WO1995006973A1 - Power supply arrangement for a multiple electric motor line drive - Google Patents

Power supply arrangement for a multiple electric motor line drive Download PDF

Info

Publication number
WO1995006973A1
WO1995006973A1 PCT/FI1994/000382 FI9400382W WO9506973A1 WO 1995006973 A1 WO1995006973 A1 WO 1995006973A1 FI 9400382 W FI9400382 W FI 9400382W WO 9506973 A1 WO9506973 A1 WO 9506973A1
Authority
WO
WIPO (PCT)
Prior art keywords
intermediate circuit
power supply
supply
rectifier
arrangement
Prior art date
Application number
PCT/FI1994/000382
Other languages
French (fr)
Inventor
Ilkka ERKKILÄ
Original Assignee
Abb Industry Oy
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 Abb Industry Oy filed Critical Abb Industry Oy
Publication of WO1995006973A1 publication Critical patent/WO1995006973A1/en

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
    • H02P5/00—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors
    • H02P5/74—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors controlling two or more ac dynamo-electric motors

Definitions

  • the present invention relates to a power supply arrangement for a multiple electric motor line drive.
  • the arrangement comprises means connected to an AC supply for supplying a DC voltage to a DC intermedi ⁇ ate circuit to which electric motors are connected via their respective frequency converters/choppers.
  • a DC intermediate circuit is a common char ⁇ acteristic of voltage-controlled motor supply units based on pulse width modulation. The most important connection benefit offered by such a DC intermediate circuit is a good cosfi when the DC voltage is main- tained in the vicinity of the maximum value obtained from the mains. Another advantage is the internal power equalization of the DC system, since in a mains connec ⁇ tion only active net power is transmitted, which again reduces losses in transformers and other supply units on the AC side.
  • a third advantage is the relative sim ⁇ plicity of the convertors that supply the motors.
  • AC controlled branches
  • DC controlled branches
  • a four-quadrant DC drive directly connected to the line has twelve controlled branches.
  • the advantage of sim ⁇ plicity is emphasized when several drives are connected in the same intermediate circuit.
  • the DC intermediate circuit is, however, attended by the drawback of double energy conversion, which is complicated and gives rise to additional losses particularly in drives that are constantly under high load. Nevertheless, the losses are small compared with additional losses produced in a conventional phase angle-controlled drive below the rated speed on the AC side. In such circumstances, the difference between the losses is very clear.
  • the conventional line drives of the kind de- scribed above implement the single drive concept.
  • a diode bridge feeds an intermediate circuit wherefrom the motor supply unit, either a frequency converter for AC motors or a chopper for DC motors, derives its energy.
  • Braking energy is supplied from the intermedi- ate circuit via a chopper to a resistance braking unit or fed via an inverter back to the mains.
  • the DC inter ⁇ mediate circuit makes it possible to decelerate the drive by utilizing the motor and supply unit losses, even though no actual braking unit were provided.
  • Figure 1 in the accompanying drawing shows an example of the construction of a conventional line drive of the kind described above.
  • a DC intermediate circuit 21 is fed by way of a common high-capacity line supply unit (rec ⁇ tifier) 20.
  • the line supply unit must also be sectionally divided, the module size being dependent on the supply transformers that have maximum outputs of 1.6 to 4 MVA in the low-voltage range, depending on the secondary voltage.
  • the actual restricting factor is the duration of the short-circuit current on the low-voltage side of the equipment.
  • the line supply unit 20 in the embodiment of Figure 1 is a rectifier bridge supplying a low-inductance DC bus 21.
  • AC motors 22 and 23 are supplied from this DC bus through frequency converters 24 and 25 and DC motor 26 through a chopper 27.
  • connection further comprises a filter capacitor 28 linking the DC bus to earthing isolation.
  • a filter capacitor 28 linking the DC bus to earthing isolation.
  • the wire section may include drive points of very heavy duty, 500-1000 kW.
  • the efficiency of a continuous drive is about 60-80% of the design value.
  • a line drive for a papermaking machine in particular, several (4-5) large drives having an average size of e.g. 300 kVA and a plurality (10-20) of smaller drives having an average size of 20 kVA are connected to the same transformer having an output of 2500 kVA, for instance.
  • the supply block com- prises 4-6 fields having a combined length of 3.2 m and comprising a switch, a semiconductor unit (e.g. a two- way thyristor bridge), an LC filter, interface units for the AC and DC sides and control relays.
  • There are five larger drive groups having a combined length of 3 m. These comprise as main parts a fuse isolator and a frequency converter.
  • Fifteen smaller drive groups are provided, having a combined length of 6 m and similar main parts as the larger drive groups.
