WO2014209127A1 - Method and system for starting electrical machines - Google Patents
Method and system for starting electrical machines Download PDFInfo
- Publication number
- WO2014209127A1 WO2014209127A1 PCT/NO2014/050108 NO2014050108W WO2014209127A1 WO 2014209127 A1 WO2014209127 A1 WO 2014209127A1 NO 2014050108 W NO2014050108 W NO 2014050108W WO 2014209127 A1 WO2014209127 A1 WO 2014209127A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- transformer
- electrical machine
- machine
- power source
- starting
- Prior art date
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
- H02P1/00—Arrangements for starting electric motors or dynamo-electric converters
- H02P1/16—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters
Definitions
- the present invention relates to a method for starting electrical machines driven from a power source via one or more transformers between the electrical machine and the power source, according to the preamble of claim 1.
- the present invention also relates to a system for starting electrical machines driven from a power source via one or more transformers between the electrical machine and the power source, according to the preamble of claim 13.
- the typical solution is to use transformers for stepping up the voltage for transmission over the long cable and then stepping it down nea r the electrica l mach ine to match its voltage rating. Similar systems are described in, for example, W09318566A1 or in WO2013039404A1. If voltage rating of the converter is lower than that of electrical machine there can be used only step-up transformer. In such a case transmission voltage is the same as the machine voltage.
- the long step-out systems with at least one transformer between the converter and the machine has a ma in challenge during sta rt-up, when low frequency and low voltage is formed by the frequency converter for the electrical machine, - the challenge is conversion of power at very low frequencies ( ⁇ 0...2 Hz) in the transformer which may cause saturation in the transformer.
- ⁇ 0...2 Hz very low frequencies
- induction motors can be started from frequencies of 1.5 Hz or even higher.
- the transformer can have double size compared to the one designed for rated frequency.
- the requirement to apply very low frequency ( ⁇ 0...1 Hz) is especially important when starting permanent magnet synchronous machines. If starting at higher frequencies the machine may not catch up the rotating magnetic field. Transformer for such system would be especially large - several times larger than the one designed for rated frequency.
- WO 2007/058782 and WO 2008/130411 describe bypass solutions for soft starters.
- transformer size may be reasonable, though larger than the one designed for the rated frequency.
- transformer size may be unacceptably large.
- the main object of present invention is to solve the problem of prior art for the systems with transformers between power source and electrical machine and ensure reliable start and control of electrical machines without oversizing the transformers.
- Another object is to solve the problem of prior art for the systems with long step-outs, i.e. long cables and at least one transformer between power source and electrical machine.
- Final object is to enable reliable start and control of permanent magnet machines in the systems with at least one transformer between power source and permanent magnet machine.
- a system for ensuring reliable start and control of electrical machines driven through transformers without oversizing the transformer according to the present invention is described in claim 13. Preferable features of the system are described in the claims 14-23.
- the present invention is related to starting electrical machines (motors) driven from frequency converters via long cables and where transformers are arranged between the electrical machines and a power source.
- the present invention it is proposed to by-pass at least one of the transformers during start-up of the electrical machine. Without transformer between the power source (e.g. frequency converter) and the electrical machine it is possible to transfer power at very low frequencies or even at DC.
- Starting an AC machine (motor) requires both low frequency (usually 0-10 % of rated frequency) and low voltage (usually 0-20 % of rated voltage), therefore, voltage rating of the power source will be enough and stepping the voltage up with the help of the transformer is not necessary.
- the transformer can be connected again to provide higher voltage.
- the transformer can be pre-magnetized before connecting it to limit rush -in current.
- step-up and step-down transformers are by-passed during start up.
- step-up or step-down transformer is by-passed during start up.
- subsea transformer should be oversized to ensure start-up without by-passing. In such a case only step-up transformer can be by-passed at start-up.
- the by-pass is achieved by means of a by-pass arrangement including a by-pass circuit and switches, e.g. three switches, where e.g. one switch is arranged in the by-pass circuit and one switch is arranged at each side of the transformer in a power line of a system. By means of the switches the transformer can be connected or by-passed as desired.
