JPS6352699A - Controller for variable speed generator-motor - Google Patents

Abstract

PURPOSE:To enhance the stability of a system, by discriminating whether an accident is generated in the AC system or in a power converter, based on the input/output current deviation value of the power converter and a state that excess current is generated or is not generated. CONSTITUTION:On the accident of an AC system, the waveform of a current value IIN obtained via a cyclo-converter input side current detector 22 is almost the same as that of an output side current value IOUT, and so the output I of a comparator 19 is set to be almost zero. At this time, an input current value is equal to or more than an allowable value K2, thereby the output of excess current suppression control command GO2 is generated from an operation continuing discriminator 20, and excess current is suppressed. On the communication failure of a cyclo-converter, the input current is set to be equal or more than the allowable value K2. In the meantime, the output current IOUT=0 is set, thereby the absolute value of the output I of the comparator 19 is set to be equal to or more than an allowable value K1, and from the operation continuing discriminator 20, the output of main machinery emergency stop command ST is generated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a variable speed generator motor control device, and in particular, the present invention relates to a variable speed generator motor control device, and in particular, the present invention relates to a variable speed generator motor control device, and in particular, it controls the active power output and the reactive power output by sudden changes on the AC system side while operating a pump water turbine or the like at variable speed. This invention relates to a control device for a variable speed generator motor that is suitable for stable control even at times, and is suitable for highly public power systems that require continuity of power supply.

[Conventional technology]

Conventional devices in which a power converter is connected to the secondary side of an induction machine include Japanese Patent Publication No. 53-7628 and Japanese Patent Publication No. 57-60645.
As described in the issue, a method of controlling active power by controlling a secondary current component equal to the stator voltage phase as seen from the stator side, and a 90" phase difference with respect to the stator voltage phase as seen from the stator side. There are methods to control reactive power by controlling the secondary current component of the power source.These methods are suitable for power factor adjustment devices and power adjustment devices that can respond at high speed while preventing disturbances and tax adjustments6. When these systems are used as a large-capacity generator/motor device such as a variable speed pumped storage power generation device, a power conversion device (such as a cycloconverter) is connected to the secondary side to perform secondary current control.

[Problem that the invention seeks to solve]

When controlling the secondary current of the generator motor, when a voltage fluctuation occurs due to an accident on the AC system side or when the AC circuit breaker of another unit is turned on or off, the DC transient component of the primary current is induced. The rotation frequency component is superimposed on the slip frequency current component on the secondary side. For this reason, a current larger than the normal secondary current flows through the cycloconverter, but in this case, if this current value can be suppressed within the equipment rating of the cycloconverter, then the fault part can be excluded and the current can be used for power generation or pumping. There is a strong desire to continue operation from the standpoint of the stability of the entire system, and there are ways to increase the withstand capacity of equipment to achieve this, but this is not only economically disadvantageous;
If you try to apply it to Omuro TUH water power generation equipment, there are many points that are technically impossible.For this reason, it is necessary to control the overcurrent flowing to the cycloconverter, but before it reaches the overcurrent level of the thyristor. Therefore, it is necessary to perform current suppression control immediately, and it is necessary to immediately identify a fault on the AC system side.

On the other hand, a similar overcurrent may also flow due to causes such as an internal accident in the cycloconverter or a failure in commutation of the cycloconverter, but in this case, operation must be stopped immediately and control must be taken to minimize damage to the main engine. Regarding this point, in the past, only this overcurrent detection was performed, so it was impossible to determine the cause of the overcurrent. As a result, in order to protect the main engine, all main engines are stopped, and when applied to a large-capacity variable speed pumped storage power generation system connected to the power grid, it tends to worsen the stability of the power system, which is a drawback in terms of application. It became.

The present invention provides a generator-motor system in which a non-circulating cycloconverter is connected to the secondary side of a generator-motor, and at the same time improves reliability by protecting equipment from internal accidents of the cycloconverter or cycloconverter operation failures, etc. An object of the present invention is to provide a control device for a variable speed generator motor that can enhance system stability by continuing to control a cycloconverter without increasing the capacity of the equipment in the event of a side accident.

