WO2000025415A1 - Method and apparatus for reducing torque vibrations in a synchronous machine - Google Patents

Method and apparatus for reducing torque vibrations in a synchronous machine Download PDF

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Publication number
WO2000025415A1
WO2000025415A1 PCT/FI1999/000877 FI9900877W WO0025415A1 WO 2000025415 A1 WO2000025415 A1 WO 2000025415A1 FI 9900877 W FI9900877 W FI 9900877W WO 0025415 A1 WO0025415 A1 WO 0025415A1
Authority
WO
WIPO (PCT)
Prior art keywords
torque
correction signal
signal
angle
motor
Prior art date
Application number
PCT/FI1999/000877
Other languages
French (fr)
Inventor
Harri Hakala
Original Assignee
Kone Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kone Corporation filed Critical Kone Corporation
Priority to AU10480/00A priority Critical patent/AU1048000A/en
Publication of WO2000025415A1 publication Critical patent/WO2000025415A1/en

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/10—Arrangements for controlling torque ripple, e.g. providing reduced torque ripple

Definitions

  • the present invention relates to a method as defined in the preamble of claim 1 and to an apparatus as defined in the preamble of claim 6.
  • the torque of an alternating-current machine is generated by means of an armature circuit, normally the stator, a supply voltage and magnetization of an exci- tation circuit, normally the rotor.
  • the supply voltage is applied to stator windings fitted in stator slots.
  • Excitation is developed using permanent magnets or excitation windings fitted in the rotor.
  • the uniformity of the torque depends on how far the field developed in the air gap of the motor approaches the sinusoidal form. A curve form deviating from the sinusoidal form produces torque variations at a frequency determined by the harmonic components, giving rise to mechanical vibration and noise.
  • the form of the air gap field also depends on the form of the field generated by the excitation.
  • a permanent magnet synchronous motor typically produces a torque characterized by so-called “cogging", which is a result of the reluctance variation caused by the stator teeth as the angle between the rotor and stator changes.
  • the object of the invention is to achieve a solution for substantially reducing the vibration and noise generated by harmonic moments in the motor.
  • the method of the invention is characterized by the features presented in the characterization part of claim 1.
  • the apparatus of the invention is characterized by the features presented in the characterization part of claim 6.
  • the features of some preferred embodiments of the invention are presented in the subclaims.
  • a correction signal dependent on the angle between the rotor and stator is summed with the output of a torque regulator to compensate the torque ripple produced by the motor.
  • a signal processing circuit comprises a storage element from where a correcting torque component is read.
  • the stored component is preferably generated by first operating the motor without a correction signal while at the same time measuring the torque ripple component. In normal motor operation, a corresponding signal in opposite phase is summed with a torque reference. This results in compensation of the torque ripple.
  • the correction signal is generated using a neural network comprised in a signal processor.
  • the frequency of the correction signal is the same as the slot ripple frequency and its phase is locked to the rotor angle.
  • the locked phase and the amplitude preferably form two parameters which are kept constant during operation or which are made to be variable in accordance with the operating point.
  • the motor 2 is controlled using a torque regulator 4.
  • the angle between the stator and rotor of the motor is measured using angle measuring equipment 6 and the motor speed is measured by means of a velocimeter 8 connected to the shaft of the motor 2.
  • the speed data 28 is fed into a differential element 18, which is also fed by a speed reference 20.
  • the speed reference and the speed measurement are used to control the speed regulator 12 in a manner known in itself.
  • the output of the speed regulator is taken to an adder 14, to which also a correction signal 22 according to the invention is input.
  • the output of the adder 14 is passed to the torque regulator 4 controlling the motor.
  • the angle measurement data (16,26) is input to the torque regulator 4 and to the signal processor 10.
  • a correction signal 22 is generated, to be input to the adder 14 and summed with the torque reference.
  • the speed signal is also input to the signal processor 10.
  • the signal proc- essor comprises storage elements in which the correc- tion signal is stored.
  • the torque ripple can be measured and the signal corresponding to it is stored in memory.
  • a corresponding signal in opposite phase is input to the adder.
  • the frequency of the correction signal is the same as the slot ripple fre- quency of the motor and its phase is locked to the rotor angle.
  • the phase and amplitude form two parameters, which are either kept constant during operation or made to be variable in accordance with the operating point.
  • the parameters are suitably stored in mem- ory.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
  • Control Of Ac Motors In General (AREA)

Abstract

The invention relates to a method for reducing torque ripple in a motor controlled by a torque regulator. According to the invention, a correction signal dependent on the angle between the stator and the rotor is summed with the input of the torque regulator. The apparatus of the invention comprises a signal processor capable of generating a correction signal reducing the torque ripple, which correction signal can be summed with the output of the torque regulator and which can be generated in the signal processor on the basis of angle data regarding the angle between the stator and the rotor.