  • the proportion of the supply in the total length of the equipment is 26%. If there are fewer drive groups, the proportion of the supply in the total length of the equipment increases. The cost effect of the supply group tends to be even higher than its pro ⁇ portion in the length of the equipment. Factors affect- ing this include the high cost of filtering capacitors, the number of supply groups in comparison with the number of drive groups, the fact that the production numbers of the actual single drives are hundredfold as compared with the supply groups, and the fact that the supply groups comprise a wide variety of application- specific detail solutions. On account of the above factors, the benefits of serial production can be taken advantage of in the manufacture of supply groups only to a limited degree. It is an object of the present invention to provide a novel power supply arrangement wherewith the proportion of the supply group in the total length of the equipment can be diminished and substantial savings in costs achieved, particularly if units produced in large series are employed.
  • the proportion of the supply group can be diminished by means of the construction according to the invention, which is characterized in that the arrangement com- prises at least one rectifier frequency converter/ chopper unit supplying its own motor, and that the means for supplying a DC voltage to the DC intermediate circuit comprise the rectifier section of the said at least one rectifier frequency converter/chopper unit.
  • the basis for the arrangement of the invention is the idea that the advantages of a DC intermediate circuit specifically relate to the rectifying action and not as much to high powers to be transmitted. The rectifying applies both to the voltage, which must be close to the maximum voltage obtained from the line (which is achieved by way of diode supply), and to the motor power, more specifically its flow direction.
  • the filter capacitors of prior power supply arrange ⁇ ments employ costly, large capacitor bank units has bearing on centralized power supply in particular.
  • the AC power is supplied to large drive groups having a diode bridge and a frequency converter manufactured in large series.
  • the common protective device is normally a switch.
  • the filter capacitors are re-divided into drive groups, and thus there is no need to trans ⁇ port the harmonics produced by the chopping action for long distances in the DC circuit, thus making the low- inductance requirements on the circuit less severe.
  • their rectifier sections are connected in parallel to the DC inter ⁇ mediate circuit by way of inductances.
  • the rec- tifier sections of large frequency converters are connected in parallel to supply the DC intermediate circuit by way of small inductances.
  • this supply can be provided for through the connections of the braking chopper of the frequency converters.
  • the purpose of the inductances included in the connection is to produce a static state in the parallel connec ⁇ tion, which means a certain amount of resistivity.
  • the inductance also limits the speed of current rise in a short-circuit situation, in which case the protective fuses are selective.
  • the DC intermediate circuit is preferably con ⁇ nected via an inverter to an AC supply for braking the motors connected to the DC intermediate circuit.
  • This inverter connected to the DC intermediate circuit thus brakes into the mains.
  • the inverter is based on prior art line commutation or forced commutation technology. Compared with an antiparallel-connected thyristor bridge, this braking mode affords better short-term loadability on the braking side in the supply, since the motor side does not generate any basic thermal load, which is common in the present-day bridge con ⁇ structions. If dynamic braking is not needed, the inverter may be omitted. Also in that case, the motor and supply unit losses can be utilized to enhance the braking by coasting.
  • the sectional division of the power supply in the above manner is based on the above-stated dimensioning/design principle according to which the thermal load on massive drive groups varies over the range 20-80%, and thus the remaining rectifying capacity can be utilized in the smaller groups.
  • the power ratios are approximately 1:10 in typical appli- cations.
  • Figure 1 shows a power supply arrangement according to the prior art
  • Figure 2 is a schematic view of a power supply arrangement according to the present invention.
  • the power supply arrangement according to the invention as described in Figure 2 for a multiple elec- trie motor line drive comprises two integrated rec ⁇ tifier frequency converter units 5a and 5b arranged to supply AC motors 6 and 7.
  • the rectifier sections of these rectifier frequency converter units 5a and 5b are connected via fuse isolators 14a and 14b and small in- ductances 11 and 12 in parallel to the DC intermediate circuit 2.
  • AC motors 8 and 9 of substantially lower power ratings than motors 6 and 7 are connected to the DC intermediate circuit 2 via fuse isolators 15a and 15b and frequency converters 3a and 3b.
  • the motors 6 and 7 in practice have a power rating at least twice the power rating of the motors 8 and 9.
  • the DC inter ⁇ mediate circuit further has connected to it a DC motor 10 supplied from the DC intermediate circuit 2 via a fuse isolator 16 and chopper 4.
  • the connection further includes a fre ⁇ quency converter 13, by way of which electric power can be supplied from the DC intermediate circuit 2 to an AC supply 1.
  • Both the rectifier frequency converter units 5a, 5b and the inverter 13 are connected to the AC supply via fuse isolators 17a, 17b and 18. The entire line drive can be isolated from the AC supply by way of a switch 19.

