WO2005027301A1 - Method for operating a frequency converter of a generator - Google Patents

Method for operating a frequency converter of a generator Download PDF

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Publication number
WO2005027301A1
WO2005027301A1 PCT/EP2003/010269 EP0310269W WO2005027301A1 WO 2005027301 A1 WO2005027301 A1 WO 2005027301A1 EP 0310269 W EP0310269 W EP 0310269W WO 2005027301 A1 WO2005027301 A1 WO 2005027301A1
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WO
WIPO (PCT)
Prior art keywords
converter
reducing
link circuit
generator
grid
Prior art date
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Ceased
Application number
PCT/EP2003/010269
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French (fr)
Inventor
Detlef Menke
Wilhelm Janssen
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General Electric Co
Original Assignee
General Electric Co
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 General Electric Co filed Critical General Electric Co
Priority to CNB03827194XA priority Critical patent/CN100449904C/en
Priority to PCT/EP2003/010269 priority patent/WO2005027301A1/en
Priority to CA2539355A priority patent/CA2539355C/en
Priority to US10/571,735 priority patent/US7787266B2/en
Priority to AU2003270200A priority patent/AU2003270200B2/en
Priority to EP03750550.0A priority patent/EP1665493B1/en
Priority to ES03750550.0T priority patent/ES2565029T3/en
Priority to BRPI0318500A priority patent/BRPI0318500B1/en
Priority to DK03750550.0T priority patent/DK1665493T3/en
Publication of WO2005027301A1 publication Critical patent/WO2005027301A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/40—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC
    • H02M5/42—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC by static converters
    • H02M5/44—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC by static converters using discharge tubes or semiconductor devices to convert the intermediate DC into AC
    • H02M5/453—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC by static converters using discharge tubes or semiconductor devices to convert the intermediate DC into AC using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M5/458—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC by static converters using discharge tubes or semiconductor devices to convert the intermediate DC into AC using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M5/4585—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into DC by static converters using discharge tubes or semiconductor devices to convert the intermediate DC into AC using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only having a rectifier with controlled elements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for AC mains or AC distribution networks
    • H02J3/38—Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for AC mains or AC distribution networks
    • H02J3/38—Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
    • H02J3/46—Controlling the sharing of generated power between the generators, sources or networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2101/00—Supply or distribution of decentralised, dispersed or local electric power generation
    • H02J2101/20—Dispersed power generation using renewable energy sources
    • H02J2101/22—Solar energy
    • H02J2101/24—Photovoltaics
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2101/00—Supply or distribution of decentralised, dispersed or local electric power generation
    • H02J2101/20—Dispersed power generation using renewable energy sources
    • H02J2101/28—Wind energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects

Definitions

  • the present invention relates to the operation of power converters for supplying electrical power to a grid and, in particular, to a frequency converter of a generator of a wind energy turbine.
  • Electric power in public power grids is supplied by diverse energy sources converting mechanical energy into electrical energy.
  • the main energy sources supporting public power grids are coal power plants and nuclear power plants.
  • a method for operating a frequency converter of a generator in particular of a wind energy turbine in the event of a substantial grid voltage drop
  • the frequency converter includes an AC/DC converter, to be connected to the generator, a DC/AC converter to be connected to the voltage grid, and a DC link circuit for connecting the AC/DC converter to the DC/ AC converter
  • the method including the step of reducing an output voltage of the DC link circuit for increasing an output current of the DC/ AC converter and/or reducing the operation frequency of electronic switches of the DC/AC converter for increasing the output current of the DC/ AC converter.
  • the increase of the output current of the DC/AC converter i.e. of the frequency converter
  • the increase of the output current of the DC/AC converter is performed by reducing the output voltage of the DC link circuit of the frequency converter, the output voltage being the operating voltage for the DC/AC converter of the frequency converter.
  • the electronic switches typically transistors
  • the electronic switches includes transistors, (e.g., IGBT modules) as is generally known by those of ordinary skill in the art.
  • the switching frequency of the electronic switches of the DC/AC converter is reduced resulting in an increase of the output current of the DC/AC converter supplied to the power grid. Also, according to this aspect of the invention, when a substantial grid voltage drop occurs, there are substantially no changes of the energy losses in the electronic switches which are given under normal operation conditions of the frequency converter.
  • the steps described above whereby the output voltage and operating frequency are reduced can occur simultaneously.
  • the output voltage of the DC link circuit can be reduced by reducing the output voltage of the DC link circuit within the DC link circuit itself, i.e. by activating voltage dividers or the like.
  • Yet another advantageous approach relates to controlling the time interval for which electronic switches of the AC/DC converter are in their on-state. Namely, depending on the operating state (on or off) of the electronic switches, (typically thyristors), the output voltage of the AC/DC converter can be controlled. The shorter the time interval for the on-state of the electronic switches of the AC/DC converter is, the lower the output voltage of the AC/DC converter is.
  • the reducing step described above or at least one of the reducing steps is performed when, for a short time (msec up to sec), the grid voltage is decreased.
  • the level of voltage decrease for initiating at least one of the reducing steps depends on the design of components.
  • the reducing step or at least one of the reducing steps is terminated when, for a short time (msec up to sec), the normal grid voltage is increased again up a certain level (near nominal value).
  • a frequency converter 10 as used for providing electrical power to a power grid is shown.
  • the frequency converter is arranged between the output 12 of a generator 14 of a wind energy turbine (not shown) and the input 16 of a power grid 18.
  • the frequency converter 10 includes three major stages, namely an input stage, an intermediate stage, and an output stage.
  • the input stage is configured as an AC/DC converter 20, while the output stage includes a DC/AC converter 22. These two converters 20,22 are connected by the intermediate stage which is configured as a DC link circuit 24.
  • the AC/DC converter 20 and the DC/AC converter 22 both typically includes electronic semiconductor power elements. However, other electronic or electrical elements are also possible to be used.
  • the AC/DC converter 20 includes six thyristors 25 controlled by a control unit 26, which in turn is controlled by depending on the current operation parameters of the wind energy turbine and environmental conditions.
  • diodes can be used in place of the thyristors 25.
  • the DC/AC converter 22 includes six transistors 28, which are also controlled by the control unit 26.
  • Various types of transistors can be used according to the present invention for electrical power converters, such as IGBT modules.
  • the DC/ AC converter 22 includes a filtering device at its output end, which in this embodiment includes three inductors 30.
  • the DC link circuit 24 normally includes at least one filter for the DC link current which can configured as DC link chokes (not shown). Moreover, the DC link circuit includes an electrical energy storage device 32, which can be for example a capacitor bank, a battery, a super-capacitor or the like.
  • Grid voltage drops can be sensed by means of a grid voltage sensor 34 connected to the control unit 26.
  • the output voltage of the generator 14 can be sensed by a stator voltage sensor 36 also connected to the control unit 26.
  • the first approach according to the present invention relates to the reduction of the output voltage V z of the DC link circuit 24, which can be achieved for example by controlling the AC/DC converter 20 accordingly.
  • the thyristors 25 of the AC/DC converter 20 needs to be controlled according to the phase shifts of the stator of the generator 14. Also the frequency of the stator has to be detected or determined.
  • the control of the thyristors 25 is amended so as to reduce the output voltage V 2 of the DC link circuit 24.
  • the output current I c of the DC/ AC converter 22 can be increased without changing the power losses in the transistors 28 so that these power losses are substantially left unchanged when compared with the conditions under normal operation.
  • the output voltage V z of the DC link circuit 24 is 600 V and the output current I c is 1600 A.
  • the allowable temperature of a transistor 28 is 125 °C and the duty cycle of the transistors 28 is 1.
  • the energy losses E on when switching on a transistor 28 is 210 mWs
  • the energy losses E 0 f when switching off a transistor 28 is 260 mWs
  • the energy losses E rec during the interval in which a transistor 28 is switched off is 115 mWs. It is to be noted that these parameters are merely examples and that variations are possible accordingly.
  • the power losses based on E on , E 0ff , and E rec as well as the power loss P sw during the on-state of a transistor 28 are as follows:
  • the output current I c can be increased by approximately about 30 % up to
  • I c 2100 A (for 2407.5 W).
  • the percentage of the increase of the maximum output voltage I c is independent from type of transistor 28 used.
  • Another measure for increasing the output voltage I c in the event of an grid voltage drop is to reduce the switching frequency f for the transistors 28.
  • the transistors 28 are switched on for a shorter period of time, when maintaining the current unchanged, the energy losses are reduced. Accordingly, if the energy losses can be left unchanged, the current can be increased.
  • the output current I c can be increased up to
  • Ic 2200 A (for 2212.5 W).

