Yes, basically the "brushless dc," "permanent magnet synchronized motor," etc etc - there is no standard - are mostly 3 phase motors. Your greyhound chasing the magnetic field description works pretty well.
By using 3 phases, one can create a smoothly rotating magnetic field. Of course more phases could also do it, buy why bother with all the extra hardware??
The Toyota Synergy drive is basically a "buried permanent magnet synchronized motor" where they optimized the affect of the reluctance torque created by the shape of the steel laminations used to contain the permanent magnets. Look into "switched reluctance" motors to get a feel for what I'm attempting to describe. The buried permanent magnet design has the additional benefit that the magnets are held in place by the rotor laminations. The problem of keeping the magnets from flying off the rotor at high speed has been eliminated.
By optimizing the relationship between the reluctance torque and the direct torque created by the magnetic field and the neodynium magnets, Toyota was able to reduce the BEMF at high speed, which allows a lower DC bus voltage.
That is why the FOC feature of this controller is so important for the Synergy drive, vs a standard brushless dc drive. One CAN control that crucial relationship for much better performance.
Regarding selfsyn/resolvers - I suppose there is a completely analog way to do what I'm doing, which is a hybrid between digital and analog. I'm providing the carrier frequency for the resolver and filtering the resolver's output so the digital AtoD converter can do something useful with it. This may be possible with completely analog circuitry, but I'm not that good.
It would take a really experienced, wise, old-school EE to figure that one out. Oh, yea - and the controller is digital, so
eventually the analog signal will have to be converted to digital for the controller to do anything useful with it. As far as the resolution of the resolver, I have NO idea what he's talking about. The resolver is an analog device, and from that perspective all it's "resolution" is dependant on the quality of the carrier frequency and decoding.
- E*clipse
Quote:
Originally Posted by freebeard
Apparently the DC controller has no application to Toyota Synergy Drive components. Which is why E*clipse is working on the resolver details.
Reverse would be just switching A and B, right?
Edit: e*clipse -- I looked at the page I linked to to define selsyn (self synchonizing) motors and about 80% of the way down the page there is a section on Resolvers. Quoting:
Maybe something useful there?
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