Abstract

The invention relates to a power supply arrangement for a multiple electric motor line drive, the arrangement comprising means connected to an AC supply (1) for supplying a DC voltage to a DC intermediate circuit (2) to which electric motors (8, 9, 10) are connected via their respective frequency converters (3a, 3b)/choppers (4). In accordance with the invention, the arrangement comprises at least one rectifier frequency converter/chopper unit (5a, 5b) supplying its own motor (6, 7), and the means for supplying a DC voltage to the DC intermediate circuit comprise the rectifier section of the said at least one rectifier frequency converter/chopper unit (5a, 5b).

Description

Power supply arrangement for a multiple electric motor line drive
The present invention relates to a power supply arrangement for a multiple electric motor line drive. The arrangement comprises means connected to an AC supply for supplying a DC voltage to a DC intermedi¬ ate circuit to which electric motors are connected via their respective frequency converters/choppers. A DC intermediate circuit is a common char¬ acteristic of voltage-controlled motor supply units based on pulse width modulation. The most important connection benefit offered by such a DC intermediate circuit is a good cosfi when the DC voltage is main- tained in the vicinity of the maximum value obtained from the mains. Another advantage is the internal power equalization of the DC system, since in a mains connec¬ tion only active net power is transmitted, which again reduces losses in transformers and other supply units on the AC side. A third advantage is the relative sim¬ plicity of the convertors that supply the motors. In four-quadrant operation, only six controlled branches (AC) or four controlled branches (DC) are needed, whilst a four-quadrant DC drive directly connected to the line has twelve controlled branches. There also exists a two-branch twin quadrant version and one- branch single quadrant version of a DC chopper which is employed to supply DC motors. The advantage of sim¬ plicity is emphasized when several drives are connected in the same intermediate circuit. The DC intermediate circuit is, however, attended by the drawback of double energy conversion, which is complicated and gives rise to additional losses particularly in drives that are constantly under high load. Nevertheless, the losses are small compared with additional losses produced in a conventional phase angle-controlled drive below the rated speed on the AC side. In such circumstances, the difference between the losses is very clear.
The conventional line drives of the kind de- scribed above implement the single drive concept. A diode bridge feeds an intermediate circuit wherefrom the motor supply unit, either a frequency converter for AC motors or a chopper for DC motors, derives its energy. Braking energy is supplied from the intermedi- ate circuit via a chopper to a resistance braking unit or fed via an inverter back to the mains. The DC inter¬ mediate circuit makes it possible to decelerate the drive by utilizing the motor and supply unit losses, even though no actual braking unit were provided. Figure 1 in the accompanying drawing shows an example of the construction of a conventional line drive of the kind described above. In the line drive of Figure 1, having several consumption points of very different sizes, a DC intermediate circuit 21 is fed by way of a common high-capacity line supply unit (rec¬ tifier) 20. As the power increases, the line supply unit must also be sectionally divided, the module size being dependent on the supply transformers that have maximum outputs of 1.6 to 4 MVA in the low-voltage range, depending on the secondary voltage. The actual restricting factor is the duration of the short-circuit current on the low-voltage side of the equipment. The line supply unit 20 in the embodiment of Figure 1 is a rectifier bridge supplying a low-inductance DC bus 21. AC motors 22 and 23 are supplied from this DC bus through frequency converters 24 and 25 and DC motor 26 through a chopper 27. The connection further comprises a filter capacitor 28 linking the DC bus to earthing isolation. In equipment involving high moments of inertia or large masses to be transported, suitable dimen¬ sioning of the drive is a significant technical and economic factor. In papermaking machines, acceleration and deceleration times of about five minutes have been adopted. This makes the dimensioning of transmission means and motors less critical.