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Eletrric Generators (AREA)

Abstract

The method relates to the operation of a frequency converter of a generator in particular of a wind energy turbine, in the event of a substantial grid voltage drop, wherein the frequency converter (10) comprises an AC/DC converter (20), to be connected to the generator (14), a DC/AC converter (22) to be connected to the voltage grid (18), and a DC link circuit (24) for connecting the AC/DC converter (20) to the DC/AC converter (22). The method comprises the step of reducing an output voltage of the DC link circuit (24) for increasing an output current of the DC/AC converter (22) and/or reducing the operation frequency of electronic switches (28) of the DC/AC converter (22) for increasing the output current of the DC/AC converter (22).

Description

TITLE
Method for operating a frequency converter of a generator BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to the operation of power converters for supplying electrical power to a grid and, in particular, to a frequency converter of a generator of a wind energy turbine.
Related Prior Art
Electrical power in public power grids is supplied by diverse energy sources converting mechanical energy into electrical energy. The main energy sources supporting public power grids are coal power plants and nuclear power plants. Several other types of energy sources, in particular power plants of regenerative energy like solar power plants, water power plants or wind energy turbines, also contribute to support the public power grid.
In the past, in the event of a significant grid voltage drop in a public power grid, it was required that in such an event wind energy turbines are shut down automatically. However, due to the increased number of wind energy turbines it becomes more and more important that these turbines support the public power grid in the event of a substantial grid voltage drop. However, due to thermal stresses applied to the electronic components of the frequency converter of a generator converting mechanical energy into electrical energy, increasing the output current of the converter in the event of a grid voltage drop is critical and limited.
Accordingly, it is an object of the present invention to increase the output current of a generator in particular of a wind energy turbine in the event of a substantial grid voltage drop.
SUMMARY OF THE INVENTION
According to the invention there is provided a method for operating a frequency converter of a generator in particular of a wind energy turbine, in the event of a substantial grid voltage drop, wherein the frequency converter includes an AC/DC converter, to be connected to the generator, a DC/AC converter to be connected to the voltage grid, and a DC link circuit for connecting the AC/DC converter to the DC/ AC converter, the method including the step of reducing an output voltage of the DC link circuit for increasing an output current of the DC/ AC converter and/or reducing the operation frequency of electronic switches of the DC/AC converter for increasing the output current of the DC/ AC converter.
The solution proposed by the present invention for solving the above- mentioned object relates to an increase of the current to be supplied into the public power grid in the event of a substantial grid voltage drop. According to a first aspect of the invention, the increase of the output current of the DC/AC converter, i.e. of the frequency converter, is performed by reducing the output voltage of the DC link circuit of the frequency converter, the output voltage being the operating voltage for the DC/AC converter of the frequency converter. By means of reducing the output voltage of the DC link circuit it is possible to increase the current flowing through the electronic switches (typically transistors) of the DC/ AC converter without increasing the energy losses of the electronic switches which occur under normal operation conditions of the frequency converter. In particular, the electronic switches includes transistors, (e.g., IGBT modules) as is generally known by those of ordinary skill in the art.
According to a second aspect of the present invention, the switching frequency of the electronic switches of the DC/AC converter is reduced resulting in an increase of the output current of the DC/AC converter supplied to the power grid. Also, according to this aspect of the invention, when a substantial grid voltage drop occurs, there are substantially no changes of the energy losses in the electronic switches which are given under normal operation conditions of the frequency converter.
