WO2011045263A1 - Damping of drive train oscillations by dc-link absorption means - Google Patents
Damping of drive train oscillations by dc-link absorption means Download PDFInfo
- Publication number
- WO2011045263A1 WO2011045263A1 PCT/EP2010/065172 EP2010065172W WO2011045263A1 WO 2011045263 A1 WO2011045263 A1 WO 2011045263A1 EP 2010065172 W EP2010065172 W EP 2010065172W WO 2011045263 A1 WO2011045263 A1 WO 2011045263A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- power
- circuit
- generator
- operatively connected
- converter
- 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
- H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
- H02P9/10—Control effected upon generator excitation circuit to reduce harmful effects of overloads or transients, e.g. sudden application of load, sudden removal of load, sudden change of load
-
- 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
- H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
- H02P9/007—Control circuits for doubly fed generators
-
- 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
- H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
- H02P9/48—Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle
-
- 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
- H02P2101/00—Special adaptation of control arrangements for generators
- H02P2101/15—Special adaptation of control arrangements for generators for wind-driven turbines
Definitions
- Torsional drive train oscillations are a well-known phenomenon within the wind turbine community. These oscillations cause the speed of rotation of the drive train of a wind turbine to vary around a nominal value with a frequency of typical 1-2 Hz. Obviously torsional drive train oscillations need to be reduced to an absolute minimum in order to avoid unnecessary mechanical wear of the drive train components, the most critical drive train component being the wind turbine gearbox.
- wind power facility should be understood very broad. Thus, the term wind power facility may cover a single, isolated wind turbine, or it may cover a group of wind turbines forming a wind power plant.
- the method is applicable to both wind turbine facilities with full scale power converter and wind turbine facilities with doubly fed induction generators.
- essentially all electrical power fluctuations may be absorbed in the power storing and/or power dissipating means so that essentially all electrical power fluctuations caused by drive train damping schemes are kept, and thereby dealt with, within a wind turbine facility.
- essentially no electrical power fluctuations are provided to an associated power supply grid.
- the amount of electrical power to be provided to the absorbing means including capacitive means such as capacitors, batteries, resistive dump loads and/or other suitable devices may be provided from the intermediate DC circuit of the power converter via a traditional chopper or a similar power regulating circuitry.
- the power generator 3 here an induction generator, receives it magnetisation via the power converter in that the grid converter 7 draws AC power from the three winding transformer 4 and converts it to DC power.
- the DC power is reconverted to AC power with an appropriate frequency by the rotor converter 6.
- the rotor current of the AC power provided to the rotor magnetizes the induction generator whereby power can be drawn from the stator.
- the rotor of the power generator is operatively connected to a set of rotatably mounted rotor blades 1 via an optional gearbox 2.
- a low speed shaft (LSS) transfers captured wind energy to the gearbox.
- a high speed shaft (HSS) transfers mechanical energy from the gearbox to the rotor of the power generator 3.
- the next step is to determine whether the value of U DC is larger or smaller than the nominal value of U DC , i.e. the value of U DC during normal operation of the wind turbine. If the value of U DC exceeds the nominal value of U DC - for example during the positive half period - a DC chopper (reference numeral 10 in Fig. 1), including a resistive dump load and/or a storage element, is activated (step 13).
- the DC chopper is, as depicted in Fig. 1, electrically connected to the intermediate DC circuit 8 whereby power in excess of a given power level can be dissipated and/or stored within the intermediate DC circuit 8.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Eletrric Generators (AREA)
Abstract
The present invention relates to methods for damping torsional drive train oscillations in a wind turbine facility, said wind turbine facility comprising a power generator and a power converter operatively connected thereto, the power converter comprising a generator-side inverter and a grid-side converter interconnected by an intermediate DC circuit, the methods comprising the steps damping torsional oscillations of the drive train by controlling the power generator in such a way that electrical power generated by said power generator fluctuates in response to said torsional oscillations, and at least partly absorbing said electrical power fluctuations in power storing and/or power dissipating means operatively connected to the intermediate DC circuit of the power converter. The present invention further relates to an arrangement for carrying out the methods.
Description
DAMPING OF DRIVE TRAIN OSCILLATIONS BY DC-LINK ABSORPTION MEANS FIELD OF THE INVENTION
The present invention relates to a method and an arrangement for reducing, or even totally preventing, that electrical power fluctuations originating from torsional drive train oscillations in wind turbines disturb power distribution grids operatively connected to such wind turbines. In particular, the present invention relates to a method and an arrangement where a DC-link absorption means, such as a DC-link capacitor and/or a DC-link resistive dump load, at least partly absorb the electrical power fluctuations.
