Patent US2030412A successfully refreshed from Google Patents.
Patent US3448066A successfully refreshed from Google Patents.
Patent US3806785A successfully refreshed from Google Patents.
US3806785A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brushless d. c. electric machine
Assignee: Bpifrance Financement SA
•
Filing: 1972-06-01
•
Granted: 1974-04-23
•
Expires: 1992-06-01
Abstract
Abstract The invention relates to a D.C. brushless electric motor which comprises a rotor formed by a permanent magnet which is the seat of a magntic field directed along at least one diameter of the rotor, and a three-phase stator whose three windings, connected in star at one end, are connected at their other ends to the positive or negative terminal of a source of direct or rectified current, each through two electronic switching members with opposite polarities, wherein the assembly of switches is controlled by an angular position sensor driven by the rotor, and actuated to supply the windings of the three phases by currents of the same shape, but offset through 120*, and having an amplitude which varies by steps of the same value and of a duration corresponding to at maximum a 60 electrical degrees of rotation of the rotor between a positive and a negative peak values, the minimum positive step being separated from the minimum negative step by a step of same duration having a zero value, said motor comprising rotor and stator structures so arranged that the reluctance of the gap is substantially constant during a rotation of the rotor through 360 electric degrees, an induction type position sensor being driven by the rotor shaft to control the electronic switching members, and wherein there is provided between the rotor and the position sensor adjustable coupling means allowing the angle, formed between the vector representing the magnetic flux of the rotor and the vector representing the rotating flux of the stator, to be given an optimum value.
Inventors
- 👤 Valroger P De
- 👤 M Lavet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:23
CPC Classifications
H; H02; H02K; H02K29/00; H02K29/06; H02K29/12
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
264 words
A brushless D.C. electric motor of the type comprising a rotor provided with means for generating a constant magnetic field directed along at least one diameter thereof, and a three phase stator having three starconnected windings which are coupled at their other ends to the positive and negative terminals of a D.C. or rectified supply, each through two electronic switching means with opposed polarities respectively, an angular position sensor driven by the rotor and controlling the switching members to supply the three phase stator windings currents of the sAme quasi-sinusoidal shape but offset by 120* and having an amplitude which aries by steps of the same value and duration corresponding to at maximum, a 60 electrical degrees of rotation of the rotor between positive and negative peak values, the minimum positive step being separated from the minimum negative step by a step of same duration having a zero value, said motor comprising in combination: rotor and stator structures so arranged that the total value of the reluctance of the magnetic circuits of the motor is substantially constant for all positions of the rotor during a rotation of the rotor through 360 electric degrees, an induction type position sensor having a rotor driven by the motor rotor shaft and a stator connected to said switching means, and adjustable coupling means between the rotor of the position sensor and the rotor shaft of the motor, the angle formed between the vectors representing the rotating flux of the three phase stator and the magnetic flux of the motor rotor being controlled to be at an optimum value.
Claim 2
Dependent Claim
264 words
A brushless D.C. electric motor of the type comprising a rotor provided with means for generating a constant magnetic field directed along at least one diameter thereof, and a three phase stator having three starconnected windings which are coupled at their other ends to the positive and negative terminals of a D.C. or rectified supply, each through two electronic switching means with opposed polarities respectively, an angular position sensor driven by the rotor and controlling the switching members to supply the three phase stator windings currents of the sAme quasi-sinusoidal shape but offset by 120* and having an amplitude which aries by steps of the same value and duration corresponding to at maximum, a 60 electrical degrees of rotation of the rotor between positive and negative peak values, the minimum positive step being separated from the minimum negative step by a step of same duration having a zero value, said motor comprising in combination: rotor and stator structures so arranged that the total value of the reluctance of the magnetic circuits of the motor is substantially constant for all positions of the rotor during a rotation of the rotor through 360 electric degrees, an induction type position sensor having a rotor driven by the motor rotor shaft and a stator connected to said switching means, and adjustable coupling means between the rotor of the position sensor and the rotor shaft of the motor, the angle formed between the vectors representing the rotating flux of the three phase stator and the magnetic flux of the motor rotor being controlled to be at an optimum value.
Claim 3
Dependent Claim
62 words
A motor according to claim 1 wherein the motor rotor comprises a heteropolar inductor comprising at least one double-pole permanent magnet having wide pole pieces having an extent approximating a pole-pitch and being separated by narrow gaps, whereby the motor rotor is prevented from being acted upon by strong magnetic attraction or repulsion forces having particular directions in the absence of current.
Claim 4
Dependent Claim
33 words
A motor according to claim 1 having a laminated motor stator with narrow-mouthed slots and with a three-phase winding distributed in said slots, whereby the permeance of the annular air-gap is substantially constant.
Claim 5
Dependent Claim
69 words
A motor according to claim 1, wherein the motor stator is provided with two three-phase windings formed respectively by sets of conductors located a short distance from the pole faces of the motor rotor and directed at right-angles to the force lines passing from said motor rotor, one of the windings serving as a three phase sensor and the other winding producing the driving forces actuating the motor rotor.