Description

METHOD AND APPARATUS FOR REDUCING TORQUE VIBRATIONS IN A SYNCHRONOUS MACHINE
The present invention relates to a method as defined in the preamble of claim 1 and to an apparatus as defined in the preamble of claim 6.
The torque of an alternating-current machine is generated by means of an armature circuit, normally the stator, a supply voltage and magnetization of an exci- tation circuit, normally the rotor. The supply voltage is applied to stator windings fitted in stator slots. Excitation is developed using permanent magnets or excitation windings fitted in the rotor. The uniformity of the torque depends on how far the field developed in the air gap of the motor approaches the sinusoidal form. A curve form deviating from the sinusoidal form produces torque variations at a frequency determined by the harmonic components, giving rise to mechanical vibration and noise.
In addition to the supply voltage frequency, the form of the air gap field also depends on the form of the field generated by the excitation. A permanent magnet synchronous motor typically produces a torque characterized by so-called "cogging", which is a result of the reluctance variation caused by the stator teeth as the angle between the rotor and stator changes.
The object of the invention is to achieve a solution for substantially reducing the vibration and noise generated by harmonic moments in the motor. To imple- merit this, the method of the invention is characterized by the features presented in the characterization part of claim 1. Correspondingly, the apparatus of the invention is characterized by the features presented in the characterization part of claim 6. The features of some preferred embodiments of the invention are presented in the subclaims.
According to a preferred embodiment of the invention, a correction signal dependent on the angle between the rotor and stator is summed with the output of a torque regulator to compensate the torque ripple produced by the motor.
According to a preferred embodiment, a signal processing circuit comprises a storage element from where a correcting torque component is read. The stored component is preferably generated by first operating the motor without a correction signal while at the same time measuring the torque ripple component. In normal motor operation, a corresponding signal in opposite phase is summed with a torque reference. This results in compensation of the torque ripple.
Further, according to a preferred embodiment, the correction signal is generated using a neural network comprised in a signal processor.
According to another preferred embodiment, the frequency of the correction signal is the same as the slot ripple frequency and its phase is locked to the rotor angle. The locked phase and the amplitude preferably form two parameters which are kept constant during operation or which are made to be variable in accordance with the operating point. The invention provides a cheap and reliable solution for eliminating the torque ripple caused by slot harmonics in a permanent magnet synchronous motor with an axial air gap. The invention is especially applicable to an elevator drive motor.
In the following, the invention will be described by the aid of an embodiment example with reference to the drawing, which presents a motor regulator according to the invention.
The motor 2 is controlled using a torque regulator 4. The angle between the stator and rotor of the motor is measured using angle measuring equipment 6 and the motor speed is measured by means of a velocimeter 8 connected to the shaft of the motor 2. The speed data 28 is fed into a differential element 18, which is also fed by a speed reference 20. The speed reference and the speed measurement are used to control the speed regulator 12 in a manner known in itself. The output of the speed regulator is taken to an adder 14, to which also a correction signal 22 according to the invention is input. The output of the adder 14 is passed to the torque regulator 4 controlling the motor.
The angle measurement data (16,26) is input to the torque regulator 4 and to the signal processor 10. In the signal processor 10, a correction signal 22 is generated, to be input to the adder 14 and summed with the torque reference. As shown in the figure, the speed signal is also input to the signal processor 10.
According to a preferred embodiment, the signal proc- essor comprises storage elements in which the correc- tion signal is stored. By operating the motor without a correction signal, the torque ripple can be measured and the signal corresponding to it is stored in memory. During normal operation, a corresponding signal in opposite phase is input to the adder. Naturally, it is also possible to store a correction signal generated in the manner described above directly in memory.
According to an embodiment, the frequency of the correction signal is the same as the slot ripple fre- quency of the motor and its phase is locked to the rotor angle. The phase and amplitude form two parameters, which are either kept constant during operation or made to be variable in accordance with the operating point. The parameters are suitably stored in mem- ory.
In the foregoing, the invention has been described by the aid of a few of its embodiments. However, the presentation is not to be regarded as constituting a limitation of the sphere of patent protection, but different embodiments are possible within the scope of the inventive idea defined in the claims.

