JPH05284798A - Ac-excited dynamotor - Google Patents

Abstract

PURPOSE:To add a function for operating a synchronous machine characteristics, in the case of stopping generation, and starting pumping, to an AC-excited dynamotor since an operation of the characteristics at the time of stopping the generation, starting pumping though the dynamotor can be output-controlled rapidly and accurately as compared with a conventional synchronous machine when applied to a variable speed pumped storage hydroelectric generator system. CONSTITUTION:A 2-phase output of a slip phase detector 9 is shifted from outputs a slip phase calculator 13, a phase compensating calculator 37 to outputs of an oscillator output calculator 38, a synchronous operation time phase calculator according to a command from a state switching logic 33 at the time of stopping generation, starting initiation of pumping. After the initiation of pumping is completed, Iq is regulated by an Iq regulator 39, an Iq controller 41 to be reversely shifted from that at the time of stopping the generation, starting the initiation of the pumping. Thus, an operation by synchronous machine characteristics is executed to obtain stopping of generation, starting pumping of easy operation safely in a variable speed pumped storage hydroelectric generator system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable speed generator-motor device and a flywheel generator-motor device using an AC excitation synchronous machine, and by incorporating the advantages of both the variable speed operation and the synchronous machine operation, the function in operation is improved. The present invention relates to an AC excitation generator-motor device suitable as an adjusting device for the purpose of improvement.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 1-231698 and Japanese Patent Application No. 1-24 are known as conventional examples of an AC excitation generator-motor.
There are inventions described in the specification of No. 5240. These will be described with reference to FIGS. 14 and 15. First, FIG.
In the example of No. 231698, the main transformer 3 is connected to the AC system 1 via the system breaker 2a, and the low voltage side of the main transformer is directly connected to the reversible pump turbine 4 via the synchronous closing breaker 2b. The armature winding 5a of the AC excitation synchronous machine 5 is connected. On the other hand, the frequency conversion device 6 includes a thyristor power conversion device 8 for converting the AC system frequency power stepped down by the excitation transformer 7 into low frequency AC power, and is provided for each phase of the excitation winding 5b. There is.

A phase detector 9 for obtaining an AC excitation frequency signal comprises a voltage transformer 10 for detecting a system voltage phase θv, a voltage phase calculator 11, and a rotation phase represented by an electrical angle of the AC excitation synchronous machine 5. a resolver device 12 for detecting θr,
It also comprises a slip phase calculator 13.

The exciting current control device 14 has a slip phase θs.
The amplitude and phase of the three-phase alternating current command rotating together are adjusted by biaxial current commands Iq and Id orthogonal to each other, so that the exciting winding current of the alternating-current excitation synchronous machine 5 matches the current command. The firing angle signal 15 is output to the automatic pulse phase shifter 16. The automatic pulse phase shifter 16 outputs the ignition pulse signal 17 of the thyristor power converter 8.

The current command signal adjusted by the exciting current control device 14 is disclosed in Japanese Patent Publication No. 53-7628 and Japanese Patent Publication No. 5628.
It is given by the method described in 7-60645. That is, the active power output can be controlled by adjusting the current component Iq having the same phase as the slip phase θs, and the voltage can be controlled by adjusting the current component Id having a phase delayed by 90 ° from the slip phase signal θs. it can.

The active power output and voltage to the AC system 1 are converted from the signals of the current transformer 18 for instruments and the voltage transformer 10 for instruments into DC signals by the measuring instrument 19, and the automatic active power control device 20 and automatic It is input to the voltage control device 21.

The slip phase signal from the slip phase calculator 13 is converted into a slip frequency signal fs by the frequency / voltage converter 22 and output only when the slip frequency fs is out of the range of (-fm≤fs≤ + fm). A slip frequency signal is input to the dead zone 23. The output of the dead zone 23 is added to the command P ₀ to the automatic active power control device 20 as an output command ΔP ₀ by relaxing the output change by the first-order lag element 24. Here, P ₀ and ΔP ₀ both define a positive direction of acceleration as an electric motor.

Next, FIG. 15 shows an example described in the specification of Japanese Patent Application No. 1-245240. It should be noted that reference numerals 1 to 24 in this figure indicate the same parts as in FIG.

The slip phase calculator 25 performs the same calculation as the slip phase calculator 13 of FIG. 14, but is configured so as to hold the slip phase outputs sin θs and cos θs when the contact X of 26 is closed. Therefore, when the contact X is closed, the DC excitation operation starts.

