US5751128A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for electronically commuting an electric motor
Assignee: NXP USA Inc
•
Filing: 1996-11-12
•
Granted: 1998-05-12
•
Expires: 2016-11-12
Abstract
Abstract In a method for operating an electric motor especially a permanent magnet motor, the voltage applied to the windings of the stator of the motor are commuted electronically. The timing of the commutation events is determined by sensing and low pass filtering the differential voltages between the windings and detecting the zero crossings of the filtered differential voltages. At the time the zero crossings take place or within a short time afterwards the commutation events take place.
Inventors
- 👤 Leos Chalupa
- 👤 Miroslav Patocka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:55
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/14; H02P6/16; H02P6/18
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
78 words
A method of operating an electric motor having a set of windings for producing a rotating magnetic field and a rotor adapted to rotate in response to said magnetic field, said method comprising the steps of sensing and low pass filtering the differential voltages between said windings; detecting points of time when said filtered differential voltages become zero; and commuting the voltages applied to said windings from a power source in accordance with said detected points of time.
Claim 2
Independent Claim
78 words
A method of operating an electric motor having a set of windings for producing a rotating magnetic field and a rotor adapted to rotate in response to said magnetic field, said method comprising the steps of sensing and low pass filtering the differential voltages between said windings; detecting points of time when said filtered differential voltages become zero; and commuting the voltages applied to said windings from a power source in accordance with said detected points of time.
Claim 3
Dependent Claim
29 words
The method according to claim 1 further comprising the step of calculating the speed of said rotor from the duration between at least two of said points of time.
Claim 4
Dependent Claim
52 words
The method according to claim 2 further comprising the steps of comparing said calculated speed of said rotor with an speed input value and deriving an error signal therefrom; and changing a duty cycle of a pulse width modulation of said voltages applied to said windings in accordance with said error signal.
Claim 5
Dependent Claim
40 words
The method according to claim 3 further comprising the steps of sensing the total input current of said motor; and changing said duty cycle of said pulse width modulation according to said total input current, if an error signal occurs.
Claim 6
Independent Claim
134 words
An apparatus for electronically commuting an electric motor, said motor having a set of windings with external connections coupled for power supply, the set of windings producing a rotating magnetic field to rotate a rotor in said motor, said apparatus comprising: a low pass filter coupled to the external connections of said set of windings: a sensor coupled to said low pass filter and sensing filtered differential voltages between said windings; a position recognition circuit coupled to said sensor and detecting points of time when said filtered differential voltages become zero; and a control circuit coupled to said position recognition circuit and to the external connections of said set of windings, said control circuit commuting voltages applied to said set of windings from a power source in accordance with said detected points of time.
Claim 7
Independent Claim
134 words
An apparatus for electronically commuting an electric motor, said motor having a set of windings with external connections coupled for power supply, the set of windings producing a rotating magnetic field to rotate a rotor in said motor, said apparatus comprising: a low pass filter coupled to the external connections of said set of windings: a sensor coupled to said low pass filter and sensing filtered differential voltages between said windings; a position recognition circuit coupled to said sensor and detecting points of time when said filtered differential voltages become zero; and a control circuit coupled to said position recognition circuit and to the external connections of said set of windings, said control circuit commuting voltages applied to said set of windings from a power source in accordance with said detected points of time.
Claim 8
Dependent Claim
50 words
The apparatus of claim 5 further comprising a pulse width modulator coupled to said position recognition circuit and to said control circuit, said pulse width modulator modulating said voltages applied to said set of windings, a period of said pulse width modulation being short in comparison to a commutation period.
Claim 9
Dependent Claim
37 words
The apparatus of claim 6 further comprising a motor speed logic circuit coupled to said position recognition circuit and calculating a speed of said rotor from a duration between at least two of said points of time.
Claim 10
Dependent Claim
90 words
The apparatus according to claim 7 further comprising: a comparator coupled to said motor speed logic circuit and coupled for receiving a speed control signal, said comparator comparing said calculated speed of said rotor with the speed control signal and deriving an error signal therefrom; and a duty cycle logic circuit coupled to said comparator and to said pulse width modulator, said duty cycle logic circuit adjusting a duty cycle of a pulse width modulation of said voltages applied to said set of windings in accordance with said error signal.
Claim 11
Dependent Claim
47 words
The apparatus according to claim 8 further comprising a sensor coupled to said control circuit and sensing a total input current of said motor, wherein said pulse width modulator is adapted to change said duty cycle according to said total input current, if said error signal occurs.
Claim 12
Dependent Claim
21 words
The apparatus according to claim 5 wherein said position recognition circuit and said control circuit are coupled to a ground potential.
Claim 13
Dependent Claim
86 words
An electric motor having a set of windings for producing a rotating magnetic field and a rotor adapted to rotate in response to said magnetic field, said electric motor further comprising means for electronically commuting an electric motor comprising means for sensing and low pass filtering the differential voltages between said windings; means for detecting points of time when said filtered differential voltages become zero; and means for commuting voltages applied to said windings from a power source in accordance with said detected points of time.
Claim 14
Dependent Claim
86 words
An electric motor having a set of windings for producing a rotating magnetic field and a rotor adapted to rotate in response to said magnetic field, said electric motor further comprising means for electronically commuting an electric motor comprising means for sensing and low pass filtering the differential voltages between said windings; means for detecting points of time when said filtered differential voltages become zero; and means for commuting voltages applied to said windings from a power source in accordance with said detected points of time.
Claim 15
Dependent Claim
90 words
A electric apparatus comprising an electric motor having a set of windings for producing a rotating magnetic field and a rotor adapted to rotate in response to said magnetic field, said electric motor further comprising means for electronically commuting an electric motor comprising means for sensing and low pass filtering the differential voltages between said windings; means for detecting points of time when said filtered differential voltages become zero; and means for commuting voltages applied to said windings from a power source in accordance with said detected points of time.
Claim 16
Dependent Claim
90 words
A electric apparatus comprising an electric motor having a set of windings for producing a rotating magnetic field and a rotor adapted to rotate in response to said magnetic field, said electric motor further comprising means for electronically commuting an electric motor comprising means for sensing and low pass filtering the differential voltages between said windings; means for detecting points of time when said filtered differential voltages become zero; and means for commuting voltages applied to said windings from a power source in accordance with said detected points of time.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-05-11 | 2001-11-10 | 2002-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-11 | 2005-11-10 | 2006-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-11 | 2009-11-10 | 2010-05-12 | $7700.00 | Window Closed / Lapsed |