- a by-pass arrangement including a by-pass circuit and switches, e.g. three switches, where e.g. one switch is arranged in the by-pass circuit and one switch is arranged at each side of the transformer in a power line of a system.
- the switches of the by-pass arrangement are controlled by a control unit provided with means and/or software for this.
- the control unit can be an integral part of the frequency converter or can be a separate unit. Further preferable features and advantageous details of the present invention will appear from the following example description.
- Figure 1 shows a torque curve of subsea pump-motor unit
- Figure 2 shows a prior art system with one step-up transformer
- Figure 3 shows a prior art system with two transformers; step-up and step-down,
- Figure 4 shows a first embodiment of a system according to the present invention
- Figure 5 shows a second embodiment of a system according to the present invention.
- Figure 6 shows a third embodiment of a system according to the present invention.
- FIG. 1 shows a torque curve of subsea pump-motor unit.
- stiction torque ST is quite high at start-up, while main torque curve MT is "quadratic", i.e. torque is proportional to speed squared.
- FIG. 2 shows a prior art system with one step-up transformer 14.
- the system contains main switch 17, grid side transformer 16 with three windings, power source 15 in the form of a static frequency converter, cable 13, as well as an electrical machine (motor) 12 and a driven mechanism 11.
- the system with only one transformer 14 (step-up) can be used when voltage rating of the frequency converter 15 is lower than voltage rating of the electrical machine 12 and at the same time transmission distance is not long, usually below 5 km.
- FIG. 3 shows a prior art system with two transformers; step-up 14 and step-down 18.
- the system with two transformers is used, for example, when distance between the power source and the driven mechanism is long, usually over 5-10 km. Then power transmission should be done at high voltage to minimize losses.
- FIG. 4 shows a system according to a first embodiment of the present invention provided with a by-pass arrangement for by-passing the step-up transformer 14 of the system in Figure 2 in the operation of starting the electrical motor 12.
- the by-pass arrangement according to an embodiment of the present invention includes three switches 19, 20 and 21, wherein switches 20 and 21 are arranged on each side of the step-up-transformer 14, respectively, and the third switch 19 is arranged in a by-pass circuit 30.
- the switches 19-21 can be "mechanical", "solid state” or of other suitable types. Example of starting of the electrical machine 12 is described in the table below.
- phase angle shift When switching to normal run (connecting the transformer 14) it is important to have the same voltage phase angle at both sides of the transformer 14.
- a preferable way to ensure this is by using a transformer without phase shift (e.g. YyO, DdO), i.e. use a transformer that has a vector group without phase shift.
- Another way is to change phase angle of the voltage at the moment of switching with the help of the frequency converter 15. The phase angle shift should take place at the moment of switching the transformer 14 between the power source 15 and the electrical machine 12.
- the transient processes (oscillations etc.) due to the switching can affect stability of operation of the electrical machine 12. This is especially relevant for permanent magnet synchronous machines (PMSM), which can fall out of synchronism.
- PMSM permanent magnet synchronous machines
- a damper winding (not shown) can be arranged at a rotor of the PMSM.
- Figure 5 shows a system according to a second embodiment of the present invention provided with a by-pass arrangement for both step-up 14 and step-down 18 transformers for the system in Figure 3 in the operation of starting the electric motor 12.
- the by-pass arrangement in this embodiment consists of six switches 19-24, i.e. two times the by-pass
- FIG. 6 shows a system according to a third embodiment of the present invention provided with by-pass arrangement for both step-up 14 and step-down 18 transformers, used for starting subsea rotary frequency converter, comprising several electrical machines (motors) 12 connected in parallel driving subsea pumps or compressors 11.
- the electrical machine 12 can in other embodiments be part of a cascade, i.e. there can be other electrical machines between the electrical machine 12 and the driven equipment 11.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Motor And Converter Starters (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
- Control Of Multiple Motors (AREA)
Abstract
Method and system for starting an electrical machine (12) driven by a power source (15) via at least one transformer (14, 18) between the power source (15) and the electrical machine (12), which electrical machine (12) is arranged to a driven mechanism (11), which includes by-passing the at least one transformer (14, 18) when starting the electrical machine (12) by means of a by-pass arrangement.
