Experimental Investigations with Fuzzy Controller for PV Fed DC Motor Incorporating SEPIC Converter as Efficient Power Interface

Abstract

The design and implementation of solar energy fed power electronic interface using SEPIC converter incorporating fuzzy logic controller for a DC motor has been attempted. The proposed scheme consists of a Photovoltaic (PV) array, a SEPIC DC-DC converter, a PIC microcontroller and a DC motor. The SEPIC converter has been fabricated using IGBT and associated circuit components. A PIC microcontroller has been programmed to automatically vary the duty cycle of the SEPIC converter with fuzzy logic controller depending upon the required speed of the motor. The Simulink model of the proposed scheme has been built using MATLAB/PSB. To test the satisfactory performance of the program written for PIC microcontroller, the program is loaded into the PROTEUS VSM simulator and the waveform of the gate pulses obtained from the simulator using MPLAB coding is studied. After confirming the satisfactory generation of the gate pulses by the simulator, the program is loaded into PIC microcontroller using PIC start plus and gate pulses generated is fed to the DC-DC converter for firing the IGBT. Experiments have been carried out on a 230V, 4.5A, 0.75 kW, 1500 rpm separately excited DC motor and the results are furnished for different load conditions. Various reference speeds have been set and the system automatically adjusts the actual speed of the DC motor close to the set speed. The PV array used in the system consists of the panels connected in series, each panel being rated for 18V and 5A. The comparison of experimental and simulation results show very close agreement between the two thus validating the proposed scheme.