FOC: Switching from wye to delta

Aug 11, 2008 1 Replies

I've a design that drives wye-/star-connected PM synchronous motors by means of field oriented control (FOC). I'm wondering what has to be modified in order to make it work with delta-connected motors as well.



My literature says that a wye-delta reconfiguration introduces a phase shift of 30 electrical degrees in the DQ model meaning that the "motor control must be adapted accordingly".



What parts of the motor control has to be adapted accordingly? My wild guess is that the park transform has to be modified. Does that mean the following two (park transform) equations (to be found in every textbook of motor control) are only valid for wye configuration?



Id = Ialpha*cos(theta) + Ibeta*sin(theta) Iq = -Ialpha*sin(theta) + Ibeta*cos(theta)



Thanks, Markus



If it's sensorless you shouldn't have to change anything at all.

If it's got sensors, the motor data sheet should show how the phases must go w.r.t. the commutation pulses.

Tim Wescott Control systems and communications consulting http://www.wescottdesign.com Need to learn how to apply control theory in your embedded system? "Applied Control Theory for Embedded Systems" by Tim Wescott Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

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