JPH0777492B2 - Variable speed induction generator motor controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable speed induction generator / motor controller, and particularly to a sudden change in active power output or reactive power output on the AC system side while operating a pump turbine or the like at a variable speed. The present invention relates to a variable speed induction generator / motor controller suitable for stable control.

[Prior art]

As a conventional device in which a power converter is connected to the secondary side of an induction machine, as described in JP-B-53-7628 and JP-B-57-60645, a secondary equivalent to the stator voltage phase as seen from the stator side. There is a method of controlling the active power by controlling the current component, and a method of controlling the reactive power by controlling the secondary current component having a 90 ° phase difference with respect to the stator power phase when viewed from the stator side. These methods are suitable as a power factor adjusting device and a power adjusting device capable of high-speed response while preventing disturbance and step-out.

[Problems to be Solved by the Invention]

When these methods are used as a large-capacity generator-motor device such as a variable speed pumped storage generator, a thyristor forming a power converter connected to the secondary side also has a large capacity. When a cycloconverter is used as the power conversion device, the non-circulation current type cycloconverter is suitable for reducing the thyristor capacity.

When controlling the secondary current of the induction machine, the rotational frequency component induced by the DC transient component of the primary current is superimposed on the secondary slip frequency current component when voltage fluctuations occur due to an accident on the AC system side. To be done. Therefore, a current larger than the normal secondary current value flows through the cycloconverter, but in this case,
If this current value is within the rating of equipment such as a cycloconverter, there is a strong demand for the purpose of system stability that power generation or pumping operation is to be continued. However, an overcurrent will also flow due to an internal accident in the cycloconverter or failure in the commutation of the cycloconverter.In this case, however, the operation must be stopped immediately and control must be performed to minimize damage to the main engine. I have to. Conventionally, this overcurrent detection is performed, and it is impossible to determine the cause of the overcurrent. Therefore, in order to protect the main engine, control is performed to stop all the main engines.

An object of the present invention is to improve reliability by protecting a device from a cycloconverter internal accident, a cycloconverter commutation failure, or the like in a generator-motor device in which a non-circulation type cycloconverter is connected to a secondary side of an induction machine. The objective is to improve the system stability by continuing the control of the cycloconverter in the event of a system side failure without increasing the capacity of the equipment.

[Means for Solving the Problems]

In the present invention, a thyristor converter including an induction machine whose primary side is connected to an AC system, a positive connection side thyristor converter, and a reverse connection side thyristor converter anti-parallel to the induction side thyristor converter is provided on each secondary side of the induction machine. A thyristor power converter for supplying a secondary current by connecting to a phase, and a phase detector for detecting a slip phase equal to the difference between the voltage phase of the AC system and the secondary side rotational phase of the induction machine expressed in electrical angle. And a current command generator that generates the secondary current command value of the induction machine of two components that differ in phase by π / 2 with respect to this slip phase, and the current command value and the slip phase of the phase detector. A current pattern generator that generates a current pattern of each phase of the secondary side of the induction machine, a current detector that detects an output current of the thyristor power converter, and a current pattern of the current detector and the current pattern generator. Phase control device for controlling the thyristor firing phase of the thyristor power converter so that the deviation of the thyristor becomes zero, and the thyristor power from the current detection value of the current detector and the current pattern of the current pattern generator. In an inductively-generated power device comprising a polarity switching device that generates a forward / reverse switching signal of a converter, an input current detection device that detects an input current of the thyristor power converter, and a detection device when an overcurrent is detected. Of the detection value of the thyristor power converter and the deviation of the detection value of the output current detector for detecting the output current of the thyristor power converter are monitored, and the value of the deviation is used to determine whether it is an AC system fault or an internal fault of the thyristor power converter. An input / output current deviation monitor was installed to continue operation in the event of a system failure.

[Action]

The present invention focuses on detecting the input current and output current of the cycloconverter connected to the secondary side of the induction machine and monitoring the deviation thereof, and when overcurrent is detected, the cause is an internal accident or cyclone of the cycloconverter. It distinguishes between converter commutation failure and AC system fault, and in case of AC system side fault, controls the operation command to the anti-parallel connected thyristor converter that constitutes the cycloconverter so that the cycloconverter continues to operate. To do.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The variable speed induction generator motor in this embodiment is shown in FIG.

1 is an AC system, 2 is an induction machine connected to the AC system 1, 3
Is a phase detector that detects a slip phase equal to the difference between the voltage phase of the AC system 1 and the rotation angle represented by the electrical angle of the induction machine 2. The rotor of No. 3 is connected to the rotating shaft of the induction machine 2, and the rotor side is provided with a three-phase winding connected in parallel with the primary winding of the induction machine 2. The fixed side of 3 has an electrical angle of π
One Hall converter is provided at a position where the phase is different by / 2, and a signal in phase with the voltage of the AC system 1 as seen from the secondary side of the induction machine 2 is detected by the Hall converter.

