A Fuzzy based DSP Implementation for Power Quality Improvement of a three phase AC-AC Converter

This paper proposes the use of a fuzzy logic controller (FLC) that serves to enhance the power quality of a three phase ac-ac converter system with a dc link. The FLC is designed so as to shape the load current to a nearly sinusoidal fashion and contribute in improving the input power factor, lowering the total harmonic distortion (THD) and eliminating higher order harmonics. The Digital Signal Processor (DSP), besides generating the PWM gating pulses for the power switches, is programmed to function as PI/FUZZY controller in the feedback loop. The algorithm allows the modulation index to vary, in order to regulate the load voltage. Simulation and experimental results are included to highlight the fact that the scheme also enables to maintain a constant output voltage over a wide range of load variations,