[Means for solving problems]

In order to solve the above problems, the present invention provides an AC system with one
A variable speed power generator comprising: a generator motor to which a secondary side is connected; and a power converter comprising an anti-parallel power control element that receives power from the alternating current system and supplies a secondary current to the secondary side of the generator motor. In the electric device, an input current detector that detects the input current of the power conversion device, an eight current detector that detects the output current of the power conversion device, and a deviation value between the input current detection value and the output current detection value. an input/output current comparator that calculates an input/output current comparator, an input current overcurrent detector of the power converter, and an input/output current comparator that determines whether the fault is internal to the power converter or an AC system fault based on the detected current value and the detected overcurrent value. The present invention is characterized by being equipped with an operation continuation determination device that makes a determination and outputs an operation stop command in the event of an internal accident, and outputs an overcurrent suppression command in the event of an AC system accident.

[Effect]

According to the configuration of the present invention, the input/output current deviation of the power converter is calculated by the input/output current comparator based on the input current detected value from the input current detector and the output current detected value from the output current detector. The value is input to the operation continuation judgment device,
Further, the overcurrent detection value from the input overcurrent detector is input to the operation continuation determination device. The operation continuation judgment device determines whether an overcurrent condition has occurred, and if it is an overcurrent condition, determines whether the difference value of the flow side is within an allowable range or not. It determines whether the fault is within the equipment, and if it is an AC system fault, issues a command to suppress the overcurrent, ensuring stability and continuity of the system without shutting down the entire system. On the other hand, in the case of an accident within the power converter, the operation of the generator motor can be stopped in an emergency to ensure safety.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

FIG. 2 shows a variable speed generator motor and the entire control system. In FIG. 2, a generator motor 2 is connected to an AC system 1. In FIG. In this generator motor 2.

A phase detector 3 is connected, and the phase detector 3 detects a slip phase equal to the difference between the voltage phase of the AC system 1 and the rotation angle expressed in electrical angles of the generator motor 2. That is, the rotor of the phase detector 3 is connected to the rotating shaft of the 5-generator motor 2, and a 3-phase winding connected in parallel with the primary winding of the generator motor 2 is provided on the rotor side. On the stator side of the 0-phase detector 3, Hall converters are provided at positions whose phase differs by π/2 in electrical angle.
A signal whose phase matches the voltage of the AC system 1 viewed from the primary side of the generator motor 2 is detected by the Hall converter.

4 is a device that generates a command value of a component of the secondary current of the generator motor 2 that is equal to the voltage phase of the AC system 1 when viewed from the primary side (hereinafter referred to as the q-axis component).

The q-axis component current command generator 4 generates a q-axis component current command I4- from the deviation between the active power output setting value and the output detected by the power detector 21.

5 generates a command value for a component of the secondary current of the generator motor 2 that differs in phase by π/2 in electrical angle from the voltage phase of the AC system 1 when viewed from the primary side (hereinafter referred to as the d-axis component). It is a device. This d-axis component current command generator 5 is connected to the AC system 1
A d-axis component current command knee is generated from the deviation between the voltage setting value and the detected value.

The above q-axis component current command 11 and d-axis component current command knee are given to the current command calculator 6.

The current command calculator 6 calculates the output signal cosθ of the phase detector 3.
and sin θ, the q-axis component current command from the q-axis component current command generator 4 and the d-axis component current command I4- from the d-axis component current command generator 5 are used to generate the secondary side of the generator motor 2. Each phase current command I 11 , I y*.

Ic" is calculated using the following equation (1). However, K
is a constant.

+ + N- Figure 3 shows the detailed circuit configuration of this current command calculator 6.
The secondary current command values (I-, I-, IcII) are calculated by the multiplier 9 and the amplifier 10, as shown in the case of FIG.

Returning to FIG. 2 again, reference numeral 7 indicates a power conversion device that supplies current to each phase of the secondary side of the generator motor 2 in accordance with the command value of the current calculator 6. The detailed circuit configuration of this power conversion device 7 is shown in FIG. 4 and FIG. 1.

