Sistema automatizado de irrigação por pivô central: uma proposta para melhoria da eficiência energética através do uso de controladores lógicos programáveis em conjunto com inversor de frequência e rede sem fio ZigBee

Abstract

The installation of an automated system consisting of a programmable logic controller, pressure sensors, moisture and positioning, variable frequency drive and the use of networks industrial for the pumping station control of the central pivot, Campus UFLA, allowed: (1) determine, under actual operating conditions in the field, the optimal values of the operation parameters of motor pump in different angular positions assumed by the mobile side of the pivot (i - gauge total height varying between 77.6 and 85.2 mca, ii - pump speed varied between 3.250 and 3.390 rpm; and iii - supply frequency of electric motor of pump drive ranging between 57.03 and 54.66 Hz); (2) demonstrate, through proximity observed between the ideal values of operation of motor-pump certain in field and those predicted by theoretical calculation process, the calculation procedure proposed allows to accurately predict the optimal values of the parameters of pump operation in various angular positions assumed by the mobile side, and (3 ) stated that the various strategies tested of control the supply frequency of the motor drive pump are equivalent, allowing to achieve a reduction in energy consumption about 19%, resulting from the reduction of the average electrical power consumed one full turn in the mobile side of 13.2 kW (without inverter) to 10.8 kW (with inverter). Besides the reduction in energy consumption achieved by using the inverter, also observed an improvement in power factor, which increased from 0.84 to 0.88.