CA2213202A1 - Drive having a three-phase asynchronous motor with slip ring rotor - Google Patents
Drive having a three-phase asynchronous motor with slip ring rotorInfo
- Publication number
- CA2213202A1 CA2213202A1 CA002213202A CA2213202A CA2213202A1 CA 2213202 A1 CA2213202 A1 CA 2213202A1 CA 002213202 A CA002213202 A CA 002213202A CA 2213202 A CA2213202 A CA 2213202A CA 2213202 A1 CA2213202 A1 CA 2213202A1
- Authority
- CA
- Canada
- Prior art keywords
- frequency
- motor
- rotor
- stator
- voltage
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
Links
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
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
- H02P25/24—Variable impedance in stator or rotor circuit
- H02P25/26—Variable impedance in stator or rotor circuit with arrangements for controlling secondary impedance
Abstract
In order to increase the power of a three-phase asynchronous motor (1) with a slip ring rotor (3) in a drive with a variable speed of rotation and to reduce the amount of equipment required for that purpose, the motor (1) is fed at the stator side by a frequency converter (5) that regulates the stator voltage or current (IS) and the stator frequency (fS) and at the rotor side by another frequency converter (I) that regulates the rotor voltage or current (IL) and the rotor frequency (fL). The frequency converters (5, 9) are controlled by a controller (12) so that the motor power is distributed to a predetermined extent between both frequency converters (5, 9) and that a predetermined speed of rotation of the motor results from the stator frequency (fS) and rotor frequency (fL). In order to operate the motor (1) with high voltages and the frequency converters (5, 9) with low voltages, transformers (4, 8) are arranged between the motor (1) and the frequency converters (5, 9). In order to keep small the transformers (4, 8), the stator frequency (fS) and the rotor frequency (fL) never fall below a predetermined minimum frequency. The speed of rotation of the motor may be nevertheless regulated over small values all the way down to its standstill.
Description
Description Drive having a three-phase asynchronous motor with slip ring rotor The invention relates to a drive having a three-phase asynchronous motor with slip ring rotor It is known in the case of variable-speed drives to feed three-phase asynchronous motors on the stator side via converters in the form of current-source con-verters, voltage-source converters or direct converters.
In this case, the stator voltage or the stator current and the stator frequency are controlled by means of the converter in order to set the motor speed. Thus, for example, DE 40 14 608 discloses using a slowly r~lnn;ng direct drive for rollers in draughting systems of sp;nn;ng machines, both the stator w;n~;ng and the rotor W; n~; ng being fed with an alternating voltage, the rotational speed of the motor resulting from the diffe-rence between the two alternating voltages. Drives for such sp;nn;ng machines are, however, small to medium motors. The drive disclosed in DE 40 14 608 therefore cannot be transferred directly for motors of high power since, in the case of a high motor power, the converter must be designed for a correspo~;ngly high power range, and is therefore complicated and expensive.
Furthermore, a cost effective solution of the drive requires that the voltage level of the converter and that of the motor are matched to one another. If the voltage levels of converter and motor differ, this can be adjusted via a transformer. However, this presupposes that, apart from tran~ition proces~e~, a ;n; fre-quency is not undershot at the output of the converter, with the result that motor speeds situated therebelow down to motor standstill cannot be set.
It is therefore the object of the invention to specify a drive, optimized with respect to the outlay on design and costs, having a three-phase asynchronous AMENDED SHEET
GR 95 P 3078 - la -motor, in particular for high motor power~. In accordance with the in~ention, the object in achieved by mean~ of the drive specified in Patent Claim 1.
AMENDED SHEET
CA 02213202 1997-08-1~
, Advantageous developments of the drive according to the invention are specified in the subclaims.
Owing to the fact that the motor is respectively fed via a converter both on the stator side and on the rotor side, it is possible to split up the motor power between the two converters, with the result that the latter can be respectively designed for a power range which is smaller by comparison with the motor power.
The motor speed is yielded from the difference between the stator frequency and the rotor frequency.
