JPH0586159B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an AC excitation generator-motor device, and in particular to a variable-speed pumped storage power generation system, etc., which contributes to system stability by transferring operating energy of rotating parts into and out of the power system. The present invention relates to an AC excitation generator-motor device suitable for realizing stable and low-loss startup of the device.

[Conventional technology]

As a conventional AC excitation generator/motor device,
As described in No. 53-7628 and Japanese Patent Publication No. 57-60645, there was a method of controlling active power and reactive power by controlling the secondary current of an AC exciter. These systems are suitable for power adjustment devices and power factor adjustment devices that respond quickly while preventing disturbances and step-outs.
A variable-speed pumped storage power generation system in which a cycloconverter is used as a frequency converter to constitute an AC-excited generator-motor and a pump-turbine is directly connected to an AC-excited synchronous machine is as announced at the 1985 Kansai Branch Federation of Electrical Engineering Associations. Suitable for frequency adjustment of power systems.

On the other hand, when starting an AC-excited generator motor, the normal operation method of AC excitation using a frequency converter can only operate within a certain speed range centered on the synchronous speed of the AC-excited synchronous machine, so a different starting operation method is required. It is necessary to use it.

When an AC-excited generator-motor device is used as a pumped storage power generation device, it is possible to accelerate from a stopped state to a speed that allows AC-excited operation by adjusting the opening degree of the guide vanes of the water turbine when operating the water turbine. During pumping operation, there is a method of using a starting motor in the same way as the starting method of a conventional DC-excited synchronous machine.

Among the conventional techniques mentioned above, in the method using a starting motor, the loss generated by the resistor provided on the secondary side of the starting motor is large, and the starting motor has a shaft end like the current collector ring of an AC-excited synchronous machine. There was a problem that the structure was complicated because it was installed in the

Furthermore, the method using a startup frequency conversion device has the problem that the device requires a large installation space.

All of the above conventional techniques require special equipment for starting, but Japanese Patent Laid-Open No. 59-63988 discloses a method that uses an AC excitation frequency converter even during starting. In this conventional example, it is necessary to operate the switching equipment to switch the operation mode at around 50% of the synchronous speed. Because of this, there was a problem that it could not be started smoothly.

In order to solve this problem, a patent application was proposed for a system in which the frequency converter is operated as a circulating current type cycloconverter at startup, eliminating circuit switching during startup.
61-186828.

This conventional example focuses on the fact that the capacity of the frequency converter required at startup is generally smaller than the capacity of the frequency converter for AC excitation, and uses the common insulating transformer winding that makes up the non-circulating current type cycloconverter. One of the positive group thyristor converters and the negative group thyristor converter that is being powered is de-energized from the transformer windings, and the two converters that are being powered from the other transformer windings are of reverse polarity. By stopping power supply to the converter and using a circulating current type cycloconverter, it is possible to accelerate to a variable speed range using induction motor operation.

This conventional example will be explained below with reference to the drawings. Fourth
In the figure, AC excited synchronous machine 1 is frequency converter 2a, 2
AC excitation is carried out by b and 2c. During normal operation, the switch 3 is closed, the switch 4 is opened, and the primary side of the AC excitation synchronous machine 1 is connected to the AC system.
The control mode switch 5a is closed and the control mode switch 5b is opened. Control mode switchers 6a and 6c are opened, and 6b
and 6d are closed.

Under the above conditions, the slip phase signal θ _s obtained from the difference between the detection signal θ _v of the AC system voltage phase detector 7 and the detection signal θ _r of the rotational phase detector 8 is input to the current control device 9 as the phase signal θ. . On the other hand, the voltage control device 11 transmits the current command signal I _d * to the current control device 9 so that the deviation between the voltage signal of the voltage detector 10 and the command value becomes zero.
Output to. Further, the power control device 13 outputs the current command signal I _q * to the current control device 9 so that the deviation between the detection signal of the active power detector 12 and the command value becomes zero. Furthermore, the power control device 13 has a function of correcting the active power command signal when the detection signal of the rotational speed detection device 14 falls within a set range or when the rate of change of the signal falls within a set range. ing.

It should be noted that the current command signals I _q * and I _d * are current command values expressed in orthogonal coordinates whose origin is the rotation center on a coordinate system that rotates together with the phase signal θ. The current command for each phase on the secondary side is given by orthogonal projection onto a straight line on a stationary coordinate system having a direction corresponding to the phase difference from the reference winding.

