DE19827261C1 - Power fluctuation compensation method for generator e.g. of wind-power station - Google Patents

Abstract

A method for compensating/correcting power fluctuations (delta P) of a generator in which the stator (36) of the generator is driven directly from a production machine, and the rotor (38) of the generator is driven directly from a speed- variable drive (58) in such a way that a detected power fluctuation (delta P) is adjusted to zero by changing the actual rotor revs (nr). Depending on the actual stator revs rate (ns) and a calculated desired revs rate (n*sy), which is proportional to a mains radian frequency (omega N) of a mains network (12) connected to the stator (36) of the generator, a desired rotor revs rate (n*r) is determined and is superimposed by a speed (revs) correction value (n*p) depending on an ascertained power fluctuation (delta P).

Description

The invention relates to the preamble of claim 1 or 4 to a method or a device for Ausre performance fluctuations and according to claim 14 a generator for this device.

In a stochastically driven generator, for example se a wind turbine, occur as a result of a stochastic occurring wind power fluctuations that previously were corrected by means of a rotor blade adjustment. With tels this rotor blade adjustment of the wind turbine only a slow power control possible.

In Fig. 1 is a from the publication "connection of wind turbines to the public power supply network", published in the German Journal "Electricity Industry", Volume 89 (1990), No. 24, pages 1384 to 1394, known concept of a wind turbine 2 shown . This wind energy plant 2 has a rotor 4 , a gear 6 and an asynchronous generator 8 . If the generator voltage is not equal to the mains voltage, a matching transformer is connected downstream of the asynchronous generator 8 . The wind turbine 2 is linked to a network 12 by means of a circuit breaker 10 . This concept, which is also referred to as direct network coupling, is inexpensive, but technically not very reliable since, for example, a gear 6 must also be used. The advantage of the asynchronous generator is that it produces no harmonics. However, the voltage change plays an important role in an asynchronous generator 8 . It may happen that the Windener gieanlage 2 may go to the network 12 with a lower than planned power or that the power to be fed in must be limited. In this publication, a further re network connection is shown, which additionally has a converter compared to the direct network connection. With this converter, the generator / rotor speed is completely decoupled from the mains frequency.

In FIG. 2 is also a well-known concept of a wind turbine depicted 2 (Brown Boveri Mitt. 3-82, pages 57 to 64). This wind turbine shown 2 has egg NEN rotor 4 , a synchronous generator 14 and a converter 16 . If the converter output voltage is not equal to the mains voltage of a network 12 , a matching transformer is also required. This Windenergieanla ge 2 is connected to the network 12 by means of a circuit breaker 10 . The converter 16 has a more pulsed, for example 12-pulse, rectifier 18 on the input side and a multi-pulse, for example 12-pulsed, pulse inverter 20 on the output side, the rectifier 18 and the pulse inverter 20 being connected to one another by means of a DC voltage intermediate circuit 22 .

Compared with the wind turbine 2 shown in FIG. 1 is at the wind turbine 2 shown in FIG. 2, the rotor 4 directly connected to the synchronous generator 14. A multi-pole generator is provided as the synchronous generator 14 , for example with a number of pole pairs p <40. The higher the number of pole pairs p, the smaller the synchronous speed of the generator. As the number of pole pairs p increases, the price of such a generator also increases. Smaller wind-related speed fluctuations are not noticeable in the network 12 , since the multi-pole synchronous generator 14 delivers the generated energy to the network 12 by means of a converter 16 . The pulse inverter 20 it also generates harmonic currents that can be compensated for by appropriate filters. If larger fluctuations in speed and thus power fluctuations occur as a result of a stochastically occurring wind, these power fluctuations can be corrected by means of a rotor blade adjustment mentioned at the beginning. With this rotor blade adjustment, however, only dynamic power control is not possible.