Consequently, low motor speeds down to motor standstill can be set without the stator frequency or the rotor frequency themselves having to be reduced as far as zero.
Given that the stator frequency and/or the rotor fre-quency are restricted to values above a minimum fre-quency, transformers of st~n~rd size can be arranged between the converters and the motor in order to trans-form ~the output voltages of the converters to higher values for the stator and rotor voltages. This, in turn, renders it possible to use cost-effective st~n~rd converters for low voltages.
For the purpose of expl~; n i ng the invention further, reference is made below to the figures of the drawing, in which Figure 1 shows a typical circuit for the drive according to the invention, and Figure 2 shows an example of an acceleration operation.
Figure 1 shows a three-phase asynchronous motor 1 having a stator 2 and a slip ring rotor 3 which, in the case of large variable-speed drives, is used for various applications, in particular in ba~ic industry, for example shaft hoi~ting equipment. Because of the high motor power required, the motor 1 is designed to be fed with medium voltage. To this end, the motor 1 is connec-ted on the stator side via a motor-side transformer 4, a converter 5 and a line-side transformer 6 to a three-phase medium-voltage system 7 having a voltage of, for example, 5 kV.
The line-side transformer 6 transforms this medium voltage into a low voltage of, for example, 690 volts, by which the converter 5 i8 operated. The motor-side output voltage of the converter 5 i8 transformed into the medium-voltage range again by means of the transformer 4.
On the side of the rotor 3, the motor 1 is likewise connected, via a further motor-side transformer 8, a further converter 9 and a further line-side trans-former 10, to a three-phase medium-voltage system 11, which can be identical to the three-phase system 7. The further line-side transformer 10 transforms the medium voltage into a low voltage by which the further converter 9 is operated. The motor-side output voltage of the further converter 9 i8 transformed by means of the transformer 8 into the voltage range required for the rotor feed, for example 1 kV. In the case of relatively low rotor voltages, the transformer 8 can also be elimin-ated and the rotor 3 can be connected directly to the converter 9.
The motor speed and the motor torque or the motor power are regulated as a function of a desired speed value n~ and a desired torque value M~ or a desired current value I~ representing the latter, the desired values being fed for this purpose to a control device 12.
On the basis of the desired values n~, M and I , the control device 12 controls the converter 5 such that the latter generates a stator voltage Us with a stator fre-quency fs for the motor 1 and sets a stator current Is thereby, and also controls the converter 9, with the result that the latter sets for the motor 1 a rotor voltage UL with a rotor frequency fL, and thereby sets a rotor current I~. The setting of the current~ Is and IL
and the frequencies fs and fL by the two converters 5 and 9 is split up in thi~ case by the control device 12 such that each of the two converters 5 and 9 supplies a pre-scribed compo~nt of the total motor power and that the desired motor speed is yielded from the difference between the stator frequency fs and the rotor frequency fL-CA 02213202 1997-08-1~
., In this process, the stator frequency f5 and the rotor frequency fL are set such that they do not under-shoot a minimum frequency of, for example, 5 ~z. The transformers 4 and 8 must thus transmit only currents and voltages above this minimum frequency, and can therefore be of correspon~;ngly small overall size. Leaving aside the ohmic voltage drops, the voltages required by the motor 1, and thus also the converted powers, are propor-tional to the respective frequencies.
At a motor power of, for example, 2000 kVA, up to 60% (1200 kVA) for example can be supplied via the stator-side converter 5, and up to 40% (800 kVA) can be supplied via the rotor-side converter 9.
Figure 2 show~ an example of how the stator voltage Us and stator frequency f5 as well as the rotor voltage UL and rotor frequency f~ are to be guided as a function of time t for an acceleration operation. The motor speed n is yielded in a proportional way from the difference between the stator frequency and rotor fre-quency fs ~ fL-The specified numerical values serve only toexplain the exemplary embodiment of the drive according to the invention, and thus represent only examples.
