satisfactorily, but with reduced speed. The minimum yield of the grater was estimated at 800 g/min and its use in 4 hours per day, which represents a minimum daily production of 192 kg of grated Cassava and a payback of less than one month. It is concluded, with the elaboration of this study, that it is possible to optimize the energy use in PVPS-VSD by sharing the variable-speed drive with two different motor loads. The programming and adjustment in the PID controller are shown to be compatible with both motors used, so the final application becomes easy to operate and therefore suitable for the rural sector