Parametrizable FPGA-Embedded Digital Controller of an AC to DC Power Converter for Teaching Practices

摘要

This paper introduces the design and implementation of a parametrizable digital embedded FPGA controller for an AC/DC power converter commanded by the controlled-activation triggering of a thyristor bridge. The rectifier was developed modularly, destined to teaching practice in the “Industrial Electronics and Automatization” orientation of the careers Electronic Engineering and Electric Engineering of the Universidad Nacional de Tucumán. By the digital control implemented in a FPGA device that is connected to a 4x20 LCD display and a 4x4 matrix keyboard it is possible to parameterize the operation of the converter. It is adopted the type of rectification (single-phase, two-phase or three-phase), the mode of rectification half-wave or full-wave, firing angle of the thyristor bridge with an accuracy of +/1% of the period of the alternating voltage and the firing mode (step type, single pulse or pulse train). The complete system tests are implemented, in three-phase full-wave mode, measuring the output signal in a resistive load of 75Ω / 100W. It is made a sweep of the trigger angle from 0 ° to 90 ° in 5 ° steps and the average and effective voltage in the load is measured. Also, the effective voltages of the harmonic components of the load signal is measured. As a result, an output signal is obtained with a THD% (Total Harmonic Distortion) that varies from 5.5% to 16.5% depending on the firing angle and without contemplating the filtering stage.