In this case, the stator voltage or the stator current and the stator frequency are controlled by means of the converter in order to set the motor speed. Thus, for example, DE 40 14 608 discloses using a slowly r~lnn;ng direct drive for rollers in draughting systems of sp;nn;ng machines, both the stator w;n~;ng and the rotor W; n~; ng being fed with an alternating voltage, the rotational speed of the motor resulting from the diffe-rence between the two alternating voltages. Drives for such sp;nn;ng machines are, however, small to medium motors. The drive disclosed in DE 40 14 608 therefore cannot be transferred directly for motors of high power since, in the case of a high motor power, the converter must be designed for a correspo~;ngly high power range, and is therefore complicated and expensive.
Furthermore, a cost effective solution of the drive requires that the voltage level of the converter and that of the motor are matched to one another. If the voltage levels of converter and motor differ, this can be adjusted via a transformer. However, this presupposes that, apart from tran~ition proces~e~, a ;n; fre-quency is not undershot at the output of the converter, with the result that motor speeds situated therebelow down to motor standstill cannot be set.
It is therefore the object of the invention to specify a drive, optimized with respect to the outlay on design and costs, having a three-phase asynchronous AMENDED SHEET
GR 95 P 3078 - la -motor, in particular for high motor power~. In accordance with the in~ention, the object in achieved by mean~ of the drive specified in Patent Claim 1.
AMENDED SHEET
CA 02213202 1997-08-1~
, Advantageous developments of the drive according to the invention are specified in the subclaims.
Owing to the fact that the motor is respectively fed via a converter both on the stator side and on the rotor side, it is possible to split up the motor power between the two converters, with the result that the latter can be respectively designed for a power range which is smaller by comparison with the motor power.
The motor speed is yielded from the difference between the stator frequency and the rotor frequency.
Consequently, low motor speeds down to motor standstill can be set without the stator frequency or the rotor frequency themselves having to be reduced as far as zero.
Given that the stator frequency and/or the rotor fre-quency are restricted to values above a minimum fre-quency, transformers of st~n~rd size can be arranged between the converters and the motor in order to trans-form ~the output voltages of the converters to higher values for the stator and rotor voltages. This, in turn, renders it possible to use cost-effective st~n~rd converters for low voltages.
For the purpose of expl~; n i ng the invention further, reference is made below to the figures of the drawing, in which Figure 1 shows a typical circuit for the drive according to the invention, and Figure 2 shows an example of an acceleration operation.
Figure 1 shows a three-phase asynchronous motor 1 having a stator 2 and a slip ring rotor 3 which, in the case of large variable-speed drives, is used for various applications, in particular in ba~ic industry, for example shaft hoi~ting equipment. Because of the high motor power required, the motor 1 is designed to be fed with medium voltage. To this end, the motor 1 is connec-ted on the stator side via a motor-side transformer 4, a converter 5 and a line-side transformer 6 to a three-phase medium-voltage system 7 having a voltage of, for example, 5 kV.
The line-side transformer 6 transforms this medium voltage into a low voltage of, for example, 690 volts, by which the converter 5 i8 operated. The motor-side output voltage of the converter 5 i8 transformed into the medium-voltage range again by means of the transformer 4.
On the side of the rotor 3, the motor 1 is likewise connected, via a further motor-side transformer 8, a further converter 9 and a further line-side trans-former 10, to a three-phase medium-voltage system 11, which can be identical to the three-phase system 7. The further line-side transformer 10 transforms the medium voltage into a low voltage by which the further converter 9 is operated. The motor-side output voltage of the further converter 9 i8 transformed by means of the transformer 8 into the voltage range required for the rotor feed, for example 1 kV. In the case of relatively low rotor voltages, the transformer 8 can also be elimin-ated and the rotor 3 can be connected directly to the converter 9.
The motor speed and the motor torque or the motor power are regulated as a function of a desired speed value n~ and a desired torque value M~ or a desired current value I~ representing the latter, the desired values being fed for this purpose to a control device 12.
