مقایسه عملکرد مقایسه توپولوژی های آنالوگ چندمنظوره برای محرک موتور القایی کنترل شده با حلقه بسته

This work focuses on investigating the closed loop model of Multilevel inverter fed Induction Motor Drive with constant V/f method. Multi level inverter generates stepped sinusoidal waveforms of lower harmonics with increasing levels. Cascaded MLI of 5 level and conventional VSI are synthesized using sinusoidal pulse width modulation (SPWM). The multi level inverter output so developed assuring the least THD is then passed through a filter to get a better sinusoid output. The filtered output is then fed to the induction motor, mathematically modeled using procedural sequence of equations. Induction motor speed control is employed by regulating the slip speed maintaining constant V/f. PI controller is implemented to ensure the motor speed at its reference speed. Closed loop scheme is tested for various reference speed and disturbances in dynamic load and speed. Comparative evaluation of transient and steady state performance characteristics, system efficiency and cost effectiveness is analyzed for closed loop MLI as well as VSI fed induction motor drive. MATLAB/SIMULINK setup, an effective tool for simulation is used for validating the results.