BACKGROUND OF THE INVENTION Torsional drive train oscillations are a well-known phenomenon within the wind turbine community. These oscillations cause the speed of rotation of the drive train of a wind turbine to vary around a nominal value with a frequency of typical 1-2 Hz. Obviously torsional drive train oscillations need to be reduced to an absolute minimum in order to avoid unnecessary mechanical wear of the drive train components, the most critical drive train component being the wind turbine gearbox.
Torsional drive train oscillations can be damped in various ways. One common method for damping these unwanted oscillations implies that the power generator of the wind turbine is controlled in such a way that it provides a counter acting torque to the generator shaft. However, in order to provide this counter acting torque the generated electrical power from the power generator fluctuates with the drive train oscillations. These electrical power fluctuations penetrate the electrical power system of the wind turbine, including the power converter of the wind turbine, and ends up as unwanted power fluctuations on an associated power supply grid. There is a need for a method and an arrangement capable of at least partly reducing these unwanted power fluctuations. It may be seen as an object of embodiments of the present invention to reduce electrical power fluctuations originating from torsional drive train oscillations in wind turbines.
It may be seen as a further object of embodiments of the present invention to totally eliminate electrical power fluctuations originating from torsional drive train oscillations in wind turbines.
DESCRIPTION OF THE INVENTION
The above-mentioned objects are complied with by providing, in a first aspect, a method for damping torsional drive train oscillations in a wind turbine facility, said wind turbine facility comprising a power generator and a power converter operatively connected thereto, the power converter comprising a generator-side inverter and a grid-side converter
interconnected by an intermediate DC circuit, the method comprising the steps
- damping torsional oscillations of the drive train by controlling the power generator in such a way that electrical power generated by said power generator fluctuates in response to said torsional oscillations, and - at least partly absorbing said electrical power fluctuations in power storing and/or power dissipating means operatively connected to the intermediate DC circuit of the power converter.
The provided method aims at disturbing a power supply grid connected to the wind turbine facility as little as possible by absorbing the electrical power fluctuations in appropriate power storing means, such as capacitors, batteries or other suitable storing means, and/or power dissipating means, such as a resistive dump load. Generally, power storing means is, in the present context, to be understood as an electrical power reservoir where electrical energy may be stored optionally for later use.
The term wind power facility should be understood very broad. Thus, the term wind power facility may cover a single, isolated wind turbine, or it may cover a group of wind turbines forming a wind power plant.
It is an advantage of the method according to the first aspect of the present invention that electrical power fluctuations originating from attempts to compensate for torsional drive train oscillations are at least partly kept inside the wind turbine facility. Ideally, all electrical power fluctuations originating from attempts to compensate for torsional drive train oscillations are dealt with inside the wind turbine facility. Attempts to compensate for torsional drive train oscillations may involve rotor current control of an induction generator in a doubly fed system.
However, the principle of the method according to the present invention applies to both wind turbine facilities with full scale power converter and wind turbine facilities with doubly fed induction generators.
In one embodiment of the present invention at least part of the electrical power fluctuations may be stored in capacitive or other suitable storing means operatively connected to the intermediate DC circuit of the power converter. By storing electrical energy in such capacitive or other suitable storing means the traditional uninterruptible power supply (UPS) may be omitted because electrical energy may be provided by such capacitive/storing means, for example during a start-up procedure (black-start).
In terms of implementation the capacitive/storing means may be implemented as for example a capacitor and/or a battery. The capacity of the capacitor/battery should be matched to the wind turbine facility in question. For a 2 MW wind turbine facility rough energy balance calculations show that a bulk storage capacity of 20-25 kJ with a peak power capability of about 200 kW is required.
In another embodiment of the present invention at least part of the electrical power fluctuations may be dissipated in a resistive dump load operatively connected to the intermediate DC circuit of the power converter. Such resistive dump loads are known from grid fault protection systems within the wind turbine community.
In a particular interesting embodiment of the present invention essentially all electrical power fluctuations are absorbed in the power storing means and/or power dissipating means. In this embodiment no electrical power fluctuations reach the associated power supply grid.
The amount of electrical power to be provided to the power storing means and/or power dissipating means, including capacitors, batteries, resistive dump loads or other suitable devices may be provided from the intermediate DC circuit of the power converter via a traditional chopper or a similar power regulating circuitry.