At startup, the switch 13 is opened, the switch 4 is closed, and the short circuit 15 short-circuits the primary side of the AC excitation synchronous machine 1. In the embodiment of FIG. 2, the resistor 15a
An example is shown in which starting torque is easily generated through the . The control mode switch 5a is opened and the control mode switch 5b is closed. Close the control mode switchers 6a and 6c,
6b and 6d are opened.

Under the above conditions, the detection signal θ _r of the rotational phase detector 8
and the slip phase command signal _θt from the starting speed control device 16 as the phase signal θ.
Enter. Here, the frequency of the slip phase signal θ _t is adjusted according to the torque command. Furthermore, the current command signals I _q * and I _d * are configured such that signals from the starting speed control device 16 are input to the current control device 9 .

FIG. 5 shows the configuration of one phase of frequency converters 2a, 2b, and 2c. The AC-excited synchronous machine 1 receives an input three-phase AC voltage adjusted to a predetermined voltage by transformer windings 17, 181, and 182 for insulation from the AC system, and generates an AC current through two anti-parallel thyristor converter groups. The configuration is such that the power is supplied to the secondary winding of the When performing normal AC excitation operation with the configuration shown in FIG. 1, the switches 191 and 192 are closed, but the operation mode is divided into two modes. The first operation mode is when two inverse-parallel converter groups are operated in parallel, and switch 2
01 and 202 are closed and the switch 21 is opened for operation. The positive group thyristor converter 221 and the negative group thyristor converter 231 operate as a first group of non-circulating current type cycloconverters. Similarly, thyristor converters 222 and 232 operate as a second group of non-circulating current cycloconverters. The two cycloconverters consist of thyristor converters with the same specifications and are controlled to share the output current equally. Circulating current between the two groups of cycloconverters is suppressed by current limiting reactors 241 and 242. The current limiting reactors 241 and 242 are magnetically coupled so that they have a low impedance with respect to a component supplied to the secondary winding as an output current, and a high impedance with respect to a circulating current component. Thyristor converter 221, 222, 23
1,232 inputs the current signals I ₁ and I ₂ of each group detected by the current detectors 251 and 252 to the current control device 9, and adjusts the phase of the control voltage command signal and gate blocking signal output from the current control device 9. Control device 261,2
62. The phase control device 261 for the first group is the phase control device 262 for the second group.
Since they have exactly the same configuration, the functions for the first group will be explained. Control voltage command signal EP ₁ ,
EN ₁ serves as a reference signal for determining the thyristor firing phase of the positive group thyristor converter 221 and the negative group thyristor converter 231, respectively. Gate blocking signal GP ₁
When GP 1 is level 1, the firing pulse to the thyristor of the positive group thyristor converter 221 is completely blocked, and GP ₁
When the level is zero, an ignition pulse is generated at the timing determined by the control voltage command signal _EP1 . The gate blocking signal GN ₁ is configured to block all firing pulses to the negative group thyristor converter 231 when at level 1.

Next, in the second operation mode, two groups of non-circulating cycloconverters are operated in series, and switches 201 and 202 are opened and switch 21 is closed. As a result, both current signals I ₁ and I ₂ are input to the current control device 9 as output current measurement signals. Functionally, only one of the current signals I ₁ and I ₂ may be used. The functions of phase control devices 261 and 262 are the same as in parallel operation.

FIG. 6 is a diagram showing an embodiment of the current control device 9,
The start signal SW is kept at level zero in the normal operation mode. When the signal SW is at zero level, the current command generator 27 operates. The current command generator 27 generates the AC excitation synchronous machine 1 from the current commands I _q * and I _d * and the phase signal θ.
Secondary side output current command signal for each phase I _a *, I _b *, I _c *
Output. This output current command signal is generated by the gate blocking signal generator 28 and the control voltage command signal generator 2.
9 is input. When the signal SW is at level zero, the switch 31a is closed by the switch operating device 30, and the switch 31b is opened. As a result, the output current command signal and current detection values I _a1 , I _a2 ,
A control voltage command signal is generated so that the deviation of I _b1 , I _b2 , I _c1 , and I _c2 becomes zero. When the second group of non-circulating current type cycloconverters are in parallel operation mode, the output current command value is multiplied by 1/2 by a mode switching signal (not shown), and then the deviation from the current detection signal is calculated.