Applications involving particularly high moments of inertia include drying cylinder blocks, leading rollers, and winder. Leading roller motors have power ranges of 5-30 k and drying cylinder block and winder motors 100-250 kW. The average load in con¬ tinuous drive is normally 20-30% of the design value. Stopping of such drives requires dynamic braking, i.e. power control from the DC intermediate circuit to a braking resistor unit or, to avoid losses, preferably feedback to the mains.
Applications involving predominantly friction- type loads include the wire and press section of a papermaking machine. The wire section may include drive points of very heavy duty, 500-1000 kW. The efficiency of a continuous drive is about 60-80% of the design value. These drives have traditionally been stopped using the friction of the equipment, the method thus being simply to switch off the power supply from the electric drive, with no feed to the mains or resistance braking. The term used for this method is coasting.
In a line drive for a papermaking machine in particular, several (4-5) large drives having an average size of e.g. 300 kVA and a plurality (10-20) of smaller drives having an average size of 20 kVA are connected to the same transformer having an output of 2500 kVA, for instance. Such a system has convention¬ ally the following configuration: the supply block com- prises 4-6 fields having a combined length of 3.2 m and comprising a switch, a semiconductor unit (e.g. a two- way thyristor bridge), an LC filter, interface units for the AC and DC sides and control relays. There are five larger drive groups, having a combined length of 3 m. These comprise as main parts a fuse isolator and a frequency converter. Fifteen smaller drive groups are provided, having a combined length of 6 m and similar main parts as the larger drive groups.
The proportion of the supply in the total length of the equipment is 26%. If there are fewer drive groups, the proportion of the supply in the total length of the equipment increases. The cost effect of the supply group tends to be even higher than its pro¬ portion in the length of the equipment. Factors affect- ing this include the high cost of filtering capacitors, the number of supply groups in comparison with the number of drive groups, the fact that the production numbers of the actual single drives are hundredfold as compared with the supply groups, and the fact that the supply groups comprise a wide variety of application- specific detail solutions. On account of the above factors, the benefits of serial production can be taken advantage of in the manufacture of supply groups only to a limited degree. It is an object of the present invention to provide a novel power supply arrangement wherewith the proportion of the supply group in the total length of the equipment can be diminished and substantial savings in costs achieved, particularly if units produced in large series are employed.
In the arrangement of the present invention, the proportion of the supply group can be diminished by means of the construction according to the invention, which is characterized in that the arrangement com- prises at least one rectifier frequency converter/ chopper unit supplying its own motor, and that the means for supplying a DC voltage to the DC intermediate circuit comprise the rectifier section of the said at least one rectifier frequency converter/chopper unit. The basis for the arrangement of the invention is the idea that the advantages of a DC intermediate circuit specifically relate to the rectifying action and not as much to high powers to be transmitted. The rectifying applies both to the voltage, which must be close to the maximum voltage obtained from the line (which is achieved by way of diode supply), and to the motor power, more specifically its flow direction. The fact that the filters of prior power supply arrange¬ ments employ costly, large capacitor bank units has bearing on centralized power supply in particular. In the power supply arrangement of the invention, the AC power is supplied to large drive groups having a diode bridge and a frequency converter manufactured in large series. On the AC side, the common protective device is normally a switch. The filter capacitors are re-divided into drive groups, and thus