JPH11332293A - Control device of variable speed generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve stable control on system operation, by switching a current control gain according to a plurality of operation states of a variable speed generation system by giving a switch instruction to a power converter for excitation so that the rotor coil current matches a current instruction. SOLUTION: The modulation wave signal of a field current controller 32 is compared with a carrier signal by a gate pulse generator 41, and a PWM pulse signal that is obtained by the comparison result is fed to an inverse converter 40 as a power converter as a switch instruction. Then, d and q-axis current instructions Ids* and Iqs* for self starting are inputted to the field current controller 32 for switching a current control gain according to a plurality of operation states of a variable speed generation system, thus achieving stable control without depending on such operation conditions as self start and system operation, and obtaining the optimum effective power or reactive power control of the variable generation electric motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a control device for a variable speed power generation system.

[0002]

2. Description of the Related Art Recently, variable-speed pumped-storage power generation systems and variable-speed flywheel systems in which the secondary side is excited by a GTO converter or a cycloconverter are used for frequency adjustment and system stabilization of an electric power system. . In these systems, a self-starting method is used in which an exciting device and a starting device of a generator motor are used in consideration of a power plant space, economy, and the like. A winding type induction machine or an AC excitation synchronous machine is used as a generator motor of the variable speed power generation system. For this reason, the secondary excitation device requires stable current control from self-starting when the system is disconnected from the system and operation to system operation after the system is switched on. Conventionally, a current control method of this type is described in Japanese Patent Application Laid-Open No. 2-246797 and the document "Theory and Design of AC Servo System (Sogo Denshi Publishing Co., published May 8, 1995)". It has been known. That is, there has been proposed a non-interference method for decomposing a secondary excitation current into d- and q-axis components of a rotating coordinate axis to eliminate mutual interference therebetween. But,
This method is a general analysis of non-interference control, and if the stator-side leakage inductance of the generator motor changes greatly depending on self-starting and system operation, control cannot follow and the operating state is not good. There is a problem of becoming stable.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control device for a variable-speed power generation system that enables stable control during self-starting and during system operation after being connected to the system. .

[0004]

A control device for a variable speed power generation system according to the present invention provides a switching command to an exciting power converter so as to match a rotor winding current with a current command, and controls a plurality of variable speed power generation systems. The current control gain is switched according to the operation state of. Here, the plurality of operating states are, for example, a system side-by-side operating state in which the variable speed power generation system is connected to the system and a self-starting state in which the system is separated from the system. According to the present invention, since the current control gain is switched according to the operating state, stable control of the variable speed power generation system can be performed.

Preferably, the current command is a current command for adjusting the active power on the stator winding side to the active power command. Also, preferably, the rotor winding current is a d-axis or q-axis current in the rotating coordinate axis, the current command is a d-axis or q-axis current command, and the current control gain is a d-axis or q-axis current control gain, or The q-axis current is used as a q-axis current command for adjusting the active power on the stator winding side to the active power command. According to these, high-speed power control can be performed.

Further, the control device for a variable speed power generation system according to the present invention provides a switching command to an exciting power converter so that the stator winding voltage of the AC generator motor is adjusted to the voltage command. The voltage control gain is switched according to the operation state of. According to this configuration, stable power control can be performed similarly to the above configuration, and stable voltage control can be performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a configuration diagram of the variable speed pumped storage power generation system. In FIG. 1, the power system VO
Are connected to a generator motor 36 via a main transformer Mtr and a synchronous closing circuit breaker 33, while the synchronous closing circuit breaker 33 is connected to a short circuit 35 via a starting circuit breaker 34. An exciting device 37 is further connected from the same main transformer Mtr via an exciting transformer Etr.
7, a variable frequency alternating current is generated to excite the rotor winding of the generator motor 36. The exciter 37 is a forward converter (converter) 3 for converting AC to DC.
8. It comprises a capacitor 39 for reducing the output voltage ripple of the forward converter 38, and an inverter (inverter) 40 for further converting the DC of the capacitor 39 into an AC having a desired frequency. In addition, this exciting device 37 can also be constituted by a cycloconverter.

The inverter 40 is controlled by the exciting current regulator 32 to output a variable frequency alternating current. The phase of the alternating current is determined by the voltage phase of the fixed frequency alternating current connected to the stator and the rotational phase of the generator motor. And the output voltage of the excitation device is controlled such that the current flowing on the rotor side of the generator motor, that is, the excitation current has a predetermined magnitude and phase. The excitation current regulator 32 is controlled by a current component Id in the d-axis direction that generates an induced voltage of the generator motor and a q-axis that is electrically orthogonal to the current component Id and changes only the active power regardless of the induced voltage of the generator motor. The control is performed by decomposing the exciting current into two axes of the current component Iq in the direction. These axial directions can be uniquely determined from the fixed angular frequency AC voltage angular frequency connected to the stator side and the rotational angle frequency of the generator motor, so that the output from the voltage angular frequency detector 28 and the rotational angular frequency detector 29 can be determined. The slip angular frequency ωs * is calculated by the excitation angular frequency detector 30 to determine the d-axis direction and the q-axis direction. The switch element SW1 has a slip angular frequency command at the time of self-starting △ ωs
* And a switch circuit for switching the output of the voltage angular frequency detector 28.

The exciting current detector 31 includes a current detecting means 50.
The excitation current phase is calculated from the ωs * calculated by the excitation angular frequency detector 30 with the AC current of the variable frequency detected by the above, and the current component (reactive current) Id on the d-axis and the current component (q Active current) Iq is detected.

Since the control of the active power can be performed by controlling the current in the q-axis direction, the active power controller 21 outputs a q-axis current command Iq * as its control output. Further, since the control of the AC voltage can be performed by controlling the current in the d-axis direction, the AC voltage regulator 27 outputs a d-axis current command Id * as its control output.

The exciting current adjuster 32 controls the current in the d-axis direction and the current in the q-axis direction detected by the exciting current detector 31 so as to match the outputs of the AC voltage adjuster 27 and the active power adjuster 21, respectively. I do. The output signal (modulated wave signal) of the exciting current controller 32 is compared with the carrier signal by the gate pulse generator 41, and the PWM pulse signal obtained thereby is transmitted to the inverter 40 by a switching command (gate signal).
give. On the other hand, d and q axis current commands Ids * and Iqs * for self-starting are input to the excitation current controller 32. By individually providing the current command for the self-starting in this way, as described later, switching of the control gain and stable current control according to the operating state of the system can be performed. It should be noted that Iqs *
May be provided.

An AC voltage detector 26 detects the size of the power system VO, and an AC voltage regulator 27 adjusts the d-axis current command Id * such that the detected AC voltage VL matches the voltage command Vc *. To control the AC voltage.

The speed detector 25 detects the rotation speed of the generator motor. The speed adjuster 23 adjusts the active power correction amount ΔP so that the rotation speed of the generator motor detected by the speed detector 25 matches the speed command value Nc *. The switch element 8 constitutes another method of self-starting.
3 is output to the active power calculator 22 and the q-axis current command I.
qs * is a switch circuit for switching to qs *. Active power calculator 22 adds active power correction amount ΔP to external active power command Pc * and outputs internal active power command value Ps *.

The active power controller 21 includes a current detecting means 51
, The active power of the system detected by the active power detector 24 matches the internal active power command value Ps * from the output current from the generator motor to the system detected by the above and the output voltage of the generator motor detected by the voltage detecting means 60. The active power of the system is controlled by adjusting the q-axis current command Iq *.

On the other hand, the forward converter 38 is controlled by the voltage regulator 42 based on the input current and the output voltage of the forward converter so that the DC voltage is constant, and a switching command is given from the gate pulse generation circuit 43. . As described above, the variable speed pumped storage power generation system controls the active power of the system. The operation as the variable-speed power generation system is performed by turning on the synchronous closing circuit breaker 33, opening the starting circuit breaker 34, and switching element SW1.
The b-side, d-axis current command Ids * and the q-axis current command Iqs * are separated, and both are performed substantially under the condition of “0”. On the other hand, in the case of self-starting, the circuit breaker 33 for synchronizing is opened to short-circuit the primary side of the generator motor, and the circuit breaker 34 for starting is closed to short-circuit the primary side of the generator motor 36. Subsequently, the switch element SW1 is set to the a side, and the d and q-axis current commands Ids * and Iqs * are given (Id * and Iq * are separated) so that the generator motor 36 has the slip frequency ωs.
* Increase speed according to.

According to the study of the present inventors, in the variable speed pumped storage power generation system, the primary side of the generator motor 36, that is, the stator side, is at the time of self-starting, at the time of AC voltage control before the system is connected, and after the system is connected. The impedance greatly changes under conditions such as system operation. FIG. 2 shows an equivalent circuit for one phase of the generator motor 36 (resistance is ignored). As shown in the drawing, the leakage inductance on the rotor side is constant, but the leakage inductance on the stator side is increased by about 20% in self-starting with AC voltage control and about 60% in system operation. Therefore, in order to perform high-speed and stable current control over the operating conditions, that is, the entire range of the stator-side impedance, it is necessary to switch the control gains of the d- and q-axis currents. As another method of self-starting, the q-axis current command I
The speed can be similarly increased by adding the output ΔP of the speed controller 23 instead of q *.

FIG. 3 shows a detailed view of an example of the exciting current regulator 32 when performing self-starting and system operation according to the present invention. In this example, a non-interference control gain is switched using a non-interference control method. Switch element SW2, SW3
Is the d, q axis current command Ids during self-start and system operation
*, Iqs * and a switch circuit for switching between Id * and Iq *, and the d-axis current controller 1 calculates a deviation between the d-axis current command Id * or Ids * and the reactive current Id, and obtains a d-axis voltage command ed1 *. Is calculated. On the other hand, the q-axis current controller 2
The shaft current command Iq * or Iqs * and the effective current Iq
Is calculated, and a q-axis voltage command eq1 * is calculated. The non-interference control circuit 10 includes multipliers 3 and 4, self-start leakage inductance constants 5a and 5b corresponding to control gains, system operation leakage inductance constants 5b and 6b, and switch elements SW4 and SW5. The switch circuit is switched according to the self-start and system operation, and the compensation voltages ed2 * and eq2 * are calculated and output. The subtractor 7 subtracts the output ed1 * of the d-axis current controller 1 and the output ed2 * of the switch SW5 to obtain a d-axis voltage command e.
A circuit for outputting d *, and the adder 8 includes an output eq1 * of the q-axis current regulator 2 and an output eq2 * of the switch SW4.
And outputs a q-axis voltage command eq *. The two-phase / three-phase converter 9 outputs three-phase voltage commands eu *, ev *, ew * from the d and q-axis voltage commands ed * and eq * based on the reference phase signal.

In the above-mentioned circuit, at the time of self-starting, by setting the switch elements SW2 to SW5 to the a side, predetermined d and q axis currents Id and Iq flow through the generator motor 36 to accelerate according to the slip frequency ωs *. Is done. Subsequently, when the speed of the generator motor 36 reaches the vicinity of the synchronous speed, the system operation is started. For this reason, by setting the switch elements SW2 to SW5 to the b side, the system can execute the d and q axis current commands Id *,
It operates according to Iq *. As a result, stable current control can be performed by switching the non-interference control gain according to self-starting and system operation, and reliability can be further improved.

As described above, the secondary excitation current of the generator motor is decomposed into the d- and q-axis components of the rotating coordinate axis and controlled, and the control gains of the d- and q-axis components are provided for each self-start and system operation. By switching the control gain according to both operations, stable current control can be performed from self-starting to system operation, so that reliability can be improved.

FIG. 4 shows another embodiment of the present invention. Figure 1
The same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. The difference from FIGS. 1 and 3 is that the slip angular frequency calculator 4
3, where the reference phase generator 44 and the switch element 10 are provided. The slip angular frequency calculator 43 calculates the slip angular frequency ωs * (ωs * = 1 / T ₂ · Iqs * / Ids) from the output Iqs * of the speed controller 23 and the d-axis current command Ids *.
*) Is calculated. The switch element 10 is a switch circuit for switching between self-start and system operation, and the reference phase generator 44 is a slip angular frequency (ωss * or ωs *).
Is a circuit for generating SINθ and COSθ serving as reference phases of the two-phase / three-phase converter 9 from. At the time of self-starting, all the switch elements (SW2, SW3, SW10) are set to the a side, and the speed command Nc * (ωc *) is given.
The slip angle frequency ωs * is calculated according to the rotation frequency ωr, and the speed can be increased in the same manner as described above.

FIG. 5 shows another embodiment of the present invention. In the variable-speed power generation system, the circuit impedance on the generator motor stator (primary) side also greatly changes between the open state and the system operation in the AC voltage control, similarly to the current control system. Therefore, by switching the compensation gain of the AC voltage regulator 27, stable AC voltage control can be performed. The AC voltage regulator 27a is set with the compensation gain before the system is connected, and the AC voltage regulator 27b is set with the compensation gain after the system is connected. As a result, stable and high-response AC voltage control can be performed from the open state of the generator motor stator (primary) side to the system operation, thereby improving reliability. In the case where the current control gain is not changed, high-speed voltage control is possible by setting the voltage control gain in consideration of the transfer function of the load and the current control system according to the conditions.

Similarly, when the ACR gain is switched at the same time as the AVR gain is switched, an optimum response can be obtained.

FIG. 6 shows another embodiment of the present invention. If the aforementioned AC voltage control is not performed stably, the AC voltage of the generator motor stator (primary) fluctuates, and the active power control system becomes unstable. Therefore, the compensation gain of the active power regulator 21b is switched according to the output VL of the AC voltage detector 26. Thereby, even if the AC voltage control system becomes unstable, the active power control is stable and the active power control with high response can be performed, so that the reliability is improved. Even when the current control gain is not changed, high-speed active power control is possible by setting the active power control gain in consideration of the load and the transfer function of the current control system according to the conditions.

FIG. 7 shows an exciting current controller according to another embodiment of the present invention. The same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. The difference from FIG. 3 is that the non-interference control of the d- and q-axis currents does not change the non-interference control gain, but changes the gains of the d-axis current regulator 1 and the q-axis current regulator 2 instead. . Integral constant 11 and proportional constant 1
Reference numerals 2 and 13 denote compensation gains for the d-axis current and the switching element SW6
Is a switch for switching the proportional constants 12 and 13,
The adder 14 outputs the output of the switching element SW6 and the integration constant 1
This is a circuit for adding the output of 1 and outputting ed1 *. Similarly, the integral constant 16 and the proportional constants 17 and 18 are the compensation gain of the q-axis current, and the switch element SW7 is the proportional constant 17
And an adder 19 are a circuit for adding the output of the switch element SW7 and the output of the integration constant 16 and outputting eq1 *. In this embodiment,
Even if the non-interference control gain is set to a constant value (for example, a starting inductance constant) and the gain of the proportional constant is switched by the switch elements SW6 and SW7 according to the load condition, the interference of the d and q-axis currents is suppressed. Can be. If a means for switching according to the status of the system to which the system is connected is used, optimal operation can be performed even in the event of a system failure (one line / two lines).

[0025]

According to the present invention, stable control can be performed regardless of operating conditions such as self-starting and system operation. Therefore, optimal active power or AC voltage (or reactive power) control of a variable speed generator motor can be performed. Can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a variable speed pumped storage power generation system according to an embodiment of the present invention.

FIG. 2 is a detailed diagram for explaining a change in impedance according to operating conditions.

FIG. 3 shows an example of an exciting current regulator according to the present invention.

FIG. 4 shows another embodiment of the present invention.

FIG. 5 is a circuit configuration diagram of AC voltage control according to another embodiment of the present invention.

FIG. 6 is a circuit configuration diagram of active power control in another embodiment of the present invention.

FIG. 7 shows an exciting current regulator according to another embodiment of the present invention.

[Description of Signs] 1 ... q-axis current regulator, 2 ... d-axis current regulator, 3,4 ... multiplier, 5a-5b ... leakage inductance constant for self-starting, 6a-6b ... leakage inductance constant for system operation, 7 ... subtractor, 8, 14, 19 ... adder, 9 ... 2 phase /
3-phase converter, 10: non-interference control circuit, 11, 16: integration constant, 12, 13, 17, 18: proportional constant, SW1 to S
W9: Switch element, Mtr: Main transformer, Etr: Exciting transformer, Pc *: Active power command value, Nc *: Speed command value, Vc *: Voltage command value, VL: System voltage detection value, Id
* ... d-axis current command value, Id ... d-axis current detection value, Iq * ...
q-axis current command value, Iq: q-axis current detection value, 21: active power controller, 21b: active power controller (with compensation gain switching function), 22: active power calculator, 23: speed controller, 24 ... Active power detector, 25 ... Speed detector, 26 ...
AC voltage detector, 27: AC voltage regulator, 27a: AC voltage regulator (compensation gain before system parallelization), 27b: AC voltage regulator (compensation gain after system parallelism), 28: voltage angular frequency detector, 29: rotational angular frequency detector, 30: exciting angular frequency detector, 31: exciting current detector, 32: exciting current adjuster, 33: synchronous closing circuit breaker, 34: starting circuit breaker, 3
5 Short circuit, 36 Generator motor, 37 Frequency converter, 38 Forward converter, 39 Capacitor, 40 Reverse converter, 41, 43 Pulse generator circuit, 42 Voltage regulator,
43: slip angular frequency calculator; 44: reference phase generator.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Mitsuyuki Honbu 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Akihiro Moka 3-chome, Sachimachi, Hitachi City, Ibaraki Prefecture No. 1 Inside Hitachi, Ltd. Hitachi Plant

Claims (21)

[Claims] 1. A control device for a variable speed power generation system comprising an AC generator motor and an exciting power converter connected to a rotor winding of the AC generator motor, wherein a rotor winding current is adjusted to a current command. A switching device is provided with a switching command to the exciting power converter to switch a current control gain according to a plurality of operating states of the variable speed power generation system. 2. The control device for a variable-speed power generation system according to claim 1, wherein said plurality of operating states include a system parallel state and a self-starting state. 3. The current command according to claim 2, wherein the current command is a current command for adjusting the active power on the stator winding side to the active power command in a system parallel state, and a current command for a self-starting state. A control device for a variable-speed power generation system, comprising: 4. The method according to claim 1, wherein the current command is a current command for adjusting the voltage on the stator winding side to a voltage command in a system parallel state, and a current command for a self-starting state. A control device for a variable speed power generation system, comprising: 5. The method according to claim 1, wherein the rotor winding current is a current component on a rotating coordinate axis of an output current of the power converter detected by current detection means, and the current command is a current component command. A control device for a variable-speed power generation system, comprising: 6. The control device for a variable speed power generation system according to claim 5, wherein said plurality of operating states include a system parallel state and a self-starting state. 7. The apparatus according to claim 5, wherein the current component is a q-axis current, the current component command is a q-axis current command, and the current control gain is a q-axis current control gain. Control device for variable speed power generation system. 8. The control device for a variable speed power generation system according to claim 7, wherein said plurality of operation states include a system parallel state and a self-start state. 9. The system according to claim 8, wherein the q-axis current command is:
A variable speed power generation system comprising: a q-axis current command for adjusting the active power on the stator winding side to the active power command in a system parallel state; and a q-axis current command for a self-starting state. Control device. 10. The method according to claim 5, wherein the current component is a d-axis current, the current component command is a d-axis current command,
A control device for a variable-speed power generation system, wherein the current control gain is a d-axis current control gain. 11. The control device for a variable speed power generation system according to claim 10, wherein said plurality of operation states include a system parallel state and a self-start state. 12. The d-axis current command according to claim 11, wherein the d-axis current command is a d-axis current command for adjusting a voltage on a stator winding side to a voltage command in a system parallel state, and a d-axis current command for a self-starting state. A control device for a variable speed power generation system, comprising: a current command. 13. The method according to claim 5, wherein the current components are a d-axis current and a q-axis current, the current component commands are a d-axis current command and a q-axis current command, and the current control gain is d.
A control device for a variable speed power generation system, wherein the control device has a shaft current control gain and a q-axis current control gain. 14. The d-axis current control according to claim 13, further comprising current adjusting means for the d-axis current and the q-axis current, and a non-interference control circuit for the d-axis current and the q-axis current. A variable speed power generation system control device, wherein the gain and the q-axis current control gain are current control gains of the non-interference control circuit. 15. The d-axis current control according to claim 13, further comprising current adjusting means for the d-axis current and the q-axis current, and a non-interference control circuit for the d-axis current and the q-axis current. A control device for a variable speed power generation system, wherein the gain and the q-axis current control gain are current control gains of the current adjusting means. 16. The control device for a variable speed power generation system according to claim 15, wherein said current adjusting means includes an integral and a plurality of proportions, and switches said current control gain by switching said plurality of proportions. 17. The apparatus according to claim 10, further comprising a plurality of AC voltage adjusting means for generating a d-axis current command for adjusting the voltage on the stator winding side to the voltage command and having mutually different compensation gains. A control device for a variable-speed power generation system, wherein the means is switched according to a plurality of operating states of the variable-speed power generation system. 18. A method according to claim 7, wherein a q-axis current command for adjusting the active power on the stator winding side to the active power command is created, and the compensation gain is switched according to the voltage on the stator winding side. A control device for a variable speed power generation system, comprising: an active power adjusting means. 19. A control device for a variable speed power generation system comprising an AC generator motor and an exciting power converter connected to a rotor winding of the AC generator motor, wherein a stator winding voltage of the AC generator motor is provided. A switching command is given to the excitation power converter so as to match the voltage command with a voltage command, and a voltage control gain is switched according to a plurality of operating states of the variable speed power generation system. 20. A variable speed power generation system according to claim 19, wherein a plurality of AC voltage adjusting means having different compensation gains are provided, and said plurality of AC voltage adjusting means are switched in accordance with said plurality of operating states. Control device. 21. The control device for a variable speed power generation system according to claim 19, further comprising: an active power adjusting means for switching a compensation gain according to a voltage of said stator winding.