Real time harmonics control technique with fixed switching in indirect field oriented control

Direct torque control, direct or indirect field-oriented control, are the most important control techniques applied in induction motor drive systems. This paper presents the indirect field-oriented control based on fuzzy logic proportional-integral controller for an induction motor. In order to reduce the loss of the power device the real time harmonics control/elimination (RTHC) strategy is proposed to control the voltage source inverter. The solutions of the switching patterns to eliminate the desired harmonics are given by using the Particle Swarm Optimization algorithm. With a different tests mode at each change of speed or load (torque), the modulation index is in reality variable as a consequence of the variability of the voltage (amplitude). A simple interpolation method called Lagrange polynomial, for generation the parameters of RTHC have been proposed. The strategy allows continuous adjustment in both amplitude and frequency of the fundamental. This paper present two novel contributions, the simulation results are given to illustrate the validity of the new method.