The frequency converter 2 and current control device 9 during normal operation are shown in FIGS. 5 and 6 above. The case where the converter operates as a circulating current type cycloconverter at startup will be described below.

In FIG. 5, switches 191 and 192 are opened, and thyristor converters 231 and 232 are stopped. The switches 201 and 202 are closed, the switch 21 is opened, and the positive group thyristor converter 221 and the negative group thyristor converter 232 are operated as a circulating current type cycloconverter.

In FIG. 6, at startup, the startup signal SW becomes level 1, and the switch 31a is opened and the switch 31b is closed by the switch operation device 30. When the signal SW is level 1, the starting current command generator 32 operates and generates a current command signal I _a1 * for operating as a circulating current type cycloconverter.
Generates I _a2 *, I _b1 *, I _b2 *, I _c1 *, and I _c2 *. The operation of the control voltage command generator 29 is the same as during normal operation to realize startup. When the signal SW is level 1,
The gate blocking signal generator is always GP _a1 , GP _b1 ,
GP _c1 , GN _a1 , GN _b2 , GN _c2 to level 0, GP _a1 ,
GP _b1 , GP _c2 , GN _a1 , GN _b1 , and GN _c1 are held at level 1.

According to this method, when operating as a circulating current type cycloconverter, the gate signal to the thyristor converter that is inactive is blocked and at the same time the input circuit is opened, so that short circuits between the positive and negative group thyristor converters due to malfunction can occur. High reliability can be achieved by providing double protection. Theoretically, either gate signal blocking or input circuit opening can be omitted. Generally, it is economically advantageous to omit the input circuit opening function and omit the switches 191 and 192.

[Problem to be solved by the invention]

As mentioned above, in the conventional example explained in Figs. 4 to 6, the output voltage of the frequency converter becomes approximately 1/2 that of normal AC excitation operation at startup, but especially for the primary winding of the AC excitation synchronous machine. When the turn ratio of the secondary winding is large, there is a problem that the voltage capacity of the frequency converter is insufficient to output the necessary acceleration torque at the time of starting.

An object of the present invention is to provide an AC excitation frequency converter suitable for achieving a function of smoothly starting and accelerating to an AC excitation operating speed range using an AC excitation frequency converter without increasing the capacity of the AC excitation frequency converter. Our objective is to provide an excitation generator motor.

[Means to solve the problem]

In the above case, when the primary winding of an AC-excited synchronous machine is larger than the secondary winding, the output of the frequency converter, which is a circulating current type cycloconverter, is connected to the primary winding, and the secondary winding is This is achieved by shorting.

[Effect]

In order to achieve the above objective, when using a circulating current type cycloconverter only at startup, the output voltage and slip frequency are compared to when the output terminal is connected to the primary side of the AC excited synchronous machine. Under the same conditions, the output torque of the induction machine changes in proportion to the square of (Nr/Ns). Here
N _s and N _r indicate the primary and secondary windings, respectively. Therefore, when N _r is larger, the output torque increases in proportion to the square of the turns ratio, making it possible to achieve smooth and rapid starting.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.
Items with the same numbers as those in FIG. 4 used to explain the conventional example in FIG. 1 indicate the same items, so their explanation will be omitted to avoid duplication.

At startup, the output voltage of the frequency converter 2 is applied to the armature winding of the AC excitation synchronous machine 1 by opening the switches 3 and 34 and closing the switch 33. Further, the switch 35 is closed to short-circuit the excitation winding of the AC excitation synchronous machine 1.

Also, connect the tap of the main transformer 43 to the frequency converter 2.
Switch the taps so that the input voltage to the

Further, the control mode switch 5a is opened and the control mode switch 5b is closed. Control mode switchers 6a and 6c are closed, and 6b and 6d are opened.

Under the above conditions, the detection signal θ _r of the rotational phase detector 8
and the slip phase command signal _θt from the starting speed control device 16 as the phase signal θ.
Enter. Here, the frequency of the slip phase signal θ _t is adjusted according to the torque command. Furthermore, the current command signals I _q * and I _d * are configured such that signals from the starting speed control device 16 are input to the current control device 9 .

At startup, the switches 191 and 192 shown in FIG. 5 are opened for the frequency converter 2, and the thyristor converters 231 and 222 are stopped. switch 201,
202 is closed, the switch 21 is opened, and the positive group thyristor converter 221 and the negative group thyristor converter 23 are connected.
2 to operate as a circulating current type cycloconverter.