According to a further aspect of the present invention, the steps described above whereby the output voltage and operating frequency are reduced, can occur simultaneously.
In another embodiment, the output voltage of the DC link circuit can be reduced by reducing the output voltage of the DC link circuit within the DC link circuit itself, i.e. by activating voltage dividers or the like. Yet another advantageous approach relates to controlling the time interval for which electronic switches of the AC/DC converter are in their on-state. Namely, depending on the operating state (on or off) of the electronic switches, (typically thyristors), the output voltage of the AC/DC converter can be controlled. The shorter the time interval for the on-state of the electronic switches of the AC/DC converter is, the lower the output voltage of the AC/DC converter is.
According to another aspect of the present invention, the reducing step described above or at least one of the reducing steps is performed when, for a short time (msec up to sec), the grid voltage is decreased. The level of voltage decrease for initiating at least one of the reducing steps depends on the design of components. The reducing step or at least one of the reducing steps is terminated when, for a short time (msec up to sec), the normal grid voltage is increased again up a certain level (near nominal value).
BRIEF DESCRIPTION OF THE DRAWINGS
A full and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying drawing schematically showing the circuitry of the frequency converter arranged between a generator and a power grid.
DESCRIPTION OF A REFERRED EMBODIMENT >
Reference will now be made in detail to the various embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, and is not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the present invention includes such modifications and variations.
In the drawing, the circuitry of a frequency converter 10 as used for providing electrical power to a power grid is shown. The frequency converter is arranged between the output 12 of a generator 14 of a wind energy turbine (not shown) and the input 16 of a power grid 18.
The frequency converter 10 includes three major stages, namely an input stage, an intermediate stage, and an output stage. The input stage is configured as an AC/DC converter 20, while the output stage includes a DC/AC converter 22. These two converters 20,22 are connected by the intermediate stage which is configured as a DC link circuit 24. In this embodiment, the AC/DC converter 20 and the DC/AC converter 22 both typically includes electronic semiconductor power elements. However, other electronic or electrical elements are also possible to be used. In particular, in this embodiment, the AC/DC converter 20 includes six thyristors 25 controlled by a control unit 26, which in turn is controlled by depending on the current operation parameters of the wind energy turbine and environmental conditions. As an alternative, diodes can be used in place of the thyristors 25. As shown herein, the DC/AC converter 22 includes six transistors 28, which are also controlled by the control unit 26. Various types of transistors can be used according to the present invention for electrical power converters, such as IGBT modules. As also known by those of ordinary skill in the art, the DC/ AC converter 22 includes a filtering device at its output end, which in this embodiment includes three inductors 30.
The DC link circuit 24 normally includes at least one filter for the DC link current which can configured as DC link chokes (not shown). Moreover, the DC link circuit includes an electrical energy storage device 32, which can be for example a capacitor bank, a battery, a super-capacitor or the like.
Grid voltage drops can be sensed by means of a grid voltage sensor 34 connected to the control unit 26. In a similar manner, the output voltage of the generator 14 can be sensed by a stator voltage sensor 36 also connected to the control unit 26.
