Control circuit for five-phase brushless DC motor

A drive circuit for a five-phase brushless DC motor having five windings and a rotor mounted for rotation relative to the windings, the windings adapted to be energized by a timed application of drive voltages producing a flow of phase currents in the respective windings, the drive circuit comprising:

• at least five sensors including a plurality of position sensors configured to generate a pattern of signals related to a rotary position of the rotor;
• electrically controllable switches coupled to the windings;
• and
• a motor controller coupled to the position sensors and the controllable switches, the motor controller configured to generate commutation control signals based upon the pattern of signals received from the position sensors and to apply the control signals to the controllable switches, wherein the controllable switches control the flow of current through the windings in response to the control signals.

A control system for a brushless DC motor adapted to be energized from a source of voltage, the motor including a stator having a plurality of windings adapted to be electronically commutated and a rotor mounted for rotation relative to the windings, the control system comprising:

• a sensing circuit configured to generate signals corresponding to a rotary position of the rotor;
• an electronic commutation circuit including switches coupled to the windings;
• and
• a control circuit coupled to the sensing circuit and the commutation circuit, the control circuit configured to limit the flow of current through the windings during start-up and determine a direction of rotation of the rotor upon start-up and, if the rotor is rotating in a wrong direction, to energize at least two windings and wait for movement of the rotor to come substantially to a stop and then energize the plurality of windings in a start-up sequence to cause the rotor to rotate in a correct direction and, when the rotor is rotating in the correct direction, to electronically commutate the windings in response to the rotary position of the rotor.

A control system for electronically commutating a brushless DC motor adapted to be energized from a source of voltage, the motor including a stator having a plurality of windings adapted to be commutated and a rotor mounted for rotation relative to the windings, the control system comprising:

• a sensing circuit configured to generate signals corresponding to the rotary position of the rotor;
• an electronic commutation circuit including switches coupled to the windings;
• a control circuit coupled to the sensing circuit and the commutation circuit, the control circuit configured to generate pulse-width modulated control signals in response to the rotary position of the rotor and to apply the control signals to the commutation circuit, wherein the commutation circuit responds to the control signals by energizing at least two windings at generally a same time and
• at least two switches through which flow of current through the energized windings is split therebetween.