(19) |
 |
|
(11) |
EP 1 676 360 B1 |
(12) |
EUROPEAN PATENT SPECIFICATION |
(45) |
Mention of the grant of the patent: |
|
13.06.2007 Bulletin 2007/24 |
(22) |
Date of filing: 11.10.2004 |
|
(51) |
International Patent Classification (IPC):
|
(86) |
International application number: |
|
PCT/FI2004/000601 |
(87) |
International publication number: |
|
WO 2005/041399 (06.05.2005 Gazette 2005/18) |
|
(54) |
METHOD AND APPARATUS FOR DETERMINING THE POSITION OF THE ROTOR OF AN ELEVATOR MOTOR
VERFAHREN UND VORRICHTUNG ZUR BESTIMMUNG DER POSITION DES ROTORS EINES AUFZUGSMOTORS
PROCEDE ET APPAREIL PERMETTANT DE DETERMINER LA POSITION DU ROTOR D'UN MOTEUR D'ASCENSEUR
|
(84) |
Designated Contracting States: |
|
DE ES FR GB IT |
(30) |
Priority: |
24.10.2003 FI 20031559
|
(43) |
Date of publication of application: |
|
05.07.2006 Bulletin 2006/27 |
(73) |
Proprietor: Kone Corporation |
|
00330 Helsinki (FI) |
|
(72) |
Inventor: |
|
- JAHKONEN, Pekka
FI-05820 Hyvinkää (FI)
|
(74) |
Representative: Zipse Habersack Kritzenberger |
|
Patentanwälte
Wotanstrasse 64 80639 München 80639 München (DE) |
(56) |
References cited: :
EP-A- 0 838 669 US-A1- 2001 004 173
|
WO-A-02/065139
|
|
|
|
|
|
|
|
|
Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
|
[0001] The present invention relates to a method as defined in the preamble of claim 1 and
an apparatus as defined in the preamble of claim 5 for determining the position of
the rotor of an elevator motor.
[0002] The torque of a synchronous motor is proportional to the angular difference between
the rotor magnetic field and the stator magnetic field, i.e. to the rotor angle. The
torque is at a maximum when the rotor angle is 90° and it falls according to the sine
function as the rotor angle changes. The torque curve of synchronous motors designed
for use in an elevator drive is a nearly sinusoidal function of the rotor angle. The
function of the control system controlling the elevator motor is to keep the torque
at the maximum point.
[0003] Currently used methods for determining the rotor position are not applicable in the
case of e.g. flat surface-magnet motors designed for use in elevators without machine
room and placed in the elevator shaft, such motors having equal Lq and Ld. Prior-art
methods intended for surface magnet motors are based on a comparison of the torque
and the angle. When used in an elevator, they cause problems relating to safety and
comfort.
[0004] A method for determining the position of the rotor of a synchronous motor disclosed
in specification
WO-A2-02/065139 allows the absolute angular position of the rotor to be computed while the rotor
is stationary by monitoring the saturation of the stator iron. In this method, an
alternating current having a certain frequency and phase angle is fed into the stator,
samples are taken at given intervals from the current fed in and the voltage obtained,
and the stator inductance is calculated from these voltage and current values. After
that, the phase angle is increased a certain number of times over the 360-degree cycle
and the current feed, sampling and calculation are repeated, thus obtaining a certain
number of calculated stator inductances. Next, the position of the d-axis relative
to the stator is determined from the minimum of the calculated stator inductance values.
This is a relatively complicated method.
[0006] The object of the present invention is to overcome the drawbacks of prior art and
create new type of arrangement that can be used to determine the position of the rotor
of an elevator motor without moving the rotor and by using relatively low magnetization.
[0007] The system of the invention is mainly based on the property of an axial motor that
it tends to work as a sound reproducer when the rotor and stator are moving on the
shaft. In the invention, the angular position of the rotor is detected without releasing
the brake by feeding a current of a frequency of about 50...200 Hz into the motor
and measuring the vibration of the machine as a function of the rotor angle.
[0008] The details of the features of the method and apparatus of the invention are presented
in the claims below.
