In the manual for a Scott Drive motor controller, they have a parameter you can set, called Motor Type. Its description reads
The motor type determines the method used to calculate the reference Id, Iq currents. The four supported motor types are Brushless DC (BLDC), Permanent Magnet Synchronous Machine (PMSM), Interior Permanent Magnet Synchronous Machine (IPMSM), and Induction.
I understand that Induction is the odd one from the group, as its drive algorithm is completely different. However I have a hard time assimilating the difference between the rest (since they are all permanent magnet machines).
Googling around I found:
- BLDC is the one with trapezoidal back-emf, meaning simplified driving (it can be an AC square-wave)
- PMSM has sinusoidal back-emf, so it needs sine-shaped drive
- IPMSM is only different in that the magnets are buried in the rotor (for added strength). The back-emf should be sine (right?). As such I don't get how the drive algorithm differs from PMSM.
How is the drive algorithm different between PMSM and IPMSM? Is it only minor tuning constants?