Selective Harmonic Elimination in Space Vector Modulated AC-AC Converter Using FPGA

Controlling converters by FPGA based system is a challenging problem because of the strict real time constraints. Nonetheless, FPGA has been applied to a wide variety of applications. This paper proposes an FPGA implementation of a particle swarm optimization (PSO) based selective harmonic elimination space vector pulse-width modulation (SHE-SVPWM) in an AC-AC converter. The present approach is utilized to generate a variable frequency high quality AC output from AC to AC converter with reduced THD and improved power quality. The objective function is formulated to ensure attainment of both sinusoidal output and reduction in THD simultaneously by incorporating a weight factor in the objective function. Harmonics up to the 13th order are attenuated by solving transcendental equations. Due to multiplicity of solutions, heuristic techniques are favored. PSO is used in offline mode to calculate the combination of switching angles and stored in look-up table, which makes easier to generate PWM signal in real time for the AC to AC converter. Experimental results are carried out to justify the performance and superiority of the present approach compared to conventional SVPWM and GA-SVPWM. An experimental prototype was developed with single phase induction motor load and test results are presented to validate the proposed design of the system.