In the event of a grid voltage drop, it is necessary that the generator 14 of a wind energy turbine is capable of supporting the grid so that the required electrical power is generated and supplied to the grid 18. There are two approaches according to the invention which can be used for increasing the electrical power supplied to the grid in the event of a grid voltage drop. The first approach according to the present invention relates to the reduction of the output voltage Vz of the DC link circuit 24, which can be achieved for example by controlling the AC/DC converter 20 accordingly. For doing so, the thyristors 25 of the AC/DC converter 20 needs to be controlled according to the phase shifts of the stator of the generator 14. Also the frequency of the stator has to be detected or determined. In accordance with these parameters, the control of the thyristors 25 is amended so as to reduce the output voltage V2 of the DC link circuit 24.
Due to the reduction of the output voltage Vz of the DC link circuit 24, in the event of a grid voltage drop the output current Ic of the DC/ AC converter 22 can be increased without changing the power losses in the transistors 28 so that these power losses are substantially left unchanged when compared with the conditions under normal operation.
In the following, an example is given showing an increase of the current in the event of a grid voltage drop.
Assuming that under normal conditions, for the frequency converter 10 the following parameters are given. The output voltage Vz of the DC link circuit 24 is 600 V and the output current Ic is 1600 A. The allowable temperature of a transistor 28 is 125 °C and the duty cycle of the transistors 28 is 1. The energy losses Eon when switching on a transistor 28 is 210 mWs, the energy losses E0 f when switching off a transistor 28 is 260 mWs, and the energy losses Erec during the interval in which a transistor 28 is switched off is 115 mWs. It is to be noted that these parameters are merely examples and that variations are possible accordingly.
Assuming further that the switching frequency f is 2500 1/s, the power losses based on Eon, E0ff, and Erec as well as the power loss Psw during the on-state of a transistor 28 are as follows:
Pon + Poff + Prec = (Eon + Eoff + Erec)*f = (0.210 Ws + 0.260 Ws + 0.115 Ws) * 2500 1/s = 0.585 Ws * 2500 1/s = 1462.5 W
Psw = Vce * Ic * (on-state interval)/(on + off state interval) = 2.4 V * 1600 A * 1/2 = 1920 W
Figure imgf000009_0001
= 3382.5 W
Assuming further that the output voltage Vz of the DC link circuit 24 is reduced to 30 % and further assuming that Pon, Pott, and Prec are substantially reduced by the same percentage, the overall sum of these power losses is as follows:
Pon + Poff + Prec = 1/3 * 1462.5 W = 487.5 W P = 1920 W + 487.5 W = 2407.5 W
In order to not exceed the power losses as under normal operational condition, the output current Ic can be increased by approximately about 30 % up to
Ic = 2100 A (for 2407.5 W).
It is to be noted that the percentage of the increase of the maximum output voltage Ic is independent from type of transistor 28 used.
Another measure for increasing the output voltage Ic in the event of an grid voltage drop is to reduce the switching frequency f for the transistors 28.
Namely, when the transistors 28 are switched on for a shorter period of time, when maintaining the current unchanged, the energy losses are reduced. Accordingly, if the energy losses can be left unchanged, the current can be increased.
In the following an example based on the above-mentioned parameters will be given for this scenario.
Assuming that the switching frequency f is reduced from 2500 1/s to 500 1/s, the following equations can be obtained:
Pon + Poff + Prec = (E0n + Eoff + Erec)*f = (0.210 Ws + 0.260 Ws + 0.115 Ws) * 500 1/s = 0.585 Ws * 500 1/s = 292.5 W
PSw = Vce * Ic * (on-state interval)/(on + off state interval) = 2.4 V * 1600 A * 1/2 = 1920 W P = 1920 W + 292.5 W = 2212.5 W
Therefore, for obtaining the same overall power losses as in the event of normal operation, the output current Ic can be increased up to
Ic = 2200 A (for 2212.5 W).
Although the invention has been described and illustrated with reference to specific illustrative embodiments thereof, it is not intended that the invention be limited to those illustrative embodiments. Those skilled in the art will recognise that variations and modifications can be made without departing from the true scope of the invention as defined by the claims that follow. It is therefore intended to include within the invention all such variations and modifications as fall within the scope of the appended claims and equivalents thereof.

