Brushless direct current motor with a ring magnet

A method for controlling a position of a rotor of a brushless direct current motor, the method comprising:

• providing a brushless direct current motor including a rotor, a stator, a motor magnet having a number of magnetic poles thereon mounted to the rotor and a ring magnet mounted on the rotor axially adjacent the motor magnet having a number of magnetic poles thereon, wherein the stator includes a plurality of windings and a plurality of sensors and wherein the number of poles on the ring magnet is twice the number of poles on the motor magnet;
• supplying an initial current to the motor;
• determining if a torque produced by the motor is in a positive or negative direction;
• determining a multiplier based on the direction of the torque;
• multiplying the initial supplied current by the multiplier to produce a current signal representative of a ring period of said motor;
• utilizing the current signal to determine a commutation sequence used to selectively control a current supplied to the motor for selectively energizing at least one of the plurality of windings thereof;
• and
• measuring a current in each of the plurality of windings.