Is there a way to Detect Motor Windmilling Speed and Position Detection with Only Current Sensors?

[toddsteinmetz]

In a sensorless design that does not measure back emf but instead uses current sensors, is there a known strategy to detect speed and position of the rotor?  Are there any papers someone could point me to?

More detail: We are using the Automotive Math and Motor Control Library.  This library provides a function for windmilling that detects speed and position of the rotor by measuring the back emf of the three phases.  The motor controller design we are using has three current sensors, one on each phase, but does not measure the back emf of the motor at all.  In this design that uses current sensors is there a known strategy to detect speed and position of the rotor?  Are there any papers someone could point me to?

[petrz_]

Unfortunately, we currently don't have a solution that could estimate the position of the unpowered motor based solely on the shunt resistors. With all mosfets turned off, there is no current flowing throught these shunts hence no voltage drop can be measured there. We will perform further research how this could be achieved (perhaps by intermittently switching on the lower half of the mosfets during the windmilling operation...?). If we figure it out, we will add the solution to the NXP motor control portfolio.

[toddsteinmetz]

petrz: thanks for the response even if there is no solution readily available at this time.