EP0189676A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Driving circuit for brushless DC motors
Assignee: Panasonic Holdings Corp
•
Filing: 1985-12-24
•
Granted: —
•
Expires: 2005-12-24
Abstract
Abstract A driving circuit for a brushless DC motor having a small amount of torque ripple comprises a magnetic pole position detecting circuit (110) for detecting positions of magnetic poles of a rotor magnet (9) for delivering polyphase signals indicating the positions, a rectifier adder circuit (40) for producing a sum of positive or negative portions of the polyphase signals from the magnetic pole position detecting circuit (110), a first error amplifier (50) for adjusting a gain of the magnetic pole position detecting circuit (110) to make an output signal of the rectifier adder circuit (40) to be proportional to an instruction signal, a power supply circuit (101, 102, 103) for supplying currents to armature coils (4, 5, 6) in response to the polyphase signals, a modulating signal producing circuit (120) for producing a modulating signal synchronised with the rotation of the motor, and a second error amplifier (70) for adjusting a gain of the power supply circuit (101, 102, 103) to make the currents supplied to the armature coils (4, 5, 6) to be proportional to the modulating signal.
Inventors
- 👤 Toshio Inaju
- 👤 Hiroshi Minakuchi
- 👤 Yoshiaki Igarashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 17:34
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/04; H02P6/10
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
207 words
A driving circuit for a brushless DC motor, comprising: a magnetic pole position detecting circuit (110) for detecting positions of magnetic poles of a rotor magnet (9) of the motor and delivering polyphase signals indicative of the positions; a rectifier adder circuit (40) for producing a sum of positive or negative portions of the polyphase signals from the magnetic pole position detecting circuit (110); an instruction signal producing circuit (80) for producing a torque instruction signal instructing a torque to be produced by the motor; a first error amplifier (50) for adjusting a gain of the magnetic pole position detecting circuit (110) to make an output signal of the rectifier adder circuit (40) to be proportional to the torque instruction signal; a power supply circuit (101,102,103) responsive to the polyphase signals for supplying currents to polyphase armature coils (4,5,6) of the motor; current detecting means (90) for detecting the currents supplied to the armature coils; a modulating signal producing circuit (120) for modulating the currents supplied to the armature coils; and a second error amplifier (70) for adjusting a gain of the power supply circuit to make an output signal of the current detecting means (90) equal to an output signal of the modulating signal producing circuit.
Claim 2
Dependent Claim
207 words
A driving circuit for a brushless DC motor, comprising: a magnetic pole position detecting circuit (110) for detecting positions of magnetic poles of a rotor magnet (9) of the motor and delivering polyphase signals indicative of the positions; a rectifier adder circuit (40) for producing a sum of positive or negative portions of the polyphase signals from the magnetic pole position detecting circuit (110); an instruction signal producing circuit (80) for producing a torque instruction signal instructing a torque to be produced by the motor; a first error amplifier (50) for adjusting a gain of the magnetic pole position detecting circuit (110) to make an output signal of the rectifier adder circuit (40) to be proportional to the torque instruction signal; a power supply circuit (101,102,103) responsive to the polyphase signals for supplying currents to polyphase armature coils (4,5,6) of the motor; current detecting means (90) for detecting the currents supplied to the armature coils; a modulating signal producing circuit (120) for modulating the currents supplied to the armature coils; and a second error amplifier (70) for adjusting a gain of the power supply circuit to make an output signal of the current detecting means (90) equal to an output signal of the modulating signal producing circuit.
Claim 3
Dependent Claim
72 words
A driving circuit as set forth in claim 1, wherein said modulating signal producing circuit (120) comprises an absolute value adder circuit (60) for converting the polyphase signals from the magnetic pole position detecting circuit (110) into absolute values and summing them up and a combining circuit for producing a combination of an output signal of the absolute value adder circuit and the torque instruction signal from the instruction signal producing circuit.
Claim 4
Dependent Claim
39 words
A driving circuit as set forth in claim 2, wherein said combining circuit produces a difference between the torque instruction signal from the instruction signal producing circuit (80) and the output signal of the absolute value adder circuit (60).
Claim 5
Dependent Claim
72 words
A driving circuit as set forth in claim 1, wherein said modulating signal producing circuit (120) comprises an absolute value circuit (61) for converting a sum of the polyphase signals from the magnetic pole position detecting circuit (110) into an absolute value, and a combining circuit for producing a combination of an output signal of the absolute value circuit (61) and the torque instruction signal from the instruction signal producing circuit (80).
Claim 6
Dependent Claim
38 words
A driving circuit as set forth in claim 4, wherein said combining circuit produces a difference between the torque instruction signal from the instruction signal producing circuit (80) and the output signal of the absolute value circuit (61).
Claim 7
Dependent Claim
44 words
A driving circuit as set forth in any one of the previous claims, wherein said current detecting means (90) pass the currents to be supplied to the polyphase armature coils through a common resistor to convert a sum of the currents into a voltage.
Claim 8
Dependent Claim
63 words
A driving circuit as set forth in any previous claim, wherein the magnetic pole position detecting circuit (110) comprises a subtractor circuit (31,32,33) for producing difference signals between two of the polyphase signals from the magnetic pole position detecting circuit; and the rectifier adder circuit is for producing a sum of positive or negative portions of the difference signals from the subtractor circuit.
Claim 9
Dependent Claim
61 words
A driving circuit as set forth in any previous claim wherein the magnetic pole position detecting circuit (110) comprises a plurality of magnetoelectric converter devices (1,2,3) mounted on a stator (10) of the motor and detecting magnetic field generated by a rotor magnet (9) of the motor; and buffer amplifiers (21,22,23) for amplifying output signals of the magnetoelectric converter devices (1,2,3).
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.