Skogsgurra
Electrical
- Mar 31, 2003
- 11,815
Hello!
I am involved in a discussion on additional losses caused by the primitive switching patterns that were common before IGBT and MOSFET and PWM. Those switching patterns usually had only a few edges in a cycle and caused severe cogging, especially at low speeds.
The cogging (or torque ripple) is a superimposed acceleration/decelaration and therefore cause extra losses in the rotor. Not talking about eddy current in the iron, but "microstarting" currents in the rotor (and "microbraking", of course).
I have looked around to find any written references to it but my googling has not been successful so far.
Anyone knowing a good source?
Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
I am involved in a discussion on additional losses caused by the primitive switching patterns that were common before IGBT and MOSFET and PWM. Those switching patterns usually had only a few edges in a cycle and caused severe cogging, especially at low speeds.
The cogging (or torque ripple) is a superimposed acceleration/decelaration and therefore cause extra losses in the rotor. Not talking about eddy current in the iron, but "microstarting" currents in the rotor (and "microbraking", of course).
I have looked around to find any written references to it but my googling has not been successful so far.
Anyone knowing a good source?
Gunnar Englund
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
