PMSM current control test

Question

First tests for the field oriented control (FOC) of a pmsm may be conducted only on an inductance or a stator, i.e. not at the rotating machine, e.g. when the machine has more or less high power I want to be sure that the controller works.

My question is if it is actually possible to control a three phase current in the phases of a stator or at a standing still pmsm, when the angle is generated by the software.

In other words explained, the set-up is the following:

1. I measure the phase currents ia, ib, ic
2. I generate a rotating angle in software for fixed speed
3. The currents ia, ib, ic are transformed in dq- coordinates with the generated angle
4. The transformed currents and set points for Id, Iq enter PI controllers respectively for d and q.
5. An inverse clark transform is performed for the outputs of the PI controllers using the generated angle.
6. Space vector modulation is performed to generate duty cycles
7. Duty cycles steer a 3 phase inverter in order to implement the phase currents in the stator windings

Could this actually work, or do I have a mistake in my understanding of FOC? Since the motor is indeed not rotating.

Answer 1

In a typical control you'd want to have the rotor field and the stator field rotating at the same speed when steady-state conditions are reached. Since you have a PMSM with a locked rotor, the rotor field is stationary. Thus, the stator field would be expected to rotate at the same speed, i.e. zero, which is probably not what you are looking for.

So unless you come up with a controller that considers different speeds for the rotor and the stator fields (which seems quite unusual), the proposed procedure is unlikely to give you any meaningful results.