At startup, the startup signal SW becomes level 1 in FIG. 6, and the switch 31a is opened and the switch 31b is closed by the switch operation device 30. When the signal SW is level 1, the starting current command generator 32 operates and generates a current command signal I _a1 * for operating as a circulating current type cycloconverter.
Generates I _a2 *, I _b1 *, I _b2 *, I _c1 *, and I _c2 *. The operation of the control voltage command generator 29 is the same as during normal operation to realize startup. When the signal SW is level 1,
The gate blocking signal generator is always GP _a1 , GP _b1 ,
GP _c1 , GN _a1 , GN _b2 , GN _c2 to level 0, GP _a1 ,
GP _b1 , GP _c2 , GN _a1 , GN _b1 , and GN _c1 are held at level 1.

Accelerate the AC excitation synchronous machine 1 using the above method, and when the speed reaches a speed higher than that at which normal AC excitation operation is possible, shift the control voltage command signals EP ₁ and EN ₂ to change the currents I ₁ and I 2 of the frequency converter ₂ . After narrowing down to 0, the gate blocking signals GP ₁ and GN ₂ are set to level 1 and the frequency converter 2 is stopped. Next, after opening the switches 33 and 35,
The switch 34 is closed and the tap of the main transformer 43 is returned to the normal tap position.

Next, the control mode switch 5a is closed and 5b is opened. Control mode switchers 6a and 6c are opened,
6b and 6d are closed.

After starting the current control device 9 in the above state and establishing the voltage of the AC excitation synchronous machine 1, the switch 3 is closed and normal AC excitation operation begins. The operations of the frequency converter 2 and the current controller 9 are the same as in the conventional example.

According to this embodiment, by switching the tap of the main transformer at the time of startup, it is possible to increase the output voltage of the frequency converter 2, and the acceleration torque at the time of startup can be increased.

Furthermore, since the frequency converter 2 is stopped after shifting the control voltage command signal after acceleration, the influence of residual magnetic flux in the rotor circuit can be suppressed.

Hereinafter, embodiments of the second claim of the present invention will be described with reference to the drawings. The overall configuration of the AC excitation generator-motor device is the same as the second embodiment described in the first embodiment of claim 1.
It is the same as the figure, and the explanation will be omitted.

FIG. 2 shows the configuration of one phase of frequency converters 2a, 2b, and 2c. The configuration is such that three-phase AC voltage is fed to the antiparallel thyristor converters using transformer windings 17, 181, and 182 for insulation from the AC system. When performing normal AC excitation operation with the configuration shown in Figure 2, output short circuits 421 and 422 are opened, positive group thyristor converters 361 and 362 are connected in series, and negative group thyristor converters 371 and 372 are connected in series. The current limiting reactor 381, 3 is connected between the positive and negative groups.
Connected with 82. Current combiner 401, 402
combines the input currents of the positive group thyristor converters 421 and 422 to synthesize the converter output current. For the negative group, current combiners 411 and 412 are used. These output current composite values I ₁ and I ₂ are input to the current control device 9, and the control voltage command signal and gate blocking signal output from the current control device 9 are input to the phase control devices 391 and 392. . Since the phase control device 391 for the positive side thyristor converter and the phase control device 392 for the negative side thyristor converter have exactly the same configuration, the functions of the phase control device 391 for the positive group will be explained. The control voltage command signal EP serves as a reference signal for determining the thyristor firing phase of the positive group thyristor converter 361 and the positive group thyristor converter 362, respectively. When the gate blocking signal GP ₁ is at level 1, all firing pulses to the thyristor of the positive group thyristor converter 361 are blocked, and when GP ₁ is at level 0, firing pulses are sent at the timing determined by the control voltage command signal EP. Occur. Gate blocking signal GP ₂ is configured to block all firing pulses to positive group thyristor converter 362 when at level 1.

FIG. 3 is a diagram showing another embodiment of the current control device 9, and only the parts different from FIG. 6 will be explained. During normal operation, the signal SW is kept at level 0, and the control voltage command signal generator 29 outputs signals to the positive group and negative group thyristor converters of each phase. Unlike the case in Figure 6, there is no mode for parallel operation of two groups of non-circulating current type cycloconverters, so there is no need to generate separate control voltage command signals for the thyristor converters 361 and 362 in Figure 2, for example. do not have. Also, there is no need to multiply the current command value by 1/2 and calculate the deviation from the current detection signal.

