JPH0984268A - Control device for AC / DC converter - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] When switching the system bus, switching of the system bus can be performed without stopping power transmission between the systems, and stable operation can be continued without causing commutation failure of the converter. PROBLEM TO BE SOLVED: To provide a control device of an AC / DC converter, which is used for a DC power transmission device, and which has a forward converter side or an inverse converter side connected to a double system bus and detects a system voltage from the system bus. In a control device of an AC / DC converter having a synchronization detection control means for controlling as a synchronous power supply, when switching the system bus while the AC / DC converter is operating as the synchronization detection control means, two synchronizations are provided in the control device. A controller of an AC / DC converter for inputting a power supply and externally inputting the same command as for switching the system bus to switch the synchronous power supply and perform synchronous detection control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a DC power transmission device, and a forward converter side or an inverse converter side is connected to a double system bus, and a system voltage detected from the system bus is synchronized. The present invention relates to a control device for an AC / DC converter having synchronization detection control for controlling the power supply.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram of a conventional AC / DC converter, in which AC / DC converters 1A and 1B are transformers 4A and 4 for converters.
B is connected to the system buses 10A, 10A ', 10B, 10B' and connected to the AC systems 6A and 6B via the AC system buses, while being used for DC transmission devices connected to each other via the smoothing reactor 2. It

Further, when the power interchange operation is performed in the DC power transmission equipment, the disconnecting switches 60A, 61A, 62A, 63A, 6 are instructed by the system busbar switching operation devices 33A, 33B.
0B, 61B, 62B and 63B are switched to switch the system bus from 10A to 10A 'or 10B to 10B'.

This switching operation signal is input to the synchronous power supply switching devices 70A and 70B to switch the synchronous power supply and sent to the converter control devices 200A and 200B, and the pulse amplification circuit 3
A gate pulse signal is given to each converter via 0A and 30B.

System buses 10A, 10A ', 10B, 10
Even in the case of B ', even if it is double, the voltage is normally applied to the two buses, and the facilities and routes to be connected are only slightly different. The switching is performed when the route in which the accident has occurred is separated or when the inspection is performed.

FIG. 8 is a block diagram of a control device for an AC / DC converter, which includes a start / stop control circuit 101A which controls coordinated start / stop of a forward converter and an inverse converter, and a command from the start / stop control circuit 101A. Control arithmetic circuit (basic control circuit) 100A configured by a circuit that constantly controls the DC current, DC voltage, etc. of the DC transmission system, and this control arithmetic circuit 100A
A phase control circuit 29A that determines the firing phase of the converter device by the output signal of the above, a protection circuit 102A that outputs an optimum protection command at the time of an accident, and an abnormality monitoring circuit 103A that monitors the occurrence of an abnormality in each circuit. Converter controller 20
0A and a pulse amplifier circuit 30A for sending out a sequential firing pulse by the output signal of the phase control circuit 29A in the control device 200A.

FIG. 9 is a block diagram of the control functions of the AC / DC converters 1A and 1B. The DC sides of the AC / DC converters 1A and 1B are connected via a DC reactor 2, and each AC / DC converter 1 is connected.
The AC side of A, 1B is connected to each of the AC systems 6A, 4A, 4B for converters, and 5A, 5B for converters.
6B is connected.

The converters 1A and 1B are provided with constant margin angle control circuits 12A and 12B, constant voltage control circuits 11A and 11B, and constant current control circuits 13A and 13B.

The constant margin angle control circuits 12A and 12B operate so that the margin angles of the AC / DC converters 1A and 1B follow the margin angle reference signals output from the margin angle setters 18A and 18B.

A voltage / voltage conversion circuit 16A for detecting a voltage reference signal output from the DC voltage setters 14A and 14B and a DC voltage by the DC voltage detector 15A and converting it into a value that can be easily handled by the control circuit. Adder circuit 17A, 1
The difference from the DC voltage signal input to 7B is obtained by the adder circuits (summing circuits) 17A and 17B, and the value of the difference is input to the constant voltage control circuits 11A and 11B, so that the DC voltage is the voltage reference. Will be controlled to follow.