Claim 6
Dependent Claim
96 words
A motor according to claim 1, wherein the motor rotor is in the form of a cup surrounding the motor stator and comprises a circular array of thin magnets of the type known as ''''tiles'''', which array is surrounded by a ring having great inertia and a flat multipole inducting magnet arranged at right-angles to the shaft, whereas the main three-phase winding of the motor stator is distributed over the periphery of a central cylindrical core, while the sensor winding is fixed on one of the circular faces of this core opposite the multipolar inducting magnet.
Claim 7
Dependent Claim
31 words
A motor according to claim 1 wherein the adjustable coupling provided to connect the rotor of the position sensor to the rotor shaft of the motor comprises two interengaging toothed rings.
Claim 8
Dependent Claim
80 words
A motor according to claim 1 having said three phase star connected stator winding wherein each pair of electronic switching means comprises a PNP power transistor and a NPN power transistor, means being provided for applying the signals from the position sensor to the bases of said transistors the emitters of which are connected to the positive and negative terminals of the D.C. supply and the collectors of which are connected to the free end of the corresponding phase winding.
Claim 9
Dependent Claim
82 words
A motor according to claim 1 having said three phase star connected stator winding, wherein each pair of electronic switching means for each phase winding comprises two power transistors of the same conductivity type, connected in opposition to the terminals of the D.C. supply respectively, a diode being arranged in series between the positive terminal of the supply and the collector of one of the transistors, and the collector of the other transistor being connected to the negative terminal of the supply.
Claim 10
Dependent Claim
95 words
A motor according to claim 1, wherein each pair of electronic switching comprises two power thyristors mounted in opposition, the gatEs of these thyristors being controlled by the position-sensor, and there are associated with each pair of power thyristors two extinguishing thyristors the gates of which are likewise controlled by the sensor, each extinguishing thyristor being arranged in parallel with the corresponding power thyristor and being connected to the latter through a condenser, a charging resistor being connected in series to the extinguishing thyristor and in parallel with the corresponding phase winding of the motor.
Claim 11
Dependent Claim
72 words
A motor according to claim 7, comprising a shunt arranged in series with the winding of at least one phase of the motor stator, this shunt being connected between the base and the emitter of an auxiliary transistor, the saturation of which causes the feed of the power transistor to be interrupted, and a tunnel diode being arranged in series with said shunt, whereby the current is limited when starting the motor.
Claim 12
Dependent Claim
61 words
A motor according to claim 7, comprising means for limiting the start-up current, including a power transistor in series with at least one phase of the motor stator, a biassing resistor connected between the base of said transistor end the opposite and of the corresponding phase winding, and a second resistor connected between the collector and the emitter of said transistor.
Claim 13
Dependent Claim
52 words
A motor according to claim 1, wherein the sensing-means includes a small heteropolar inductor similar to the motor rotor and rotated by the shaft of the motor, and a stator having ferromagnetic cores carrying induced coils so arranged as to produce polyphase voltages applied to control electrodes of the electronic switching means.
Claim 14
Dependent Claim
134 words
A motor according to claim 1, wherein the position sensor is formed by a variable coupling transformer comprising a magnetic core driven by the shaft of the motor and having two wide lateral pole pieces extending on a part of its periphery and a fixed central coil surrounding said core, an audio-frequency auxiliary oscillator to continuously feed the oscillations generated thereby to said central fixed coil, a plurality of induced coils the number of which is equal to the number of positions to be detected by the sensor and uniformly distributed around said central coils, magnetic cores on which said induced coils are arranged and having radially inwardly directed narrow pole pieces cooperating with said wide polar pieces of the central core to provide successive couplings between the central coil and the induced coils.
Claim 15
Dependent Claim
85 words
A motor according to claim 13 wherein the position sensor comprises three induced coils arranged around the central coil, and three transformers having their primary windings connected to said induced coils respectively and each provided with two secondary windings connected to the gate of a power thyristor and to the gate of an extinguishing thyristor respectively, rectifying means being provided between said secondary windings and said gates respectively to allow control pulses of appropriate polarity to be transmitted in each control circuit of said gates.
Claim 16
Dependent Claim
75 words
A motor according to claim 1, acting as a pilot motor to control the frequency of a polyphase power system, the wherein electronic switching means connected to the phase windings of said motor stator are simultaneously connected to the phase conductors of said system to supply said system with polyphase alternating currents resulting from the conversion of the D.C. energy of the D.C. supply, means being provided for adjusting the speed of the pilot motor.
Claim 17
Dependent Claim
22 words
A motor according to claim 8 wherein the two power transistors of each pair of electronic switching means comprises two NPN transistors.
References Cited (Backward Citations)
US3042847A
Cited
US3386019A
Cited
US3242405A
Cited
US3274471A
Cited
US3461367A
Cited
US3339133A
Cited
US3585474A
Cited
US3590353A
Cited
US3611081A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-22 | 1977-10-22 | 1978-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-22 | 1981-10-22 | 1982-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-22 | 1985-10-22 | 1986-04-23 | $7700.00 | Window Closed / Lapsed |