Claims

1. Method for operating a frequency converter of a generator in particular of a wind energy turbine, in the event of a substantial grid voltage drop, wherein the frequency converter (10) comprises an AC/DC converter (20), to be connected to the generator (14), a DC/ AC converter (22) to be connected to the voltage grid (18), and a DC link circuit (24) for connecting the AC/DC converter (20) to the DC/AC converter (22), the method comprising the step of reducing an output voltage of the DC link circuit (24) for increasing an output current of the DC/AC converter (22) and/or reducing the operation frequency of electronic switches (28) of the DC/AC converter (22) for increasing the output current of the DC/AC converter (22).
2. Method according to claim 1, wherein the reducing step or at least one of the reducing steps is performed when, for a few seconds, the grid voltage is decreased up to at least about 10 % of its normal value and wherein the reducing step of at least one of the reducing steps is terminated when, for a few seconds, the normal grid voltage is increased again up to at least about 80 % of its normal value.
3. Method according to claim 1, wherein the reducing step or at least one of the reducing steps is performed when, for a few seconds, the grid voltage is decreased up to at least about 20 % of its normal value and wherein the reducing step of at least one of the reducing steps is terminated when, for a few seconds, the normal grid voltage is increased again up to at least about 90 % of its normal value.
4. Method according to any one of claims 1 to 3, wherein the step of reducing the output voltage of the DC link circuit (24) comprises controlling the time interval between a crossover of the output voltage of a phase of the generator (14) and an operation of an electronic switch (25) of the AC/DC converter (20).
5. Method according to any one of claims 1 to 3, wherein the step of reducing the output voltage of the DC link circuit (24) comprises reducing the pulse width interval of the electronic switch (25) of the AC/DC converter (20).
6. Method according to any one of claims 1 to 5, wherein the reduction of the output voltage of the DC link circuit (24) and/or the reduction of the operational frequency of the DC/AC converter (22) is/are performed such that an increased current flows without a substantial change of the energy losses in the electronic switches (28) of the DC/AC converter (22).
PCT/EP2003/010269 2003-09-16 2003-09-16 Method for operating a frequency converter of a generator Ceased WO2005027301A1 (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
CNB03827194XA CN100449904C (en) 2003-09-16 2003-09-16 Method for operating a frequency converter of a generator
PCT/EP2003/010269 WO2005027301A1 (en) 2003-09-16 2003-09-16 Method for operating a frequency converter of a generator
CA2539355A CA2539355C (en) 2003-09-16 2003-09-16 Method for operating a frequency converter of a generator
US10/571,735 US7787266B2 (en) 2003-09-16 2003-09-16 Method for operating a frequency converter of a generator
AU2003270200A AU2003270200B2 (en) 2003-09-16 2003-09-16 Method for operating a frequency converter of a generator
EP03750550.0A EP1665493B1 (en) 2003-09-16 2003-09-16 Method for operating a frequency converter of a generator
ES03750550.0T ES2565029T3 (en) 2003-09-16 2003-09-16 Operating procedure of a frequency converter of a generator
BRPI0318500A BRPI0318500B1 (en) 2003-09-16 2003-09-16 method for operating a frequency converter from a generator
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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007138137A3 (en) * 2006-05-30 2008-01-24 Gamesa Innovation & Tech Sl Use of oriented grain rolling in a wind turbine generator
DE102006053367A1 (en) * 2006-11-10 2008-05-21 Repower Systems Ag Method and device for operating an inverter, in particular for wind energy installations
US7425771B2 (en) 2006-03-17 2008-09-16 Ingeteam S.A. Variable speed wind turbine having an exciter machine and a power converter not connected to the grid
US7525208B2 (en) 2003-09-23 2009-04-28 Aloys Wobben Method for operating a wind turbine during a disturbance in the grid
DE102008017715A1 (en) 2008-04-02 2009-10-15 Nordex Energy Gmbh Method for operating a wind turbine with a double-fed asynchronous machine and wind turbine with a double-fed asynchronous machine
US7622815B2 (en) 2006-12-29 2009-11-24 Ingeteam Energy, S.A. Low voltage ride through system for a variable speed wind turbine having an exciter machine and a power converter not connected to the grid
WO2010079234A1 (en) 2009-01-12 2010-07-15 Vestas Wind Systems A/S Reconfigurable power converter module
WO2010079235A2 (en) 2009-01-12 2010-07-15 Vestas Wind Systems A/S Load dependent converter switching frequency
WO2010108979A3 (en) * 2009-03-25 2011-01-06 Vestas Wind Systems A/S Improved frequency control
US20120193991A1 (en) * 2011-02-01 2012-08-02 Kim Hoej Jensen Active desynchronization of switching converters
US8264094B2 (en) 2006-03-17 2012-09-11 Ingeteam Power Technology, S.A. High voltage direct current link transmission system for variable speed wind turbine
ITMI20111180A1 (en) * 2011-06-28 2012-12-29 Wilic Sarl WIND POWER PLANT FOR THE GENERATION OF ELECTRICITY
WO2013041737A1 (en) * 2011-09-22 2013-03-28 Ingeteam Power Technology, S.A. Electric power converter system with parallel units and fault tolerance
WO2015128647A1 (en) * 2014-02-26 2015-09-03 Bowman Power Group Ltd Power conversion
EP2530816A3 (en) * 2011-05-30 2017-10-25 General Electric Company System and method for converter switching frequency control
US9920746B2 (en) 2012-07-13 2018-03-20 Wobben Properties Gmbh Method for controlling an electric generator
WO2018202772A1 (en) * 2017-05-05 2018-11-08 Wobben Properties Gmbh Wind turbine with overload-capable converter system
EP3214719B1 (en) 2016-03-03 2019-01-23 General Electric Company System and method for controlling dc link voltage of a power converter for doubly-fed induction generators
EP4002678B1 (en) 2020-11-16 2024-01-03 Nordex Energy SE & Co. KG Method for operating a wind turbine and a wind turbine