there is no need to trans¬ port the harmonics produced by the chopping action for long distances in the DC circuit, thus making the low- inductance requirements on the circuit less severe. When there are at least two integrated rec¬ tifier frequency converter/chopper units in the power supply arrangement of the invention, their rectifier sections are connected in parallel to the DC inter¬ mediate circuit by way of inductances. Thus the rec- tifier sections of large frequency converters are connected in parallel to supply the DC intermediate circuit by way of small inductances. Typically this supply can be provided for through the connections of the braking chopper of the frequency converters. The purpose of the inductances included in the connection is to produce a static state in the parallel connec¬ tion, which means a certain amount of resistivity. The inductance also limits the speed of current rise in a short-circuit situation, in which case the protective fuses are selective.
In the power supply arrangement of the inven¬ tion, the DC intermediate circuit is preferably con¬ nected via an inverter to an AC supply for braking the motors connected to the DC intermediate circuit. This inverter connected to the DC intermediate circuit thus brakes into the mains. The inverter is based on prior art line commutation or forced commutation technology. Compared with an antiparallel-connected thyristor bridge, this braking mode affords better short-term loadability on the braking side in the supply, since the motor side does not generate any basic thermal load, which is common in the present-day bridge con¬ structions. If dynamic braking is not needed, the inverter may be omitted. Also in that case, the motor and supply unit losses can be utilized to enhance the braking by coasting.
In the power supply arrangement according to the invention, the sectional division of the power supply in the above manner is based on the above-stated dimensioning/design principle according to which the thermal load on massive drive groups varies over the range 20-80%, and thus the remaining rectifying capacity can be utilized in the smaller groups. The power ratios are approximately 1:10 in typical appli- cations.
The power supply arrangement of the invention will now be described in greater detail with reference to the accompanying drawing, in which
Figure 1 shows a power supply arrangement according to the prior art, and Figure 2 is a schematic view of a power supply arrangement according to the present invention.
The power supply arrangement according to the invention as described in Figure 2 for a multiple elec- trie motor line drive comprises two integrated rec¬ tifier frequency converter units 5a and 5b arranged to supply AC motors 6 and 7. The rectifier sections of these rectifier frequency converter units 5a and 5b are connected via fuse isolators 14a and 14b and small in- ductances 11 and 12 in parallel to the DC intermediate circuit 2. AC motors 8 and 9 of substantially lower power ratings than motors 6 and 7 are connected to the DC intermediate circuit 2 via fuse isolators 15a and 15b and frequency converters 3a and 3b. The motors 6 and 7 in practice have a power rating at least twice the power rating of the motors 8 and 9. The DC inter¬ mediate circuit further has connected to it a DC motor 10 supplied from the DC intermediate circuit 2 via a fuse isolator 16 and chopper 4. For braking of motors 8, 9 and 10, the connection further includes a fre¬ quency converter 13, by way of which electric power can be supplied from the DC intermediate circuit 2 to an AC supply 1. Both the rectifier frequency converter units 5a, 5b and the inverter 13 are connected to the AC supply via fuse isolators 17a, 17b and 18. The entire line drive can be isolated from the AC supply by way of a switch 19.
In the above, the power supply arrangement of the invention has been illustrated by means of one exemplary embodiment only, and it is to be understood that a variety of modifications may be made therein without departing from the scope defined by the appended claims. Thus there may be a greater number than described of large rectifier frequency converter/ chopper units the rectifier section of which supplies the DC intermediate circuit. Typically also the number of smaller drives provided in connection with the DC intermediate circuit is distinctly greater than in the embodiment shown in Figure 2.

