3 ms·
I'm wondering if performance could be improved by controlling the polarity of the rotor coil fields, to push against the stator-induced ones. Since some semicon
by MayeulC 3y ago
I'm wondering if performance could be improved by controlling the polarity of the rotor coil fields, to push against the stator-induced ones. Since some semiconductor rectifiers are necessary in the stator, it doesn't sound much more complex to control the polarity. Part of the control logic could be handled before the inductive power transfer mechanism, by modulating the frequency, though it gets complex as you probably want to tune the resonant frequencies of the sender and receiver.
- Animats 3y agoWind turbines work that way. Early wind turbines had to mechanically rotate at a fixed speed to match the grid. With modern ones, the field is sometimes electrically rotated to adjust for rotor RPM. This can be done quickly as the wind changes. The range of control is not large, though. This is a quick adjustment made electronically until the blade pitch can slowly be changed by motors to re-tune the wind turbine for the current wind speed. Look up "doubly fed induction generator".
- MayeulC 3y agoInteresting to know, thank you. They seem to mostly use this to adjust the frequency of the induced current in the stator, as they control the rotation speed of a "virtual rotor" (rotation of the rotor + rotation of the magnetic field around the rotor). That's indeed similar, but in the wind turbine use-case, the stator is passive. A direct application could be to tune the torque/speed response, or improve motor weight by reducing the number of coils on one of the elements.