JPH0542236B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a variable speed generator motor control device,
In particular, it relates to a variable-speed generator-motor control device that is suitable for stable control of active power output and reactive power output during variable-speed operation of pump-turbines, etc. even during sudden changes in the AC system, and ensures continuity of power supply. Suitable for highly public power systems that require [Prior art] 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-
As described in No. 60645, a method of controlling active power by controlling a secondary current component that is equal to the stator voltage phase when viewed from the stator side, and a method that controls active power by controlling a secondary current component that is approximately 90 degrees to the stator voltage phase when viewed from the stator side. There is a method of controlling reactive power by controlling the secondary current component of the phase difference. These systems are suitable for power factor adjustment devices and power adjustment devices that can respond at high speed while preventing disturbances and step-outs. On the other hand, 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. [Problems to be solved by the invention] When controlling the secondary current of the generator motor, it is necessary to The rotational frequency component induced by the DC transient component of the side current 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. To achieve this, there is a method of increasing the withstand capacity of the equipment, but this is not only economically disadvantageous, but is often technically impossible when applied to large-capacity pumped storage power generation equipment. For this reason, control to suppress the overcurrent flowing through the cycloconverter is required, but current suppression control must be executed before the overcurrent level of the thyristor is reached, and the fault can be detected immediately on the AC system side. It is necessary to distinguish between On the other hand, if a similar overcurrent flows due to a cycloconverter internal accident or cycloconverter commutation failure, etc., in this case, operation must be stopped immediately and control must be taken to minimize damage to the main engine. Must be. 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 application. Ta. 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 the Problems] In order to solve the above problems, the present invention provides a generator-motor whose primary side is connected to an AC system, and a generator-motor that receives electric power from the AC system.
A power converter comprising an anti-parallel power control element that supplies a secondary current to the next side; and an input current detector for detecting an input current of the power converter; an output current detector that detects an output current of the device; an input/output current comparator that calculates a deviation value between the input current detection value and the output current detection value; an input current overcurrent detector of the power conversion device; Based on the input/output current detection value and the overcurrent detection device, it is determined whether the power converter is in an internal accident or an AC system accident, and in the event of an internal accident, an operation stop command is output, and in the event of an AC system accident, an overcurrent suppression command is output. It is characterized by being equipped with an operation continuation determination device. [Operation] According to the configuration of the present invention, the power conversion device is calculated by the input/output current comparator based on the input current detection value from the input current detector and the output current detection value from the output current detector. The input/output current deviation value is input to the operation continuation determination device, and the overcurrent detection value from the input overcurrent detector is input to the operation continuation determination device. The operation continuation determination device determines whether an overcurrent condition has occurred, and if it is an overcurrent condition, determines whether the input/output current deviation value is within an allowable range, thereby determining whether an accident occurs in the AC system or in the power converter. It determines whether it is an accident, 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, an example of the present invention will be described based on the drawings. Figure 2 shows the variable speed generator motor and the entire control system. In FIG. 2, a generator motor 2 is connected to an AC system 1. This generator motor 2 has
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 generator motor 2, and a three-phase winding connected in parallel with the primary winding of the generator motor 2 is provided on the rotor side. ing. One Hall converter is provided on the stator side of the phase detector 3 at a position where the phase differs by π/2 in electrical angle, and the voltage and phase of the AC system 1 seen from the primary side of the generator motor 2 are A signal with matching values is detected by the Hall converter. 4 is a device that generates a command value of a component (hereinafter referred to as q-axis 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. The q-axis component current command generator 4 generates a q-axis component current command _q * 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 (hereinafter referred to as d-axis component) of the secondary current of the generator motor 2, which has a phase difference of π/2 in electrical angle from the voltage phase of the AC system 1 when viewed from the primary side. It is a device that does This d-axis component current command generator 5 generates a d-axis component current command _d * based on the deviation between the voltage setting value of the AC system 1 and the detected value.
The above q-axis component current command _q * and d-axis component current command _d * are given to the current command calculator 6. The current command calculator 6 uses the output signals θ and θ of the phase detector 3 to calculate the q-axis component current command generator 4.
The q-axis component current command _q * from the d-axis component current command generator 5 and the d-axis component current command _d * from the d-axis component current command generator 5 create the secondary side each phase current commands _a *, _b of the generator motor 2.
*, _c * are calculated using the following calculation formula (1). However, K is a constant.

〔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. Further, 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 economical efficiency as a generator motor.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of a control device according to the present invention, Fig. 2 is a block diagram showing the entire control system of a variable speed generator motor, and Fig. 3 is a block diagram showing an example of the configuration of a current calculator. 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 operation waveforms of each part when the AC system is normal, Figure 6 is a waveform diagram showing the operation waveforms of each part when the voltage of the AC system suddenly changes, and Figure 7 is the internal details of the operation continuation judgment device. Flowchart showing logic,
FIG. 8 is a circuit diagram showing a specific example of an input current detector,
Fig. 9 is a waveform diagram showing the operation of the operation continuation judgment circuit in the event of a system fault, Fig. 10 is a waveform diagram showing the operation of the operation continuation judgment circuit in the event of a cycloconverter commutation failure, and Fig. 11 is a generator failure detection It is a circuit diagram of a circuit. 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, 152...Thyristor converter, 16...Polarity switching command generator, 17...
Forward/reverse switching logic circuit, 18... Current zero detector, 19...
Comparator, 20...operation continuation determination device, 21...active power detector, 22...output current detector.

Claims (1)

[Claims] 1. Consists of 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; Detection value and
an input/output current comparator that calculates a deviation value of the output current detection value; an input current overcurrent detector of the power conversion device; and an input/output current comparator that calculates a deviation value of the output current detection value; Control of a variable speed generator-motor device characterized by being equipped with an operation continuation determination device that determines whether it is an accident or an AC system accident and outputs an operation stop command in the case of an internal accident, and outputs an overcurrent suppression command in the case of an AC system accident. Device.