In order to compensate for the drive train torsional oscillations the power generator may be controlled so as to generate a counter acting torque to the generator shaft. The counter acting torque may be generated by controlling the generator in various ways. In case the power generator is an induction generator the counter acting torque may be generated by varying the rotor current in response to measured drive train oscillation. Thus, a rotor current control parameter may be applied as a control input parameter to an inner current control loop responding to the active component of the generator current. Alternatively, a rotor current control parameter may be applied as a control input parameter to an outer power control loop responding to the active power, said outer power control loop providing a current reference to the inner current control loop.
In a second aspect the present invention relates to a method for keeping at least part of electrical power fluctuations caused by drive train damping schemes within a wind turbine facility, said wind turbine facility comprising a power generator and a power converter operatively connected thereto, the power converter comprising a generator-side inverter and a grid-side converter interconnected by an intermediate DC circuit, the method comprising the steps of
- damping torsional oscillations of the drive train by controlling the power generator in such a way that electrical power generated by said power generator fluctuates in response to said torsional oscillations, and - at least partly absorbing said electrical power fluctuations by storing and/or dissipating associated electrical power variations in power storing and/or power dissipating means operatively connected to the intermediate DC circuit of the power converter.
Generally, the method according to the second aspect may be implemented by following the implementation steps given in connection with the first aspect of the present invention. Thus, it is an advantage of the method according to the second aspect that electrical power fluctuations originating from attempts to compensate for torsional drive train oscillations are at least partly kept, and thereby dealt with, inside the wind turbine facility. Similar to the first aspect of the present invention this advantage is provided by absorbing said electrical power fluctuations in suitable power storing means, such as in for example capacitors, batteries or other suitable storing means, or by dissipating said electrical power fluctuations in suitable power dissipation means, such as in for example resistive dump loads. The method according to the second aspect may thus aim at disturbing a power supply grid connected to the wind turbine facility as little as possible - preferably not disturbing the power supply grid at all.
Similar to the method according to the first aspect of the present invention the term wind power facility should be understood very broad. Thus, the term wind power facility may cover a single, isolated wind turbine, or it may cover a group of wind turbines forming a wind power plant.
The method is applicable to both wind turbine facilities with full scale power converter and wind turbine facilities with doubly fed induction generators. In a particular interesting embodiment essentially all electrical power fluctuations may be absorbed in the power storing and/or power dissipating means so that essentially all electrical power fluctuations caused by drive train damping schemes are kept, and thereby dealt with,
within a wind turbine facility. In this embodiment essentially no electrical power fluctuations are provided to an associated power supply grid.
At least part of the electrical power fluctuations may be absorbed by capacitive means operatively connected to the intermediate DC circuit of the power converter. By storing electrical energy in such capacitive means the traditional uninterruptible power supply (UPS) may be omitted because electrical energy may be provided by the capacitive means, for example during a start-up procedure (black-start).
In terms of implementation the capacitive means may be implemented as a capacitor and/or a battery. The capacity of the capacitor/battery should be matched to the wind turbine facility in question. For a 2 MW wind turbine facility rough energy balance calculations show that a bulk storage capacity of 20-25 kJ with a peak power capability of about 200 kW is required.
In another embodiment of the present invention at least part of the electrical power fluctuations may be dissipated in a resistive dump load operatively connected to the intermediate DC circuit of the power converter. The amount of electrical power to be provided to the power storing and/or power dissipating means, including capacitors, batteries, resistive dump loads and/or other suitable devices may be provided from the intermediate DC circuit of the power converter via a traditional chopper or a similar power regulating circuitry.
In order to compensate for the drive train torsional oscillations the power generator may be controlled so as to generate a counter acting torque to the generator shaft. The counter acting torque may be generated by controlling the generator in various ways. In case the power generator is an induction generator the counter acting torque may be generated by varying the rotor current in response to measured drive train oscillation. Thus, a rotor current control parameter may be applied as a control input parameter to an inner current control loop responding to the active component of the generator current. Alternatively, a rotor current control parameter may be applied as a control input parameter to an outer power control loop responding to the active power, said outer power control loop providing a current reference to the inner current control loop.
In a third aspect, the present invention relates to a wind turbine facility comprising a power generator and a power converter operatively connected thereto, the power converter comprising a generator-side inverter and a grid-side converter interconnected by an intermediate DC circuit, the wind turbine facility further comprising
- means for controlling the power generator in order to damp drive train torsional oscillations, said control means being adapted to control the power generator in such a way that electrical power generated by said power generator fluctuates in response to said drive train torsional oscillations, and - means for absorbing at least part of said electrical power fluctuations, said absorbing means being operatively connected to the intermediate DC circuit of the power converter.