On the basis of the desired values n~, M and I , the control device 12 controls the converter 5 such that the latter generates a stator voltage Us with a stator fre-quency fs for the motor 1 and sets a stator current Is thereby, and also controls the converter 9, with the result that the latter sets for the motor 1 a rotor voltage UL with a rotor frequency fL, and thereby sets a rotor current I~. The setting of the current~ Is and IL
and the frequencies fs and fL by the two converters 5 and 9 is split up in thi~ case by the control device 12 such that each of the two converters 5 and 9 supplies a pre-scribed compo~nt of the total motor power and that the desired motor speed is yielded from the difference between the stator frequency fs and the rotor frequency fL-CA 02213202 1997-08-1~
., In this process, the stator frequency f5 and the rotor frequency fL are set such that they do not under-shoot a minimum frequency of, for example, 5 ~z. The transformers 4 and 8 must thus transmit only currents and voltages above this minimum frequency, and can therefore be of correspon~;ngly small overall size. Leaving aside the ohmic voltage drops, the voltages required by the motor 1, and thus also the converted powers, are propor-tional to the respective frequencies.
At a motor power of, for example, 2000 kVA, up to 60% (1200 kVA) for example can be supplied via the stator-side converter 5, and up to 40% (800 kVA) can be supplied via the rotor-side converter 9.
Figure 2 show~ an example of how the stator voltage Us and stator frequency f5 as well as the rotor voltage UL and rotor frequency f~ are to be guided as a function of time t for an acceleration operation. The motor speed n is yielded in a proportional way from the difference between the stator frequency and rotor fre-quency fs ~ fL-The specified numerical values serve only toexplain the exemplary embodiment of the drive according to the invention, and thus represent only examples.
Claims (7)
- Claim 1 1. Drive having a three-phase asynchronous motor (1) fed with medium voltage with slip ring rotor (3) for use in hoisting equipment, for example shaft hoisting equipment, which is connected on the stator side to a three-phase system (7) via a converter (5) for setting the stator voltage or the stator current (Is) and the stator frequency (fs), and is connected on the rotor side to a three-phase system (11) via a further converter (9) for setting the rotor voltage or the rotor current (IL) and the rotor frequency (fL), and having a control device (12) which controls the two converters (5, 9) in such a way that the motor power is split up to a predetermined extent between the two converters (5, 9) and that the motor speed results from the difference between the stator frequency (fs) and the rotor frequency (fL), both the stator frequency (fs) and the rotor frequency (fL) being kept above a minimum frequency, and the motor standstill being reached by equating the stator frequency (fs) and the rotor frequency (fL).
Claims - 2. Drive according to Claim 1, characterized in that the minimum frequency, which is undershot by neither the stator frequency (fs) nor the rotor frequency (fL), is 5 Hz.
- 3. Drive according to Claim 1 or 2, characterized in that a motor-side transformer (4) is connected between the stator-side converter (5) and the motor (1).
- 4. Drive according to Claim 3, characterized in that the stator-side converter (5) is connected to the three-phase system (7) via a line-side transformer (6).
- 5. Drive according to one of the preceding claims, characterized in that a further motor-side transformer (8) is connected between the further converter (9) and the motor (1).
- 6. Drive according to Claim 5, characterized in that the further converter (9) is connected to the three-phase system (11) via a further line-side transformer (10).
