Let's say, an induction motor is connected to NPC inverter as a load. Will there any unusual phemenon happen of induction machine rotation due to dc-link voltage unbalance of 3 level 3 phase NPC inverter.
Dear Debottam,
The most suitable voltage wave form to feed the 3 phase induction motor is a balanced sinusoidal three phase supply. Any deviation from this idea waveform will lead to more losses in the rotor and stator causing to operate the motor under smaller load called derating in order not to damage the motor. Both unbalanced three phas voltage with distorted waveforms in form of harmonics will cause excessive heating either in the stator or in the rotor of the motor. This problem was studied in the literature. As an example please follow the link for more information:http://www.ichqp2016.org/ichqp/public/files/PID4386903-1.pdf
Best wishes
Hi, of course there are problems when feeding an IM with unbalanced voltage, a technique to obtain a balanced voltage is to apply an extra topology of capacitor balancing, as shown in this inverter:
http://www.tandfonline.com/doi/abs/10.1080/15325008.2014.949910?journalCode=uemp20
regards
Hello,
I believe that appropriate (closed loop) control of the converter allows supplying an undistorted current to the motor although the input voltage is unbalanced. Of course this implies applying a duty cycle pattern that differs from the theoretical one.
Regards.
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