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100642554B1 (en) * 2001-04-20 2006-11-03 알로이즈 우벤 How to Operate a Wind Power Plant
DE10119624A1 (en) 2001-04-20 2002-11-21 Aloys Wobben Operating wind energy plant involves regulating power delivered from generator to electrical load, especially of electrical network, depending on current delivered to the load
US7615904B2 (en) * 2007-01-24 2009-11-10 Raven Energy Alternatives, Llc Brushless high-frequency alternator and excitation method for three-phase AC power-frequency generation
US7786608B2 (en) 2008-11-17 2010-08-31 General Electric Company Protection system for wind turbine
CN101800510B (en) * 2009-02-10 2013-09-18 株式会社日立制作所 Wind power generation system
WO2010140248A1 (en) * 2009-06-05 2010-12-09 三菱重工業株式会社 Wind power generator and control method thereof and wind power generation system
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WO2011160643A2 (en) * 2010-06-25 2011-12-29 Vestas Wind Systems A/S A wind turbine and a method of operating a wind turbine
DE102011002657A1 (en) * 2011-01-13 2012-07-19 Converteam Gmbh Method for operating an inverter of an arrangement for generating electrical energy
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US10337930B2 (en) * 2015-05-12 2019-07-02 GM Global Technology Operations LLC Online IGBT junction temperature estimation without the use of a dedicated temperature estimation or measurement device
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DK179832B1 (en) * 2018-01-15 2019-07-24 Vestas Wind Systems A/S Controling a wind turbine during over-voltage ride through
WO2021170074A1 (en) 2020-02-26 2021-09-02 国网浙江省电力有限公司电力科学研究院 Flexible excitation system and control method therefor
CN111463796B (en) * 2020-02-28 2021-10-08 广东电网有限责任公司 A voltage stability evaluation method and device considering wind power output

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10010350A1 (en) * 2000-03-03 2001-09-13 Setec Elektronische Antriebsre Pulse converter operating method involves using parallel current inverters in intermediate circuit operated with clock synchronous pulse width modulation to reduce resonance stimulation
US20030126060A1 (en) 2000-12-29 2003-07-03 Abb Ab System, method and computer program product for enhancing commercial value of electrical power produced from a renewable energy power production facility