Thus, according to the third aspect of the present invention a wind turbine facility suitable for performing the methods of the first and second aspects is provided.
Again, the term wind power facility should be understood very broad. Thus, the term wind power facility may cover a single, isolated wind turbine, or it may cover a group of wind turbines forming a wind power plant. The wind turbine facility in question may be a full scale wind turbine facility or a doubly fed wind turbine facility. The wind turbine facility may also be of another type.
The absorbing means may comprise capacitive means for storing electrical energy, said capacitive means being operatively connected to the intermediate DC circuit of the power converter. Alternatively or in addition, the absorbing means may comprise a resistive dump load for dissipating electrical energy, said resistive dump load being operatively connected to the intermediate DC circuit of the power converter.
In terms of implementation the capacitive means may be implemented as a capacitor, a battery and/or any other suitable device for storing electrical energy. The capacity of the capacitor/battery should be matched to the wind turbine facility in question. For a 2 MW wind turbine facility rough energy balance calculations show that a bulk storage capacity of 20-25 kJ with a peak power capability of about 200 kW is required.
The amount of electrical power to be provided to the absorbing means, including capacitive means such as capacitors, batteries, resistive dump loads and/or other suitable devices may be provided from the intermediate DC circuit of the power converter via a traditional chopper or a similar power regulating circuitry.
In a particular interesting embodiment, the absorbing means is adapted to absorb essentially all electrical power fluctuations so that an associated power supply grid is left essentially undisturbed in the case of drive train torsional oscillations.
By storing electrical energy in capacitive means the traditional uninterruptible power supply (UPS) may be omitted because electrical energy may be provided by the capacitive means, for example during a start-up procedure (black-start). As already mentioned the capacitive means may be implemented as a capacitor, a battery and/or any other suitable device for storing electrical energy. The capacity of the capacitor/battery should be matched to the wind turbine facility in question. For a 2 MW wind turbine facility rough energy balance calculations show that a bulk storage capacity of 20-25 kJ with a peak power capability of about 200 kW is required.
In a fourth aspect the present invention relates to a method for damping torsional drive train oscillations in a wind turbine facility, said wind turbine facility comprising a power generator and a power converter operatively connected thereto, the power converter comprising a generator-side inverter and a grid-side converter interconnected by an intermediate DC circuit, the method comprising the steps of
- determining an actual voltage level of the intermediate DC circuit, - comparing the determined actual voltage level of the intermediate DC circuit with a predetermined voltage level of the intermediate DC circuit, and
- controlling power storing and/or power dissipating means operatively connected to the intermediate DC circuit of the power converter in response to said comparison.
The predetermined voltage level may be within a range of 20%, such as 15%, such as 10%, such as 5%, above a nominal DC voltage level of the intermediate DC circuit. Thus, the voltage level of the intermediate DC circuit may be allowed to vary up to 20% from a nominal DC level before the torsional damping mechanism is activated.
Electrical power from the power generator may be stored/dissipated in the power storing and/or power dissipating means when the determined actual voltage level exceeds the predetermined voltage level. The power storing and/or power dissipating means may comprise capacitive means operatively connected to the intermediate DC circuit of the power converter, and/or it may comprise a resistive dump load operatively connected to the intermediate DC circuit of the power converter.
The predetermined voltage level may alternatively be within a range of 20%, such as 15%, such as 10%, such as 5%, below a nominal DC voltage level of the intermediate DC circuit. In that case electrical power may be drawn from power storing means operatively connected
to the intermediate DC circuit when the determined actual voltage level is below the predetermined voltage level.
In order to compensate for the drive train torsional oscillations the power generator may be controlled so as to generate a counter acting torque to the generator shaft. The counter acting torque may be generated by controlling the generator in various ways. In case the power generator is an induction generator the counter acting torque may be generated by controlling the rotor converter in such a way that the rotor current is varied in response to measured drive train oscillation. A rotor current control parameter may be applied as a control input parameter to an inner current control loop responding to the active component of the generator current. Alternatively, a rotor current control parameter may be applied as a control input parameter to an outer power control loop responding to the active power, said outer power control loop providing a current reference to the inner current control loop.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be explained in further details with reference to the accompanying figures, wherein
Fig. 1 shows a doubly fed system, and
Fig. 2 shows a flow chart of an embodiment of the present invention.