In Fig. 3, a device for dynamic power control of a stochastically driven synchronous generator is shown. This device is known from the older national patent application with the official file number 197 52 940.2. This wind turbine 2 has a rotor 4 , a gear 6 , a low-pole synchronous generator 24 , a variable-speed drive 26 and a worm gear 28 . In addition, this wind turbine 2 has two position sensors and a regulating and control device, which are not shown in more detail for reasons of clarity. The stand of this synchronous generator 24 is rotatably mounted and its windings are each electrically connected to a terminal ring of the synchronous generator 24 with a slip ring and a brush ste. Electrical generators, in particular AC synchronous generator, whose stands are also rotatably mounted, are known for example from US Pat. No. 4,229,689, DE 37 24 835 A1 or DE 40 24 269 A1. The output-side gear of the worm gear 28 encloses the stand and is non-positively connected to its outer surface. The drive-side gear is positively connected to an actuator of the variable-speed drive 26 . The rotor of the synchronous generator 24 is connected to the rotor 4 by means of the gear 6 . This synchronous generator 24 and the variable-speed drive 26 can each be connected to a network 12 by means of a circuit breaker 10 and 30 . The regulating and control device determines, depending on the measured stator currents and voltages, the measured mains phase voltages, the determined actual position values and a predetermined desired power value, a manipulated variable and control signals therefrom for the pulse inverter 32 of the voltage intermediate circuit converter 34 of the variable-speed drive 26 . By means of this drive 26 , the stator of the synchronous generator 24 can be rotated in the direction of rotor rotation or in the opposite direction of the rotor. As a result, the actual load angle value δ is regulated to the load angle target value δ ^{* of} the synchronous machine, which is calculated by means of a superimposed power control as a function of a predetermined desired power value. Due to the dynamic rotation of the stator of the synchronous generator 24 stochastic Lei fluctuations are compensated for, so that the stochastically driven synchronous generator can deliver a constant power.

Since the synchronous generator 24 has a low-pole design in this wind energy installation 2 , a gear 6 between the rotor 4 and the rotor of the synchronous generator 24 is also required. By means of this gear 6 , the speed of the rotor 4 is adapted to the synchronous speed of the synchronous generator 24 . The transmission 6 can only be dispensed with if a multi-pole synchronous machine is used as the synchronous generator 24 . In the power range of a few MW, the costs for the transmission are 10 to 15 times higher than the costs for a low-pole synchronous generator. The most expensive embodiment of the wind turbine 2 is the embodiment according to FIG. 2.

The invention is based on the object of a method and a device for regulating power fluctuations gene by means of a stochastically rotating work machine ne driven generator to specify, no gear more between rotor and generator and for this generator also no multi-pole synchronous machine must be used.

This object is achieved with the features of claim 1 and claim 4.

Because the stochastically rotating work machine directly drives the stator of the generator and its rotor by means of a variable-speed drive is driven in such a way that a determined fluctuation in performance due to a lei opposite fluctuation of rotor rotation number this determined fluctuation in output is corrected. The rotor speed is equal to the synchronous speed of the Ge nerators reduced by those driven by the wind Rotors. The rotor speed is controlled so that in stationary the balance of the moments in the air gap ben is. Since there is this equilibrium of moments, they have to mechanical and electrical moments mutual and un be equal to each other. This equality is demonstrated by the Re achieved rotor speed in relation to the rotor speed.

Due to the additional rotor speed control, con stanter and small number of pole pairs of the generator a desired te mechanical angular velocity are maintained, whether the stator angular velocity is variable.  

In an advantageous method, the rotor speed is Setpoint depending on a measured stator speed Actual value and a calculated speed setpoint telt, which is proportional to a mains voltage at the rotating Stator of the generator connected network. Thereby the generator adapts to any network angular velocity Automatically on, with frequency fluctuations in the network at Läu speed control are taken into account. By a Fre fluctuation in the frequency of the network also fluctuates the desired mechani cal angular velocity. Thus, by means of these runners speed control with constant and small number of pole pairs each desired mechanical angular velocity observed although the stator angular velocity is variable.

The device for controlling power fluctuations Nes generator comprises a generator, the stator of egg ner stochastically rotating machine and its runner directly driven by a variable-speed drive are driven, the rotor speed depending on egg measured stator speed and rotor speed actual value and a determined power fluctuation changed in this way is that these fluctuations in performance become zero. The means, compared to the device of the older national Pa The stand is not registered by means of a speed changeable drive twisted, but the runner with Approximately synchronous speed rotated and the stand directly driven by the work machine. So you can too Power fluctuations are corrected, but none Gearbox more needed between rotor and generator, whether probably the generator is only low-pole.

In a particularly inexpensive embodiment of the front direction for the regulation of power fluctuations is as variable speed drive a slip ring motor intended. Compared to an embodiment with a low pole motor and an inverter, especially a chip DC link converter, as a variable-speed drive  drove, are in this inexpensive embodiment Cost savings for one converter. With this inexpensive embodiment is a synchronous machine as a generator ne provided.

