JP2010068574A - Vibration suppressing controller for power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform secure resonant suppressing control by giving damping characteristic to a shaft torsional resonance system. <P>SOLUTION: A PCS control unit includes an AC-DC converter body (G<SB>PCS</SB>) 100A for power storage and a PCS controller 100B, and an observer 400 estimates a phase angle θ<SB>G</SB>, etc. from a system voltage V<SB>G</SB>, field magnetic flux Φ<SB>0d</SB>, and a generator current I<SB>G</SB>, and gets a current I<SB>PCS</SB>where the vibration is suppressed and controlled by the PCS controller 100B. A voltage fixing control unit 500 gets a field current I<SB>Ef</SB>so that the system voltage V<SB>G</SB>may be constant, and controls the field magnetic flux of a current-torque converter 200 with field magnetic flux Φ<SB>0d</SB>corresponding to this field current I<SB>Ef</SB>. A power generation characteristic operating part 700 gets a system voltage (generator voltage) V<SB>G</SB>from generator turning angle velocity ω<SB>G</SB>and a field magnetic flux Φ<SB>0d</SB>. An observer includes common-dimensional observers or minimum-dimensional observers, and corrects the gain of a torque-current conversion coefficient part with the estimate of the magnitude of Φ<SB>0d</SB>of the field. Furthermore, it estimates the phase θ<SB>G</SB>of the magnetic pole and further gets generator turning angle velocity ω<SB>G</SB>by its differentiation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a generator vibration suppression control apparatus that suppresses axial torsional resonance vibration of a generator.

FIG. 10 is a schematic configuration diagram of a distributed power supply device combining a turbine generator and an AC / DC converter for power storage. In FIG. 10, GT is a gas turbine, SG is a synchronous generator, PCS is an AC / DC converter for power storage, BT Is a storage battery, and LD is a load. Further, I _G is a generator output current, and this output current I _G is supplied as an input current I _PCS to the power storage AC / DC converter _PCS and a load current I _L to the load LD. The power storage AC / DC converter PCS charges the storage battery BT by controlling the input current I _PCS , and supplies the power of the storage battery BT to the load LD via the power storage AC / DC converter PCS when the generator SG fails. It has a function.

  The turbine generator used in the above-described distributed power supply apparatus is normally connected between the gas turbine and the synchronous generator via a speed reducer or the like. When power is supplied to the load from such a distributed power supply device, if the load changes suddenly, a resonance system is formed from the inertia of the generator and the gas turbine and the rigidity of the shaft, and the influence of the control of the AC / DC converter PCS for power storage is affected. Depending on conditions, it may diverge.

  When the divergence occurs, low-frequency axial torsional vibration is generated between the generator shaft system and the AC / DC converter. As a means for suppressing this axial torsional vibration, the axial torsional vibration component is detected from the electrical quantity of the system, and vibration is generated. There are some which perform the suppression (see Patent Documents 1 and 2).

As another means, there is a method of suppressing low-frequency axial torsional vibration by controlling a thyristor controlled series reactor of a TCSC (Thyristor Controlled Series Capacitor) (see Patent Document 3).
JP 2001-333533 A Japanese Patent Application Laid-Open No. 08-242584 Japanese Patent Laid-Open No. 2003-111278

  In the above background art, the method of Patent Document 3 in which the TCSC is inserted in series in the system is less desirable because the configuration becomes complicated and the equipment cost increases in a small-scale system such as a distributed power supply / emergency power supply system. In addition, the methods of Patent Documents 1 and 2 have a problem that resonance suppression cannot be performed because the mechanical system of the generator is not taken into consideration.

  The object of the present invention has been made in view of the above circumstances, and provides a vibration suppression control device for a generator that simplifies the configuration, gives damping characteristics to a shaft torsional resonance system, and enables reliable resonance suppression control. There is to do.

In order to achieve the above object, the invention according to claim 1 constitutes a distributed power supply apparatus configured to include a generator driven by a turbine and an AC / DC converter for power storage to supply power to a load. The generator vibration which gives the damping characteristic to the axial torsional resonance system of the generator by controlling the current, electric power or torque of the generator by the AC / DC converter for power storage that controls the AC / DC converter for power storage In the suppression control device,
An observer is provided to estimate the phase θ _{G of} the magnetic pole and the field magnitude Φ _0d from the detected values of the generator voltage V _G and current I _G and the characteristic equation of the generator,
The AC / DC converter for power storage is characterized by giving damping characteristics to the torsional resonance system of the generator based on the estimated value by the observer.

The invention according to claim 2 is characterized in that the AC / DC conversion controller for power storage includes:
A resonance suppression control unit for obtaining a resonance suppression control current based on the generator rotation angular velocity;
A torque-current conversion coefficient unit for converting the output of the control unit into current;
A current command calculation unit for obtaining a current command based on the AC / DC conversion power command for power storage;
A first coordinate conversion unit which is provided with an AC / DC conversion output current for power storage and converts a fixed coordinate to a synchronous rotation coordinate using a magnetic pole phase to obtain a dq axis current;
An AC / DC conversion current command output unit for power storage that obtains a deviation output between the current command output from the current command calculation unit and the current obtained from the torque-current conversion coefficient unit;
A current controller to which a deviation output between the current output from the AC / DC conversion current command output unit for power storage and the dq axis current output from the first coordinate conversion unit is supplied;
A second coordinate converter that converts the synchronous rotation coordinates into fixed coordinates using the magnetic pole phase for the current output from the current controller;
An electric power storage AC / DC converter that obtains an AC / DC conversion current for electric power storage from the output obtained in the second coordinate conversion unit,
The observer is configured by a one-dimensional observer or a minimum-dimensional observer, and the gain of the torque-current conversion coefficient unit is corrected by an estimated value of the field magnitude Φ _0d .

In the invention according to claim 3, the observer estimates the phase θ _G of the magnetic pole and gives it to the first and second coordinate conversion units as a magnetic pole phase, and differentiates the estimated value of the magnetic pole phase θ _G to obtain the magnetic field. The resonance suppression control unit is provided with a generator rotational angular velocity ω _G.

The invention according to claim 4 is characterized in that the observer obtains a differential value of the field flux Φ _0d from the field current I _Ef of the generator and uses it for the observer calculation.

  As described above, according to the present invention, there is an advantage that the configuration can be simplified, the damping characteristic can be given to the shaft torsional resonance system, and reliable resonance suppression control can be performed.

  In particular, damping characteristics can be controlled in the axial torsional resonance system of the generator without detecting the generator speed. Further, since the magnetic pole position can be estimated based on the magnitude of the field magnetic flux of the generator, the torque control becomes accurate.

(Basic configuration)
Before describing the embodiment of the present invention, the basic configuration of the present invention will be described. FIG. 11 is a block diagram of a generator vibration suppression control system targeted by the present invention, where G _CT is a turbine speed control unit, G _CG is a generator excitation control unit (AVR), and G _CPCS is a power storage AC / DC. A conversion (PCS) control unit.

Turbine speed control unit G _CT the generator turbine torque output T _GT is given from the target angular speed omega _n and the generator rotational angular velocity omega _G in turbomachinery characteristic unit G _T. Turbine mechanical properties section G _T is connected by the generator mechanical properties section G _GM and the axial torque T _X.

The generator rotational angular velocity omega _G output from the generator mechanical properties section G _GM is given to the generator characteristic portion G _G, generator torque T _G from the generator characteristic portion G _G is the generator mechanical properties section G _GM Given to.

The generator characteristic portion G _G, the exciting current I _EX is applied from the generator excitation control unit G _CG, the generator output voltage V _G is output. This generator output voltage V _G is given to the generator excitation control unit G _CG , the PCS control unit G _CPCS and the load characteristic unit G _L.

G _PCS is a PCS characteristic section. The PCS characteristic section G _PCS is supplied with the generator output voltage V _G as the PCS voltage V _PCS and the PCS control section G _CPCS is supplied with the PCS current I _PCSR .

From PCS characteristic unit G _PCS, current I _PCS is outputted, is taken the sum of the load current I _L from the load characteristic portion G _L is the current I _G is supplied to the generator characteristic portion G _G.

  In the system configured as described above, the torsional resonance of the generator can be attenuated by controlling the current or power of the PCS. This will be described in detail below.

First, assuming that the generator / mechanical system model is a two-inertia system shown in FIG. 12, the block diagram is as shown in FIG. 12 and 13, J _T is the turbine inertia moment, K _T is the shaft torsional rigidity, T _X is the shaft torque, T _G is the generator torque, J _G is the generator inertia moment, and ω _T turbine rotational angular velocity (= dθ _T / dt), ω _G is the generator rotational angular velocity (= dθ _G / dt).

In FIG. 13, the transfer function G _GM from the generator torque T _G to the generator rotational angular velocity ω _G is expressed by the following equation (1) when the loss of the mechanical system is ignored.

Since the equation (1) has no damping term, when a sudden torque is applied to the generator, such as when the load suddenly changes, shaft torsional vibration is generated in the generator and is not attenuated. Therefore, in order to attenuate this vibration, the generator rotational angular velocity ω _G is fed back to the generator torque T _G via a block of K _A (s ² + β · s) as shown in FIG.

  With the configuration as shown in FIG. 14, the transfer function is expressed by the following equation (2), and an attenuation term can be added. In equation (2), the attenuation can be adjusted by setting the value of ζ.

FIG. 15 is a block configuration diagram in which the generator angular velocity ω _G is fed back to the PCS control unit G _CPCS to attenuate shaft torsional vibration. The PCS control unit (G _CPCS ) 100 includes the generator angular velocity ω _G and the generator output. The voltage V _G and the PCS power command P _PCS ^REF are input.

The PCS control unit G _CPCS is configured in detail as shown in FIG. 16, detects the generator output voltage V _G , obtains the phase angle of the voltage by a PLL, and uses this to perform coordinate conversion (from fixed coordinates to synchronous rotating coordinates , Fixed coordinates from synchronous rotation coordinates). In order to attenuate the shaft torsional vibration, the generator rotational speed, the generator output voltage, and the PCS current are detected and input to the PCS controller G _CPCS (details will be described later).

In FIG. 15, a three-phase current I _PCS ^abc is output from the PCS control unit (G _CPCS ) 100, and this current and the load current are added by the adder 101 and input to the current-torque conversion unit 200. The current-torque converter 200 calculates “k · Φ _Gd ” (where k is the number of generator pole pairs, Φ _{Gd is the} field magnetic flux), and the generator torque T _G is obtained as the output. The generator torque _TG is input to the generator mechanical characteristic section (G _GM ) 300, and the generator rotational angular speed ω _G is obtained as an output. The generator rotational angular speed ω _G is the PCS control section (G _CPCS ) 100. The shaft torsional vibration is attenuated.

16 to become a detailed block diagram of a PCS control unit (G _CPCS) 100, the resonance suppression control unit 11 the generator rotational angular velocity omega _G is ^{_{input, K A (s 2 + β}} · shown in FIG. 14 The processing of s) is performed. Here, in consideration of practicality, the processing is performed by adding the characteristics of the low-pass filter of the following equation (3).

When the generator angular velocity is processed by the resonance suppression control unit 11, it is output as a resonance suppression torque command, and this output is input to the torque-current conversion coefficient unit 12 to obtain the dq axis current I _R ^dq command as an output. , Given to the minus end of the first deviation portion 13.

A current command from the current command calculation unit 14 is given to the plus end of the first deviation unit 13. This current command is obtained by calculating the PCS power command P _PCS ^REF input to the current command calculation unit 14.

Reference numeral 15 denotes a PLL circuit unit to which the generator output voltage V _G is input. The phase angle θ _V ^* of the voltage is obtained by the PLL circuit unit 15, and the phase angle θ _V ^* is a fixed coordinate / synchronous rotation coordinate conversion unit 16. And the synchronous rotation coordinate / fixed coordinate conversion unit 17.

The fixed coordinate / synchronous rotating coordinate conversion unit 16 converts the three-phase current I _PCS ^abc into the dq-axis current I _PCS ^dq using the phase angle θ _V ^* , and gives it to the minus end of the second deviation unit 18. A PCS current command, which is a deviation output from the first deviation unit 13, is given to the plus end of the second deviation unit 18, and after the deviation output is input to the current controller 19, synchronous rotation coordinate / fixed coordinate conversion is performed. The signal is input to the unit 17, converted into a three-phase current I _PCS ^abc using the phase angle θ _V ^* , and output from the PCS unit 20.

  In the vibration suppression by the above configuration, a damping term is given to the axial torsional resonance system by detecting and feeding back the generator rotational angular velocity or the frequency of the generator voltage, thereby obtaining the vibration suppression. Here, since the generator rotation angular velocity or the frequency of the generator voltage is detected, for example, the generator terminal voltage is detected by a PLL and the generator rotation angle is calculated. There is a difference between the rotation angle and the detection delay of the PLL. For this reason, there is a possibility that resonance suppression may be hindered. Also, the current-torque conversion coefficient Φω varies depending on the exciting current of the generator, and accurate torque control may be difficult.

  Therefore, in the present invention, as shown in FIG. 1, the generator voltage, generator current, and field flux (field current) are detected, and the generator rotor angle and angular velocity are estimated by an observer, and vibration suppression control is performed by this estimation. I do.

The configuration of FIG. 1 will be described. PCS control unit in FIG. 15 (G _CPCS) 100 is shown separately to the power storage for AC to DC conversion device main body (G _PCS) 100A and PCS controller 100B, the phase of the system voltage V _G and the generator current I _G by observer 400 The angle θ _G , the field magnetic flux Φ _{0d and the} like are estimated, and the current I _PCS which is subjected to vibration suppression control by the PCS controller 100B is obtained. The constant voltage control unit 500 obtains the field current I _Ef so that the system voltage V _G is constant, converts the field flux Φ _0d corresponding to the field current I _Ef with a coefficient value 501, and a current-torque converter. The generator voltage is controlled to be constant by controlling the field flux of 200. The constant rotation speed control unit 600 compares the detected value of the generator angular speed ω _G with the system frequency set value, and controls the generator speed to be constant by turbine speed control. The power generation characteristic calculation unit 700 outputs a system voltage (generator voltage) V _{G based} on the generator characteristics from the generator angular velocity ω _G and the field flux Φ _0d .

  Hereinafter, the estimation of the generator rotor angle and angular velocity by the observer 400 will be described in detail.

  Usually, since the generator rotational angular velocity is kept almost constant by the turbine, the rotational angular velocity is assumed to be constant, and the saliency is assumed to be small. The generator is a synchronous generator, and the characteristic equation of the generator is expressed by equations (4) and (5) in the α-β coordinate system (see FIG. 2).

  The field magnetic flux due to the field current is expressed by equation (6). From the relationship of equation (7), when equations (4) and (5) are rewritten with Ld = Lq, equation (8) is obtained.

  The derivation of the above equation (8) shows the procedure in FIG.

  As the observer in FIG. 1, the configurations of the same-dimensional observer and the minimum-dimensional observer will be described below.

(A) Same Dimension Observer The same dimensional observer is configured as follows by a general method.

  When equation (9) is configured as a block diagram, it becomes FIG. 4. From equations (8) and (9), the equation for estimation error e is

(10) and an error due to χ occurs, but the change in the magnitude of the field magnetic flux is more gradual than that of rotation, and is constantly 0, so that the equation for the error is The position of the magnetic pole can be estimated without error by designing the observer gain so that Equation (11) becomes stable.

(B) Minimum dimensional observer A minimum dimensional observer for estimating Φ _0αβ is configured by equation (8).

As

Therefore, the equation for error is

So,

If the observer gain is designed so that the root of the characteristic equation (1) falls within the stable region, the error of the observer can be eliminated.

As a result, the following formula is obtained from formula (12) and formula (13).

  This equation (17) is configured as a block diagram as shown in FIG.

The design of the observer gain of Expression (15) will be described. The observer gain K _P in equation (15) is

Then,

Thus, the characteristic equation is Equation (20). In the S plane, β determines the real axis component and α determines the imaginary axis component.

  From equation (20), β determines the position on the real axis and α determines the position on the imaginary axis in the S plane.

(Embodiment 1)
As shown in FIG. 6, the generator voltage V _G and current I _G detection signals are converted into αβ coordinate system voltages V _αβ and I _αβ by the three-phase to two-phase converter 21, and these voltages are shown. The generator rotation angle θ _G and the field magnetic flux Φ _0d are estimated from the V _αβ and I _αβ by the observer 22, and the rotational angular velocity ω _G is obtained by differentiating θ _G by the differential calculation unit 23, and the resonance suppression calculation is performed. The same-dimensional observer expressed by the equation (9) is used as the observer 22.

Further, the torque / current conversion coefficient K _P of the torque-current conversion coefficient (K _P ) unit 12 is corrected by the estimated Φ _0d . Note that the coordinate converters 16 and 17 use θ _G to convert from fixed coordinates to synchronous rotating coordinates and from synchronous rotating coordinates to fixed coordinates. The concept of resonance suppression is the same control theory as in FIG.

  According to the present embodiment, the change in the magnitude of the field due to the constant voltage control is gradual, and since the observer is configured with its derivative set to 0, an error may occur. There is no need to detect the derivative of the magnetic current. In addition, the calculation is relatively easy.

(Embodiment 2)
FIG. 7 shows the PCS control unit, and as in FIG. 6, the generator voltage and current are detected. The generator rotational angle θ _G and field Φ _0d are estimated by an observer, and the rotational angular velocity is obtained by differentiating θ _G to perform resonance suppression calculation. Further, the torque / current conversion coefficient is corrected by the estimated Φ _0d . Also, coordinate transformation (fixed coordinates to synchronous rotating coordinates, synchronous rotating coordinates to fixed coordinates) is performed using the event machine rotation angle θ _G. The same-dimensional observer expressed by the equation (9) is used as the observer 22.

The difference is that the observer of the equation (9) sets the derivative of the field flux Φ _0d to 0, but in this embodiment, the equation (21) is used to change the field flux Φ _0d from the field current I _Ef through the derivative calculator 24. The differential value is calculated and used for the observer calculation. Thereby, more accurate rotation angle and field estimation can be performed.

  The concept of resonance suppression is the same control theory as in FIG.

  According to the present embodiment, by detecting a change in the size of the field and using it as an observer, it is possible to perform estimation that is more accurate and responsive than the first embodiment.

(Embodiment 3)
FIG. 8 shows the PCS control unit. As in FIG. 6, the generator voltage and current are detected, the generator rotation angle θ _G and the field flux Φ _0d are estimated by an observer, and the rotation angular velocity ω _G is obtained by differentiating θ _G to calculate resonance suppression. I do. Further, the torque / current conversion coefficient is corrected by the estimated Φ _0d . Further, coordinate transformation (fixed coordinates to synchronous rotating coordinates, synchronous rotating coordinates to fixed coordinates) is performed using θ _G. As the observer 25, a minimum dimension observer represented by the equation (17) is used. The concept of resonance suppression is the same control theory as in FIG.

  According to the present embodiment, the configuration of the minimum dimension observer makes it possible to reduce the order of the observer as compared with the embodiment 1.2 and simplify the calculation.

(Embodiment 4)
FIG. 9 shows the PCS control unit. As in FIG. 7, the generator voltage and current are detected, the generator rotation angle θ _G and the field flux Φ _0d are estimated by an observer, the rotation angular velocity is obtained by differentiating θ _G , and the resonance suppression calculation is performed. . Further, the torque / current conversion coefficient is corrected by the estimated Φ _0d . Further, coordinate transformation (fixed coordinates to synchronous rotating coordinates, synchronous rotating coordinates to fixed coordinates) is performed using θ _G. As the observer 25, a minimum dimension observer represented by the equation (17) is used. The concept of resonance suppression is the same control theory as in FIG.

  According to the present embodiment, the configuration of the minimum dimension observer makes it possible to reduce the order of the observer as compared with the embodiment 1.2 and simplify the calculation.

Further, in the observer of the equation (9), the derivative of the field flux Φ _0d is set to 0, but in this embodiment, the derivative of the field flux Φ _0d is calculated from the value of the field current and used for the observer calculation. Thereby, more accurate rotation angle and field flux can be estimated.

1 is a block configuration diagram showing Embodiment 1 of the present invention. The vector explanatory drawing of the α-β coordinate system. The figure explaining derivation | leading-out of Formula (8). Block diagram of the same dimensional observer. Block diagram of minimum dimension observer. FIG. 3 is a detailed block configuration diagram of the PCS controller according to the first embodiment. FIG. 5 is a detailed block diagram of a PCS controller according to a second embodiment. FIG. 5 is a detailed block diagram of a PCS controller according to a third embodiment. FIG. 5 is a detailed block diagram of a PCS controller according to a fourth embodiment. The schematic block diagram of a distributed power supply device. The block diagram of the vibration suppression control system of the generator made into object by this invention. Explanatory drawing which shows a generator and a mechanical system model. Block diagram of the generator / mechanical model. The block diagram of a generator and a mechanical system model when a generator rotation angular velocity is fed back to a generator torque. The block block diagram of FIG. The detailed block block diagram of the PCS control part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100A ... AC / DC converter main body for electric power storage 100B ... PCS controller 200 ... Current-torque converter 300 ... Generator mechanical characteristic part 400 ... Observer 500 ... Constant voltage control part 600 ... Constant rotation speed control part 700 ... Electric power generation characteristic calculation part DESCRIPTION OF SYMBOLS 11 ... Resonance suppression control part 12 ... Torque-current conversion coefficient part 14 ... Current command calculating part 15 ... PLL circuit part 16 ... Fixed coordinate / synchronous rotation coordinate conversion part 17 ... Synchronous rotation coordinate / fixed coordinate conversion part 19 ... Current controller DESCRIPTION OF SYMBOLS 20 ... PCS part 21 ... 3 phase-2 phase conversion part 22 ... Observer 23, 24 ... Differential operation part

Claims (4)

The power storage AC / DC converter is configured by a generator driven by a turbine and an AC / DC converter for power storage and configured to supply power to a load, and controls the AC / DC converter for power storage. In the generator vibration suppression control device for controlling the current, power or torque of the generator to give damping characteristics to the shaft torsional resonance system of the generator,
An observer is provided to estimate the phase θ _{G of} the magnetic pole and the field magnitude Φ _0d from the detected values of the generator voltage V _G and current I _G and the characteristic equation of the generator,
A generator vibration suppression control apparatus, wherein the AC / DC conversion controller for power storage gives a damping characteristic to a torsional resonance system of a generator based on an estimated value by the observer. The AC / DC conversion controller for power storage is:
A resonance suppression control unit for obtaining a resonance suppression control current based on the generator rotation angular velocity;
A torque-current conversion coefficient unit for converting the output of the control unit into current;
A current command calculation unit for obtaining a current command based on the AC / DC conversion power command for power storage;
A first coordinate conversion unit which is provided with an AC / DC conversion output current for power storage and converts a fixed coordinate to a synchronous rotation coordinate using a magnetic pole phase to obtain a dq axis current;
An AC / DC conversion current command output unit for power storage that obtains a deviation output between the current command output from the current command calculation unit and the current obtained from the torque-current conversion coefficient unit;
A current controller to which a deviation output between the current output from the AC / DC conversion current command output unit for power storage and the dq axis current output from the first coordinate conversion unit is supplied;
A second coordinate converter that converts the synchronous rotation coordinates into fixed coordinates using the magnetic pole phase for the current output from the current controller;
An electric power storage AC / DC converter that obtains an AC / DC conversion current for electric power storage from the output obtained in the second coordinate conversion unit,
2. The power generation according to claim 1, wherein the observer is configured by a one-dimensional observer or a minimum-dimensional observer, and the gain of the torque-current conversion coefficient unit is corrected by an estimated value of a field magnitude Φ _0d. Machine vibration suppression control device. The observer estimates the phase θ _G of the magnetic pole and gives it to the first and second coordinate conversion units as a magnetic pole phase, differentiates the estimated value of the magnetic pole phase θ _G and rotates the generator to the resonance suppression control unit. 3. The generator vibration suppression control device according to claim 1, wherein the vibration suppression control device is provided as an angular velocity ω _G. 4. The vibration suppression of the generator according to claim 1, wherein the observer obtains a differential value of the field magnetic flux Φ _0d from the field current I _Ef of the generator and uses it for the observer calculation. 5. Control device.

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