System and method for control and analysis of a prime mover in an electrical machine using calculated torque

Apparatus for placing a crankshaft of a prime mover of a vehicle traction system in a desired angular position, comprising:

• an alternator for supplying electrical energy to the traction system when driven by the prime mover;
• the alternator comprising a rotor coupled to a crankshaft of the prime mover, a field coil on the rotor, and a plurality of stator phase coils;
• a sensor generating a position signal representing an angular position of the rotor;
• a processor;
• and
• a memory storing instructions which, when executed by the processor, cause the apparatus to:
• determine an initial position of a rotor of the alternator with no current flowing in the field coil or the stator phase coils, based on the position signal;
• determine a direction of torque to be produced on the rotor when the rotor is rotated from the initial position to a displacement position corresponding to the desired position;
• increase current in the field coil to an initial value;
• receive a value of torque required to begin rotation of the alternator and the crankshaft;
• calculate the amplitudes of phase currents in the stator phase coils required to produce the received torque value;
• supply 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;
• modify the amplitudes of phase currents in the stator phase coils so as to rotate the phase direct axis toward the displacement position;
• and
• cease supplying current to the stator phase coils when the position signal indicates that the rotor is in the displacement position.