A component of the device for Ausre gelation of power fluctuations is the Ge according to the invention nerator, whose stand is rotatably mounted, and the wick lungs of the multi-pole stator winding each by means of a Slip ring and a brush with a terminal connection of the Generators are electrically connected, its Runner is rotatably mounted in the rotatable stand. Through this Design you get a generator that is attached twice can be driven. By means of this double driven Ge performance fluctuations can be corrected where with neither a gear between rotor and generator nor a multi-pole synchronous generator must be used.

To further explain the invention, reference is made to the drawing Reference, in which several embodiments of the invention device according to the invention are schematically illustrated.

Figs. 1 to 3 each represent a well-known concept show a wind power plant, the

Fig. 4 shows a rotor-driven generator, where at in

Fig. 5 illustrates the associated mechanical equivalent circuit, the

Fig. 6 shows a generator according to the older national patent application, the

Fig. 7 the corresponding mechanical equivalent circuit diagram showing, in

Fig. 8 shows the mechanical structure of a generator according to the invention, in which

Fig. 9 shows the associated mechanical equivalent circuit diagram

Fig. 10 shows a first embodiment of the device according to the invention, wherein in the

Fig. 11 shows a particularly inexpensive embodiment of the device according to the invention.

Fig. 4 shows a rotor-driven generator, best consisting of a fixed stand 36 and a rotatably mounted rotor 38 , as used in the wind turbine 2 of FIG. 1. The windings of the multi-pole stator winding 40 are connected to a multi-pole network 42 by means of terminal connections of the terminal clamp gate. A work machine (not shown) with a power P _mr rotates the rotor 38 with a mechanical angular velocity ω _mr . The angular velocity ω _{ms of} the fixed stator 36 of this generator is zero. Depending on the efficiency η _gen , the power P _elr delivered by the generator is correspondingly smaller than the mechanical power P _mr delivered by the driven machine. The network angular velocity ω _nr is equal to the product of the number of pole pairs p and the mechanical angular velocity ω _mr .

The model of the mechanical part of the generator according to FIG. 4 corresponds to an integrator 44 according to FIG. 5 with an integration time which is equal to the start-up time constant of the energy system, consisting of a working machine and rotor 38 of the generator. The mechanical angular velocity ω _mr results from the integration of the difference between the mechanical and electrical moments N _mr and M _elr in the air gap of the generator. These moments are related to the Netzwinkelge speed ω _nr . The differential torque, which is also referred to as the air gap torque, acts on the rotor 38 and the stator 36 of the generator.

In Fig. 6, a generator is shown, the stand 36 is rotatable via a worm gear 28 by means of a clutch 46 ver and the rotor 38 is driven by means of a machine not shown. The windings of the multi-pole stator winding 40 are each electrically connected by means of a slip ring 48 and a brush 50 to a terminal 52 of the generator. Such a generator is used in the wind turbine 2 according to FIG. 3. The work machine shown in detail with a mechanical power P _mr rotates the rotor 38 , which is rotatably mounted in the rotatable stand, with a mechanical angular velocity ω _mr . The angular velocity ω _mr in this generator is different from zero, a speed-variable drive (not shown here) having a mechanical power P _ms rotating the stator 36 via the worm gear 28 . The power P _els supplied by the generator is, depending on the efficiency gen, correspondingly smaller than the sum of the mechanical powers P _mr and P _ms delivered by the driven machine and drive. The network angular velocity ω _ns is equal to the product of the number of pole pairs p and the sum of the mechanical angular velocities ω _mr and ω _ms .

The model of this mechanical part of this generator is shown in more detail in FIG. 7 and corresponds to two integrators 44 and 54 . The integrator 44 has an integration time that is equal to the start-up time constant of the energy system, consisting of a work machine and rotor 38 of the generator. The integration time of the integrator 54 is equal to the on-time constant of the stator 36 of the generator and the variable-speed drive. The integration time of the integrator 54 is significantly shorter than the integration time of the integrator 44 . The mechanical angular velocity ω _{mr also} results from the integration of the difference between the mechanical electrical moments M _mr and M _elr in the air gap of the generator. This mechanical angular velocity ω _{mr of} the rotor 38 is superimposed on the mechanical angular velocity ω _{ms of} the stator 36 . This superposition is carried out by means of a summer 56 . The resulting mechanical angular velocity ω _m is the sum of the partial speeds ω _ms and ω _{mr of} the stator 36 and the rotor 38 of the generator.