Description
METHOD AND SYSTEM FOR STARTING ELECTRICAL MACHINES
The present invention relates to a method for starting electrical machines driven from a power source via one or more transformers between the electrical machine and the power source, according to the preamble of claim 1.
The present invention also relates to a system for starting electrical machines driven from a power source via one or more transformers between the electrical machine and the power source, according to the preamble of claim 13. Background
In many applications, e.g. in subsea oil and gas processing, electrical machines a re d riven from power sources located at a considerable distance from the driven equipment and the machines - such systems are often called "systems with long step-outs". In the long step-out systems, high voltage (for example 20-30 kV) is preferable for transmitting the power between the source and the machine with low losses. At the same time, the power source often includes static frequency converters, to control speed of the d riven electrical machines, and such converters have limited voltage ratings (in most cases 0.4-11 kV). Also insulation design of the electrical machines is often limited to the level of 11 kV. Thus, the voltage ratings of the static frequency converter and the driven machine are considerably lower than the desirable transmission voltage. The typical solution is to use transformers for stepping up the voltage for transmission over the long cable and then stepping it down nea r the electrica l mach ine to match its voltage rating. Similar systems are described in, for example, W09318566A1 or in WO2013039404A1. If voltage rating of the converter is lower than that of electrical machine there can be used only step-up transformer. In such a case transmission voltage is the same as the machine voltage.
The long step-out systems with at least one transformer between the converter and the machine has a ma in challenge during sta rt-up, when low frequency and low voltage is formed by the frequency converter for the electrical machine, - the challenge is conversion of power at very low frequencies (≡ 0...2 Hz) in the transformer which may cause saturation in the transformer. To prevent this transformers have in some cases been oversized. The lower the frequency is, the la rger the transformer must be.
Usually induction motors can be started from frequencies of 1.5 Hz or even higher. For such frequency the transformer can have double size compared to the one designed for rated frequency.
The requirement to apply very low frequency (≡ 0...1 Hz) is especially important when starting permanent magnet synchronous machines. If starting at higher frequencies the machine may not catch up the rotating magnetic field. Transformer for such system would be especially large - several times larger than the one designed for rated frequency.
Some loads require high torque right at the start-up - at low frequency. For example, in subsea pumps there is so-called "stiction torque" (see Figure 1.) which must be overcome at start-up. That means that enough current should be provided for the machine at start-up, which in turn means there should be enough voltage at the transformer secondary winding, i.e. the transformer should not be saturated.
WO 2007/058782 and WO 2008/130411 describe bypass solutions for soft starters.
To summarize, start-up of an electrical machine via transformer at very low frequency requires oversizing the transformer. In the case of starting an induction machine, transformer size may be reasonable, though larger than the one designed for the rated frequency. In the case of starting permanent magnet machine transformer size may be unacceptably large.
Object
The main object of present invention is to solve the problem of prior art for the systems with transformers between power source and electrical machine and ensure reliable start and control of electrical machines without oversizing the transformers.
Another object is to solve the problem of prior art for the systems with long step-outs, i.e. long cables and at least one transformer between power source and electrical machine.
Final object is to enable reliable start and control of permanent magnet machines in the systems with at least one transformer between power source and permanent magnet machine. The invention
A method for ensuring reliable start and control of electrical machines driven through transformers without oversizing the transformer according to the present invention is described in claim 1. Preferable features of the method are described in the claims 2-12.
A system for ensuring reliable start and control of electrical machines driven through transformers without oversizing the transformer according to the present invention is described in claim 13. Preferable features of the system are described in the claims 14-23.
The present invention is related to starting electrical machines (motors) driven from frequency converters via long cables and where transformers are arranged between the electrical machines and a power source.