The horizontal axis current command switch 27 includes 28 contacts Z.
When is closed, the horizontal axis current command Ig is set to zero and input to the exciting current control device 14.

The two-phase oscillator 29 has a slip frequency setting value F
Output the s ₀ sine wave. The slip phase switch 30 has 3
When the contact Y of 1 is closed, the output of the two-phase oscillator 29 is connected to the exciting current controller 14. As described above, contact points X and Y
By opening and closing, the slip frequency can be set to Fs ₀ or DC and the synchronous machine operation can be started. In addition, by closing the contact Z, the mode for controlling only the vertical axis current is entered, as in a normal synchronous machine.

[0012]

In the prior art, no consideration was given to the driving operation at the time of stopping the power generation and the driving operation at the start of pumping, and there were the following problems in each driving operation. That is, the cause of stopping the power generation system is mechanical failure such as bearing failure of the pump / turbine generator / motor or failure of the hydraulic system in addition to the failure on the electric side. In such a case, the generator / motor is stopped immediately. There is a need.

Therefore, at this time, it is necessary to prevent the rotation speed from increasing, but in the case of the variable speed generator-motor, the output of the water turbine should be adjusted in accordance with the closing of the water turbine guide vanes at the time of stop. The generator output command must be reduced by this, and if this balance is not achieved, the rotation speed will fluctuate, and if the generator output decreases quickly, the rotation speed will increase and this will adversely affect mechanical failure. If the variable speed operation range determined by the upper limit of the voltage is exceeded, the generator output has to be disconnected from the system before it is reduced, and the disturbance to the system becomes large.

Further, at the time of pumping start, conventionally, the AC excitation operation was started immediately after the parallel operation, but when the pump priming water pressure was established, the load torque of the pump rapidly increased, so that the rotation speed decreased, and There is a possibility of exceeding the speed change operation range. In this case, there is no way but to increase the gain of the rotation speed control system to suppress the rotation speed fluctuation or to raise the rotation speed command value in advance.

However, if the gain of the rotation speed control system is increased, the pumping input control characteristic during normal operation deteriorates. To prevent this, if the gain is switched, the control system becomes complicated. Yes, on the other hand,
Increasing the rotation speed command value causes a problem of increasing pumping start time.

An object of the present invention is to solve the above problems without adding a special sequence by shifting to an operation equivalent to that of a synchronous machine as needed at the time of stopping power generation or starting pumping.

Further, as a method of exciting at a constant frequency of alternating current in order to keep the rotation speed constant, the above-mentioned Japanese Patent Application No.
Although there is an invention described in the specification of No. 245240, this prior art does not consider the driving operation at the time of pumping start, and the generator motor is AC-excited at a constant frequency from the pressing of the water surface to the establishment of the priming water pressure. Although it is operated, if a load is applied to the pump turbine at this time, the generator output fluctuates, and in some cases, the fluctuation diverges.

Another object of the present invention is to solve the fluctuation that occurs when the AC exciter synchronous machine is operated with constant frequency excitation, that is, the unstable phenomenon, by performing phase compensation of the excitation signal.

[0019]

In order to achieve the above object, the following functions are added.

(1) A function of generating a phase signal for performing synchronous machine operation at a constant excitation frequency of uniaxial current Id control, as well as a phase signal for biaxial current control in variable speed operation.

(2) A function that enables stable switching from variable speed operation to synchronous operation.

(3) A function for stably realizing switching from synchronous operation to variable speed operation.

(4) A function for compensating the phase of the excitation signal when an unstable phenomenon occurs during synchronous operation.

[0024]

The oscillator output calculator operates to restore the AC excitation synchronous machine to the normal synchronous machine characteristics. Therefore, it is possible to obtain power generation stop characteristics and pumping start characteristics equivalent to those of the synchronous machine.

The Ig regulator operates so that the phase becomes continuous when the synchronous machine characteristic operation is changed to the variable speed operation after the pumping start is completed. This prevents the system from becoming unstable due to switching.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An AC excitation generator-motor apparatus according to the present invention will be described below in detail with reference to the illustrated embodiments.

FIG. 1 is a block diagram when the present invention is applied to a pumped-storage power generation system, and FIG. 2 is a diagram for explaining the function of each part of the system centering on the slip phase detector shown in FIG. Further, FIG. 3 shows the slip output calculator 4 in FIG.
2, FIG. 4 shows the details of the output calculator 40, and FIG. 5 shows the details of the oscillator output calculator 38. In addition, hereinafter, the numbers given to the devices in the text correspond to the numbers of the devices described in FIGS. 1 and 2. Further, in the following description, the terms “switching” and “switching” or “switching” and “switching” are used in a mixed manner, but these mixed use have no particular meaning, and both are used in the same meaning. There is.

First, the configuration of the AC excitation generator motor used in the variable speed pumped storage power generation system, its peripheral equipment, and the control system will be described with reference to FIG.

Main transformer 3, synchronous circuit breaker 2 in AC system 1
The armature of the AC excitation synchronous machine 5 directly connected to the pump turbine 4 via b is connected, and the frequency conversion device 6 has three sets of 1
A two-phase non-circulating current type cycloconverter 8 and an excitation transformer 7 are used. In this system, an AC exciting current command is generated from the reference slip phase signal θs.

The slip phase detector 9 detects the voltage phase θ of the system.
Voltage transformer 10 for detecting v and system voltage positive phase calculation 11, resolver device 12 for detecting rotor electric machine angle θr of AC excitation synchronous machine 5, rotational phase positive phase calculation 34, slip phase θs (= θv− θr) and a slip phase calculator 13 that calculates a phase signal that changes in a sinusoidal manner with a constant amplitude. The system voltage positive phase calculation 11 and the rotational phase positive phase calculation 3
An external digital input "pumping / power generation" 4 performs rotation direction switching calculation. It should be noted that even if a bar superscript is used in the figure, all the superscript bars are omitted in the description here.

On the other hand, the biaxial current command (Iq, Id) is adjusted by the APR (automatic voltage regulator) 20 and the AVR 21 so that the detected value of the output sensor 19 and the command value match, and the exciting current command computing device 14 is operated. Then, it is combined with the slip phase signal and becomes the exciting current command value for each phase.

The exciting current control device 15 outputs the firing angle command to the automatic pulse phase shifter 16 so that the detected exciting current value and the exciting current command value match.

In the first embodiment of the present invention, the phase compensation calculator 37 provided on the output side of the slip phase calculator 13 for variable speed operation is based on the slip frequency calculator 35. Output δ of the device 36 and slip phase calculator 1
The output of 3 is added. This utilizes the fact that the measurement delay and calculation delay of the slip phase detector 9 are determined by the slip frequency.

According to this embodiment, the slip phase calculator 13
This is effective in compensating for the slip phase error output from the slip phase detector, and obtaining the true slip phase required for the slip phase detector 9.

A second embodiment of the present invention will be described with a focus on the internal configuration of the oscillator output calculator 38 shown in FIGS.

The slip frequency hold 50 always inputs the slip frequency fs from the slip frequency calculator 35, but the external digital input "power generation stop command" or the external digital input "slip oscillator" is switched by the state switching logic 3
When the digital output "slip / oscillator" input switching from the state switching logic 33 is input to the slip frequency hold 50, the slip frequency fs is held and that frequency is output.

The oscillator 47 inputs the held slip frequency fosc and outputs the cos and sin sinusoidal two-phase signals cosθosc and sinθosc based on the held slip frequency fosc. Input fs and output a frequency signal equal to it.

The phase shift 51 is a two-phase signal cosθ'add provided from the memory 54 to the sinusoidal two-phase signals cosθosc and sinθosc from the oscillator 47 via the angle addition SW 55.
, Sin θ'add are added and output.

The phase error calculation 52 is a phase shift two-phase signal c
Phase compensation device two-phase signal from the phase of osθ'osc, sinθ'osc
The phase difference θer is calculated by subtracting the phases of cosθs 'and sinθs'.

The angle addition 53 is a two-phase signal from the memory 54.
Two-phase signal c from phase error calculation 52 for cos θM and sin θM
Add osθer and sinθer.

The angle addition SW 55 receives the digital output: angle addition input from the state switching logic 33, and adds the angle addition 5
It operates so that the two-phase signal from 3 is output to the phase shift 51 and the memory 54.

The memory 54 is a two-phase signal from the angle addition 53.
Cos θadd and sin θadd are stored, and are output to the phase shift 51 through the angle addition SW 55 in the next sample period and also output to the angle addition 53.

The oscillator two-phase signals cos θ'osc and sin θ'osc whose phases have been adjusted by the phase shift 51 are output to the output calculator 40.

