This paper presents an approach to Field oriented control (FOC) of Brushless DC (BLDC) motor producing significantly less torque ripple. The sensorless Field oriented control of BLDC motor is more efficient in terms of torque generation compared to back emf zero crossing technique. It allows independent control of torque and rotor flux by controlling the torque and flux producing current components. The space vector pulse width modulation generates switching pulses for inverter switches aids improved system performance with reduced total harmonic distortion compared to other PWM technique. The simulation of SVPWM based sensorless indirect field oriented control of BLDC motor with necessary vector (Clark-Park) transformation is carried out using MATLAB/SIMULINK.

The design of H-Bridge Multilevel-multicarrier inverter fed variable frequency drive is discussed. A nine level inverter is proposed to drive a half hp induction motor. Simulation studies carried out on Single phase and three phase inverters using Simulink/MATLAB. The results are compared with a hardware module of single phase multi carrier inverter. The design aspects of three phase multicarrier inverter including the transformer design are presented in this paper.