Starting method for hall-less single-phase BLDCM
AssigneeDelta Electronics, Inc.
InventorsWeizi Wang, Zhigan Wu, Wanbing Jin, Jianping Ying, Lijian Wu, Shih-Ming Huang, Wen-Shi Huang
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Abstract
The methods for starting a Hall-less single-phase BLDCM having an asymmetrical air gap are proposed. The provided methods are employed to input a specific amount of current impulse and stop the current impulse at a specific time such that the rotor of the single-phase BLDCM having an asymmetrical air gap can be realized to rotate in the pre-determined direction through one of the cogging torque and the rotor inertia after that specific time so as to accomplish the normal starting of a motor without the Hall-effect sensor.
Claims20
A method for starting a brushless DC motor (BLDCM) having a stator, a rotor, a winding and an asymmetrical air gap, wherein said stator has a specific tooth and said rotor has a specific magnetic pole, comprising the steps of:
- (a) exciting said winding with a current impulse such that said stator generates a magnetic field and then going to one of steps (b) and (d);
- (b) driving said rotor to rotate in a first direction with said current impulse if a polarity of a portion of said specific tooth of said stator close to said air-gap and a polarity of said specific magnetic pole of said rotor corresponding to said specific tooth are opposite and then going to step (c);
- (c) stopping said current impulse at a specific moment such that said rotor is rotated in a second direction by a cogging torque and then going to step (f);
- (d) driving said rotor to rotate in a specific direction with said current impulse if a polarity of a portion of said specific tooth of said stator close to said air-gap and a polarity of said specific magnetic pole of said rotor corresponding to said specific tooth are the same and then going to step (e);
- (e) stopping said current impulse at a specific time such that said rotor is rotated in said specific direction by an inertia and then going to step (f);
- and
- (f) detecting a back electromotive force (BEMF) in said winding when said rotor rotates such that said motor is controlled for commutating according to said BEMF.
A method for starting a brushless DC motor (BLDCM) having a stator, a rotor and a winding, comprising the steps of:
- (a) exciting said winding with a current impulse such that said stator generates a magnetic field and then going to step (b);
- (b) driving said rotor to rotate in one of a first and a second directions with said current impulse and then going to step (c);
- (c) stopping said current impulse at a specific moment such that said rotor is rotated in said second direction by one of a cogging torque and an inertia, and then going to step (d);
- and
- (d) detecting a back electromotive force (BEMF) in said winding when said rotor rotates such that said motor is controlled for commutating according to said BEMF.
Dependencies are inferred from the claim text.