In FIG. 4, 11 is a secondary current detector of the generator motor 2, and 12 is a current control device that commands the thyristor firing phase to a phase shifter 13 that compares the current command value I- with the detected value. There is. Note that the synchronous power supply supplied to the phase shifter 13 is supplied to the thyristor converter 15 via the isolation transformer 24.
141 and 1 using input currents i of 1 and 152.
42 is a gate pulse amplifier that energizes the thyristor gates of the positive connection side thyristor converter 151 and the reverse connection side thyristor converter 152, respectively. 16 is a polarity switching command generator for the secondary current, 17 is a forward/reverse switching logic circuit, and a forward/reverse switching command PN (command level is 1 when energization is commanded to the forward connection side).
) and the output signal ZD of the current zero detector 18 (the output level when it is assumed that the current is 0 is O1, and the output level is 1 when it is assumed that the current is flowing), and the positive side Start-up and stop signals GP and G of gate pulse amplifier 141 and reverse side gate pulse amplifier 142
N (signal level when starting is 1, signal level when stopping is 0)
) occurs.

The control operation when the generator motor 2 is operated by the above control system will be explained with reference to the operation waveforms of each part shown in FIGS. 5 and 6.

FIG. 5 shows a waveform when the voltage of the AC system 1 is normal and in a steady state. When the polarity of the current command value knee changes from negative to positive at time Q, the output signal of the forward/reverse switching command generator 16 P
N changes from level 0 to 1, and the forward/reverse switching logic circuit 17 starts a forward/reverse switching operation. Then, at the time point m when the two large currents Is become O, the GN signal level that was giving the activation command to the opposite side gate pulse amplifier 142 becomes O, and the thyristor gate pulse on the opposite side connection disappears. After that, at time n, after a time corresponding to the turn-off time of the thyristor, the signal level of the start command GP to the pulse amplifier 141 on the positive side changes from O to 1, and the gate of the thyristor converter on the positive side is energized and the The secondary current in the direction begins to flow.

Next, FIG. 6 shows operating waveforms when the voltage of the AC system 1 changes suddenly and suddenly. The operation up to the point θ is the same as that shown in FIG. 5, so the description thereof will be omitted. When the voltage of the AC system M1 suddenly changes at the time θ, a transient current having a rotational frequency component is generated on the secondary side. Due to the superimposed rotational frequency component, the two large currents Is become 0 at the time P, but the polarity of the command value I- remains unchanged, so
The forward/reverse switching command generator 16 does not operate, and the PN signal maintains level 1. Since the ON signal remains at level O even at time p, the power converter 7 is stopped, and at time q the positive side converter starts flowing again. In this way, overcurrent occurs instantaneously, so if the secondary current of the generator motor 2 is detected and overcurrent protection is implemented, the main engine will always stop to protect the main engine if the current exceeds the equipment's rating. It controls the system to do the following.

In order to solve this problem, in this embodiment, a configuration as shown in FIG. 1 was adopted instead of the configuration in FIG. 4.

In FIG. 1, the same elements are denoted by the same reference numerals, and a functional explanation will be omitted, and different parts will be described below. 22
is the input current detector and the cycloconverter input current II
Detect N. Further, 19 is a comparator, and the input current I
Compare IN and the cycloconverter output current l0UT detected by the current detector 11, and output the result (deviation) Δworking of IIN-IUT). Further, 23 is an overcurrent detector whose output OC was conventionally (FIG. 4) directly connected to the emergency stop circuit 86, but here it is connected to the operation continuation determination device 20.

FIG. 7 shows the detailed internal logic of the operation continuation determination device 2o.
First, if the output signal Oc of the overcurrent detector 23 (signal level "IJ" at the time of overcurrent detection) is rOJ (100), it is determined that the output current of the power converter 7 is normal (104).
, outputs the operation continuation command GOI to the current control device 12 and the polarity switching command generator 16 (107), and performs normal operation. However, even if the output signal oC of the overcurrent detector 23 is "0", the suppression control is performed. Returns from command G○2 output.