Claims

1. Method for reducing torque ripple in a motor controlled by means of a torque regulator, characterized in that a correction signal dependent on the angle be- tween the stator and the rotor is summed with the input of the torque regulator.
2. Method as defined in claim 1, characterized in that the correction signal is generated by first operating the motor without a correction signal while simultane- ously measuring the torque ripple component produced, which is stored in a storage element, and that during normal operation the torque ripple component is read from the storage and a signal corresponding to it in opposite phase is summed with the torque reference.
3. Method as defined in claim 1 or 2 , characterized in that the correction signal is generated using a neural network .
4. Method as defined in any one of claims 1 - 3, characterized in that the frequency of the correction sig- nal is the same as the slot ripple frequency of the motor and its phase is locked to the rotor angle.
5. Method as defined in claim 4, characterized in that the phase and amplitude form two parameters which are either kept constant during operation or which are made to be variable in accordance with the operating point.
6. Apparatus for reducing torque ripple in a motor controlled by a torque regulator, characterized in that the apparatus comprises a signal processor capa- ble of generating a correction signal reducing the torque ripple, which correction signal can be summed with the output of the torque regulator and which can be generated in the signal processor on the basis of angle data regarding the angle between the stator and the rotor.
7. Apparatus as defined in claim 6, characterized in that the apparatus comprises a storage element in which the correction signal or a signal in opposite phase relative to the correction signal can be stored.
PCT/FI1999/000877 1998-10-22 1999-10-22 Method and apparatus for reducing torque vibrations in a synchronous machine WO2000025415A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU10480/00A AU1048000A (en) 1998-10-22 1999-10-22 Method and apparatus for reducing torque vibrations in a synchronous machine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI982287 1998-10-22
FI982287A FI110371B (en) 1998-10-22 1998-10-22 Procedures and devices for reducing synchronous machine torque vibrations

Publications (1)

Publication Number Publication Date
WO2000025415A1 true WO2000025415A1 (en) 2000-05-04

Family

ID=8552759

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1999/000877 WO2000025415A1 (en) 1998-10-22 1999-10-22 Method and apparatus for reducing torque vibrations in a synchronous machine

Country Status (3)

Country Link
AU (1) AU1048000A (en)
FI (1) FI110371B (en)
WO (1) WO2000025415A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4525657A (en) * 1983-03-09 1985-06-25 Matsushita Electric Industrial Co., Ltd. Torque ripple compensation circuit for a brushless D.C. motor
US4910449A (en) * 1987-05-18 1990-03-20 Ebara Corporation System for preventing unbalance vibrations and synchronous disturbance vibrations
US5229677A (en) * 1991-09-18 1993-07-20 Newport News Shipbuilding And Dry Dock Company Electric propulsion motor for marine vehicles
US5444341A (en) * 1993-11-04 1995-08-22 Cincinnati Milacron Inc. Method and apparatus for torque ripple compensation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4525657A (en) * 1983-03-09 1985-06-25 Matsushita Electric Industrial Co., Ltd. Torque ripple compensation circuit for a brushless D.C. motor
US4910449A (en) * 1987-05-18 1990-03-20 Ebara Corporation System for preventing unbalance vibrations and synchronous disturbance vibrations
US5229677A (en) * 1991-09-18 1993-07-20 Newport News Shipbuilding And Dry Dock Company Electric propulsion motor for marine vehicles
US5444341A (en) * 1993-11-04 1995-08-22 Cincinnati Milacron Inc. Method and apparatus for torque ripple compensation

Also Published As

Publication number Publication date
FI982287A (en) 2000-04-23
FI110371B (en) 2002-12-31
AU1048000A (en) 2000-05-15
FI982287A0 (en) 1998-10-22

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