Claims

Claims :
1. A power supply arrangement for a multiple electric motor line drive, the arrangement comprising means connected to an AC supply (1) for supplying a DC voltage to a DC intermediate circuit (2) to which electric motors (8, 9, 10) are connected via their respective frequency converters (3a, 3b)/choppers (4), c h a r a c t e r i z e d in that the arrangement com- prises at least one rectifier frequency converter/ chopper unit (5a, 5b) supplying its own motor (6, 7), and that the means for supplying a DC voltage to the DC intermediate circuit comprise the rectifier section of the said at least one rectifier frequency con- verter/chopper unit (5a, 5b).
2. A power supply arrangement as claimed in claim 1, c h a r a c t e r i z e d in that there are at least two rectifier frequency converter/chopper units (5a, 5b) and that their rectifier sections are connected in parallel to the DC intermediate circuit (2) via inductances (11, 12).
3. A power supply arrangement as claimed in claim 1 or claim 2, c h a r a c t e r i z e d in that for braking of the motors (8, 9, 10) connected to the DC intermediate circuit (2), the DC intermediate circuit is connected to the AC supply (1) via an inverter (13).
PCT/FI1994/000382 1993-08-31 1994-08-30 Power supply arrangement for a multiple electric motor line drive WO1995006973A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI933811 1993-08-31
FI933811A FI933811A (en) 1993-08-31 1993-08-31 Power supply arrangement for line operation with several electric motors

Publications (1)

Publication Number Publication Date
WO1995006973A1 true WO1995006973A1 (en) 1995-03-09

Family

ID=8538504

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1994/000382 WO1995006973A1 (en) 1993-08-31 1994-08-30 Power supply arrangement for a multiple electric motor line drive

Country Status (2)

Country Link
FI (1) FI933811A (en)
WO (1) WO1995006973A1 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1376842A1 (en) * 2002-06-19 2004-01-02 Fanuc Ltd. Motor driving controller.
WO2005086335A1 (en) * 2004-02-27 2005-09-15 York International Corporation Variable speed drive for multiple loads
WO2006078546A2 (en) 2005-01-18 2006-07-27 Research Frontiers Inc. Methods and circuits for distributing power to spd loads
AT414290B (en) * 1997-12-17 2006-11-15 Siemens Ag Oesterreich Converter arrangement
US7193826B2 (en) 2004-02-27 2007-03-20 York International Corporation Motor disconnect arrangement for a variable speed drive
US7207183B2 (en) 2004-04-12 2007-04-24 York International Corp. System and method for capacity control in a multiple compressor chiller system
US7231773B2 (en) 2004-04-12 2007-06-19 York International Corporation Startup control system and method for a multiple compressor chiller system
US7793509B2 (en) 2004-04-12 2010-09-14 Johnson Controls Technology Company System and method for capacity control in a multiple compressor chiller system
US7960865B2 (en) 2007-02-15 2011-06-14 Kone Corporation Apparatus and method for controlling the motor power
RU2488215C2 (en) * 2008-08-08 2013-07-20 Шуньсинь ЧЖОУ System for rotor frequency variation and speed control in asynchronous and simultaneous way for several electric motors driven by one inverter
EP2631104B1 (en) 2012-02-21 2015-07-08 ALSTOM Transport Technologies DC-link decoupling circuit for parallel inverters

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4263535A (en) * 1978-09-29 1981-04-21 Bucyrus-Erie Company Motor drive system for an electric mining shovel
DE3641569C1 (en) * 1986-12-05 1988-03-24 Skf Textilmasch Komponenten Circuit arrangement for spinning or twisting machines
US5237494A (en) * 1990-09-10 1993-08-17 Barmag Ag Frequency inverting apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4263535A (en) * 1978-09-29 1981-04-21 Bucyrus-Erie Company Motor drive system for an electric mining shovel
DE3641569C1 (en) * 1986-12-05 1988-03-24 Skf Textilmasch Komponenten Circuit arrangement for spinning or twisting machines
US5237494A (en) * 1990-09-10 1993-08-17 Barmag Ag Frequency inverting apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Vol. 15, No. 22, E-1024; & JP,A,02 266 892 (YASKAWA ELECTRIC MFG CO LTD), 31 October 1990. *