In the output computing unit 40, the input SW 48 receives the digital output "slip / oscillator" input switching from the state switching logic 33, and outputs the two-phase signals cosθ'osc and sinθ'osc from the oscillator output computing unit 38. It operates to output to the rotation direction switch 49.

The rotation direction switching 49 calculates the rotation direction during power generation because the external digital input "pumping / power generation" is "power generation", and "pumping" indicates the rotation direction during pumping. The two-phase signals cosθs, s
It outputs inθs and generates the output as a slip phase detector.

Next, an example of application to a variable speed pumped storage power generation system will be described based on the system configuration diagram of FIG.

In the case of power generation stop, the state switching logic 3
3 outputs an Iq hold command to the Iq controller 41. Then, the Iq controller 41 fixes Iq and outputs it to the exciting current command computing device 14.

Then, the pump turbine 4 gradually closes the guide vanes, and when the guide vane opening reaches 10%, the synchronous circuit breaker 2b is opened and the guide vanes are fully closed.

According to this embodiment, the frequency is continuous and the phase is continuous at the time of switching from the variable speed operation due to the slip frequency due to the stop of power generation to the synchronous operation due to the constant slip frequency, and there is a risk of step-out accompanying the switching. There is no effect, and after switching, the power generation is stopped by the synchronizing force, which facilitates the control, which is effective.

Next, another example of the present invention applied to a variable speed pumped storage hydropower system will be described with reference to FIGS.

At the time of pumping start, after paralleling to the system, by inputting the external digital input "slip → oscillator" switching, the state switching logic 33 outputs a digital output: "sliding / oscillator" input switching and an Iq hold command, Oscillator output calculation 3
8 and the input SW 48 operate in the same manner as in the above embodiment.

When the external digital input “oscillator → slip” switching is input after the pumping priming water pressure is established after the water surface depression is released, the adjustment operation by the Iq adjustment 39 is started.

The Iq adjustment 39 is S from the phase error calculation 52.
The phase error θer is calculated on the basis of the in component, and it is determined whether or not it is a value to output the Iq increase command or the Iq decrease command.

Then, if θer> ε ₀ (ε ₀ is a set value), an Iq increase command is output, and if θer <−ε ₀ , an Iq decrease command is output. If −ε ₀ <θer <ε ₀ , neither the Iq increase command nor the Iq decrease command is output.

The Iq adjustment 39 outputs the phase error θer to the state switching logic 33, and the state switching logic 33 outputs -ε ₀ <θer.
When <ε ₀ , digital output: "slip / oscillator"
Outputs the input switching and cancels the Iq hold command.

Along with this, the input SW 48 outputs the two-phase signal from the slip output computing unit 42. At this time, the rotation direction switching 49 operates in the same manner as in the above embodiment.

As a background of the present embodiment, it is necessary to continuously switch both the frequency and the phase when shifting from the synchronous operation to the variable speed operation. However, unless the frequency is out of step, the frequency before and after the switching is changed. At, the frequencies are equal and automatically become continuous.

However, with respect to the phase, no matter whether the slip phase or the oscillator output phase is corrected, the phases do not match. Therefore, Iq input to the exciting current command calculation unit 14 in FIG. 1 should be increased or decreased. Therefore, the method of reducing the phase difference is adopted.

Here, FIG. 6 is a vector diagram when the slip phase is subtracted from the oscillator output phase, that is, the phase error θer exceeds the set value ε ₀ , and FIG. 7 is the phase error θ.
The vector diagram when er is less than the set value −ε ₀ is shown.

First, in FIG. 6, an oscillator phase angle θosc1 composed of a horizontal axis current component Iq and a vertical axis current component Id.
And the slip phase θs1 is θ'er1. This θ'er1
The set value ε _{0 is} also large, and we want to keep this θ′er1 within the range of ε ₀ . At this time, by outputting the Iq increasing command, the horizontal axis current component Iq increases to Iqinc, the oscillator phase angle changes to θ′osc1, and the phase error decreases to θ ″ er1.

When Iq is further increased to Iq'inc, the phase error is further reduced to θ ″ er1, and therefore,
By repeating the increase of Iq in this way, the phase error can be kept within the range of ε ₀ .

Similarly in FIG. 7, the horizontal axis current component Iq is reduced to Iqdec and Iq'dec by the Iq reduction command, and the phase error is changed from θ'er2 to θ "er2.
, And further to θ ′ ″ er, and by repeating this, the phase error can be kept within the range of the set value ε ₀ .

According to the present embodiment, the pumping start is performed by the synchronizing force from the pressing down of the water surface to the establishment of the priming water pressure, whereby the control is facilitated, and after completion of the pumping start, high speed,
High-accuracy variable-speed operation is effective.

Next, another example of the present invention applied to a variable speed pumped storage hydropower system is shown in FIG.
~ It demonstrates using FIG. 5, FIG. 8, and FIG. 9.

In FIGS. 2 to 5, at the start of pumping, the pump turbine comes into contact with water after the water pressure is released to establish the priming water pressure, but before the water pressure is released, the external digital input " By inputting the "slip → oscillator" switching, the two-phase signal input of the output computing unit 40 is switched from the phase compensation computing unit 37 to the oscillator output computing 38. At this time, in this embodiment, FIG. The phase compensation is performed on the two-phase signal outputs cos θ'osc and sin θ'osc of the oscillator output calculation 38.

A functional diagram of the slip phase detector in this embodiment is shown in FIGS. In the oscillator phase compensation 56 of FIG. 9, the frequency command to the oscillator 47 and the slip frequency calculator 3
The frequency deviation calculation 57 calculates the deviation from 5, and the phase compensation amount calculation 58 calculates the phase compensation amount based on the frequency deviation.
The phase compensation 59 adds to the phase shift 51.

FIG. 10 shows the operation at the start of pumping when the synchronous operation is performed without performing the phase compensation, and FIG. The pumping start operation at the time of synchronous operation when the phase compensation of is performed is shown. Here, PGM is the generator output [MW], PPT is the pump turbine output [MW], fs
Is the slip frequency, θr is the rotation phase, ΔV is the change in the generator voltage, and ΔTd is the change in the vertical axis current Id. In addition,
The time rate is 0 when starting contact with water when starting pumping.

First, in the case of FIG. 10, it is found that the fluctuations of PGM and fs, θr, ΔV, and ΔId diverge, and it is unstable, while in the case of FIG. 11, the fluctuation of fs. Phase compensation is performed according to the minutes, which results in PGM,
It can be seen that θr, ΔV, and ΔId converge and are heading toward a stable direction.

Next, FIG. 12 shows the movement of the power generation sudden stop during the synchronous operation, where fs is the slip frequency and θr is the same.
Indicates the rotation phase. The time rate is set to 0 at the time of the sudden stop operation, and phase compensation is not performed.

At this time, the variation of fs is small, and when the phase compensation shown in FIG. 13 is performed in the same manner as in the embodiment of FIG. Compared with the operation in the case of the stop, there is not much difference in the movement of the phase compensation. Therefore, as in this example,
Even when the oscillator phase compensation is provided, there is no particular adverse effect on the power generation operation, and if the instability phenomenon at the time of pumping start is sufficiently suppressed, it is effective.

[0071]

As described above, according to the present invention, in the AC excitation generator-motor device, the operation due to the characteristics of the synchronous machine can be stably and continuously performed. It can be started easily and safely.

[Brief description of drawings]

FIG. 1 is a block diagram of a pumped storage power generation system to which an embodiment of an AC excitation generator-motor apparatus according to the present invention is applied.

FIG. 2 is a block diagram showing an embodiment of a slip phase detector according to the present invention.

FIG. 3 is a block diagram showing a part of components of a slip phase detector according to an embodiment of the present invention.

FIG. 4 is a block diagram showing another part of the components of the slip phase detector in the embodiment of the present invention.

FIG. 5 is a block diagram showing still another part of the components of the slip phase detector in the embodiment of the present invention.

FIG. 6 is a vector diagram showing a phase movement according to an embodiment of the present invention.

FIG. 7 is a vector diagram showing a phase movement according to another embodiment of the present invention.

FIG. 8 is a block diagram showing another embodiment of the slip phase detector according to the present invention.

FIG. 9 is a block diagram showing a part of components of a slip phase detector according to another embodiment of the present invention.

FIG. 10 is a time chart showing the operation at the start of pumping in one embodiment of the present invention.

FIG. 11 is a time chart showing the operation at the time of starting pumping in another embodiment of the present invention.

FIG. 12 is a time chart showing the operation of power generation sudden stop in one embodiment of the present invention.

FIG. 13 is a time chart showing the operation of power generation sudden stop according to another embodiment of the present invention.

FIG. 14 is a block diagram showing a conventional example of an AC excitation generator-motor device.

FIG. 15 is a block diagram showing another conventional example of an AC excitation generator-motor device.

[Explanation of symbols]

 1 AC system 3 Main transformer 4 Pump turbine 5 AC excitation synchronous machine 6 Frequency converter 7 Excitation transformer 8 Thyristor power converter 9 Sliding phase detector 13 Sliding phase calculator 20 Automatic active power controller 21 Automatic voltage controller 35 Slip Frequency Calculator 37 Phase Compensation Calculator 38 Oscillator Output Calculation 39 Iq Adjustment 40 Output Calculator 41 Iq Controller 56 Oscillator Phase Compensation

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroto Nakagawa 3-3-22 Nakanoshima, Kita-ku, Osaka Kansai Electric Power Co., Inc. No.22 in Kansai Electric Power Co., Inc.

Claims (4)

[Claims] 1. An AC excitation synchronous machine having a winding structure similar to a winding type induction machine in which an armature winding is connected to an AC system,
A frequency converter connected between the armature winding and the excitation winding of this AC excitation synchronous machine, and changes with a slip phase equal to the difference between the voltage phase of the AC system and the rotation phase of the AC excitation synchronous machine. Input a slip phase calculator that generates a sine wave signal of constant amplitude, and input the output of this slip phase calculator as a reference phase signal, and set the horizontal axis current component command value and 90 degree phase delay in phase with this reference phase signal. Of the vertical axis current component command value, the excitation current command value calculation device for calculating the command value of the excitation current to be supplied from the frequency conversion device and supplying it to the frequency conversion device. , A slip frequency calculator for calculating a slip frequency equal to the rate of change of the slip phase, and a position for compensating the phase of the output signal of the slip phase calculator according to the output of the slip frequency calculator. A compensator calculator provided, AC excitation generator-motor apparatus, characterized in that the output signal of the phase compensator calculator configured to provide a reference phase signal for the excitation current command value calculation device. 2. An AC excitation synchronous machine having a winding structure similar to a winding type induction machine in which an armature winding is connected to an AC system,
A frequency converter connected between the armature winding and the excitation winding of this AC excitation synchronous machine, and changes with a slip phase equal to the difference between the voltage phase of the AC system and the rotation phase of the AC excitation synchronous machine. Input a slip phase calculator that generates a sine wave signal of constant amplitude, and input the output of this slip phase calculator as a reference phase signal, and set the horizontal axis current component command value and 90 degree phase delay in phase with this reference phase signal. Of the vertical axis current component command value, the excitation current command value calculation device for calculating the command value of the excitation current to be supplied from the frequency conversion device and supplying it to the frequency conversion device. , A slip frequency calculator that calculates the slip frequency equal to the rate of change of the slip phase, and a reference phase that controls the phase of the output signal using the output signal of this slip frequency calculator as the frequency command. No. oscillator, and a reference signal switcher for switching the reference phase signal to be input to the exciting current command value calculating device between the output of the slip phase calculator and the output of the reference phase oscillator. Due to
When the reference phase signal input of the exciting current command value computing device is switched from the output signal of the slip phase computing unit to the output signal of the reference phase oscillator, the frequency command for the reference phase oscillator is immediately before the switching time point. An alternating-current excitation generator-motor device characterized by being set to a value so that the phase is continuous. 3. The invention according to claim 2, wherein a phase difference calculator for calculating a phase difference between the output signal of the slip phase calculator and the output signal of the reference phase oscillator is provided, and the reference of the exciting current command value calculator is provided. When switching the phase signal input from the output signal of the reference phase oscillator to the output signal of the slip phase calculator, the horizontal axis current component command value is corrected in advance by the exciting current command value calculating device, and the phase difference calculator is used. An alternating-current excitation generator-motor apparatus, characterized in that the operation of the reference signal switcher is delayed until the magnitude of the calculated phase difference decreases to a predetermined set value. 4. The invention according to claim 2, wherein when the reference phase signal input of the exciting current command value computing device is switched to the output signal of the reference phase oscillator, the frequency command and the slip for the reference phase oscillator are set. An AC-excited generator-motor apparatus, characterized in that the phase of the output signal of the reference phase oscillator is compensated according to the deviation from the output signal of the frequency calculator.