Reference numeral 4 is a device that generates a command value of a component (hereinafter, abbreviated as q-axis component) of the secondary current of the induction machine 2 that is equal to the voltage phase of the AC system 1 when viewed from the primary side. The q-axis component current command generator 4 generates a q-axis component current command I _q * from the deviation between the active power output set value and the output detected by the power detector 21.

Reference numeral 5 generates a command value of a component (hereinafter, abbreviated as d-axis component) having a phase difference of π / 2 in electrical angle from the voltage phase of the AC system 1 as seen from the primary side of the secondary current of the induction machine 2. It is a device.
The d-axis component current command generator 5 generates a d-axis component current command I _d * from the deviation between the voltage setting value and the detected value of the AC meter 1. 6 is a current command calculator at the phase detector output signal cosθ and sinθ q-axis component current command generator 4 with an output I _q * and d-axis component current command generator 5 outputs I _d * from the induction machine 2 the secondary phase current command I _a *, I _b *, are calculated by arithmetic expressions (1) and I _c *. However, K is a constant.

FIG. 3 shows a detailed circuit configuration of the current command calculator 6 when K = 1. The multiplier 9 and amplifier 10 secondary current command value _{(I a *, I b *} , I c *) for calculating a. In FIG. 2, 7 is a power converter that supplies current to each secondary side phase of the induction machine 2 according to a command value of the current calculator 6, and 8 is a power receiving transformer connected from the AC system 1 to the power converter 7. It is a vessel. FIG. 4 shows a detailed circuit configuration of the power conversion device 7.

11 is a secondary current detector of the induction machine 2 and 12 is a current command value I *
And a detection value I _M to compare the detected value I _M with the phase shifter 13 to instruct the thyristor firing phase. 141 and 142 are respectively a positive connection side thyristor converter 151 and a reverse connection side thyristor converter 152.
Gate pulse amplifier for energizing a thyristor gate, 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 (the signal level is 1 when an energization command is supplied to the positive connection side) and an output signal of the current zero detector 18. ZD
(The output level when the current is considered to be 0 is 0, and the output level when the current is considered to be flowing is 1.)
Is input to generate start and stop signals GP and GN (the signal level at the time of start is 1 and the signal level at the time of stop is 0) of the positive side gate pulse amplifier 141 and the reverse side gate pulse amplifier 142.

FIG. 5 and FIG. 6 show the operation waveforms of each part when the induction machine 2 is operated in the above embodiment.

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 I * changes from negative to positive when the polarity is 1, the output signal PN of the forward / reverse switching command generator 16 changes from level 0 to level 1 and the forward / reverse switching logic circuit 17 starts the forward / reverse switching operation. To do. And the secondary current I _M became 0 2
At this time, the GN signal level that has given the start command to the reverse side gate pulse amplifier 142 changes from 1 to 0, and the thyristor gate pulse on the reverse connection side disappears. After that, at a time point 3 after a time corresponding to the turn-off time of the thyristor, the signal level of the start command GP to the positive side pulse amplifier 141 changes from 0 to 1, and the gate of the positive connection side thyristor converter is energized and the secondary in the positive direction is activated. Side current begins to flow.

FIG. 6 shows operation waveforms when the voltage of the AC system 1 suddenly changes suddenly. The operation up to the point of time 4 is the same as in FIG. When the voltage of the AC system 1 suddenly changes at the time point of 4, the transient current of the rotation frequency component is generated on the secondary side. Secondary current I _M is zero but the command value I * of the polarity are immutable sex reverse switching command generator at 5 by superimposing the rotation frequency component
16 does not operate, and the PN signal holds level 1. Since the GN signal remains at level 0 even at the time of 5, the power converter 7 is stopped, and at the time of 6, the positive converter starts to flow again. In this way, if an overcurrent protection is implemented by detecting the secondary current of the air conduction to induce the overcurrent instantaneously, if the current exceeds the rated value of the equipment, the main engine must be stopped for the purpose of main engine protection. To control.

In order to solve this, in this embodiment, the structure shown in FIG. 1 is used instead of the structure shown in FIG. In FIG. 1, the same reference numerals indicate the same items, and the description of their functions is omitted. A current detector 22 detects the cycloconverter input current IIN. A comparator 19 compares the input current IIN with the cycloconverter output current IOUT detected by the current detector 11.
Further, 20 is a deviation monitoring device, and when it is judged that the cause of the overcurrent is an AC system accident and it is possible to continue the operation, the operation continuation command GO is issued, and when the cycloconverter internal accident or the cycloconverter commutation failure occurs, the main engine operation is started. The stop command ST is output to the emergency stop circuit 86. Next, the function of the above circuit
This will be described with reference to FIGS.