In FIG. 8, the mechanical structure is shown of a generator according to the invention. This generator consists of a rotatable stand 36 and a rotatable rotor 38 . The stan of 36 is driven directly by a working machine, for example a rotor 4 , by means of the coupling 46 . The working machine with a mechanical power P _ms rotates the stand 36 with a mechanical angular velocity ω _ms . The windings of the multi-pole stator winding 40 are each electrically connected to a terminal connection 52 of the generator by means of a slip ring 48 and a brush 50 . A variable-speed drive 58 with a mechanical power P _mr rotates the rotor 38 of the generator with a mechanical angular velocity ω _mr . The variable-speed drive 58 consists of a low-pole motor 60 and a converter 62 . This low-pole motor 60 is linked directly to the rotor 38 of the generator by means of a clutch 64 . According to the energy conservation law, the generator power P _{els is} equal to the sum of the supplied mechanical power P _ms and P _mr multiplied by the efficiency η _{gen of} the generator.

The model of the mechanical part of the generator according to FIG. 8 is shown in more detail in FIG. 9. This mechanical part of the generator corresponds to two integrators 44 and 54 , which are linked together on the output side by means of a summer 56 . The integration time of the integrator 44 is equal to the start-up time constant of the working machine and the stator 36 of the generator, the integration time of the integrator 54 being equal to the start-up time constant of the drive and the rotor 38 of the generator. The integration time constant of the integrator 44 is much larger than the integration time constant of the integrator 54 . The mechanical angular velocity ω _{mr of} the rotor 38 results from the integration of the difference between the mechanical and electrical moments M _mr and M _elr in the air gap of the generator. The mechanical angular velocity ω _{ms of} the stator 36 also results from the integration of the difference between the mechanical and electrical moments M _ms and M _els in the air gap of the generator. The sum of the electrical moments M _{elr, s} acts equally on the stator 36 and the rotor 38 of the double-driven generator. The resulting mechanical angular velocity ω _m is equal to the sum of the partial angular velocities ω _ms and ω _mr by means of the summer 56 . The network angular velocity ω _ns is equal to the product of the number of poles p and the resulting mechanical angular velocity ω _m .

Because in stationary operation of this generator the equilibrium of the moments M _ms , M _mr and M _{elr, s} must be given in the air gap, the mechanical M _ms and M _mr and the electrical moments M _elr and M _{els must be} mutually and mutually the same. This means that the variable-speed drive 58 must be controlled so that the torque is the same in stationary operation.

Fig. 10 shows a first embodiment of the device for compensation of erfindungsge MAESSEN Leistungsschwankun gen .DELTA.P. This device has the generator shown in FIG. 8, consisting of the stator 36 driven directly by a rotor 4 and the rotor 38 driven directly by the variable-speed drive. The winding of the multi-pole stator winding 40 are electrically conductively connected to the network 12 via slip rings 48 , brushes 50 , terminal connections 52 and the circuit breaker 10 . A voltage measurement value acquisition 66 is arranged in the network 12 and is used to determine the network phase voltages u _{NR, S, T.} On the stator side, the generator has a voltage and current measurement value acquisition 68 and 70 , with which the stator voltages u _{1R, S, T} and the stator currents i _{1R, S, T are} measured. The stator 36 of the generator and the low-pole motor 60 of the rotational speed changeable drive 58 are each provided with a speed measuring value measurement 72 and 74 . As converter 62 of the variable-speed drive 58 , a voltage intermediate circuit converter is provided in this embodiment, which has an uncontrolled line-side converter 76 and a load-side pulse converter 78 . Such an inverter 62 with a downstream low-pole motor 60 is known from the drive technology. The line-side converter 76 can be connected to the circuit breaker 30 with the network 12 in an electrically conductive manner.

A regulating and control device 80 is provided so that the rotor speed n _{r of} the generator can be regulated by means of the variable-speed drive 58 . This regulating and control device 80 has a device 82 for generating a manipulated variable n _y with a downstream device 84 for generating a control variable Sν. The device 82 in turn has a power control device 86 , a rotor speed control device 88 and a setpoint generator 90 . The outputs of the setpoint generator 90 and the power control device 86 are linked to one another by means of a summer 92 , the output of which is connected to a setpoint input of the rotor speed control device 88 .