While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of examples in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION As previously mentioned the present invention is applicable to both doubly fed and full scale wind turbine systems. In the following, the invention will be disclosed with reference to a doubly fed system. However, this should not be considered a limitation regarding the applicability of the invention.
Fig. 1 shows a traditional doubly fed wind turbine system comprising a power generator 3 in the form of an induction generator having a rotatably mounted rotor surrounded by a stator. The power generator 3 converts mechanical energy to electrical energy. The stator of the power generator 3 is electrically connected to a three winding transformer 4 whereas the rotor is electrically connected to a power converter in order to receive its rotor current therefrom. The three winding transformer 4 matches the voltages levels of the stator, the grid converter 7 and the voltage level of the associated power supply grid 11.
As depicted in Fig. 1 the power converter comprises a rotor converter 6 and a grid converter 7 separated by an intermediate DC circuit 8. The rotor converter 6 is electrically connected to the rotor of the power generator 3 whereas the grid converter 7 is electrically connected to the three winding transformer 4. As indicated in Fig. 1 all AC connections between power generator, converters and the three winding transformer are three phase connections.
The power generator 3, here an induction generator, receives it magnetisation via the power converter in that the grid converter 7 draws AC power from the three winding transformer 4 and converts it to DC power. The DC power is reconverted to AC power with an appropriate frequency by the rotor converter 6. The rotor current of the AC power provided to the rotor magnetizes the induction generator whereby power can be drawn from the stator.
The rotor of the power generator is operatively connected to a set of rotatably mounted rotor blades 1 via an optional gearbox 2. On the blade side of the gearbox 2 a low speed shaft (LSS) transfers captured wind energy to the gearbox. A high speed shaft (HSS) transfers mechanical energy from the gearbox to the rotor of the power generator 3.
A wind turbine control system 9 controls the overall functionality of the wind turbine, including the operation of the rotor converter 6 and the grid converter 7. Moreover, the control system provides a control reference to a pitch controller 5 in order to control the pitching angle of the rotor blades 1.
Drive train oscillations can be measured by for example an encoder (not shown in Fig. 1) as oscillations of the speed of rotation of the drive train, including speed of rotation oscillations of the low and high speed shafts. An encoder is a well-known device which produces an output signal representing a measured speed of rotation of the drive train. The frequency of the drive train oscillations is typically around 1.5 Hz.
When no drive train oscillations are measured, the value of a Drive Train Damper (DTD) current reference equals zero. This zero value of the DTD current reference indicates that the wind turbine operates in a normal mode of operation.
If drive train oscillations are measured by an encoder, the value of the DTD current reference will differ from zero. This non-zero value of the DTD current reference indicates that the power generator 3 should generate a counter acting torque in order to compensate for the measured drive train oscillations. The required counter acting torque is provided by varying the rotor current provided by the rotor converter 6 in accordance with the measured drive train oscillations.
The DTD current reference may be applied in various ways, such as being an input reference signal to a current control loop or an input reference signal to a power control loop. Typically, the current control loop is implemented within the power control loop, i.e. the current control loop is implemented an inner control loop within the power control loop.
Fig. 2 shows a flow chart of an embodiment of the present invention. The wind turbine controller 9 (in Fig. 1) is responsible for the individual process steps illustrated in Fig. 2. As indicated in the embodiment depicted in Fig. 2 a DTD current reference different from zero (step 10) will disable the UDC control scheme (step 11), where UDC denotes the voltage level of the intermediate DC circuit separating the rotor converter and the grid converter. During normal operation the grid converter is controlled so as to keep UDC at a substantially constant level.
Contrary to the normal operation scenario UDC is allowed to vary when the power generator, here implemented as an induction generator, is operated so as to compensate for drive train oscillations. As previously mentioned this compensation is provided by varying the rotor current via the rotor converter so as to create a counteracting torque. Thus, by letting UDC vary the grid converter output can be kept at a substantially constant voltage level whereby the grid voltage becomes essentially undisturbed by the measured drive train oscillations. Typically, while compensating for drive train oscillations UDC is allowed to vary ± 10% around the nominal DC voltage level of the intermediate DC circuit. However, UDC may also be allowed to vary around 20%, such as 15%, such as 10%, such as 5% above and/or below the nominal DC voltage level of the intermediate DC circuit.
As illustrated in Fig. 2 the next step (step 12) is to determine whether the value of UDC is larger or smaller than the nominal value of UDC, i.e. the value of UDC during normal operation of the wind turbine. If the value of UDC exceeds the nominal value of UDC - for example during the positive half period - a DC chopper (reference numeral 10 in Fig. 1), including a resistive dump load and/or a storage element, is activated (step 13). The DC chopper is, as depicted in Fig. 1, electrically connected to the intermediate DC circuit 8 whereby power in excess of a given power level can be dissipated and/or stored within the intermediate DC circuit 8.
