Practical Realization of Three Phase Buck AC Converter Feeding Three Phase Star Connected RL Load Using FPGA Real Time Controller: Advanced Study

A three phase bidirectional AC to AC buck converter circuit using power MOSFET is designed, rigged
up and analyzed with three phase star connected RL load for electrical parameters such as output
voltage, input current, input power factor, harmonic profile and efficiency using FPGA real time
controller. The various PWM techniques such as ramp-DC symmetrical PWM (RDSPWM), ramptriangular
asymmetrical PWM (RTAPWM), sinusoidal asymmetrical PWM type-1 [SAPWM1] and
sinusoidal asymmetrical PWM type-2 [SAPWM2] techniques are generated using FPGA real time
controller in order to analyze the harmonic profile, input power factor and efficiency of the converter It
is required to consider both harmonic profile and input power factor in order to increase the efficiency
of power electronic converter. It is observed from experimental results that the RDSPWM technique
gives lesser total harmonic distortion [THD] of output voltage and input current than other techniques.
It is also observed that the SAPWM1 switching strategy gives high input power factor, more output
voltage, high efficiency and moderate improvement of harmonic profile for the entire range of
modulation index MI compared to other PWM techniques. Hence SAPWM1 technique is preferred for
AC to AC converter than other techniques that renders easy filtration at lower cost.