Abstract
This Field Programmable Gate Array (FPGA)
based digital controller has been developed to improve the output
of the frequency converter using Hardware Description
Language. An attempt has been made to analyze converters using
three modulation techniques namely sinusoidal pulse width
modulation (SPWM), delta modulation (DM) and trapezoidal
modulation (TM) to reduce the harmonics. It has been found that
for the Sine PWM, the total harmonic distortion factor (THD) is
high when the output frequency is greater than input frequency.
The output is improved with delta modulation scheme where the
total harmonic distortion is found minimum as compare to the
SPWM and TM techniques. The circuit has been tested
qualitatively by observing various waveforms on digital storage
oscilloscope (DSO). The overall system is compact and no
external memory system is required. Tests have been carried out
to show the effectiveness and flexibility of the proposed method.