CN-121993446-A - Redundant servo control system of governing valve

CN121993446ACN 121993446 ACN121993446 ACN 121993446ACN-121993446-A

Abstract

The invention discloses a redundant servo control system of a regulating valve, which belongs to the technical field of industrial servo control and comprises a redundant servo module and two paths of redundant servo control oil paths, wherein the servo control oil paths are arranged in parallel and used for controlling the oil quantity of a rodless cavity of an oil engine, and each path of servo control oil path comprises a servo valve, a switching electromagnetic valve and a blocking valve. The redundant servo module comprises a main servo module and a slave servo module, wherein the main servo module is connected with servo valve coils connected in parallel in one path of servo control oil path, and the slave servo module is connected with servo valve coils connected in parallel in the other path of servo control oil path. The invention adopts the redundant double servo modules and the redundant double servo control oil paths, so that the safety control of the valve can be realized under various failure working conditions, and the switching disturbance and non-switching fault disturbance can be reduced, thereby solving the problem that the existing servo control system cannot be adapted to the application scene of a master/slave servo valve (with a switching electromagnetic valve).

Inventors

ZENG GUANGMING
SUN TAO
LIU JIONG
PENG MIN
ZHANG YAO
ZHOU HAI

Assignees

东方电气自动控制工程有限公司

Dates

Publication Date: 20260508
Application Date: 20260331

Claims (9)

1. A redundant servo control system of a regulating valve is characterized by comprising a redundant servo module and two redundant servo control oil paths (3), The servo control oil way (3) is arranged in parallel and used for controlling the oil quantity of a rodless cavity of the oil motor (9), each servo control oil way (3) comprises a servo valve (4), a switching electromagnetic valve (5) and a blocking valve (6), two coils of the servo valve (4) are connected in parallel, the servo valve (4) is connected with the rodless cavity of the oil motor (9), the blocking valve (6) is connected between the servo valve (4) and the rodless cavity of the oil motor (9), the switching electromagnetic valve (5) is used for controlling the blocking valve (6), the blocking valve (6) is opened when the switching electromagnetic valve (5) is deenergized, the oil way between the servo valve (4) and the rodless cavity of the oil motor (9) is communicated, the blocking valve (6) is closed when the switching electromagnetic valve (5) is electrified, and the oil way between the servo valve (4) and the rodless cavity of the oil motor (9) is disconnected; The redundant servo module comprises a main servo module (1) and a slave servo module (2), wherein redundant RS422 network communication is adopted between the main servo module (1) and the slave servo module (2), the main servo module (1) is connected with a servo valve (4) coil connected in parallel in one path of servo control oil path (3), the slave servo module (2) is connected with a servo valve (4) coil connected in parallel in the other path of servo control oil path (3), the main servo module (1) and the slave servo module (2) are respectively integrated with DO channels of two paths of optical MOS relays, and the two paths of DO channels of the main servo module (1) are connected with the two paths of DO channels of the slave servo module (2) in parallel to respectively control two switching electromagnetic valves (5).
2. A redundant servo control system for a regulator valve according to claim 1, comprising a master-slave switching anti-disturbance strategy, wherein when switching from the slave servo module (2) to the master servo module (1), a short pulse is generated from the slave servo module (2), during which pulse time the built-in PI regulator is forced from the servo module (2) to the proportional regulation mode, and then the PI regulator returns to normal, effecting a smooth transition of master-slave switching.
3. The redundant servo control system of the regulating valve according to claim 1, further comprising a double-solenoid valve power-failure control strategy, wherein when all the switching solenoid valves (5) in the redundant servo control oil circuit (3) are powered off, the main servo module (1) outputs a current signal to the corresponding servo valve (4) after PI operation, and simultaneously outputs a small current from the servo module (2) to the corresponding servo valve (4) so as to keep the oil circuit constant in flow.
4. A redundant servo control system for a regulator valve according to claim 1, further comprising a safety position control strategy, in particular, when the servo valve (4) is completely uncontrollable, a safety current is output to the servo valve (4) from the servo module (2) corresponding to the main servo module (1), forcing the spool of the servo valve (4) to move towards the safety position.
5. A redundant servo control system for a regulator valve according to any one of claims 1-4, wherein said servomotor (9) is provided with two 6-wire LVDT sensors, one for each of the master servo module (1) and the slave servo module (2).
6. The redundant servo control system of the regulating valve according to claim 5, wherein the redundant servo control system further comprises an LVDT coil disconnection disturbance prevention strategy, and particularly when two LVDT sensors are disconnected, the redundant servo module adopts valve position feedback and the LVDT sensor with smaller instruction deviation to participate in calculation.
7. The redundant servo control system of the regulating valve according to claim 1, wherein the redundant servo module is connected with the main control system through a redundant communication module, the redundant servo module and the redundant communication module are connected through a redundant CAN network, the redundant communication module and the main control system form a redundant communication network through RS485 or Ethernet, the redundant communication module comprises an A communication module (10) and a B communication module (11), and redundant RS422 network communication is adopted between the A communication module (10) and the B communication module (11).
8. The redundant servo control system of a regulating valve according to claim 1, further comprising an unloading valve (8), wherein a control cavity of the unloading valve (8) is communicated with a safety oil pipeline, and a working cavity of the unloading valve (8) is respectively communicated with a rodless cavity of an oil motor (9) and a pressure oil pipeline.
9. The redundant servo control system of the regulating valve according to claim 1, wherein an oil inlet of the servo valve (4) is connected with a pressure oil pipeline, an oil inlet of the switching electromagnetic valve (5) is connected with a safety oil pipeline, and a manual stop valve (7) is connected with an oil inlet of the servo valve (4) and an oil outlet of the locking valve (6).