In case the DC-chopper includes a storage element, such as a capacitor and/or a battery and/or any other means suitable for storing electrical energy, stored electrical energy may be drawn from the storage element during a negative half period of a voltage fluctuation of UDC, i.e. when a measured value of UDC is smaller than the nominal value of UDC. In an embodiment, in order to protect the wind turbine damping of drive train oscillations according to the present invention is only be performed when UDC is within certain voltage limits. These limits are typically given by the semiconductor components hardware. Typically, 1.6-1.7 kV components are used, and by operating with a margin to this value UDC is typically limited to 1.4-1.5 kV It is checked at step 14 whether UDC exceed these limits. If UDC exceed these limits the DC- chopper is deactivated when the grid converter has regained control over UDC (step 15), and has returned to normal operation where UDC is kept at a substantially constant level (Step 16). The power generator is still controlled so as to generate the required counter acting torque, but the resulting electrical power fluctuations are allowed to flow through the system and enter the associated power supply grid via the three winding transformer.
It should be noted that the DC chopper, including the dump load and/or the storage element, operatively connected to the intermediate DC circuit may also be activated in response to grid faults, such as in response to low voltage ride-through events. By using the DC chopper in this way the wind turbine can be operated at a nominal power level until the wind turbine has been pitched out of the wind by the pitch controller.
Claims
1. A method for damping torsional drive train oscillations in a wind turbine facility, said wind turbine facility comprising a power generator and a power converter operatively connected thereto, the power converter comprising a generator-side inverter and a grid-side converter interconnected by an intermediate DC circuit, the method comprising the steps of
- damping torsional oscillations of the drive train by controlling the power generator in such a way that electrical power generated by said power generator fluctuates in response to said torsional oscillations, and
- at least partly absorbing said electrical power fluctuations in power storing and/or power dissipating means operatively connected to the intermediate DC circuit of the power converter.
2. A method according to claim 1, wherein at least part of the electrical power fluctuations are absorbed by capacitive means operatively connected to the intermediate DC circuit of the power converter.
3. A method according to claim 1 or 2, wherein at least part of the electrical power fluctuations are dissipated in a resistive dump load operatively connected to the intermediate DC circuit of the power converter.
4. A method according to any of claims 1-3, wherein essentially all electrical power fluctuations are absorbed in the power storing and/or power dissipating means.
5. A method according to any of claims 1-4, wherein the power generator is controlled so as to generate a counter acting torque to the drive train torsional oscillations.
6. A method for keeping at least part of electrical power fluctuations caused by drive train damping schemes within a wind turbine facility, said wind turbine facility comprising a power generator and a power converter operatively connected thereto, the power converter comprising a generator-side inverter and a grid-side converter interconnected by an intermediate DC circuit, the method comprising the steps of
- damping torsional oscillations of the drive train by controlling the power generator in such a way that electrical power generated by said power generator fluctuates in response to said torsional oscillations, and - at least partly absorbing said electrical power fluctuations by storing and/or dissipating associated electrical power variations in power storing and/or power dissipating means operatively connected to the intermediate DC circuit of the power converter.
7. A method according to claim 6, wherein essentially all electrical power fluctuations are absorbed in the power storing and/or power dissipating means so that essentially all electrical power fluctuations caused by drive train damping schemes are kept within a wind turbine facility.
8. A method according to claim 6 and 7, wherein the power generator is controlled so as to generate a counter acting torque to the drive train torsional oscillations.
9. A method according to any of claims 6-8, wherein at least part of the electrical power fluctuations are absorbed by capacitive means operatively connected to the intermediate DC circuit of the power converter.
10. A method according to any of claims 6-9, wherein at least part of the electrical power fluctuations are dissipated in a resistive dump load operatively connected to the intermediate DC circuit of the power converter.
11. A wind turbine facility comprising a power generator and a power converter operatively connected thereto, the power converter comprising a generator-side inverter and a grid-side converter interconnected by an intermediate DC circuit, the wind turbine facility further comprising - means for controlling the power generator in order to damp drive train torsional oscillations, said control means being adapted to control the power generator in such a way that electrical power generated by said power generator fluctuates in response to said drive train torsional oscillations, and
- means for absorbing at least part of said electrical power fluctuations, said absorbing means being operatively connected to the intermediate DC circuit of the power converter.