[0009] The invention increases the areas of application of especially permanent-magnet synchronous
motors with no angle feedback used in elevators. In addition, the arrangement of the
invention is an advantageous way of finding the rotor angle. Moreover, the invention
is safe because the brakes need not be released and the correct angle can be determined
more reliably than by prior-art methods. Furthermore, the method of the invention
can be relatively easily automated, because the elevator is not moving and therefore
fewer monitoring and safeguarding measures are required.
[0010] In the following, the invention will be described in detail with reference to an
example and the attached drawing, wherein
[0011] Fig. 1 is a simplified diagrammatic representation of the apparatus of the invention
for determining the rotor angle of an elevator motor.
[0012] Fig. 1 presents an apparatus comprising an elevator motor 1, which may be a flat
axial motor placed in the elevator shaft and which has a permanent magnet rotor 11
and a stator 12, which is driven by means of a frequency converter 2. The frequency
converter is controlled by a control unit 3.
[0013] In the invention, the angular position of the rotor is detected without releasing
the brake by feeding a current of a frequency of about 50...200 Hz into the motor
and measuring the vibration of the machine as a function of the rotor angle.
[0014] The motion on the shaft is at a maximum when the stator current is in the direction
of the d-axis, which means that the stator and rotor have maximum attractive and repelling
forces (arrows) but no torque. If the current is in the direction of the q-axis, then
the torque is at a maximum while the attractive and repelling forces are at a minimum.
[0015] When an alternating current of a frequency of 50...200 Hz is used, the motor noise
varies very much depending on the position of the rotor. If the frequency is near
the resonant frequency, the amplitude of the noise may vary by tens of dB.
[0016] It is possible to increase acoustic feedback or acceleration feedback e.g. by using
a resolver. By adding a very simple microphone (sound reproducer) 4 or an acceleration
sensor attached to the motor body, the adjustments can be automated by finding the
minimum signal. The magnetization current may be small, even only a few hundred mA,
and the brake of the motor can be kept closed.
[0017] By using the invention, the maximum torque angle can be found but its direction can
not be detected unambiguously. To achieve this, it is possible to release the brake
and check the torque direction in connection with the start of motion.
[0018] It is obvious to the person skilled in the art that different embodiments of the
invention are not limited to the example described above, but that they may be varied
within the scope of the claims presented below. Instead of a current signal, it is
possible to use a voltage signal, and the direction of the current is estimated by
utilizing the motor parameters (resistance, inductance).
1. A method for determining the position of the rotor (11) of a synchronous motor (1)
used as an elevator motor, in which method: an alternating current or voltage of a
certain frequency is fed into the stator of the motor, and a quantity produced by
the alternating current or voltage is measured and used to determine the position
of the rotor; characterized in that, in the method, the vibration of the machine is measured as a function of the rotor
angle, and the position of the rotor (11) is determined by utilizing the said vibration.
2. A method according to claim 1, characterized in that the vibration is measured by means of a microphone or acceleration sensor attached
to the motor body and utilized to provide feedback.
3. A method according to claim 1, characterized in that, in the method, a minimum signal is found, whereupon it is possible e.g. to detect
the maximum torque angle.
4. A method according to claim 1, characterized in that, in the method, a maximum signal is found, whereupon it is possible e.g. to detect
the minimum torque angle and the maximum torque can be obtained with a 90° phase shift.
5. An apparatus for determining the position of the rotor (11) of a synchronous motor
(1) used as an elevator motor, comprising: supply means used to feed an alternating
current or voltage of a certain frequency into the motor, and a unit used to measure
a quantity produced by the alternating current or voltage fed in, characterized in that the apparatus comprises elements used to measure the vibration of the machine as
a function of the rotor angle, the said vibration being utilized to determine the
position of the rotor (11).
6. An apparatus according to claim 5, characterized in that the apparatus comprises a microphone (4) or an acceleration sensor fitted to the
motor body and used to produce feedback.
