Patent ID: 9000709
Filing Date: 2015-04-07
Classification: G01M,G05B

Abstract:
1. A method for placing a crankshaft of a prime mover in a desired angular position, the crankshaft being coupled to a rotor of an electrical machine, the electrical machine having a field coil and a plurality of stator phase coils, the method comprising: determining an initial position of a rotor of the electrical machine with no current flowing; determining the direction of the torque to be produced on the rotor when the rotor is rotated from the initial position to a displacement position corresponding to the desired crankshaft position; increasing current in the field coil to an initial value; receiving a value of torque required to begin rotation of the electrical machine; calculating the amplitudes of phase currents in the stator phase coils required to produce the received torque value; supplying the calculated phase currents to the stator phase coils, such that a phase direct axis of the stator phase coils is aligned with the initial rotor position; modifying the amplitudes of phase currents in the stator phase coils so as to rotate the phase direct axis toward the displacement position; generating a signal representing the angular position of the rotor; and ceasing supply of current to the stator phase coils when the position signal indicates that the rotor is in the displacement position.