12. A wind turbine facility according to claim 11, wherein the absorbing means comprises capacitive means for storing electrical energy, said capacitive means being operatively connected to the intermediate DC circuit of the power converter.
13. A wind turbine facility according to claim 11 or 12, wherein the absorbing means comprises a resistive dump load for dissipating electrical energy, said resistive dump load being operatively connected to the intermediate DC circuit of the power converter.
14. A wind turbine facility according to any of claims 11-13, wherein the absorbing means is adapted to absorb essentially all electrical power fluctuations.
15. A method for damping torsional drive train oscillations in a wind turbine facility, said wind turbine facility comprising a power generator and a power converter operatively connected thereto, the power converter comprising a generator-side inverter and a grid-side converter interconnected by an intermediate DC circuit, the method comprising the steps of - determining an actual voltage level of the intermediate DC circuit,
- comparing the determined actual voltage level of the intermediate DC circuit with a predetermined voltage level of the intermediate DC circuit, and
- controlling power storing and/or power dissipating means operatively connected to the intermediate DC circuit of the power converter in response to said comparison.
16. A method according to claim 15, wherein the predetermined voltage level is within a range of 20% above a nominal DC voltage level of the intermediate DC circuit.
17. A method according to claim 15 or 16, wherein electrical power from the power generator are stored/dissipated in the power storing and/or power dissipating means when the determined actual voltage level exceeds the predetermined voltage level.
18. A method according to any of claims 15-17, wherein at least part of the power storing and/or power dissipating means comprises capacitive means operatively connected to the intermediate DC circuit of the power converter.
19. A method according to any of claims 15-18, wherein at least part of the power storing and/or power dissipating means comprises resistive dump load operatively connected to the intermediate DC circuit of the power converter.
20. A method according to claim 15, wherein the predetermined voltage level is within a range of 20% below a nominal DC voltage level of the intermediate DC circuit.
21. A method according to claim 20, wherein electrical power is drawn from power storing means operatively connected to the intermediate DC circuit when the determined actual voltage level is below the predetermined voltage level.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DKPA200970155 | 2009-10-12 | ||
| DKPA200970155 | 2009-10-12 | ||
| US25110309P | 2009-10-13 | 2009-10-13 | |
| US61/251,103 | 2009-10-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2011045263A1 true WO2011045263A1 (en) | 2011-04-21 |
Family
ID=43385640
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP2010/065172 WO2011045263A1 (en) | 2009-10-12 | 2010-10-11 | Damping of drive train oscillations by dc-link absorption means |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2011045263A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104931838A (en) * | 2015-07-01 | 2015-09-23 | 河海大学 | System damping on-line monitoring method and system based on traction load impact response |
| EP3048333A1 (en) * | 2015-01-23 | 2016-07-27 | Rolls-Royce plc | Method and system for damping torsional oscillations |
| CN112368901A (en) * | 2018-06-26 | 2021-02-12 | 维斯塔斯风力***集团公司 | Enhanced multi-voltage dip ride through for renewable energy power plants with battery storage system |
| EP3779183A1 (en) * | 2019-08-14 | 2021-02-17 | Siemens Gamesa Renewable Energy A/S | Control of wind turbine during mechanical oscillation damping |
| US11251742B2 (en) | 2019-01-15 | 2022-02-15 | Abb Schweiz Ag | Damping torsional oscillations in a drive system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060238929A1 (en) * | 2003-02-07 | 2006-10-26 | Nielsen John G | Method for controlling a power-grid connected wind turbine generator during grid faults and apparatus for implementing said method |
| EP1965075A1 (en) * | 2005-11-21 | 2008-09-03 | Ingeteam Technology S.A. | System for controlling and protecting against symmetrical and asymmetrical faults for asynchronous-type generators |
-
2010
- 2010-10-11 WO PCT/EP2010/065172 patent/WO2011045263A1/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060238929A1 (en) * | 2003-02-07 | 2006-10-26 | Nielsen John G | Method for controlling a power-grid connected wind turbine generator during grid faults and apparatus for implementing said method |