In the present invention it is proposed to by-pass at least one of the transformers during start-up of the electrical machine. Without transformer between the power source (e.g. frequency converter) and the electrical machine it is possible to transfer power at very low frequencies or even at DC. Starting an AC machine (motor) requires both low frequency (usually 0-10 % of rated frequency) and low voltage (usually 0-20 % of rated voltage), therefore, voltage rating of the power source will be enough and stepping the voltage up with the help of the transformer is not necessary. According to the present invention, after the successful start-up, when the electrical machine has started rotating (or started moving in linear machine case) and the frequency is high enough, i.e. stiction torque is overcome (this can be seen by considerable load reduction on the power source), the transformer can be connected again to provide higher voltage. The transformer can be pre-magnetized before connecting it to limit rush -in current.
According to an embodiment of the present invention both step-up and step-down transformers are by-passed during start up.
According to another embodiment of the present invention only the step-up or step-down transformer is by-passed during start up. For example, if it is desirable to avoid using subsea switchgear then subsea transformer should be oversized to ensure start-up without by-passing. In such a case only step-up transformer can be by-passed at start-up.
It can be also an advantage to warm up the electrical machine before starting it by supplying the machine with current of very low frequency (e.g. below 1 Hz), pulsing current or direct current (DC). It is possible when there is no transformer between the power source and the electrical machine, i.e. when the transformer is by-passed.
The by-pass is achieved by means of a by-pass arrangement including a by-pass circuit and switches, e.g. three switches, where e.g. one switch is arranged in the by-pass circuit and one switch is arranged at each side of the transformer in a power line of a system. By means of the switches the transformer can be connected or by-passed as desired.
The switches of the by-pass arrangement are controlled by a control unit provided with means and/or software for this. The control unit can be an integral part of the frequency converter or can be a separate unit.
Further preferable features and advantageous details of the present invention will appear from the following example description.
Example
The present invention will below be described in further detail with references to the attached drawings, where:
Figure 1 shows a torque curve of subsea pump-motor unit,
Figure 2 shows a prior art system with one step-up transformer,
Figure 3 shows a prior art system with two transformers; step-up and step-down,
Figure 4 shows a first embodiment of a system according to the present invention,
Figure 5 shows a second embodiment of a system according to the present invention, and
Figure 6 shows a third embodiment of a system according to the present invention.
Reference is now made to Figure 1 which shows a torque curve of subsea pump-motor unit. As the figure shows, stiction torque ST is quite high at start-up, while main torque curve MT is "quadratic", i.e. torque is proportional to speed squared.
Reference is now made to Figure 2 which shows a prior art system with one step-up transformer 14. The system contains main switch 17, grid side transformer 16 with three windings, power source 15 in the form of a static frequency converter, cable 13, as well as an electrical machine (motor) 12 and a driven mechanism 11. The system with only one transformer 14 (step-up) can be used when voltage rating of the frequency converter 15 is lower than voltage rating of the electrical machine 12 and at the same time transmission distance is not long, usually below 5 km.
Reference is now made to Figure 3 which shows a prior art system with two transformers; step-up 14 and step-down 18. The system with two transformers is used, for example, when distance between the power source and the driven mechanism is long, usually over 5-10 km. Then power transmission should be done at high voltage to minimize losses.
Reference is now made to Figure 4 which shows a system according to a first embodiment of the present invention provided with a by-pass arrangement for by-passing the step-up transformer 14 of the system in Figure 2 in the operation of starting the electrical motor 12. The by-pass arrangement according to an embodiment of the present invention includes three switches 19, 20 and 21, wherein switches 20 and 21 are arranged on each side of the step-up-transformer 14, respectively, and the third switch 19 is arranged in a by-pass circuit 30. The switches 19-21 can be "mechanical", "solid
state" or of other suitable types. Example of starting of the electrical machine 12 is described in the table below.
Table 1. Switching states at start (variant).
When switching to normal run (connecting the transformer 14) it is important to have the same voltage phase angle at both sides of the transformer 14. A preferable way to ensure this is by using a transformer without phase shift (e.g. YyO, DdO), i.e. use a transformer that has a vector group without phase shift. Another way is to change phase angle of the voltage at the moment of switching with the help of the frequency converter 15. The phase angle shift should take place at the moment of switching the transformer 14 between the power source 15 and the electrical machine 12.
