Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1996-05-20
1999-11-09
Ramirez, Nestor
Electrical generator or motor structure
Dynamoelectric
Rotary
310179, 310180, H02K 300
Patent
active
059820675
ABSTRACT:
A brushless DC motor has a permanent magnet rotor comprising p magnetic poles and a stator having an integer multiple of 6*p*n slots containing windings, n being a positive, non-zero integer, and the poles and slots being skewed by one slot pitch with respect to each other. The windings in the slots are electrically connected in two separate groups of three-phase windings with each group having three phase terminals, the windings of each group being distributed in phase belts occupying alternate sectors of 30 electrical degrees and the windings of the first group alternating with the windings of the second group. Since the trapezoidal back EMF voltage curve has a wider top it exhibits less droop, compared with an equivalent three-phase brushless DC motor of the prior art, over the 60 electrical degree period centered on maximum back EMF in which torque producing current is applied. In addition, the maxima of back EMF voltage across pairs of terminals in the two groups of three phase windings are 30 electrical degrees out of phase with each other, so that variations in back EMF voltage in the two groups tend to cancel each other as torque producing current is applied to both groups. The result is significantly less torque ripple due to back EMF variation, compared with an equivalent three-phase brushless DC motor of the prior art, and less vibration coupled to the steering wheel of an electric power steering system in which the motor is used as a power assist actuator.
REFERENCES:
patent: 3601642 (1971-08-01), Willyoung
patent: 4132914 (1979-01-01), Khutoretsky et al.
patent: 4200817 (1980-04-01), Bratoljic
patent: 4424463 (1984-01-01), Musil
patent: 4546294 (1985-10-01), Ban et al.
patent: 4551645 (1985-11-01), Takashashi et al.
patent: 4703211 (1987-10-01), Yazaki et al.
patent: 4882524 (1989-11-01), Lee
patent: 4950960 (1990-08-01), Krefta et al.
patent: 4960178 (1990-10-01), Abukawa et al.
patent: 5006745 (1991-04-01), Nishio et al.
patent: 5034642 (1991-07-01), Hoemann et al.
patent: 5122705 (1992-06-01), Kusase et al.
patent: 5266859 (1993-11-01), Stanley
patent: 5323077 (1994-06-01), Brandes
patent: 5442250 (1995-08-01), Stridsberg
patent: 5491393 (1996-02-01), Uesugi
patent: 5506776 (1996-04-01), Fushimi et al.
Investigation Into a Class of Brushless DC Motor W/Aqasisquare Voltages & Currents; H. R. Bolton & N. M. Mallinson; IEE Proceedings, vol. 133, Pt. B, No. 2; Mar. 1986.
Influence of Motor Design & Feed Current Waveform on Torque Ripple in Brushless DC Drives H. R. Bolton * R. A. Ashen; IEE Proceedings, vol. 131, Pt. B, No. 2; May 1984.
Evaluation of Brushless Permanent Magnet Motor Rotor Configurations for Square Wave Current Excitation; R. Vyas, S. Murthy, T. Sebastian; Proceedings-1996 Int'l Conference on Power Electronics Drive & Energy Systems for Industrial Growth; New Delhi, India; Jan. 1996 pp. 895-899.
Collier-Hallman Steven James
Sebastian Tomy
Anderson Edmund P.
General Motors Corporation
Nguyen Tran N
Ramirez Nestor
Sigler Robert M.
LandOfFree
Brushless DC motor having reduced torque ripple for electric pow does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Brushless DC motor having reduced torque ripple for electric pow, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brushless DC motor having reduced torque ripple for electric pow will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1460613