| EP1965075A1 (en) * | 2005-11-21 | 2008-09-03 | Ingeteam Technology S.A. | System for controlling and protecting against symmetrical and asymmetrical faults for asynchronous-type generators |
Non-Patent Citations (2)
| Title |
|---|
| HANSEN A D ET AL: "Multi-pole permanent magnet synchronous generator wind turbines' grid support capability in uninterrupted operation during grid faults", IET RENEWABLE POWER GENERATION,, vol. 3, no. 3, 8 September 2009 (2009-09-08), pages 333 - 348, XP006033760, ISSN: 1752-1424, DOI: DOI:10.1049/IET-RPG:20080055 * |
| QIAO W ET AL: "Grid Connection Requirements and Solutions for DFIG Wind Turbines", ENERGY 2030 CONFERENCE, 2008. ENERGY 2008. IEEE, IEEE, PISCATAWAY, NJ, USA, 17 November 2008 (2008-11-17), pages 1 - 8, XP031423663, ISBN: 978-1-4244-2850-2 * |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3048333A1 (en) * | 2015-01-23 | 2016-07-27 | Rolls-Royce plc | Method and system for damping torsional oscillations |
| CN104931838A (en) * | 2015-07-01 | 2015-09-23 | 河海大学 | System damping on-line monitoring method and system based on traction load impact response |
| CN104931838B (en) * | 2015-07-01 | 2017-08-29 | 河海大学 | System damping on-line monitoring method and system based on traction load shock response |
| CN112368901A (en) * | 2018-06-26 | 2021-02-12 | 维斯塔斯风力***集团公司 | Enhanced multi-voltage dip ride through for renewable energy power plants with battery storage system |
| US11251742B2 (en) | 2019-01-15 | 2022-02-15 | Abb Schweiz Ag | Damping torsional oscillations in a drive system |
| EP3779183A1 (en) * | 2019-08-14 | 2021-02-17 | Siemens Gamesa Renewable Energy A/S | Control of wind turbine during mechanical oscillation damping |
| WO2021028198A1 (en) * | 2019-08-14 | 2021-02-18 | Siemens Gamesa Renewable Energy A/S | Control of wind turbine during mechanical oscillation damping |
| CN114245845A (en) * | 2019-08-14 | 2022-03-25 | 西门子歌美飒可再生能源公司 | Wind turbine control during damping of mechanical oscillations |
| EP4209675A1 (en) * | 2019-08-14 | 2023-07-12 | Siemens Gamesa Renewable Energy A/S | Control of wind turbine during mechanical oscillation damping |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| DK2594005T3 (en) | Control unit for damping power oscillation | |
| DK2573895T3 (en) | A method for operating a wind farm, the wind farm control unit and wind farm | |
| US8120932B2 (en) | Low voltage ride through | |
| WO2019035760A1 (en) | Virtual power system inertia apparatus and methods of operation thereof | |
| US8237301B2 (en) | Power generation stabilization control systems and methods | |
| US8994200B2 (en) | Power system frequency inertia for power generation system | |
| EP2798718B1 (en) | A wind turbine generator | |
| CN108604795B (en) | Wind turbine fault ride-through capability | |
| EP3745550A1 (en) | Multivariable modulator controller for power generation facility | |
| US20150008672A1 (en) | Method for damping drive train oscillations in a wind turbine generator | |
| CN108092577B (en) | Wind power generation system and control method suitable for same | |
| EP3987174B1 (en) | Control of wind turbine during mechanical oscillation damping | |
| US11962262B2 (en) | Wind turbine with virtual synchronous generator and DC link control | |
| EP3633847B1 (en) | A method for handling sub-synchronous resonances | |
| US20190383265A1 (en) | Control system for wind turbines for reducing disturbances in an electrical grid | |
| WO2011045263A1 (en) | Damping of drive train oscillations by dc-link absorption means | |
| EP2075890A1 (en) | Method for fast frequency regulation using a power reservoir | |
| Yoo et al. | Power smoothing of a variable-speed wind turbine generator based on a two-valued control gain | |
| EP3949109A1 (en) | Control of a wind turbine using split power reference signals | |
| Faria et al. | Robust Nonlinear Double Integral Sliding Mode Controller Design for Mitigating SSR in DFIG-Based Wind Farms | |
| Musarrat et al. | A fractional order SMC approach to improve the reliability of wind energy systems during grid faults | |
| TWI543491B (en) | Method for feeding electrical energy into an electrical supply grid by means of a wind power installation or wind farm, and wind power installation and wind farm for feeding electrical energy into an electrical supply grid | |
| Margaris et al. | Dynamic security issues in autonomous power systems with increasing wind power penetration | |
| Yang et al. | Frequency control scheme with dynamic droop characteristics of a DFIG for mitigating the frequency fluctuations | |
| KR101235907B1 (en) | Apparatus of controlling a wind power generation system and method thereof |
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: 10766025 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: 10766025 Country of ref document: EP Kind code of ref document: A1 |