The transient processes (oscillations etc.) due to the switching can affect stability of operation of the electrical machine 12. This is especially relevant for permanent magnet synchronous machines (PMSM), which can fall out of synchronism. To ensure stable operation a damper winding (not shown) can be arranged at a rotor of the PMSM.
Reference is now made to Figure 5 which shows a system according to a second embodiment of the present invention provided with a by-pass arrangement for both step-up 14 and step-down 18 transformers for the system in Figure 3 in the operation of starting the electric motor 12. The by-pass arrangement in this embodiment consists of six switches 19-24, i.e. two times the by-pass
arrangement 30 in Figure 4, one associated with each transformer 14 and 18, respectively. In the case of subsea application, the transformer 18 as well as the switches 22-24 will need to have subsea design.
It will be an advantage to use transformers without phase shift or to have phase shifts compensating each other (e.g. step-up transformer Yy6 and step-down transformer Yy6 as well). Example of starting is described in the table below.
Table 2. Switching states at start (variant).
Reference is now made to Figure 6 which shows a system according to a third embodiment of the present invention provided with by-pass arrangement for both step-up 14 and step-down 18 transformers, used for starting subsea rotary frequency converter, comprising several electrical machines (motors) 12 connected in parallel driving subsea pumps or compressors 11.
The electrical machine 12 can in other embodiments be part of a cascade, i.e. there can be other electrical machines between the electrical machine 12 and the driven equipment 11.
Other similar embodiments of the system should be apparent to a person skilled in the art.
List of numerals:
11. Driven mechanism (pump, compressor, etc.)
12. Electric machine (motor)
13. Cable
14. Step-up transformer
15. Frequency converter
16. Grid side transformer
17. Main switch
18. Step-down transformer
19. Switch by-passing step-up transformer
20. Switch 1 connecting step-up transformer
21. Switch 2 connecting step-up transformer
22. Switch by-passing step-down transformer
23. Switch 1 connecting step-down transformer
24. Switch 2 connecting step-down transformer 30. by-pass circuit
Claims
1. Method for starting an electrical machine (12) driven by a power source (15) via at least one
transformer (14, 18) between the power source (15) and the electrica l machine (12), wh ich electrical machine (12) is arranged to a driven mechanism (11), characterized by by-passing the at least one transformer (14, 18) when starting the electrical machine (12) by means of a by-pass a rrangement.
2. Method according to claim 1, characterized by using a by-pass arrangement including a by-pass circuit (30) and switches (19-24) for by-passing the at least one transformer (14, 18).
3. Method accord ing to claim 1, characterized by by-passing only step-up (14) or step-down (18) transformer(s) during start up.
4. Method according to claim 1, characterized by by-passing both step-up (14) and step-down (18) transformers during start up.
5. Method according to any one of the cla ims 1-4, characterized by removing the by-pass of the at least one transformer (14, 18) when the electrical machine (12) has started rotating or moving, and stiction torque is overcome.
6. Method according to claim 5, characterized by pre-magnetizing the at least one transformer (14, 18) before connecting it.
7. Method according to any one of the cla ims 1-6, characterized by using a frequency converter as the power source (15) and using the frequency converter (15) to change phase angle of voltage at the moment of removing the by-pass.
8. Method according to claim 1, characterized by using an AC machine as the electrica l machine (12).
9. Method according to claim 8, characterized by using a permanent magnet synchronous machine as the electrical machine (12).
10. Method according to claim 9, characterized by providing the permanent magnet synchronous machine (12) with a damper winding at a rotor thereof.
11. Method according to any one of the claims 1-10, characterized by warming up the electrical machine (12) before starting up by supplying the electrical machine (12) with a very low frequency current or direct current.
12. Method according to claim 1, characterized by using transformers (14, 18) having a vector group without phase shift.
13. System for starting an electrical machine (12) driven by a power source (15) via at least one
transformer (14, 18) between the power source (15) and the electrical machine (12), which electrical machine (12) is arranged to a driven mechanism (11), characterized in that a by-pass arrangement is arranged in connection with the at least one transformer (14, 18) for by-passing the at least one transformer (14, 18) when starting the electrical machine (12).
