Title:
METHOD AND APPARATUS OF CONTROLLING A BRUSHLESS PERMANENT-MAGNET MOTOR
Document Type and Number:
WIPO Patent Application WO/2017/187129
Kind Code:
A3
Abstract:
A method of controlling a brushless permanent-magnet motor that comprises sequentially exciting and freewheeling a phase winding of the motor, wherein the phase winding is freewheeled when the phase current exceeds an upper threshold and freewheeling comprises one of: (i) freewheeling for a fixed period of time, and (ii) freewheeling until the phase current falls below a lower threshold. The method further comprises measuring a parameter corresponding to one of: (i) the magnitude of the phase current during or at the end of freewheeling when the phase winding is freewheeled for the fixed period of time, and (ii) the time interval between either the start and end of freewheeling or the start and end of excitation when the phase winding is freewheeled until the phase current falls below the lower threshold. The measured parameter is compared against a saturation threshold, and the rotor is determined to be at a predetermined position when the measured parameter is less than the saturation threshold. In response to determining that the rotor is at the predetermined position, the phase winding is commutated after a commutation period has elapsed.
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Inventors:
ZHENG LIBO (GB)
Application Number:
PCT/GB2017/050905
Publication Date:
January 04, 2018
Filing Date:
March 30, 2017
Export Citation:
Assignee:
DYSON TECHNOLOGY LTD (GB)
International Classes:
H02P6/185
Foreign References:
| GB2501370A | 2013-10-23 | |||
| US20130234633A1 | 2013-09-12 |
Attorney, Agent or Firm:
LOBBAN, Colin et al. (GB)
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