In addition, the current reference signal output from the current reference value output circuit 27 and the direct current are converted into direct current detectors 21A and 2A.
The DC current signal detected by 1B and converted into a value that can be easily handled as a control circuit by the current / voltage conversion circuits 22A and 22B is input to the addition circuits 23A and 23B. By inputting the value of the difference into the constant current control circuits 13A and 13B,
The DC current flowing through the DC reactor 2 is controlled so as to follow the current reference signal.

The switches 24A and 24B are AC / DC converters 1.
Only the AC / DC converters 1A and 1B, which operate A and 1B as inverse converters, are closed, and the current margin output from the current margin setters 25A and 25B becomes the adder circuits 23A and 23B.
Is input to The function of the current margin, the constant margin angle control circuits 12A and 12B, and the constant voltage control circuit 11
A, 11B, a control advance angle priority circuit 2 that outputs only the output of the constant current control circuits 13A, 13B that has the most advanced control angle of the converters 1A, 1B.
It operates as follows by the functions of 8A and 28B.

That is, assuming that the switch 24B is closed and the switch 24A is open, the control lead angle priority circuit 28A is provided with the constant current control circuit 13.
The output of A is output, and the constant advance angle priority circuit 28B includes the constant margin angle control circuit 12B and the constant voltage control circuit 1.
The output of 1B which is advancing as the control angle, generally the output of the constant voltage control circuit 11B is output.

Each of the control advance angle priority circuits 28
The outputs of A and 28B are input to the phase control circuits 29A and 29B, the AC voltage detectors 50A and 50B to detect the system voltage and the synchronizing signals of the synchronizing signal detecting circuits 34A and 34B, and the points of the AC / DC converters 1A and 1B. It is configured so that it is converted into a pulse signal that determines the arc timing and is given as a gate pulse signal to each of the AC / DC converters 1A and 1B via the pulse amplifier circuits 30A and 30B.

The synchronization detection circuits 34A and 34B have PLLs (Phase Locked) due to the progress of digital technology.
Loop-based digital sync detection circuits have come into wide use. In particular, as a high-speed synchronization detection circuit that follows a frequency change and a phase change of an AC sync signal at high speed with an increase in capacity of the thyristor converter and diversification of purpose of use, a phase continuous comparison PLL applying a PLL circuit.
Circuits have been used.

FIG. 10 shows the synchronization detection circuit 34 shown in FIG.
The detailed block diagram of A, 34B, ie, the continuous phase comparison PLL circuit, is shown. In FIG. 10, reference numeral 108A denotes a three-phase / two-phase conversion circuit that converts a three-phase AC synchronous signal (synchronous power supply) into two orthogonal phases, and 109A generates an output signal of the three-phase / two-phase conversion circuit 108A and a feedback signal. An arithmetic circuit that obtains a phase difference from the output signals of the sine wave generation circuit 113A and the cosine wave generation circuit 114A, 110A is an error amplification circuit that removes noise and distortion of frequency components higher than the output of the arithmetic circuit 109A, and amplifies the error (generally proportional 111A is a voltage control transmission circuit (VCO) which is controlled by the output voltage of the error amplification circuit 110A and transmits the voltage.
2A is a counter that calculates the output of the VCO 111A and uses it as a synchronization signal for phase control. 113A is a sine wave generation circuit that creates a sine wave from the output of the counter 112A. 114A is a cosine wave that similarly generates a cosine wave from the output of the counter 112A. It is composed of a wave generation circuit.

The control device for the conventional AC / DC converter described above is well known.

[0018]

The forward converter side or the inverse converter side is connected to a double system bus, and is provided with a synchronization detection circuit 34A which detects a system voltage from the system bus and controls it as a synchronous power supply. When the control device of the AC / DC converter is applied, the following problems occur.