The embodiments of the frequency converter 2 and the current control device 9 during normal operation have been shown in FIGS. 2 and 3 above. below,
The operation as a circulating current type cycloconverter at startup will be explained.

In Fig. 2, open the output short circuits 421 and 422,
Thyristor converters 361 and 372 are deactivated.
The positive group thyristor converter 362 and the negative group thyristor converter 371 are operated as a circulating current type cycloconverter.

In FIG. 3, at startup, the startup signal SW becomes level 1, and the switch 31a is opened and the switch 31b is closed by the switch operation device 30. When the signal SW is level 1, the starting current command generator 32 operates and generates a current command signal I _a1 * for operating as a circulating current type cycloconverter.
Generates I _a2 *, I _b1 *, I _b2 *, I _c1 *, and I _c2 *. The operation of the control voltage command generator 29 is the same as during normal operation to realize startup. When the signal SW is level 1,
The gate blocking signal generator is always GP _a1 , GP _b1 ,
GP _c1 , GN _a1 , GN _b1 , GN _c1 to level 1, GP _a2 ,
GP _b2 , GP _c2 , GN _a1 , GN _b1 , and GN _c1 are held at level 0.

According to the present invention, smooth startup can be achieved by simply adding an output short circuit even when series-parallel switching of the cycloconverter is not performed.

〔Effect of the invention〕

According to the present invention, AC excitation is performed using a non-circulating current type cycloconverter during normal operation, and acceleration to the normal operating speed region is achieved by induction motor operation using a circulating current type cycloconverter only during startup without using a separate power converter. Since the loss is small and there is no need to complicate the structure, reliability is maintained.
This has the effect of realizing smooth startup even when the number of turns of the excitation winding is large. Furthermore, since the capacity of the thyristor for the frequency converter is determined by the capacity of the non-circulating current type cycloconverter, there is an effect of realizing downsizing of the frequency converter.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of claim 1 of the present invention, FIG. 2 is a diagram showing the configuration of a frequency converter according to an embodiment of claim 2 of the present invention, and FIG. A diagram showing an embodiment of the current control system, FIG. 4 is a diagram showing the configuration of a conventional example, FIG. 5 is a diagram showing the configuration of a frequency converter also in the conventional example, and FIG. FIG. 1... AC excitation synchronous machine, 3, 33, 34, 35...
Switch, 27... Current command generator, 32... Starting current command generator, 43... Main transformer, 221, 222,
361, 362...Positive group thyristor converter, 23
1,232,371,372...Negative group thyristor converter, 241,242,381,382...Current limiting reactor, 421,422...Output short circuit.

Claims (1)

[Scope of Claims] 1. An AC excitation synchronous machine connected to an AC system via a switching device, and a plurality of sets of three-phase AC windings insulated from each other by a transformer from the AC system voltage, each of which A non-circulating current type cycloconverter having a configuration in which two sets of thyristor converters that output current in opposite directions are connected to the phase AC winding is connected to each phase on the secondary side of the AC excited synchronous machine to generate current. A frequency converter to be supplied, a secondary current command generator that generates an output current command value of the non-circulating current type cycloconverter that constitutes the frequency converter, and a current detector that detects the secondary current of the AC excitation synchronous machine. and a phase control device that controls the firing phase of the thyristor converter constituting the frequency converter so that the deviation between the secondary current command value and the secondary current detected value becomes zero. In the device,
a first switch provided between the primary side terminal of the AC excitation synchronous machine and the output terminal of the frequency converter; a short circuit on the secondary side of the AC excitation synchronous machine; this short circuit and the output of the frequency converter; a second switch provided between the terminals, a current limiting reactor provided between the positive group thyristor converter and the negative group thyristor converter constituting the non-circulating current type cycloconverter, and the non-circulating current type cycloconverter. Some of the multiple thyristor converters that make up the converter are stopped,
The frequency converter is connected as a circulating current type cycloconverter to the primary side of the AC excitation synchronous machine via the first switch to supply current, and the second switch is opened to supply the AC An alternating current excitation generator-motor device characterized by being provided with a starting current command generator that generates a current command signal for operating an induction machine by short-circuiting the excitation secondary side. 2. In claim 1, an output short circuit is provided at the output end of the converter that constitutes the frequency converter but is stopped during startup operation, and when operating as a circulating current type cycloconverter during startup, this output short circuit is provided. An alternating current excitation generator/motor device characterized by having a configuration in which a short circuit is short-circuited.