US 12,294,323 B2
Method for pre-positioning rotor of outdoor fan in high-speed counter-rotation state before operation
Fei Yang, Zhongshan (CN); Min Wang, Zhongshan (CN); Song Luo, Zhongshan (CN); and Chao Li, Zhongshan (CN)
Assigned to Zhongshan Broad-Ocean Motor Co., Ltd., Zhongshan (CN)
Filed by Zhongshan Broad-Ocean Motor Co., Ltd., Zhongshan (CN)
Filed on Jul. 13, 2023, as Appl. No. 18/221,869.
Claims priority of application No. 202211478597.1 (CN), filed on Nov. 24, 2022.
Prior Publication US 2024/0178777 A1, May 30, 2024
Int. Cl. H02P 21/34 (2016.01); H02P 21/18 (2016.01)
CPC H02P 21/34 (2016.02) [H02P 21/18 (2016.02); H02K 2213/03 (2013.01); H02P 2207/05 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for pre-positioning a rotor of an outdoor fan in a high-speed counter-rotation state before operation, the outdoor fan comprising a permanent-magnet synchronous motor and a wind wheel; the permanent-magnet synchronous motor comprising a motor body and a motor controller; the motor body comprising a stator assembly and a permanent-magnet rotor assembly; the motor controller comprising a microprocessor and an inverter circuit; the inverter circuit comprising a plurality of bridge arms, and each bridge arm comprising an upper bridge arm and a lower bridge arm; each upper bridge arm comprising an upper electronic switching tube, and each lower bridge arm comprising a lower electronic switching tube, the method comprising:
1) during a high-speed counter-operation state, sending, by the microprocessor, a signal to the inverter circuit to turn off all upper electronic switching tubes and turn on all lower electronic switching tubes, thereby achieving a short-circuit brake to reduce a counter-rotation speed of the wind wheel;
2) measuring a phase current of each phase coil winding in the stator assembly;
3) calculating a back electromotive force of each phase coil winding in the stator based on the phase current of each phase coil winding;
4) calculating a position angle θ0 of the rotor assembly based on the back electromotive force of each phase coil winding;
5) checking if the phase current of each phase coil winding is all smaller than a preset threshold current I0; if not, return to 1); if yes, proceed to 6); and
6) calculating a resistance torque to stop the rotor assembly based on the position angle θ0 of the rotor assembly, and then stopping the rotor assembly to achieve pre-positioning before starting.