Electrical machine and method of controlling the same

A method of controlling an electrical machine comprising

• a stator comprising a core and a plurality of windings disposed on the core in a three-phase arrangement, the three-phase arrangement comprising a first phase, a second phase, and a third phase having a first terminal, a second terminal, and a third terminal, respectively, and
• a rotor disposed adjacent to the stator to interact with the stator, the method comprising:
• applying a pulsed voltage differential from the first terminal to the second terminal resulting in movement of the rotor;
• after the applying step,
• monitoring the back electromotive force (BEMF) of each of the first, second, and third phases to determine the direction of rotation of the rotor,
• determining whether the rotor is rotating in a desired direction, and
• electrically commutating the motor based on the rotor is rotating in the desired direction,
• wherein monitoring the BEMF of each of the first, second, and third phases comprises monitoring for changes in at least one of the following conditions
• whether the BEMF of the first phase is greater than the BEMF of the second phase, and
• whether the BEMF of the second phase is greater than the BEMF of the third phase, and
• whether the BEMF of the third phase is greater than the BEMF of the first phase;
• and
• determining the direction of rotation of the rotor based on the monitoring for changes step.

A method of controlling an electrical machine including a stator having a core and a plurality of windings disposed on the core in a multiple phase arrangement, and a rotor disposed adjacent to the stator to interact with the stator, the method comprising:

• applying a first pulsed voltage to a first terminal of a first phase of the multiphase arrangement;
• monitoring back electromotive force (BEMF) of at least one phase of the multiphase arrangement;
• obtaining a first monitored value of BEMF;
• obtaining a second monitored value of BEMF at an interval after the obtaining the first monitored value;
• comparing the second monitored value with the first monitored value;
• determining whether the rotor is rotating based of the comparison;
• determining a period indicative of rotational movement of the rotor in response to the first monitored value being less than the second monitored value by at least an amount;
• determining a rotational direction of the rotor;
• and
• preventing movement of the rotor in response to determining the rotational direction of the rotor being different than a desired rotational direction.