The power control device 86 has a comparator 94 and a power controller 96 which is connected downstream of the comparator 94 . The non-inverting input of this comparator 94 is connected to an output of a power setpoint generator 98 , the inverting input of the comparator 94 being linked to an output of a power actual value calculator 100 . The measured stator voltage u _{1R, S, T} and stator currents i _{1R, S, T are present} at the inputs of this power actual value calculator 100 , from which the actual power value P _{1 is} calculated using a stored equation.

The power setpoint generator 98 is used in a stochastically operating machine. This power setpoint generator 98 has a function generator 102 on the input side and a ramp generator 104 on the output side. The function generator 102 is connected on the output side to the input of the ramp generator 104 , a wind speed measured value V _wind being present at the input of the function generator 102 . At the output of the ramp generator 104 there is a stochastic power setpoint P ^* . An enable signal S _{FG is present} at a control input of the function generator 102 and the ramp generator 104 , which is generated after the circuit breaker 10 is closed. The function generator 102 and the ramp generator 104 are started by means of this release signal S _FG .

The setpoint generator 90 has a computing device 106 and a comparator 108 , the non-inverting input of which is connected to an output of the computing device 106 . The inverting input of this comparator 108 is linked to the output of the speed measurement value acquisition 72 , at the output of which a stator speed actual value n _s is present. A rotor speed setpoint n ^* _{r is present} at the output of the comparator 108 . The measured network phase voltages u _{NR, S, T are} supplied to the computing device 106 . From these network phase voltages u _{NR, S, T} , voltages of the positive sequence system are first eliminated, the zero crossings of which are evaluated. At the output of this computing device 106 there is then a speed setpoint n ^* _sy which is proportional to the network angular velocity ω _{N of} the network 12 .

The rotor speed device 88 has a comparator 110 and a speed controller 112 , which is connected downstream of the comparator 110 . The non-inverting input of this comparator 110 is connected to the output of the adder 92 and the inverting input of this comparator 110 is connected to the output of the speed measurement value 74, at whose output a measured rotor speed value n _r is pending.

This measured rotor speed actual value n _r is compared with a corrected rotor speed setpoint n ^* _Kr and a manipulated variable n _{y is} generated from a determined control deviation by means of the speed controller 112 such that this control deviation becomes zero.

Control signals S v for the pulse converter 78 of the converter 62 of the variable-speed drive 58 are generated from this manipulated variable n _y by means of the device 84 . Since this device 84 generates control signals Sν for a pulse converter 78 , this device 84 is also referred to as a modulator.

In Fig. 11, a particularly economical form of execution is illustrated of the inventive device. This embodiment differs from the embodiment according to FIG. 10 in that a slip ring rotor motor 114 is provided as the variable-speed drive 58 , which is linked to a controllable resistor 116 . The device 84 now generates a control signal S _R from the generated manipulated variable n _y , with the aid of which the controllable resistor 116 is adjusted in such a way that the actual rotor speed value n _{r is} equal to a corrected rotor speed setpoint n ^* _Kr .

The mode of operation of the device according to the invention for controlling power fluctuations ΔP according to FIG. 10 will now be explained:

At standstill, the stator 36 of the generator is held by means of a brake 118 . The double-driven generator is started by closing the circuit breaker 30 and the isolator 120 . As a result, the converter 62 of the variable-speed drive 58 is connected to the network 12 and is supplied with energy. Then the rotor speed control device 88 is released. The rotor 38 of the generator is now regulated to a calculated speed setpoint n ^* _sy . This speed setpoint n ^* _sy is proportional to the network angular velocity ω _{N of} the network 12 and is calculated by means of the computing device 106 from the measured network phase voltages U _{NR, S, T.} Since the stator 36 of the double-driven generator is held by means of the brake 118 , the actual stator speed value n _s is zero. The rotor speed setpoint n ^* _r is thus equal to the calculated speed setpoint n ^* _sy . Since, due to the braked stator 36 of the double-driven generator, no power P _{1 is} generated, the speed correction value n ^* _P determined as a function of an ascertained power fluctuation ΔP is zero, so that the corrected rotor speed setpoint n ^* _{Kr is} equal to that determined Rotor speed setpoint n ^* _r is. The rotor speed control device 88 regulates the actual rotor speed value n _r to the determined rotor speed setpoint value n ^* _Kr , which corresponds to a synchronous speed of the generator. By this speed control of the rotor 38 of the double-driven generator, a pole wheel voltage u _{P is} induced in the stator 36 , the frequency of which is equal to the angular velocity ω _{N of} the mains and the magnitude of the mains voltage u ₁ by means of an excitation (not shown ₎ .