If normal operation is to be performed, a return process 109 to normal operation is required. Therefore, it is checked whether the overcurrent suppression control command GO2 has been output in the past (108), and if it has been output, the operation continuation command GOI is output after performing the recovery process (109). Here, return processing (109
) is as follows.

i) Part of the calculation result of a certain current control device 12 is initialized based on the current circuit current while remaining in the state before detecting overcurrent.

ii) Tell the current firing states of the forward and reverse thyristors to the polarity switching command generator 16 and the forward/reverse switching logic circuit 17 to initialize them.

On the other hand, if the output signal Oc of the overcurrent detector 23 is "1", the value of the output signal Δ of the comparator 19 is further determined (
101), If the Δ engineering is within the allowable value K1 and there is no generator failure, it is determined that the overcurrent was due to a system fault or the operation of the circuit breaker of another unit.103), the current control device 12 and the polarity switching The overcurrent suppression control command GO2 is output to the command generator 16 (106), and the suppression control command G
The O2 output is recorded by a flip-flop circuit in order to perform the process 109 for returning to the job function.

Further, if the value of the output signal ΔΔ of the comparator 19 is greater than or equal to the allowable value K1, 1! It was determined that the overcurrent was caused by an internal fault in the force converter 7.

Outputs the main engine emergency stop command ST to the emergency stop circuit 86 (
105).

Here, even in the event of an internal accident in the generator, there is a possibility that Δwork will be within the allowable value, so after determination 101, it is necessary to determine whether or not there is an internal accident in the generator (110).

In the unlikely event that there was a generator accident, call (111).

The main engine emergency stop command ST is output to the emergency stop circuit 86 as in the case of an internal power converter accident without executing overcurrent suppression control (105).

Here, a generator failure detection circuit is shown in FIG.

In FIG. 11, the stator side of one generator motor 2 is connected to the AC system 1 via a system breaker 52 and a main transformer 53. For failure detection of the generator motor 2, a ratio differential relay 87 is used, and when the generator motor 2 is in failure, the current detectors 54, 55 are The ratio differential relay 87 is operated by the different currents flowing between the two, and the operating contact is turned on. This contact point is used to perform the determination 110 in FIG.

FIG. 8 shows details of the current detection circuit. AC power is supplied to the thyristor converter 151 by the power receiving converter 8 connected to the AC system 1 . Note that this figure only shows the thyristor converter on the positive connection side. Thyristor converter 151
The output current output from the generator motor 2 becomes one phase of the excitation current of the generator motor 2 by passing through the rotor coil U of the generator motor 2. Similarly, the rotor coils v and W have a similar configuration, and it is possible to excite one generator motor 2 with three-phase alternating current. The input current detector 22 is arranged at each phase on the secondary side of the power receiving transformer 8, and the output signals of these three detectors are rectified by the rectifier 25, and the OR output for the three phases is used as the cycloconverter input current IIN. . The output current detector 11 is arranged on the output side of the thyristor converter 151, and this output corresponds to the cycloconverter output current l0U.
It becomes T.

The thyristor converter 151 includes six thyristor elements TY.
Consisting of I to TY6, TYI and TY6 or TYI and T
Y5, TY2 and TY4 or TY2 and TY6. Like the combination of TY3 and TY4 or TY3 and TY5, the gate of each thyristor is controlled to be ON, and TY is always on.
Among I to TY6, two thyristors are turned on in the above combination. Therefore, the input current IIN and the output current IIN have almost the same waveform, and it is possible to compare these current values.

Furthermore, details of the overcurrent suppression control command GO2 shown in FIG. 7 will be explained using FIG. 8. As an example of the suppression means here, a thyristor switch TYS shown in FIG. 8 is used. For example, if an overcurrent is applied to the rotor coil U,
By turning on the thyristor switch TYS, the overcurrent flowing through the thyristor converter 151 is shunted to the thyristor switch TYS. By turning on this thyristor switch TYS, the thyristor converter 151 is
In this case, thyristor forward/reverse switching control is performed in accordance with a rotation frequency higher than that in normal operation, and the command is transmitted to the current control device 12 and forward/reverse switching generator 16 to suppress overcurrent of one rotation frequency component. Thereafter, the transient phenomenon OC caused by the system accident or the shutdown of another unit returns to normal, and if the recovery process 109 in FIG. 7 is performed, the first generator can continue normal operation.