- 7. Drive according to one of Claims 3 to 6, characterized in that the motor (1) is a medium-voltage motor and the converters (5, 9) are low-voltage converters.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19506006A DE19506006A1 (en) | 1995-02-17 | 1995-02-17 | Drive with a three-phase asynchronous motor with slip ring rotor |
| DE19506006.7 | 1995-02-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2213202A1 true CA2213202A1 (en) | 1996-08-22 |
Family
ID=7754654
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002213202A Abandoned CA2213202A1 (en) | 1995-02-17 | 1996-02-06 | Drive having a three-phase asynchronous motor with slip ring rotor |
Country Status (6)
| Country | Link |
|---|---|
| CN (1) | CN1167548A (en) |
| CA (1) | CA2213202A1 (en) |
| DE (1) | DE19506006A1 (en) |
| PL (1) | PL321676A1 (en) |
| WO (1) | WO1996025787A1 (en) |
| ZA (1) | ZA961199B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19913624C2 (en) * | 1999-03-25 | 2001-12-13 | Siemens Ag | Method and device for avoiding stationary operation of an encoder-free, field-oriented induction machine within an impermissible stator frequency range |
| FI115012B (en) * | 2003-03-06 | 2005-02-15 | Abb Oy | Procedure and arrangement in connection with a grinding machine |
| CN102136687A (en) * | 2011-01-14 | 2011-07-27 | 唐山斯托德电气设备有限公司 | High-low-high power transmission and distribution box type switchgear |
| EP2571160A1 (en) * | 2011-09-16 | 2013-03-20 | Siemens Aktiengesellschaft | Drive system for high voltage AC motor |
| EP2617483B1 (en) | 2012-01-23 | 2015-07-15 | Siemens Aktiengesellschaft | Method for operating a stirrer and use of a device for carrying out the method |
| DE102013004191A1 (en) * | 2012-09-26 | 2014-03-27 | Sew-Eurodrive Gmbh & Co Kg | Method for operating an electric machine |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2150531A1 (en) * | 1971-10-06 | 1973-04-12 | Licentia Gmbh | METHOD FOR CONTROLLING THE SPEED OF A SLIP RING BELT AND ARRANGEMENT FOR CARRYING OUT THE METHOD |
| JPS5330718A (en) * | 1976-09-03 | 1978-03-23 | Hitachi Ltd | Controller for motor |
| JPS54158629A (en) * | 1978-06-05 | 1979-12-14 | Hitachi Ltd | Controlling device of thyristor motor |
| JPS5566296A (en) * | 1978-11-09 | 1980-05-19 | Toshiba Corp | Control circuit for dental clinic motor |
| JPS5940383B2 (en) * | 1979-02-26 | 1984-09-29 | 高砂香料工業株式会社 | Method for producing brassylic acid diester |
| DE3142185C2 (en) * | 1981-10-22 | 1985-08-22 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Circuit arrangement for the operation of three-phase machines of higher voltage with variable speed by means of an intermediate circuit converter adapted via transformers |
| JPS62181698A (en) * | 1986-02-05 | 1987-08-10 | Kansai Electric Power Co Inc:The | Controlling device for variable-speed generating system |
| JPS62131793A (en) * | 1985-11-22 | 1987-06-15 | Mitsubishi Electric Corp | Motor controller for elevator |
| DE4014608C1 (en) * | 1990-05-07 | 1991-11-14 | Zinser Textilmaschinen Gmbh, 7333 Ebersbach, De | Slow running direct drive for spinning machine - incorporates multiphase slip-ring rotor engine where stator coils have 1st frequency converter and rotor coils have 2nd frequency converter |
| JPH0731192A (en) * | 1993-07-09 | 1995-01-31 | Hitachi Ltd | Controller and control method for variable speed drive system |
| DE4324306A1 (en) * | 1993-07-20 | 1995-01-26 | Boehringer Andreas | Method and circuit arrangement for operating a convertor motor which is excited by a rotating field |
-
1995
- 1995-02-17 DE DE19506006A patent/DE19506006A1/en not_active Withdrawn
-
1996
- 1996-02-06 PL PL96321676A patent/PL321676A1/en unknown
- 1996-02-06 CA CA002213202A patent/CA2213202A1/en not_active Abandoned
- 1996-02-06 WO PCT/DE1996/000180 patent/WO1996025787A1/en active Search and Examination
- 1996-02-06 CN CN96191342A patent/CN1167548A/en active Pending
- 1996-02-15 ZA ZA961199A patent/ZA961199B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO1996025787A1 (en) | 1996-08-22 |
| ZA961199B (en) | 1996-07-29 |
| DE19506006A1 (en) | 1996-08-29 |
| PL321676A1 (en) | 1997-12-22 |
| CN1167548A (en) | 1997-12-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |