JP2001245495A - Variable speed power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve stability of effective power in the case that a power generation generator is synchronously operated in a variable speed power generation system. SOLUTION: The fluctuation component of speed is detected from the power generation generator, and given to the excitation current component of the rotor current of the power generation generator during synchronous operation start. Or an ramp current instruction is given to the torque current component of a rotor current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable speed power generation system, and more particularly to a control device for improving the stability of active power when a generator motor is operated at a fixed frequency.

[0002]

2. Description of the Related Art In a variable speed power generation system, there is a synchronous operation system in which only a voltage control is performed with a slip frequency kept constant so that a generator motor immediately returns to the range even if it deviates from a variable speed range. When this method is applied at the time of starting pumping, the torque current component of the generator motor is increased by a certain amount in order to suppress the fluctuation of the active power while increasing the active power. In the prior art, for example, as described in Japanese Patent Application Laid-Open No. 8-80094, when a generator motor is pumped and started, a torque current component of an optimum secondary current is converted from a system active power PL by a predetermined conversion formula (PL × A + B). A method has been proposed in which a target value is obtained and applied to a torque current component fixed immediately before switching to the synchronous operation method to suppress fluctuations in active power. However, in this method, it is difficult to bring the amount of excitation close to the optimal target value, for example, using the active power detection value P _L which fluctuates in a conversion formula, and setting the constants A and B to optimal values.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device for a variable speed power generation system which can stably control the active power without fluctuation even when an operation system in which a generator motor is excited at a fixed frequency is used. To provide.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to provide a variable speed motor by detecting a change in speed from the rotational speed of a generator motor and applying it to an exciting current component of a secondary exciting current of the generator motor at the same time as starting synchronous operation. Power fluctuation of the power generation system can be suppressed.

Alternatively, by giving a lamp current command or a step current command to the torque current component of the secondary excitation current of the generator motor at the same time as the start of the synchronous operation, power fluctuation of the variable speed power generation system can be suppressed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a configuration diagram of a variable speed pumped-storage power generation system having a generator motor and its control device, and FIG. 2 is a configuration diagram of a power fluctuation suppression circuit.

In FIG. 1, a stator winding of a generator motor 38 is connected to a power system V0 via a main transformer Mtr. The same main transformer Mtr as the exciting transformer
The exciter 39 is connected via Etr, and the exciter 39
Generates a variable frequency alternating current to generate
No. 8 is AC-excited. As the exciting device 39, an indirect AC converter that converts alternating current into direct current once and further converts this direct current into alternating current of a desired frequency, that is, a converter including a forward converter and an inverse converter may be used. Alternatively, a direct AC converter that directly converts AC into AC of a desired frequency without using DC may be used, that is, a so-called cyclo converter. A water turbine 40 is connected to the generator motor 38.

The exciting current controller 36 controls the exciting device 39 to output a variable frequency alternating current. The alternating current phase is determined from the voltage phase of the fixed frequency alternating current connected to the stator and the rotational phase of the generator motor. Then, the output voltage of the excitation device is controlled such that the current flowing through the rotor of the generator motor, that is, the excitation current has a predetermined magnitude and phase. As the control of the exciting current regulator 36, a current component Id in the d-axis direction (referred to as an exciting current component) for generating an induced voltage of the generator motor is electrically orthogonal to the current component Id, and is effective regardless of the induced voltage of the generator motor. A current component Iq in the q-axis direction in which only the power changes
The excitation current is separated into two axes (referred to as torque current component) for control. Since these axial directions can be uniquely determined from the voltage angular frequency of the fixed frequency AC connected to the stator and the rotational angular frequency of the generator motor, the axial direction can be determined from the outputs of the voltage angular frequency detector 32 and the rotational angular frequency detector 33. The slip angular frequency is calculated by the excitation angular frequency detector 34 to determine the d-axis direction and the q-axis direction.

The excitation current phase is calculated from the slip angular frequency output from the excitation angular frequency detector 34, and the excitation current detector 3
5 detects the d-axis current component (excitation current component) Id and the q-axis current component (torque current component) Iq from the variable frequency AC current using the result.

Since the control of the active power can be performed by controlling the current in the q-axis direction, the active power controller 24 outputs a q-axis current command (torque current command) Iq * as its output. In order to control the AC voltage, the current in the d-axis direction only needs to be controlled, so the AC voltage regulator 25 outputs a d-axis current command (excitation current command) Id * as its control output. The hold circuits 26 and 27 output the output I of the active power controller 24 based on a synchronous operation command circuit 29 described later.
q * and the output signal of the excitation angular frequency detector 34 are respectively held and output. The adder 28 adds an output Id * of the AC voltage regulator 25 and an output signal of a power fluctuation suppressing circuit 31 described later and outputs the result.

In the exciting current controller 36, the exciting current detector 3
The exciter 39 is controlled so that the current Id in the d-axis direction and the current Iq in the q-axis direction detected by step 5 coincide with the outputs of the hold circuit 26 and the adder 28, respectively. The output signal of the exciting current controller 36 is generated as a firing pulse by a gate pulse generator 37 and applied to an exciting device 39.

The AC voltage detector 22 detects the size of the power system VO, and the AC voltage adjuster 25 adjusts the d-axis current command Id * so that the detected AC voltage VL matches the voltage command value Vc *. To control the AC voltage.

The speed detector 20 detects the rotation speed of the generator motor. The speed adjuster 30 adjusts the active power correction amount ΔP so that the rotation speed of the generator motor detected by the speed detector 20 matches the speed command value Nc *. The active power calculator 23 calculates the active power correction amount △ P based on the external active power command Pc *.
And outputs an internal active power command value Ps *.

The active power controller 24 includes an active power detector 21
The active power of the system detected in step is the internal active power command value P
The active power of the system is controlled by adjusting the q-axis current command Iq * so as to match s *. As described above, a method of controlling the active power of the system so as to match the external active power command Pc * in the pumping operation state is called power priority control, and is applied to a variable speed pumping operation system.

The synchronous operation command circuit 29 shifts from operation to stop or outputs 0 or 1 at the time of pumping start, and stops or outputs the output signal of the power fluctuation suppression circuit 31. The power fluctuation suppression circuit 31 detects a change in speed based on the output of the speed detector 20.

FIG. 2 shows a detailed diagram of the power fluctuation suppressing circuit 31 of FIG. The power fluctuation suppressing circuit 31 includes a rotational speed fluctuation detecting circuit 50, a coefficient unit 51, and a multiplier 52.
The rotation speed fluctuation detecting circuit 50 detects the fluctuation of the rotation speed from the primary delay circuit and the differentiation circuit [s / (1 + Ts)]. The coefficient unit 51 adjusts the gain of the rotation speed fluctuation detection circuit 50. The multiplier 52 turns on and off the output of the coefficient unit 51 according to the synchronous operation command. As described above, in the variable speed pumped storage power generation system of the present embodiment, the active power of the system,
The generator voltage and the generator speed are controlled respectively.

In the variable speed pumped-storage power generation system according to the present embodiment, the synchronous operation command circuit 29
Is changed from 0 to 1, the fluctuation of the active power is promptly suppressed by the operation of the power fluctuation suppressing circuit 31. That is, the fluctuation of the active power is suppressed by applying the speed fluctuation △ ω detected from the rotation speed fluctuation detecting circuit 50 to the exciting current command Id * as damping, thereby suppressing the current fluctuation included in the exciting current command Id *. it can.

Next, the operation and effect of the embodiment of FIG. 1 will be described with reference to FIGS. 3 and 4,
a) is the active power command Pc * and the output of the active power detector 21 (active power P), b) is the reactive power, c) is the torque current command Iq *, and d) is the excitation current command Id *. FIG. 3 is an operation waveform diagram at the time of synchronous operation when the power fluctuation suppressing circuit 31 is not provided. When the active power command P is increased simultaneously with the start of pumping start, the active power is greatly fluctuated. The reason for this is that although the control system fixes the torque current command value Iq * during the synchronous operation and applies the excitation current at the output of the AC voltage regulator 25, the AC voltage regulator 2
The output of No. 5 increases the active power equivalently. FIG. 4 is an operation waveform diagram when the power fluctuation suppressing circuit 31 is added. By detecting the fluctuation of the rotation speed from the rotation speed fluctuation detector 50 and supplying it to the adder 28, the excitation current command Id is obtained.
* Is suppressed, and as a result, the fluctuation of the active power is suppressed. Therefore, when the power fluctuation suppressing circuit 31 is added, the active power fluctuation is suppressed, and the power priority control operates stably. Here, a description has been given of the power fluctuation suppression when the generator motor is pumped up, but the same effect is obtained when the generator motor is stopped.

As described above, by detecting the speed fluctuation from the generator motor 38 and applying it to the excitation current command Id *, stable control is possible without fluctuation of the active power even when the synchronous operation method is used. In addition, the reliability of the variable speed power generation system is improved.

FIG. 5 shows another embodiment of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
The main points different from FIG. 1 are an adding circuit 41 and a ramp generating circuit 42. The addition circuit 41 adds the output signal of the hold circuit 26 and the output signal of the ramp generation circuit 42. The lamp generation circuit 42 generates a lamp current command from a predetermined current command Iqr * based on the output of the synchronous operation command circuit 29.

FIG. 6 shows a vector diagram of the exciting current when there is no power fluctuation suppression circuit (when only the power priority control is applied). This figure shows that a shaft deviation occurs between the internal torque axis and the actual torque axis, and a current corresponding to the torque is generated. As a result, the fluctuation of the active power can be suppressed by adding the lamp current command to the torque current command Iq * from the ramp generation circuit 42 and compensating for the axis deviation of the d and q axes.

FIG. 7 is an operation waveform diagram when the embodiment of FIG. 5 is applied. A lamp current command is given to the adder 41 from the ramp generation circuit 42 simultaneously with the start of pumping start. As a result, the output fluctuation of the AC voltage regulator 25 is equivalently suppressed, and the fluctuation of the active power P is further suppressed. this is,
By giving a lamp current command to the q axis, the generator motor 3
This is because decoupling of the d and q axis currents of the 8 itself is performed.

As described above, the same effect as described above can be obtained even when the lamp current command is given to the torque current component of the secondary excitation current simultaneously with the start of the synchronous operation. The same effect can be obtained by giving a step current command stepwise instead of the lamp current command.

[0024]

According to the present invention, the power fluctuation of the variable speed power generation system can be suppressed, and the reliability of the system can be improved.

Further, according to the present invention, it is possible to operate the AC voltage control and the active power control without being disturbed, and to provide an optimal system for suppressing and stabilizing the fluctuation of the power system.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a variable speed generator motor system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a power fluctuation suppressing circuit according to an embodiment of the present invention.

FIG. 3 is an operation waveform diagram when there is no power fluctuation suppression circuit.

FIG. 4 is a waveform chart showing an operation when the embodiment of FIG. 1 is applied.

FIG. 5 is a configuration diagram of a variable speed generator motor system according to another embodiment of the present invention.

FIG. 6 is a dq current vector diagram of the generator motor itself when there is no power fluctuation suppression circuit.

FIG. 7 is a waveform chart showing an operation when the embodiment of FIG. 5 is applied.

[Explanation of symbols]

Reference Signs List 20 speed detector, 21 active power detector, 22 AC voltage detector, 23 active power calculator, 24 active power regulator, 25 AC voltage regulator, 26, 27 hold circuit, 28 Adder, 29: Synchronous operation command circuit, 30: Speed controller, 31: Power fluctuation suppression circuit, 32: Voltage angular frequency detector, 33: Rotation angular frequency detector, 34: Excitation angular frequency detector, 35: Excitation Current detector, 36: exciting current regulator, 37: gate pulse generator, 38: generator motor,
Reference numeral 40 denotes a water wheel, 42 denotes a ramp generation circuit, 50 denotes a rotation speed fluctuation detecting circuit, 51 denotes a coefficient unit, and 52 denotes a multiplier.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeta Ueda 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Akihiro Moka 3-chome, Sachimachi, Hitachi City, Ibaraki No. 1-1 Inside Hitachi, Ltd. Hitachi Works (72) Inventor Atsushi Nishioka 5-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture F Term in Hitachi, Ltd. EE01 EE20 FF01 GG02 GG04 GG05 GG07 HB07 JJ11 JJ23 JJ26 KK09 LL01 LL22 LL24 LL26 LL50 5H590 AA01 AA30 CA12 CC10 CD01 CD03 CD05 CE01 DD43 DD44 DD64 DD80 EA01 EA10 EB02 HA02 GA02 EB14 GA02 HA23

Claims (4)

[Claims] 1. A generator motor connected to an electric power system, a control device for controlling an exciting current component of a current flowing through a rotor of the generator motor, and a control device for controlling a torque current component, wherein the control device controls a torque current component. In the apparatus for exciting a current at a variable frequency, the control device includes a unit configured to detect a speed variation from a rotation speed of the generator motor, and a unit configured to add the speed variation to the excitation current component. Power generation system. 2. A variable-speed power generator according to claim 1, wherein when operating using a synchronous operation method in which the rotor current is excited at a constant frequency, the operation is switched to the synchronous operation method and at the same time a speed variation is added to the excitation current component. system. 3. A generator motor connected to an electric power system, a control device for controlling an exciting current component of a current flowing to a rotor of the generator motor, and a control device for controlling a torque current component, wherein the control device controls the torque current component. A variable-speed power generation system comprising: a controller for exciting a current at a variable frequency; wherein the control device includes a unit for generating a lamp current command and a unit for adding the lamp current command to the torque current component. 4. The variable speed as claimed in claim 3, wherein a predetermined lamp current command is added to a fixed torque current component immediately before switching to the synchronous operation mode when pumping the generator motor using the synchronous operation mode. Power generation system.