Fig. 7 shows the functions of the above circuits in the event of an AC system fault. The current value INN obtained through the cycloconverter input side current detector 22 has a waveform that is almost the same as the output side current value IOUT. The output of the device 19 has a ΔI of almost zero. The overcurrent value at this time is also within the allowable value (for example, 3.
0p, u, or less), the output of the deviation monitoring device 20 is ST = 1, and the operation is controlled to continue the operation.

Further, FIG. 8 shows a waveform when the cycloconverter commutation fails, and since the forward connection side thyristor converter 151 and the reverse connection side thyristor converter 152 of the cycloconverter are gated on at the same time, a closed circuit is assembled to detect the current. Bowl 22
An overcurrent flows through, while on the other hand, in the current detector 11, IOUT≈0. Therefore, the output ΔI of the comparator 18 becomes a large negative value, and the monitoring device 20 issues the main engine stop designation ST at the point B which exceeds the judgment value.

As described above, according to the present invention, it is possible to easily discriminate whether the accident is in the cycloconverter or the AC system side by detecting the cycloconverter input / output current. Further, the converter 7 having the structure of the non-circulation type cycloconverter can continue the thyristor phase control even in the case of an AC system failure. As a result, power generation or electric operation can be continued even when a transient phenomenon occurs on the AC system 1 side, and high reliability can be realized.

[Advantages of the Invention] According to the present invention, in a generator-motor apparatus in which a non-circulation type cycloconverter is connected to the secondary side of an induction machine, the effect of enhancing reliability by protecting the equipment from accidents inside the cycloconverter and the AC system By maintaining the cycloconverter control even during a transient phenomenon at the time of an accident, it is possible to achieve both the effect of improving the stability during the transient and improving the operational reliability. Further, since the above effect can be realized without changing the capacity of the induction machine or the cycloconverter at all, there is an effect of keeping the economy as a power generation motive.

[Brief description of drawings]

1 to 4 are views showing an embodiment of the present invention, and FIG.
FIG. 8 to FIG. 8 are diagrams showing operation waveforms of the present invention. 1 ... AC system, 2 ... induction machine, 3 ... phase detector, 6
…… Current calculator, 8 …… Reception transformer, 9 …… Multiplier, 10
...... Amplifier, 11,22 …… Current detector, 12 …… Current control device, 13 …… Phase shifter, 141,142 …… Gate pulse amplifier, 1
51,152 …… Thyristor converter, 16 …… Polarity switching command generator, 17 …… Forward / reverse switching logic circuit, 18 …… Current zero detector, 19
…… Comparator, 20 …… Deviation monitoring device, 21 …… Active power detector.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Sugisaka 5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Omika Plant (72) Inventor Eizo Kita 3 Nakanoshima, Kita-ku, Osaka-shi, Osaka 3-32, Kansai Electric Power Co., Ltd. (72) Inventor, Hiroto Nakagawa, Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture 3-322, Kansai Electric Power Co., Ltd. (72) Yasushi Ohno, Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture 3-3-22 Kansai Electric Power Co., Inc.

Claims (2)

[Claims] 1. An induction machine whose primary side is connected to an AC system,
A thyristor power converter for supplying a secondary current by connecting the induction machine to each phase on the secondary side of a thyristor converter consisting of a positive connection side thyristor converter and a reverse connection side thyristor converter anti-parallel thereto. And a phase detector for detecting a slip phase equal to the difference between the voltage phase of the AC system and the rotational phase of the secondary side of the induction machine expressed by an electrical angle, and a phase difference of π / 2 with respect to the slip phase. A current command generator that generates the secondary current command value of the induction machine of two components, and a current pattern that generates a current pattern of each phase on the secondary side of the induction machine from the current command value and the slip phase of the phase detector. A generator, a current detector for detecting an output current of the thyristor power converter, and the current detection value of the thyristor power converter so that the deviation of the current pattern of the current pattern generator becomes zero. From the phase control device for controlling the thyristor firing phase, and the polarity switching device for generating the forward / reverse switching signal of the thyristor power converter from the current detection value of the current detector and the current pattern of the current pattern generator. In the induction power generator, the input current detection device detects an input current of the thyristor power converter, and a detection value from the detection device when an overcurrent is detected and an output current of the thyristor power converter. An input / output current deviation monitoring device that monitors the deviation from the detection value of the output current detection device and determines whether the AC system accident or the internal accident of the thyristor power conversion device is based on the deviation value and continues operation when the AC system accident occurs. A variable speed induction generator motor control device, characterized by being provided with. 2. The input / output current deviation monitoring device according to claim 1, wherein when the overcurrent is detected and it is determined that the internal accident occurs, the operation of the main engine is urgently stopped due to commutation failure. Variable speed induction generator motor controller.