If the induced magnet wheel voltage u _{P is} equal to the mains voltage u ₁ and the value of the actual power value P ₁ is zero, then the stationary load angle δ, which is the angle between the two voltage indicators u _P and u _1, is zero. This load angle δ also indicates the relative position of the rotor 38 to the stator rotating field. This state of the Ge generator is synchronous operation in idle mode. In this state, the power setpoint generator 98 is released by means of the release signal S _FG, the power switch 10 being closed beforehand. This is sicherge provides that the generator is connected to the network 12 without bumps. The brake 118 is then released, as a result of which the rotor 4 and thus the stator 36 of the double-driven generator are rotated by means of the wind. As a result, the actual stator speed n _{s increases} to a value corresponding to the prevailing wind. As a result of the rotary movement of the generator 36 , the rotor speed setpoint n ^* _{r is} reduced. The rotor speed control means 88 then controls the speed of the rotor 88 such that the rotor rotational speed value n _r of the modified rotor speed command value n ^* _r is tracked.

Power P _{1 is} generated by the driven stator 36 of the double-driven generator and fed into the network 12 . This actual power value P ₁ is compared with a desired power value P ^* derived from the wind speed V _wind . A speed correction value n ^* _{P is} determined from a determined power fluctuation ΔP, which corrects the rotor speed setpoint value n ^* _{r in} such a way that this power fluctuation ΔP is corrected. Assuming that the wind is constant, in the stationary state, the stator 36 of the double-driven generator rotates with the constant wind speed V _Wind and the rotor 38 with a constant speed n _r , which is equal to the synchronous speed and reduced by the constant stator speed. Actual value is n _s .

However, since the wind is stochastic, the generation of the power P _{1 of} the double-driven generator is also stochastic. This results in a stochastic power fluctuation ΔP, which results in a stochastically fluctuating speed correction value n ^* _P. By means of this stochaically fluctuating speed correction value n ^* _P , the rotor speed setpoint n ^* _{r is} corrected, whereby the speed n _{r of} the rotor 38 is regulated by means of the variable-speed drive 58 such that these stochastic power fluctuations ΔP are corrected. A constant power P ₁ is thus delivered to the network 12 .

If a synchronous machine is used as a double-driven generator, a proportional controller, also referred to as a P controller, is used as the power controller 96 . When using a synchronous machine as a double-driven generator, the speed correction value n ^* _{P is} zero in stationary load operation.

Is used as a double-drive generator Asynchronma machine, so power controller 96 is used as a propor tional-integral action controller, also known as PI controller described net used. When using an asynchronous machine as a generator, the speed correction n ^* _{P is} not equal to zero in stationary load operation. The reason for this is given by the torque characteristic of the asynchronous machine. The torque of the asynchronous machine is zero when the mechanical speed corresponds to the synchronous speed, which the rotor speed control device 88 would effect without the speed correction n ^* _P. The power control device 86 increases the rotor speed n _r above the synchronous speed and brings the slip of the asynchronous machine into the negative range, which corresponds to the generator operation.

Through the use of a variable-speed drive 58 , which drives the rotor 38 of a double-driven generator and by the fact that the working machine drives the stand of the 36 of this double-driven generator, the expensive transmission 6 between the working machine 4 and the generator is saved, but none expensive multi-pole generator must be used. A low-pole, inexpensive generator can be used as the generator, and a low-pole, inexpensive motor 60 can be used as the motor of the variable-speed drive 58 . If a slip ring rotor motor 114 is used as the variable-speed drive 58 instead of a converter-fed motor 60 , the most cost-effective embodiment of the device according to the invention is obtained.

In the representation of the device according to the invention the application for wind technology explained. This device However, the device can be used wherever the inte Gration time constant of the machine side at least  is twenty times greater than the integration time constant of variable speed drive side.