Description

Redundant servo control system of governing valve Technical Field The invention belongs to the technical field of industrial servo control, and particularly relates to a redundant servo control system of an adjusting valve. Background In the operation control of an electric power unit, the control and adjustment of a steam turbine regulating valve are important for the stable and reliable operation of the unit. The electrohydraulic servo valve is used for controlling the regulating valve of the steam turbine, the servo module receives the control command sent by the main control system, forms a comparison link with the LVDT feedback signal installed on the hydraulic actuating mechanism, outputs a servo driving signal after PI operation to control the opening degree of the servo valve to drive the oil motor to move, so that the regulating valve is stabilized to a designated opening degree position, and finally, the aim of controlling the steam flow is fulfilled. The restarting of the power unit after the fault shutdown can bring huge economic loss, and the reliability of the system can be increased by improving the redundancy. In the control design of the electric power unit, three measuring points are usually adopted for important input signals, three-taking-two algorithms are adopted for digital quantity, three-taking-middle or more complex filtering algorithms are adopted for analog quantity to increase reliability, and double redundancy frameworks are adopted for system constitution. In order to ensure reliability, the servo valve is provided with two redundant coils, and the combined moment of the two coils determines the opening degree and the deflection direction of an oil port of the servo valve. This design has a serious problem such as failure of the drive circuit of one coil to cause maximum output, and the other coil cannot normally control the valve even if the operating circuit is normal. Conventional servo modules are often single modules, but while supporting redundant LVDT operation and dual servo coil drive, two sets of redundant designs, such as MPU or FPGA related designs, that are not completely independent, are typically not redundant designs. Once the single-loop design points are out of order, the servo module is in an uncontrollable state, so that the load of the unit greatly fluctuates, and abnormal shutdown can be caused for an application scene of single-regulating valve control (such as a part of industrial turbine units or a small steam turbine with a 100% feed pump). At present, a scheme for realizing servo control by adopting a redundant servo module has been proposed in the industry, wherein patent document with publication number of CN211264095U discloses a redundant servo system with a cooperative work function after double-card simultaneous fault. Two redundant servo cards in the system are respectively and independently connected with an LVDT sensor and one path of driving coil of a servo valve, and the two redundant servo cards are communicated through a bottom plate at the back of the chassis to realize data interaction. The technology adopts a structure of combining redundant double-servo cards with a single-servo valve, not only realizes online card replacement, but also can ensure the normal operation of a system under the condition of single-card faults and even double-card faults, and the adopted data sharing technology can ensure the normal operation of the system under the condition of non-identical faults (such as the disconnection of LVDT (linear variable differential drive) corresponding to one servo card and the disconnection of servo drive of the other servo card), and can cut off one servo drive circuit when the maximum uncontrollable output occurs to the other servo drive circuit, thereby ensuring the normal control of the other servo drive circuit. However, after careful analysis, the following technical problems still exist in the technology: 1. the technology is only suitable for application scenes of single servo valves (redundant coils), the requirements of the application scenes of master/slave servo valves (with switching electromagnetic valves) on the safe operation level of the unit are higher, the technology cannot adapt to the scenes, and when the clamping working condition of the servo valves occurs, the technology still causes abnormal shutdown in the unit controlled by the single regulating valve. 2. If the valve is uncontrollable due to the working conditions such as double LVDT faults, the valve needs to be moved to a safe position, and the valve is normally closed to the safe position, but the heating valve is in a fully opened position to the safe position. This technique only sets a default door closing current, resulting in a failure to adapt to the safety position requirements of different scenarios. 3. The action time of switching the electromagnetic valve is longer, and the disturbance in the switching process is unavoidable due to t