When the system power bus is switched from 10A to 10A 'during the power interchange operation in the DC power transmission equipment of FIG. 7, the input of the synchronization detection circuit 34A in the converter control device 200A is for three phases (one bus). ) In the synchronous power supply switching device 70
When the switching command is given from the system bus switching operation device 33A in a configuration in which the input value is switched at A, there is a state where there is no synchronous power supply at the switching timing and a phase difference may occur in the synchronization detection circuit 34A. The phase control system in the converter controller follows with a certain time delay,
If the phase of the system bus on the inverse converter side suddenly changes or the voltage greatly decreases, the margin angle becomes insufficient and commutation fails. This will have the same effect on the converter controller.

Occurrence of commutation failure causes disturbance such as power fluctuation on the system side. Further, if they occur continuously, severe stress is applied to the thyristor valve. Normally, a continuous generation trips the converter. However, there is a possibility that commutation failure may occur each time the bus bar is switched, and it is completely unfavorable to stop the trip each time because of the electric power situation in which there is a need for continuous operation.

The object of the present invention is to solve the problems of the above-mentioned conventional example, and it is used in a DC power transmission device, and the forward converter side or the inverse converter side is connected to a double system bus.
In a control device for an AC / DC converter equipped with a synchronous detection control that controls the system voltage detected from the system bus as a synchronous power supply, when switching the system bus, the system bus without stopping the power transmission between the systems An object of the present invention is to provide a control device for an AC / DC converter, which can perform stable operation without switching and causing commutation failure of the converter.

[0022]

[Means for Solving the Problems] The present invention is configured as follows to achieve the above object.

The invention of claim 1 is used in a DC power transmission device, wherein the forward converter side or the inverse converter side is connected to a double system bus, and a system voltage detected from the system bus is synchronized. In a control device for an AC / DC converter having a synchronous detection control means for controlling as a power source, when the synchronous detection control means switches the system bus during operation of the AC / DC converter, two synchronous power supplies are provided in the control device. Input,
The control device for an AC / DC converter is characterized in that the same command as for switching the system bus is externally input into the control device to switch the synchronous power source to perform synchronous detection control.

According to the first aspect of the present invention, when the AC / DC converter is in operation and power is being transmitted by DC interconnection, a switching command of the disconnecting switch connecting the double system bus causes
It is operated at the same time as the switching operation of the disconnector. With such a configuration, it is possible to switch at the same time as switching the system busbars, so that it is possible to prevent a situation where there is no synchronous power supply, a sudden phase change, a short margin angle on the inverse converter side, and a commutation failure. it can.

The invention of claim 2 is used in a DC power transmission device, wherein the forward converter side or the inverse converter side is connected to a double system bus, and a system voltage detected from the system bus is synchronized. In a control device for an AC / DC converter having a synchronous detection control means for controlling as a power supply, when the synchronous detection control means switches the system bus while the AC / DC converter is in operation, two synchronous power supplies are input into the control device. However, in both cases of inputting the same command as the switching of the system bus from the outside into the control device to switch the synchronous power source and in the case where there is an external synchronous power source switching device, synchronization detection control is performed by switching the switch. A control device for an AC / DC converter, which is characterized in that the time constant is delayed to stabilize the synchronous detection control even when there is no voltage time.

According to the second aspect of the present invention, when the AC / DC converter is in operation and power is transmitted by DC interconnection, the switching command of the disconnecting switch connecting the double system busbars causes
Simultaneously with the switching operation of the disconnector, the time constant of the synchronous detection control is slowed down. As a method of changing the time constant, there are a method of switching the coefficient itself and a method of preparing two synchronization detection controls and switching the block. With this configuration, it is possible to prevent sudden phase changes even when there is no synchronous power supply at the time of switching the system bus, and to prevent commutation failure due to insufficient margin on the inverse converter side. You can

The invention of claim 3 is used in a DC power transmission device, wherein the forward converter side or the inverse converter side is connected to a double system bus, and a system voltage detected from the system bus is synchronized. In a control device for an AC / DC converter having a synchronous detection control means for controlling as a power source, when the synchronous detection control means switches the system bus during operation of the AC / DC converter, two synchronous power supplies are provided in the control device. Input,
A control device for an AC / DC converter, wherein two synchronous power supplies are constantly sampled, and the synchronous power supply having the larger absolute value is used as a synchronous voltage for synchronous detection control.

According to the third aspect of the present invention, when there is no switching command from the outside, it is possible to prevent a sudden change in the phase due to the absence of the synchronous power supply when the system bus is switched. It is possible to prevent the flow failure from occurring.

The present invention of claim 4 is used in a DC power transmission device, wherein a forward converter side or an inverse converter side is connected to a double system bus, and a system voltage detected from the system bus is synchronized. In a control device for an AC / DC converter having a synchronous detection control means for controlling as a power source, when switching the system bus during operation of the AC / DC converter as the synchronous detection control means, two synchronous power sources are input into the control device. Then
Externally input the same command as the switching of the system bus,
Regardless of whether the synchronous power source is switched or an external synchronous power source switching device is provided, the β advance control is operated when the switch is on the inverse converter side, and the β advance control is performed when the synchronization detection control is stable. Is a control device for an AC / DC converter.

According to the fourth aspect of the present invention, when the system bus is switched with a relatively simple method and at a low cost, there is no voltage, the phase changes suddenly, the margin angle on the inverse converter side becomes insufficient, and commutation fails. This can be reliably prevented.

According to a fifth aspect of the present invention, which is used in a DC power transmission device, the forward converter side or the inverse converter side is connected to a double system bus, and a system voltage detected from the system bus is synchronized. In a control device for an AC / DC converter having a synchronous detection control means for controlling as a power supply, when the synchronous detection control means switches the system bus while the AC / DC converter is in operation, two synchronous power supplies are input into the control device. However, in both cases of inputting the same command as the switching of the system bus from the outside to switch the synchronous power supply and when there is an external synchronous power supply switching device, bypass the switch once by the switching of the switch. Put in a pair,
This is a control device for an AC / DC converter, which is restarted when the synchronization detection control becomes stable.

According to the invention of claim 5, when the system bus is switched, the BPP is entered even if there is no voltage, so that there is no possibility of loss from the claim 4, and it is certain.
It is possible to return to operation after the system voltage stabilizes.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> (Configuration) FIG. 1 is a diagram for explaining a first embodiment of the invention corresponding to claim 1. 1, FIG. 7, FIG.
Devices that perform the same functions as in FIG. 10 are assigned the same reference numerals. In the following description, the AC / DC converter 1A is operating as an inverse converter, and the double system bus 10A is connected to the disconnectors 60A, 62.
Description will be made assuming that the disconnectors 61A and 63A are connected by A and are disconnected. Since the operation is the same when the AC / DC converter 1B is in the reverse converter operation and when the disconnectors 60B and 62B are included and the disconnectors 61B and 63B are disconnected, the description thereof will be omitted.

The converter control unit 200A receives an operation command for switching the system busbars from the system busline switching operation device 33A, and switches the synchronous power supply.
It has 1A.

(Effect) When the converter 1A is in operation and power is being transmitted by direct current interconnection, a switching command for the system busbar switching operation device 33A is issued to the disconnectors 60A and 62A connecting the double system busbar 10A. , The disconnecting switches 60A, 62A are cut off, and the disconnecting switches 61A, 63A are inserted to switch the system busbar 10A to the double system busbar 10A '.

The synchronous power supply switching circuit 8 in the converter control unit 200A receives the same signal as this system bus switching operation command.
1A, the synchronous power source detected by the AC voltage detector 50A is simultaneously switched to the synchronous power source detected by the AC voltage detector 50A '.

With such a configuration, it is possible to switch at the same time as switching the system bus, so that there is no synchronous power supply, the phase suddenly changes, the margin angle on the inverse converter side becomes insufficient, and commutation failure occurs. Can be prevented.

<Second Embodiment> Next, claim (2)
A second embodiment of the invention corresponding to will be described.
2 and 3 are views for explaining the configuration of the embodiment of claim (2) according to the present invention. Devices that perform the same functions as in FIG. 1 are assigned the same reference numerals.

The configuration of FIG. 2 has a converter controller 200A.
To the synchronous power supply switching circuit 81A and the synchronization detection circuit 34A from the system bus switching operation device 33A, and the synchronous power switching circuit 81A
The synchronous power source detected by the AC voltage detector 50A is switched to the synchronous power source detected by the AC voltage detector 50A ',
The synchronization detection circuit 34A includes a circuit that delays the time constant.

Further, the configuration of FIG. 3 has a synchronous power source switching device 70A externally, from the synchronous power source detected by the AC voltage detector 50A by the system bus switching operation command of the system bus switching operating device 33A. Switching to the synchronous power source detected by the AC voltage detector 50A '. In addition, the converter control device 200A also includes a system bus switching operation device 3
A circuit for delaying the time constant of the synchronization detection circuit 34A in response to an operation command for switching the system bus of 3A is provided.

When the converter 1A is in operation and power is being transmitted by DC interconnection, the system busbar switching operation device 3 is connected to the disconnectors 60A and 62A connecting the double system busbar 10A.
By giving a switching command of 3A, the disconnector 60A,
62A is cut off, and the disconnectors 61A and 63A are turned on to switch the system busbar to the double system busbar 10A '. The AC voltage detector 5 is sent to the synchronous power supply switching circuit 81A in the converter control device 200A by sending the same signal as this system bus switching operation command.
AC voltage detector 50 from the synchronous power source detected at 0A
When switching to the synchronous power source detected at A ', the time constant of the proportional-plus-integral element of the synchronous detection circuit is delayed to delay the follow-up to the system voltage and operate.

As a method of changing the time constant, there are a method of switching the coefficient of proportional integration and a method of switching two blocks by preparing two fast proportional integration and two slow proportional integration in the synchronization detection circuit.

There is also a method of confirming that the waveform distortion has disappeared, and returning the coefficient to the original value when the system voltage is surely stabilized.

With this configuration, it is possible to prevent the phase from changing abruptly even when there is no synchronous power supply when the system bus is switched, so that the margin angle on the inverse converter side becomes insufficient and commutation failure occurs. prevent.

<Third Embodiment> Next, a third embodiment of the invention corresponding to claim (3) will be described. In FIG. 4, devices that perform the same functions as in FIG. 1 are designated by the same reference numerals.

The configuration of FIG. 4 has a converter controller 200A.
In addition, a circuit for taking in the synchronous power source detected by the AC voltage detector 50A and the synchronous power source detected by the AC voltage detector 50A 'and switching the synchronous power source by the maximum value detection circuit 80A is provided.

When the converter 1A is in operation and power is being transmitted by DC interconnection, the system busbar switching operation device 3 is connected to the disconnectors 60A and 62A connecting the double system busbar 10A.
By giving a switching command of 3A, the disconnector 60A,
When 62A is cut off and the disconnecting switches 61A and 63A are turned on to switch the system bus to the double system bus 10A ', the synchronous power source and the AC voltage detector 50A' detected by the AC voltage detector 50A are constantly detected by the converter control device 200A. The synchronous power supply detected in step S1 is input and sampled, and the maximum value detection circuit 80A operates the synchronous power supply having the larger absolute value as the synchronous power supply of the synchronous detection circuit 34A.

With this configuration, it is possible to prevent a sudden change in the phase due to the absence of the synchronous power supply when the system bus is switched without a switching command from the outside. Prevent failure.

<Fourth Embodiment> Next, a fourth embodiment of the invention corresponding to claim (4) will be described. In FIG. 5, devices that perform the same functions as those in FIGS. 1 and 9 are designated by the same reference numerals.

In the configuration shown in FIG. 5, the converter control device 200A includes an AND circuit 32A.

When the converter 1A is in operation and power is being transmitted by DC interconnection, the system busbar switching operation device 3 is connected to the disconnectors 60A and 62A connecting the double system busbar 10A.
By giving a switching command of 3A, the disconnector 60A,
When 62A is cut off and the disconnecting switches 61A and 63A are inserted to switch the system bus to the double system bus 10A ', a switching command is output from the system bus switching command operating circuit 33A,
During the inverse converter operation (INV), the command in which the condition of the AND circuit 32A is established is output to the β advance control circuit 31A as an operation command. In response to the command, the β advance control circuit 31A outputs a value in which β is advanced over the control angle during the normal operation of the inverse converter. This value is about 120 ° to 135 °. Due to the operation of the β advance control circuit 31A, β of the output of the control advance angle priority circuit 28A becomes larger than the control angle during the previous operation, so that the synchronous power source is switched during this period.