Claims (14)

1. A method for controlling power fluctuations (ΔP) of a generator driven by means of a stochastically rotating machine ( 4 ) with a stator ( 36 ) and a rotor ( 38 ), electrical power being removable from the stator, characterized in that the stator ( 36 ) of the generator is driven directly by the working machine ( 4 ), that the rotor ( 38 ) of the generator is driven directly by a variable-speed drive ( 58 ) of the type that a determined power fluctuation (ΔP) by changing the actual rotor speed value (n _r ) becomes zero. 2. The method according to claim 1, characterized in that as a function of a measured stator speed actual value (n _s ) and a calculated speed setpoint (n ^* _sy ), which is proportional to a network angular velocity (ω _N ) one on the stator ( 36 ) Generator connected network ( 12 ), a rotor speed setpoint (n ^* _r ) is determined, which is superimposed by a speed correction value (n ^* _P ) determined as a function of a determined power fluctuation (ΔP). 3. The method according to claim 1 or 2, characterized in that a Lei stungs fluctuation (ΔP) is determined as a function of a determined target power value (P ^* ) and a calculated actual power value (P ₁ ). 4. Device for controlling power fluctuations (ΔP) of a generator driven by means of a stochastically rotating machine ( 4 ) with a stator ( 36 ) and a rotor ( 38 ), electrical power being removable from the stator, characterized in that the stator ( 36 ) is rotatably mounted and provided with a clutch ( 46 ), that the rotor ( 38 ) is coupled to a clutch ( 64 ) with a variable-speed drive ( 58 ), that the stator ( 36 ) and the rotor ( 38 ) are each coupled egg ner speed measurement value acquisition ( 72 , 74 ) are provided that ei ne device ( 82 ) for generating a manipulated variable (n _y ) with a downstream device ( 84 ) for generating a control variable (Sν, S _R ) is provided that this Device ( 82 ) for generating a manipulated variable (n _y ) on the input side is linked to the outputs of the speed measured value recordings ( 72 , 74 ), and that the device ( 84 ) for generating a control variable (Sν, S _R ) is connected to a control input of the variable-speed drive ( 58 ). 5. The device according to claim 4, characterized in that the variable-speed drive ( 58 ) has a low-pole motor ( 60 ) and a converter ( 62 ). 6. The device according to claim 4, characterized in that the variable-speed drive ( 58 ) has a slip ring rotor motor ( 114 ). 7. Device according to one of claims 4 to 6, characterized in that the device ( 82 ) for generating a manipulated variable (n _y ) a power control device ( 86 ), a rotor speed control device ( 88 ) and a speed setpoint Image ner ( 90 ) has that the outputs of the speed setpoint generator ( 90 ) and the power control device ( 86 ) are linked by means of a summer ( 92 ) and that the output of the summer ( 92 ) with a setpoint input of the rotor -Speed control device ( 88 ) is connected. 8. The device according to claim 7, characterized in that the power control device ( 86 ) has a comparator ( 94 ) and a power controller ( 96 ) which is connected downstream of the comparator ( 94 ), whose non-inverting input with an output of a power setpoint generator ( 98 ) and its inverting input are connected to a power actual value calculator ( 100 ). That the rotor speed means (88) 9. A device according to claim 7, characterized in that a comparator (110) and a speed controller (112) which is connected downstream of the Ver same (110), whose non-inverting input connected to the output of the Summers ( 92 ) and its inverting input are connected to the output of the rotor-side speed measurement value acquisition ( 74 ). 10. The device according to claim 7, characterized in that the speed setpoint generator ( 90 ) has a computing device ( 106 ) and a comparator ( 108 ), the non-inverting input with an output of the computing device ( 106 ) and its inverting input with are connected to the output of the stator-side speed measurement value acquisition ( 72 ). 11. Device according to one of claims 4 to 10, characterized in that a voltage intermediate-circuit converter is provided as the converter ( 62 ). 12. The device according to one of claims 4 to 11, characterized, that featured as a generator a low-pole synchronous generator see is.   13. The device according to one of claims 4 to 11, characterized, that featured as a generator a low-pole asynchronous generator see is. 14. Generator for the device according to one of claims 4 to 11, characterized in that each winding of the multi-phase winding of the stator ( 36 ) by means of a slip ring ( 48 ) and a brush ( 50 ) with a terminal connection ( 52 ) of the generator is electrically conductive connected is.