Next, the operation of the operation continuation judgment bag M20 (FIG. 1) will be explained using FIGS. 9 and 10.

Figure 9 shows operation continuation judgment circuit 2 in the event of an AC system accident.
Since the current value IIN obtained via the cyglo converter input side current detector 22 has almost the same waveform as the output side current value l0UT, the output Δ is approximately O. In addition, since the overcurrent value at this time is 2 or more (for example, 3.0p, u, or less) than the allowable value, the operation continuation judgment bag f120 outputs the overcurrent suppression control command G○2 and Suppress current.

Moreover, FIG. 10 shows the waveforms when commutation of each cycloconverter fails. Since the thyristor converter 151 on the positive connection side and the thyristor converter 152 on the reverse connection side of the cycloconverter are gated on at the same time, a closed circuit is formed.
An overcurrent flows through the current detector 22, and the current exceeds the allowable value by 2 or more, as in the case of a system fault.

On the other hand, in the output current detector 11, l0UT=0.

Therefore, the absolute value of the output Δk of the comparator 19 is equal to the allowable value Kz
With the above, at point r where the tolerance value exceeds 1, it is decided to continue operation! A main engine emergency stop command ST is output from 20.

In this way, it is possible to easily determine whether the fault is inside the cycloconverter or on the AC system side by detecting the input/output currents of the cycloconverter.

Furthermore, even in the case of the converter 7 having the configuration of a non-circulating cycloconverter, thyristor phase control can be continued even in the event of an AC accident. Thereby, even when a transient phenomenon occurs on the AC system 1 side, power generation or pumping operation can be continued, and high reliability can be achieved.

〔Effect of the invention〕

According to the present invention, reliability can be improved by protecting equipment from accidents inside the power converter, and by continuing control of the power converter even during transient phenomena during AC system faults, It is possible to improve stability during transient times and to improve operational reliability. Also,
Since the above effects can be achieved without changing the capacity of the generator motor or the power converter at all, there is an effect of maintaining the economical efficiency of the generator motor.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the control device according to the present invention, Fig. 2 is a block diagram showing the entire control system of the variable speed generator motor, and Fig. 3 is a block diagram showing an example of the configuration of the current calculator. Figure 4 is a block diagram showing an example of a conventional power conversion device and control device. Figure 5 is a waveform diagram showing the operating waveforms of each part when the AC system is normal. Figure 6 is a sudden voltage change in the AC system. Figure 7 is a flowchart showing the internal detailed logic of the operation continuation determination device, Figure 8 is a circuit diagram showing a specific example of the input current detector, and Figure 9 is a waveform diagram showing the operation waveforms of each part at the time of a system fault. Waveform diagram showing the operation of the operation continuation judgment circuit, No. 10
The figure is a waveform diagram showing the operation of the operation continuation judgment circuit when commutation of the cycloconverter fails. FIG. 11 is a circuit diagram of a generator failure detection circuit. DESCRIPTION OF SYMBOLS 1... AC system, 2... Generator motor, 3... Phase detector, 6... Current calculator, 8... Power receiving transformer, 9
...Multiplier, 10...Amplifier, 11...Input current detector, 12...Current control device, 13...Phase shifter,
141, 142... Gate pulse amplifier, 151, 1
52...Thyristor converter, 16...Polarity switching command generator, 17...Forward/reverse switching logic circuit, 18...Zero current detector, 19...Comparator, 20...Continue operation Judgment device, 21... active power detector, 22... output current detector.

Claims (1)

[Claims] 1. A generator motor whose primary side is connected to an AC system, and an anti-parallel power control element that receives power from the AC system and supplies a secondary current to the secondary side of the generator motor. A variable speed generator-motor device comprising: an input current detector that detects an input current of the power converter; an output current detector that detects an output current of the power converter; an input/output current comparator that calculates a deviation value between a detected current value and an output current detected value; an input current overcurrent detector of the power conversion device; A variable speed variable speed control system characterized by being equipped with an operation continuation determination device that determines whether an accident is internal to the power converter or an AC system accident, outputs an operation stop command in the event of an internal accident, and outputs an overcurrent suppression command in the event of an AC system accident. Control device for generator motor equipment.