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT414290B (en) * 1997-12-17 2006-11-15 Siemens Ag Oesterreich Converter arrangement
US6914790B2 (en) 2002-06-19 2005-07-05 Fanuc Ltd Motor driving controller
EP1376842A1 (en) * 2002-06-19 2004-01-02 Fanuc Ltd. Motor driving controller.
US7193826B2 (en) 2004-02-27 2007-03-20 York International Corporation Motor disconnect arrangement for a variable speed drive
WO2005086335A1 (en) * 2004-02-27 2005-09-15 York International Corporation Variable speed drive for multiple loads
US7164242B2 (en) 2004-02-27 2007-01-16 York International Corp. Variable speed drive for multiple loads
US7231773B2 (en) 2004-04-12 2007-06-19 York International Corporation Startup control system and method for a multiple compressor chiller system
US7207183B2 (en) 2004-04-12 2007-04-24 York International Corp. System and method for capacity control in a multiple compressor chiller system
US7661274B2 (en) 2004-04-12 2010-02-16 York International Corporation System and method for capacity control in a multiple compressor chiller system
US7793509B2 (en) 2004-04-12 2010-09-14 Johnson Controls Technology Company System and method for capacity control in a multiple compressor chiller system
WO2006078546A2 (en) 2005-01-18 2006-07-27 Research Frontiers Inc. Methods and circuits for distributing power to spd loads
EP1847002A2 (en) * 2005-01-18 2007-10-24 Research Frontiers Incorporated Methods and circuits for distributing power to spd loads
EP1847002A4 (en) * 2005-01-18 2009-04-29 Research Frontiers Inc Methods and circuits for distributing power to spd loads
AU2006206710B2 (en) * 2005-01-18 2010-03-25 Research Frontiers Incorporated Methods and circuits for distributing power to SPD loads
EP2387121A1 (en) * 2005-01-18 2011-11-16 Research Frontiers Incorporated Methods and circuits for distributing power to SPD loads
US8174753B2 (en) 2005-01-18 2012-05-08 Research Frontiers Inc. Methods and circuits for distributing power to SPD loads
US7960865B2 (en) 2007-02-15 2011-06-14 Kone Corporation Apparatus and method for controlling the motor power
RU2488215C2 (en) * 2008-08-08 2013-07-20 Шуньсинь ЧЖОУ System for rotor frequency variation and speed control in asynchronous and simultaneous way for several electric motors driven by one inverter
EP2631104B1 (en) 2012-02-21 2015-07-08 ALSTOM Transport Technologies DC-link decoupling circuit for parallel inverters

Also Published As

Publication number Publication date
FI933811A0 (en) 1993-08-31
FI933811A (en) 1995-03-01

Similar Documents

Publication Publication Date Title
EP2636144B1 (en) Pitch motor drive circuit which can operate in emergency mode
US7446435B2 (en) Power converter system and method
DE10242658B4 (en) Power conversion device
EP1244203B1 (en) Power converter circuit for generators with dynamically varying outputpower
CA1182514A (en) Variable-speed electrical machines
US7324360B2 (en) Power converter methods and apparatus for variable speed high power machines
DE3305225C2 (en)
WO1995006973A1 (en) Power supply arrangement for a multiple electric motor line drive
CN103051281A (en) High-performance four-quadrant frequency converter
US6333578B1 (en) Induction motor
EP2027646A1 (en) Driving with inverters with low switching losses
CN103532477B (en) Share the multiple stators winding port electric system of the grid-connected wave filter of LC
Ray et al. Switched reluctance motor drives for rail traction: a second view
CN111786587A (en) Subway bidirectional converter device based on modular ANPC three-level inverter
DE69933517T2 (en) Power converter
DE2425362A1 (en) SPEED-CHANGEABLE ELECTRIC DRIVE DEVICE WITH USED BRAKING POSSIBILITY
CN110729717A (en) Parallel type traction compensation system for double full-bridge back-to-back converters
CN2788519Y (en) Integral convertor power heat radiating module for electric vehicle
CN210821908U (en) High-speed railway load characteristic adjusting device based on modularization multi-level
Dujic et al. Modular medium voltage drive for demanding applications
Kumar et al. An industrial survey on electric drives and scope of multilevel inverter based induction motor drives in sugar industry
CN207801768U (en) A kind of frequency conversion power unit of the more H bridges inversion outputs of single input
CN207559579U (en) DC fan transmission system
Hosoda et al. Large PWM inverters for rolling mills
CN2128799Y (en) Parameter voltage change induction motor and its controlling apparatus

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): JP KR US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase