Controlador fuzzy para uso em conversores de frequência aplicado à sistemas fotovoltaicos de bombeamento

Abstract

This work proposes a fuzzy controller applied to a commercial variable-speed drive (VSD) for use in direct-coupled photovoltaic pumping systems (PVPS). The fuzzy logic system used is embedded in a controlling programming device (CPD) connected to the auxiliary input of the VSD for controlling the pump's working speed according to the power provided by photovoltaic generator (PVG). The objective is to avoid unintended behaviors in the d.c. bus voltage level VSD and cause the system to operate near the point of maximum efficiency. The control methodology is based on achieving the dynamic be-havior of the irradiance with which the PVPS is subjected via two different methods of low cost sensing, namely: using a light-dependent resistor (LDR) and using a low power sensor module. Experimental tests were performed using two tests bench for motor pumps able to simulate several-head wells. The results confirm the feasibility of using fuzzy con-troller with both sensing methods. Using LDR it possible to ensure the availability of PVPS, since it could suppress the undesired undervoltage errors, as with the methodology using the sensor module, and ensure availability of the system was obtained also satisfac-tory yield assembly VSD + motor pump, with a daily average efficiency of approximately 23 %.