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4876637A (en) * 1988-03-22 1989-10-24 Kabushiki Kaisha Toshiba Power converter and method of controlling the same
US5483127A (en) * 1994-01-19 1996-01-09 Don Widmayer & Associates, Inc. Variable arc electronic ballast with continuous cathode heating
US5798631A (en) 1995-10-02 1998-08-25 The State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Performance optimization controller and control method for doubly-fed machines
JPH09205792A (en) * 1996-01-26 1997-08-05 Hitachi Ltd Motor control device
JPH09266695A (en) * 1996-03-28 1997-10-07 Mitsubishi Electric Corp Frequency converter
US6144190A (en) * 1999-03-25 2000-11-07 Coleman Powermate, Inc. Energy conversion system employing stabilized half-bridge inverter
TR200103401T2 (en) * 1999-05-28 2002-04-22 Abb Ab A method for wind power plant and control.
MXPA02005243A (en) * 1999-11-24 2003-01-28 American Superconductor Corp Voltage regulation of a utility power network.
US6542390B2 (en) * 2001-01-02 2003-04-01 General Electric Company System and method for regenerative PWM AC power conversion
DE10146527A1 (en) * 2001-09-21 2003-04-24 Siemens Ag Converter with a line and load side self-commutated pulse converter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10010350A1 (en) * 2000-03-03 2001-09-13 Setec Elektronische Antriebsre Pulse converter operating method involves using parallel current inverters in intermediate circuit operated with clock synchronous pulse width modulation to reduce resonance stimulation
US20030126060A1 (en) 2000-12-29 2003-07-03 Abb Ab System, method and computer program product for enhancing commercial value of electrical power produced from a renewable energy power production facility

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
BENNO JÄCKLI: "Energiesparen mit Frequenzumrichter", INTERNET ARTICLE, 2 December 1996 (1996-12-02), XP002284829, Retrieved from the Internet <URL:http://www.energie.ch/themen/industrie/fr/> [retrieved on 20040615] *
BERRINGER K ET AL: "Semiconductor power losses in AC inverters", 8 October 1995, INDUSTRY APPLICATIONS CONFERENCE, 1995. THIRTIETH IAS ANNUAL MEETING, IAS '95., CONFERENCE RECORD OF THE 1995 IEEE ORLANDO, FL, USA 8-12 OCT. 1995, NEW YORK, NY, USA,IEEE, US, PAGE(S) 882-888, ISBN: 0-7803-3008-0, XP010193037 *
BIRD/KING/PEDDER: "An Introduction to Power Electronics", 1993, JOHN WILEY & SONS, CHICHESTER, NEW YORK, BRISBANE, TORONTO, SINGAPORE, ISBN: 0 471 92616 7, XP002284830, 2 *
BLAABJERG F ET AL: "Power losses in PWM-VSI inverter using NPT or PT IGBT devices", POWER ELECTRONICS SPECIALISTS CONFERENCE, PESC '94 RECORD., 25TH ANNUAL IEEE TAIPEI, TAIWAN 20-25 JUNE 1994, NEW YORK, NY, USA,IEEE, 20 June 1994 (1994-06-20), pages 434 - 441, XP010549405, ISBN: 0-7803-1859-5 *

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US8294288B2 (en) 2006-03-17 2012-10-23 Ingeteam Power Technology, S.A. Collector anti-wearing and lubrication system for variable speed wind turbine
US8183704B2 (en) 2006-03-17 2012-05-22 Ingeteam Energy, S.A. Connection and disconnection sequence for variable speed wind turbine having an exciter machine and a power converter not connected to the grid
US7425771B2 (en) 2006-03-17 2008-09-16 Ingeteam S.A. Variable speed wind turbine having an exciter machine and a power converter not connected to the grid
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ES2318963A1 (en) * 2006-05-30 2009-05-01 GAMESA INNOVATION &amp; TECHNOLOGY, S.L. Use of oriented grain rolling in a wind turbine generator
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WO2007138137A3 (en) * 2006-05-30 2008-01-24 Gamesa Innovation & Tech Sl Use of oriented grain rolling in a wind turbine generator
US8084876B2 (en) 2006-05-30 2011-12-27 Gamesa Innovation & Technology, S.L. Use of oriented grain rolling in a wind turbine generator
EP1921738A3 (en) * 2006-11-10 2009-10-28 REpower Systems AG Method and device to control a dc-ac converter, particularly for a wind energy plant
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US7622815B2 (en) 2006-12-29 2009-11-24 Ingeteam Energy, S.A. Low voltage ride through system for a variable speed wind turbine having an exciter machine and a power converter not connected to the grid
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US9920746B2 (en) 2012-07-13 2018-03-20 Wobben Properties Gmbh Method for controlling an electric generator
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