14. System according to claim 13, characterized in that the by-pass arrangement includes a by-pass circuit (30) and switches (19-24).
15. System according to claim 13, characterized in that the power source (15) is a frequency
converter.
16. System according to claim 13, characterized in that the electrical motor (12) is an AC machine.
17. System according to claim 16, characterized in that the electrical machine (12) is a permanent magnet synchronous machine.
18. System according to claim 17, characterized in that a rotor of the permanent magnet synchronous machine (12) is provided with a damper winding.
19. System according to claim 13, characterized in that the transformer (14, 18) has a vector group without phase shift.
20. System according to claim 13, characterized in that electrical machine (12) is a part of a cascade.
21. System according to claim 13, characterized in that several electrical machines (12) are connected in parallel to same cable (13).
22. System according to claims 14-21, characterized in that the system includes a control unit
provided with means and/or software for controlling the switches (19-24) of the by-pass arrangement when starting the electrical machine (12).
23. System according to claim 22, characterized in that the control unit is provided with means and/or software for controlling the electrical machine (12) by supplying very low frequency current or DC current to the electrical machine (12) for warming up the electrical machine (12).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20130874 | 2013-06-24 | ||
| NO20130874A NO335419B1 (en) | 2013-06-24 | 2013-06-24 | Method and system for starting electric machines. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2014209127A1 true WO2014209127A1 (en) | 2014-12-31 |
Family
ID=52142333
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/NO2014/050108 WO2014209127A1 (en) | 2013-06-24 | 2014-06-19 | Method and system for starting electrical machines |
Country Status (2)
| Country | Link |
|---|---|
| NO (1) | NO335419B1 (en) |
| WO (1) | WO2014209127A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107947186A (en) * | 2017-11-23 | 2018-04-20 | 国网江苏省电力有限公司检修分公司 | D.C. high voltage transmission inverter side accesses the startup control method of synchronous capacitor |
| US10256762B2 (en) | 2017-06-27 | 2019-04-09 | General Electric Company | Systems and methods for active damping of a motor |
| US10263561B2 (en) | 2016-09-30 | 2019-04-16 | General Electric Company | Backspin management for electric submersible pump |
| US10778124B2 (en) | 2017-02-24 | 2020-09-15 | General Electric Company | Integrated monitoring of an electric motor assembly |
| US11773857B2 (en) | 2018-10-12 | 2023-10-03 | Baker Hughes Holdings Llc | Dual ESP with selectable pumps |
| WO2024031857A1 (en) * | 2022-08-10 | 2024-02-15 | 国电南瑞科技股份有限公司 | Control method and system for output transformer of thyristor current source-type static frequency converter |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5716585A (en) * | 1980-07-03 | 1982-01-28 | Shinko Electric Co Ltd | Operating method for motor by inverter |
| DE3150920A1 (en) * | 1981-12-18 | 1983-06-30 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Circuit arrangement for speed control of three-phase motors |
| NO20111233A1 (en) * | 2011-09-12 | 2013-03-13 | Aker Subsea As | Underwater rotating device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100452634C (en) * | 2005-11-11 | 2009-01-14 | 艾默生电气公司 | A soft starter for single-phase motor and single-phase motor with same |
| WO2008130411A1 (en) * | 2007-04-22 | 2008-10-30 | Williams Kevin R | Laser diode triggered soft start controller for a polyphase electric motor |
-
2013
- 2013-06-24 NO NO20130874A patent/NO335419B1/en unknown
-
2014
- 2014-06-19 WO PCT/NO2014/050108 patent/WO2014209127A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5716585A (en) * | 1980-07-03 | 1982-01-28 | Shinko Electric Co Ltd | Operating method for motor by inverter |
| DE3150920A1 (en) * | 1981-12-18 | 1983-06-30 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Circuit arrangement for speed control of three-phase motors |
