Method for low-speed operation of brushless DC motors
AssigneeWilo SE
InventorWaldemar Stephan
Life of this patent
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Abstract
A method to operate an electronically commutated DC motor driving a centrifugal pump and comprising a stator fitted with at least one winding and a rotor fitted with permanent magnets, said method including a monitored stepping operation within which one full revolution of the rotor is constituted by a sequence of distinct individual steps, the rotor being accelerated by applying a stator field and being decelerated to a stop before the stator field is commutated.
Claims9
A method of operating an electronically commutated DC motor in a stepping operation mode, the DC motor comprising a stator equipped with at least one winding and a rotor equipped with at least one magnet, said method comprising, within one revolution of the rotor and in series, the steps of:
- accelerating the rotor by a stator field generated by said at least one winding;
- decelerating the rotor to a stop by the stator field;
- and
- commutating the stator field;
- wherein the stator field is generated by applying at least one drive pulse to said at least one winding, the drive pulse having a predetermined pulse width and being of a predetermined voltage, the predetermined pulse width being sufficiently wide to cause both said accelerating and decelerating.
A brushless DC motor, comprising:
- a stator equipped with three windings;
- a rotor equipped with permanent magnets;
- and
- a controller coupled to the windings and supplying thereto a series of drive pulses which cause generation and commutation of a stator field in the windings so that, within each revolution of the rotor, the rotor is both accelerated and then decelerated to a stop by the stator field before the stator field is commutated;
- wherein said motor is operated in a speed range of less than 400 rpm.
A circulating pump in a cooling system of a motor vehicle, comprising:
- a brushless DC motor;
- and
- a centrifugal pump driven by said brushless DC motor;
- said brushless DC motor comprising:
- a stator equipped with three windings;
- a rotor equipped with permanent magnets;
- and
- a controller coupled to the windings and supplying thereto a series of drive pulses which cause generation and commutation of a stator field in the windings so that, within each revolution of the rotor, the rotor is both accelerated and then decelerated to a stop by the stator field before the stator field is commutated;
- wherein said motor is operated in a speed range of less than 400 rpm.
Dependencies are inferred from the claim text.