POWER CONTROL AND DRIVES COMMON MODE VOLTAGE REDUCTION WITH HARMONICS STUDY USING DIFFERENT PWM TECHNIQUES FOR A THREE PHASE AND FIVE PHASE BLDC MOTOR

Multiphase machines are emerging as a new trend in autonomous systems such as traction, ship propulsion etc. due to its inherent advantages like reduced torque pulsations, reduction in the required rating per inverter leg, greater fault tolerance, greater efficiency, better noise characteristics etc. Reduction of Common Mode Voltage (CMV) has been an issue of interest in the design of PWM techniques because CMV is known to cause electromagnetic interference, breakdown of winding insulation, and fault activation of current detector circuits and production of leakage currents that may damage the motor bearings. Different modulation techniques for three-phase machines have been proposed both for twolevel and three-level Voltage Source Inverters (VSI). All these works are, however, devoted  to three-phase drives for the last few years and now it has been extended to five phase drives. In this work different PWM techniques are used for the reduction of CMV in both three & five phase drives. Compared to three-phase case, the peak value of CMV in five-phase drives is inherently reduced. Reduction of CMV is done at the expense of voltage & current distortion. Study of harmonics is also done in this work to find better technique for driving Five-Phase BLDC motor