Further, it is confirmed that the waveform distortion has disappeared, and when the system voltage is surely stabilized, the β advance control is stopped and normal control is performed.

With this configuration, when the system buses 10A and 10A 'are switched with a relatively simple method and at low cost, there is no voltage, the phase changes suddenly, and the margin angle on the inverse converter side becomes insufficient. It is possible to reliably prevent commutation failure.

<Fifth Embodiment> Next, a fifth embodiment of the invention corresponding to claim 5 will be described with reference to FIG. In FIG. 6, devices that perform the same functions as those in FIGS. 1 and 8 are given the same reference numerals.

In the configuration of FIG. 6, the protection circuit 102A comprises a bypass pair (BPP) output circuit 150 and an off-delay circuit 151 capable of outputting for a certain period of time.

When the converter 1A is in operation and power is being transmitted by DC interconnection, the system busbar switching operation device 3 is connected to the disconnectors 60A and 62A connecting the double system busbar 10A.
By giving a switching command of 3A, the disconnector 60A,
When 62A is cut off and the disconnecting switches 61A and 63A are inserted to switch the system bus to the double system bus 10A ', the switching command is sent from the system bus switching command operating device 33A to the protection circuit 1
02A, this switching command causes the bypass pair output circuit 150 to output once to enter the BPP state, and the BPP state can be output for a certain period of time. , Reboot.

With such a configuration, when the system bus is switched, the BPP is entered even if there is no voltage time, so that there is no possibility of a loss from claim 4 and it is certain that the AC system voltage is It is possible to return to operation after stabilizing.

[0058]

According to the invention of claim 1 configured as described above, it is used in a DC power transmission device, and the forward converter side or the inverse converter side is connected to a double system bus, Adapting to the synchronous detection control means for detecting the system voltage from the bus and controlling it as a synchronous power supply, two synchronous power supplies are input into the control device, and the same command for switching the system bus is input from the outside to provide switching of the synchronous power supply. In the control device of the AC / DC converter, when the AC / DC converter is in operation and power is transmitted by DC interconnection, switching operation of the disconnector is performed by the switching command of the disconnector connecting the double system bus. Operate at the same time.

With such a configuration, it is possible to switch at the same time as switching the system bus, so that there is no synchronous power supply, the phase suddenly changes, the margin angle on the inverse converter side becomes insufficient, and commutation failure occurs. prevent.

Further, according to the invention of claim 2, it is used in a DC power transmission device, and the forward converter side or the inverse converter side is connected to the double system bus, and the system voltage is detected from the system bus. It is adapted to the synchronous detection control means for controlling as a synchronous power supply, and two synchronous power supplies are input into the control device, and the same command as the switching of the system bus is externally input and switched, and there is a synchronous power supply switching device externally. However, in either case, in the control device of the AC / DC converter equipped with the synchronous detection control that can delay the time constant of the synchronous detection control by the system bus switching signal, the DC / DC converter is operated while the AC / DC converter is in operation. When power is being transmitted, a switching command of a disconnecting switch that connects the double system bus bar is operated to increase the time constant of the synchronization detection control simultaneously with the switching operation of the disconnecting switch. Alternatively, as a method of changing the time constant, there are a method of switching the coefficient itself and a method of preparing two synchronization detection circuits and switching the block.

With this structure, when the system bus is switched, the phase is prevented from changing abruptly even if there is no synchronous power supply, so that the margin angle on the inverse converter side becomes insufficient and commutation failure occurs. prevent.

Further, according to the invention of claim 3, it is used in a DC power transmission device, and the forward converter side or the inverse converter side is connected to the double system bus, and the system voltage is detected from the system bus. Adapted to the synchronous detection control that controls as a synchronous power supply,
Since the synchronous power source is detected from the system bus, two synchronous power sources are constantly sampled, and the synchronous power source having the larger absolute value is detected as the synchronous power source for the synchronous detection control, the switching signal from the outside is provided. In addition, when switching the system bus, it is possible to prevent a sudden phase change due to the absence of the synchronous power supply, and thus prevent commutation failure due to insufficient margin on the inverse converter side.

Further, according to the invention of claim 4, it is used in the DC power transmission device, and the forward converter side or the inverse converter side is connected to the double system bus, and the system voltage is detected from the system bus. Adapting to the synchronization detection control means for controlling as a synchronous power source, when inputting two synchronous power sources into the control device and externally input the same command as the switching of the system bus to switch the synchronous power source, the synchronous power source switching device is externally provided. In some cases, there is a control means to operate the β advance control on the inverse converter side by switching the switch, so in either case, the system bus is switched with a relatively simple method at low cost. At this time, it is possible to reliably prevent a commutation failure due to a voltageless time, a sudden phase change, a shortage of a margin angle on the inverse converter side.

Further, according to the invention of claim 5, which is used in a DC power transmission device, the forward converter side or the inverse converter side is connected to the double system bus, and the system voltage is detected from the system bus. Adapting to the synchronization detection control means for controlling as a synchronous power source, when inputting two synchronous power sources into the control device and externally input the same command as the switching of the system bus to switch the synchronous power source, the synchronous power source switching device is externally provided. There are cases where there is, but in either case, once the B
Since the control means is provided for restarting when the system voltage is stable when the system voltage is stable, the system enters the BPP even when there is no voltage time when switching the system bus. It is certain that the AC system voltage has stabilized and can be returned to operation.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of DC power transmission equipment showing an embodiment of claim 1 of the present invention.

FIG. 2 is a schematic configuration diagram of DC power transmission equipment showing an embodiment of claim 2 of the present invention.

FIG. 3 is a schematic configuration diagram of a DC power transmission facility showing an embodiment of claim 2 of the present invention.

FIG. 4 is a schematic configuration diagram of a DC power transmission facility showing an embodiment of claim 3 of the present invention.

FIG. 5 is a schematic configuration diagram of a control function showing an embodiment of claim 4 of the present invention.

FIG. 6 is a schematic configuration diagram of a control device showing an embodiment of claim 5 of the present invention.

FIG. 7 is a schematic configuration diagram of DC transmission equipment of a conventional AC / DC converter.

FIG. 8 is a schematic configuration diagram of a control device for a conventional AC / DC converter.

FIG. 9 is a schematic configuration diagram of a control function of a conventional AC / DC converter.

FIG. 10 is a schematic configuration diagram of a synchronization detection circuit of a conventional AC / DC converter.

[Explanation of symbols]

1A, 1B ... AC / DC converter, 2 ... DC reactor, 4A,
4B ... Transformer for transformer, 5A, 5B ... Breaker for converter, 6A, 6B ... AC system, 10A, 10B ... System bus, 10A ', 10B' ... System bus, 11A, 11B ...
Constant voltage control circuit, 12A, 12B ... Constant margin angle control circuit,
13A, 13B ... Constant current control circuit, 14A, 14B ... DC voltage setting device, 15A ... DC voltage detector, 16A, 16
B ... Voltage / voltage conversion circuit, 17A, 17B ... Summing circuit, 18A, 18B ... Margin angle setting device, 19 ... Communication line,
21A, 21B ... DC current detector, 22A, 22B ... Current / voltage conversion circuit, 23A, 23B ... Summing circuit, 2
4A, 24B ... Switch, 25A, 25B ... Current margin setting device, 26A, 26B ... Transmission control circuit, 27 ... Current reference value output circuit, 28A, 28B ... Control advance angle priority circuit, 29A, 29B ... Phase control circuit, 30A , 30B ...
Pulse amplification circuit, 31A, 31B ... β advance control circuit, 3
4A, 34B ... Synchronous detection circuit, 50A, 50B ... AC voltage detector, 70A, 70B ... Synchronous power supply switching device, 2
00A, 200B ... Converter control device, 60A, 61A ...
Disconnector, 62A, 63A ... Disconnector, 60B, 61B ... Disconnector, 62B, 63B ... Disconnector, 100A ... Basic control circuit, 101A ... Start / stop control circuit, 102A ... Protection circuit, 103A ... Abnormality monitoring circuit, 107A ... Gate signal control circuit, 108A ... Three-phase / two-phase conversion circuit, 109A ... Arithmetic circuit, 110A ... Error amplification circuit, 111A ... Voltage control transmission circuit, 112A ... Counter, 113A ... Sine wave generation circuit, 114A ... Cosine wave generation circuit , 150A ... Bypass pair output circuit, 151A ... Off delay circuit, 33A, 3
3B ... System bus switching operation device, 32A, 32B ... AND circuit, 50A '... AC voltage detector, 81A ... Synchronous power supply switching circuit, 70A ... Synchronous power supply switching device, 80
A ... Maximum value selection circuit.

Claims (5)

[Claims] 1. A synchronization used in a DC power transmission device, wherein a forward converter side or an inverse converter side is connected to a double system bus and a system voltage detected from the system bus is controlled as a synchronous power source. In a control device for an AC / DC converter including a detection control means, when the synchronous detection control means switches the system bus while the AC / DC converter is in operation, two synchronous power sources are input into the control device, and the system A controller for an AC / DC converter, wherein the same command as that for switching the busbars is externally input into the controller to switch the synchronous power source for synchronous detection control. 2. A synchronous system used in a DC power transmission device, wherein a forward converter side or an inverse converter side is connected to a double system bus, and a system in which system voltage is detected from the system bus is controlled as a synchronous power source. In a control device for an AC / DC converter having a detection control means, when the synchronous detection control means switches the system bus during operation of the AC / DC converter, two synchronous power supplies are input into the control device, and the system bus In both cases of inputting the same command as for switching of the above from the outside to switch the synchronous power supply in the control device and in the case where there is an external synchronous power supply switching device, slow down the time constant of the synchronization detection control by switching the switch. A control device for an AC / DC converter, which stabilizes synchronization detection control even when there is no voltage time. 3. A synchronization used in a DC power transmission device, wherein a forward converter side or an inverse converter side is connected to a double system bus, and a system voltage detected from the system bus is controlled as a synchronous power source. In a control device for an AC / DC converter having a detection control means, when the synchronous detection control means switches the system bus while the AC / DC converter is in operation, two synchronous power supplies are input into the control device and always 2 A control device for an AC-DC converter, wherein two synchronous power supplies are sampled, and the synchronous power supply having the larger absolute value is used as a synchronous voltage for synchronous detection control. 4. A synchronization used in a DC power transmission device, wherein a forward converter side or an inverse converter side is connected to a double system bus, and a system in which system voltage is detected from the system bus is controlled as a synchronous power source. In a control device for an AC / DC converter having a detection control means, when the synchronous detection control means switches the system bus during operation of the AC / DC converter, two synchronous power supplies are input into the control device, and the system bus In the case of inputting the same command as for switching the above from the outside to switch the synchronous power source and when there is an external synchronous power source switching device, the β advance control is operated when the switch is switched to the inverse converter side. A control device for an AC / DC converter, wherein the β advance control is canceled when the synchronization detection control becomes stable. 5. A synchronization used in a DC power transmission device, wherein a forward converter side or an inverse converter side is connected to a double system bus, and a system in which a system voltage is detected from the system bus is controlled as a synchronous power source. In a control device for an AC / DC converter having a detection control means, when the synchronous detection control means switches the system bus during operation of the AC / DC converter, two synchronous power supplies are input into the control device, and the system bus In both cases of inputting the same command from the outside to switch the synchronous power supply and externally having a synchronous power supply switching device, once the switch is switched to the inverse converter side, once put in the bypass pair and synchronize. A control device for an AC / DC converter, which is restarted when the detection control becomes stable.