1. Verfahren zur Bestimmung der Position des Rotors (11) eines Synchronmotors (1), der
als Aufzugsmotor verwendet wird, bei welchem Verfahren dem Stator des Motors ein Wechselstrom
oder eine Spannung bestimmter Frequenz zugeführt wird, und eine Grö-ße, die durch
den Wechselstrom oder die Wechselspannung generiert wurde, gemessen und verwendet
wird, um die Position des Rotors zu bestimmen, dadurch gekennzeichnet, dass in dem Verfahren die Vibration der Maschine als Funktion des Rotorwinkels gemessen
wird, und die Position des Rotors (11) bestimmt wird durch Verwendung dieser Vibration.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass die Vibration gemessen wird mittels eines Mikrophons oder Beschleunigungssensors,
der an dem Motorkörper angebracht ist und verwendet wird, um ein Feedbacksignal bereitzustellen.
3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass in dem Verfahren ein Signalminimum gefunden wird, woraufhin es möglich ist, z.B.
den Winkel des maximalen Drehmoments zu bestimmen.
4. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass in dem Verfahren ein Signalmaximum gefunden wird, woraufhin es möglich ist, z.B.
den Winkel des minimalen Drehmoments zu bestimmen, und das maximale Drehmoment über
eine 90°-Phasenverschiebung erhalten werden kann.
5. Vorrichtung zur Bestimmung der Position des Rotors (11) eines Synchronmotors (1),
der als Aufzugsmotor verwendet wird, umfassend: Speiseeinrichtungen zur Zuführung
eines Wechselstroms oder einer Wechselspannung bestimmter Frequenz zu dem Motor, und
eine Einheit zum Messen einer Größe, die durch den/die zugeführten Wechselstrom oder
Wechselspannung hervorgerufen wurde, dadurch gekennzeichnet, dass die Vorrichtung Elemente umfasst, die verwendet werden, um die Vibration der Maschine
als Funktion des Rotorwinkels zu messen, wobei die Vibration verwendet wird, um die
Position des Rotors (11) zu bestimmen.
6. Vorrichtung nach Anspruch 5, dadurch gekennzeichnet, dass die Vorrichtung ein Mikrophon (4) oder einen Beschleunigungssensor umfasst, der an
dem Motorkörper angebracht ist und verwendet wird, um ein Feedbacksignal zu generieren.
1. Procédé permettant de déterminer la position du rotor (11) d'un moteur synchrone (1)
utilisé en tant que moteur d'ascenseur, dans lequel procédé : un courant ou une tension
alternatifs d'une certaine fréquence sont introduits dans le moteur, et une quantité
produite par le courant ou la tension alternatifs introduits est mesurée et utilisée
pour déterminer la position du rotor ;
caractérisé par le fait que, dans ce procédé, la vibration de la machine est mesurée en tant que fonction de
l'angle de rotor, et la position du rotor (11) est déterminée en utilisant ladite
vibration.
2. Procédé selon la revendication 1,
caractérisé par le fait que la vibration est mesurée au moyen d'un microphone ou d'un capteur d'accélération
reliés au corps du moteur et utilisée pour fournir un retour.
3. Procédé selon la revendication 1,
caractérisé par le fait que, dans ce procédé, un signal minimum est trouvé, après quoi il est possible par ex.
de détecter l'angle de couple maximum.
4. Procédé selon la revendication 1,
caractérisé par le fait que, dans ce procédé, un signal maximal est trouvé, après quoi il est possible par ex.
de détecter l'angle de couple minimum et le couple maximum peut être obtenu avec un
déphaseur 90°.
5. Appareil permettant de déterminer la position du rotor (11) d'un moteur synchrone
(1) utilisé en tant que moteur d'ascenseur, comportant : un moyen d'alimentation servant
à introduire un courant ou une tension alternatifs d'une certaine fréquence dans le
moteur, et une unité servant à mesurer une quantité produite par le courant ou la
tension alternatifs introduits,
caractérisé par le fait que l'appareil comporte des éléments servant à mesurer la vibration de la machine en
tant que fonction de l'angle de rotor, ladite vibration étant utilisée pour déterminer
la position du rotor (11).
6. Appareil selon la revendication 5,
caractérisé par le fait que l'appareil comporte un microphone (4) ou un capteur d'accélération montés sur le
corps du moteur et servant à produire un retour.

REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only.
It does not form part of the European patent document. Even though great care has
been taken in compiling the references, errors or omissions cannot be excluded and
the EPO disclaims all liability in this regard.
Patent documents cited in the description