| NO20111233A1 (en) * | 2011-09-12 | 2013-03-13 | Aker Subsea As | Underwater rotating device |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10263561B2 (en) | 2016-09-30 | 2019-04-16 | General Electric Company | Backspin management for electric submersible pump |
| US10778124B2 (en) | 2017-02-24 | 2020-09-15 | General Electric Company | Integrated monitoring of an electric motor assembly |
| US10256762B2 (en) | 2017-06-27 | 2019-04-09 | General Electric Company | Systems and methods for active damping of a motor |
| CN107947186A (en) * | 2017-11-23 | 2018-04-20 | 国网江苏省电力有限公司检修分公司 | D.C. high voltage transmission inverter side accesses the startup control method of synchronous capacitor |
| CN107947186B (en) * | 2017-11-23 | 2021-06-18 | 国网江苏省电力有限公司检修分公司 | Starting control method for accessing high-voltage direct-current transmission inversion side to synchronous phase modulator |
| US11773857B2 (en) | 2018-10-12 | 2023-10-03 | Baker Hughes Holdings Llc | Dual ESP with selectable pumps |
| WO2024031857A1 (en) * | 2022-08-10 | 2024-02-15 | 国电南瑞科技股份有限公司 | Control method and system for output transformer of thyristor current source-type static frequency converter |
Also Published As
| Publication number | Publication date |
|---|---|
| NO20130874A1 (en) | 2014-12-15 |
| NO335419B1 (en) | 2014-12-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2014209127A1 (en) | Method and system for starting electrical machines | |
| US6504261B2 (en) | Synchronous generator having auxiliary power windings and variable frequency power source and method for use | |
| EP3261248A1 (en) | Permanent magnet three-phase duplex motor and electric power steering device | |
| WO2006035194A3 (en) | Staged motor starting and wye/delta switching | |
| JP2009185816A (en) | High frequency electrically driven device with multipolar motor for gas pipeline and storage compression use | |
| WO2010022389A1 (en) | Multiple voltage generator and voltage regulation methodology for power dense integrated power systems | |
| WO2012140495A2 (en) | Integrated motor and generator | |
| RU2315413C2 (en) | Power matching system for turbine motor-generator (modifications) and methods for control of motor-generator | |
| KR20220167319A (en) | Mobile hybrid power system | |
| KR101237123B1 (en) | Single external feeding induction machine and controlling method thereof | |
| US20200295680A1 (en) | Position-sensorless control method and device for long-cable drive permanent magnet motor | |
| CN104795917B (en) | A kind of polyphase machine winding mechanism | |
| US8330398B2 (en) | Method and system to start multiple AC motors supplied by a power converter via a common AC bus | |
| CN108370225B (en) | Permanent magnet self-starting motor and switching-on method for same | |
| CA2947435C (en) | Motor with stator winding tap and methods for starting a motor with a variable speed drive | |
| CN108288938A (en) | Compressor and refrigeration equipment | |
| CN212114916U (en) | Permanent magnet synchronous motor with multiple working modes | |
| Popa et al. | High Speed Induction Motor used in Electric Vehicles. | |
| FI119135B (en) | A synchronous machine | |
| EP1267473B1 (en) | AC induction motor and method of starting same | |
| Mohamadein et al. | Mixed-pole reluctance machine with ring-coils on rotor poles (a novel rotor version) | |
| RU2272351C1 (en) | Synchronous motor | |
| US20110210705A1 (en) | Method for regulating the reactive power generated or absorbed by a synchronous electric generator and synchronous electric generator | |
| RU2444837C1 (en) | Device to start and compensate for reactive power of induction motor | |
| RU145061U1 (en) | SHORT-CLOSED ROTOR REDUCING RESTRICTIONS FOR ASYNCHRONOUS MOTOR |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 14817232 Country of ref document: EP Kind code of ref document: A1 |
|
| NENP | Non-entry into the national phase |
Ref country code: DE |
|
| 122 | Ep: pct application non-entry in european phase |
Ref document number: 14817232 Country of ref document: EP Kind code of ref document: A1 |