DEH redundancy system based on double-servo card independent control architecture

Abstract

The utility model discloses a DEH redundancy system based on double servo card independent control architecture relates to industrial automation control technical field, the utility model discloses double servo card independent control architecture and dynamic threshold alarm mechanism are adopted, solve DEH system single servo card architecture single point failure risk and the defect that redundancy signal can not be handled independently, including: servo module is used for controlling double servo card, including signal acquisition unit, automatic check unit, servo bias unit, fault determination unit and servo wiring unit, redundancy signal processing module includes redundancy logic judging unit and fault switching unit, real -time monitoring module includes independent communication channel unit, opening difference value calculation unit and dynamic threshold alarm unit.

Description

Technical Field

[0001] This utility model relates to the field of industrial automation control technology, specifically a DEH redundant system based on a dual servo card independent control architecture. Background Technology

[0002] The digital electro-hydraulic control system of the steam turbine is the core control equipment to ensure the safe and stable operation of the power plant. The control accuracy and reliability of its high-pressure regulating valve are directly related to the load response capability and operational safety of the unit.

[0003] In existing technologies, DEH systems generally adopt a mode of controlling dual LVDT signals with a single servo card. This technology cannot achieve true signal redundancy, posing a single point of failure risk. Failure of a single servo card will result in the loss of the entire valve control and feedback function, leading to load uncontrollability. Existing technologies lack fault diagnosis and seamless switching mechanisms, failing to guarantee the continuity of valve operation. Once the servo card itself fails, the system will lose control and cannot switch, compromising the continuity and stability of valve operation. Furthermore, existing technologies have limited monitoring functions. Due to the limitations of the single servo card architecture, the operator station typically only displays the opening value of a single LVDT or the average value after high-order selection, unable to monitor the differences between the two LVDT signals in real time. This makes it difficult to detect potential faults in a timely manner, resulting in insufficient system early warning capabilities. Alarm thresholds are mostly fixed values, unable to be dynamically adjusted according to the actual operating conditions of the valve, affecting the accurate assessment of equipment health. Utility Model Content

[0004] The purpose of this invention is to provide a DEH redundant system based on a dual servo card independent control architecture to solve the problems raised in the prior art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] In a first aspect, this utility model provides a DEH redundant system based on a dual-servo-card independent control architecture, comprising:

[0007] The servo module, used to control dual servo cards, includes a signal acquisition unit, an automatic verification unit, a servo bias unit, a fault determination unit, and a servo wiring unit. The signal acquisition unit includes a linear variable differential transformer (LVDT); the servo bias unit includes servo bias input terminals and a hardware gate-off circuit; the fault determination unit includes a fault logic determination circuit and status indicator lights; and the servo wiring unit includes servo valve coil wiring, valve position feedback signal wiring, given command wiring, ACLVDT wiring, digital input signal (DI) wiring, and digital output signal (DO) wiring.

[0008] Dual servo cards, including servo card 1 and servo card 2;

[0009] Redundant communication networks, including RS422 full-duplex differential networks and CAN bus networks;

[0010] The servo chassis includes a backplane and sockets for the dual servo cards.

[0011] In conjunction with the first aspect, in a first implementation of the first aspect of this application, the signal acquisition unit includes a linear variable differential transformer (LVDT), comprising:

[0012] Each hydraulic motor is equipped with two linear variable differential transformers (LVDTs) to collect LVDT1 and LVDT2 signals respectively.

[0013] It is compatible with 6-wire AC LVDT and 4-20mA DC LVDT, and includes an LVDT excitation signal generator and a secondary coil signal acquisition channel. For the 6-wire AC LVDT, it is used to detect broken wires, loose iron cores, and whether the machine is operating in the linear region; the 4-20mA DC LVDT supports broken wire detection.

[0014] In conjunction with the first aspect, in a second implementation of the first aspect of this application, the automatic verification unit includes:

[0015] The automatic verification unit includes verification logic control and FRAM ferroelectric memory. The verification logic control generates verification instructions, and the FRAM ferroelectric memory stores the valve's fully open and fully closed values.

[0016] In conjunction with the first aspect, in a third implementation of the first aspect of this application, the servo bias unit includes a servo bias input terminal and a hardware gate circuit, comprising:

[0017] When the servo bias input terminal is active, both the microprocessor MPU and the hardware gate-closing circuit output the maximum gate-closing signal, forcing the valve to close. Specifically, this ensures the valve closes when either the MPU or the hardware gate-closing circuit fails.

[0018] In conjunction with the first aspect, in the fourth implementation of the first aspect of this application, the fault determination unit includes a fault logic determination circuit and a status indicator light, comprising:

[0019] The fault logic determination circuit connects to each functional unit to diagnose faults. When a fault is determined in the servo module, the fault relay output terminal of the control module is activated to send a fault signal to the outside. The status indicator is used to display the module's operating status and fault type.

[0020] In conjunction with the first aspect, in the fifth implementation of the first aspect of this application, the servo wiring unit includes servo valve coil wiring, valve position feedback signal wiring, given command wiring, wired AC LVDT wiring, digital input type signal DI wiring, and digital output type signal DO wiring, including:

[0021] The servo valve coil wiring is used to connect the two redundant coils of the servo valve; the valve position feedback signal wiring connects to the LVDT to receive the output valve position feedback signal; the given command wiring consists of two independent 4-20mA standard signal wirings, connected to servo card 1 and servo card 2 respectively; the wired AC LVDT wiring is used to connect the primary coil and two secondary coils of the LVDT; the digital input type signal DI wiring is a dry contact wiring; the digital output type signal DO wiring is a relay contact output, with the relay contact capacity being 250V AC 5A and 30V DC 5A for resistive loads and 250V AC 1.5A and 30V DC 1.5A for inductive loads.

[0022] In conjunction with the first aspect, in the sixth implementation of the first aspect of this application, the dual servo cards, including servo card 1 and servo card 2, include:

[0023] Each hydraulic motor is equipped with two servo cards, namely servo card 1 and servo card 2, which receive signals from the dual LVDTs of the hydraulic motor, process them in parallel, and output control voltages U1 and U2.

[0024] In conjunction with the first aspect, in the seventh implementation of the first aspect of this application, the redundant communication network includes an RS422 full-duplex differential network and a CAN bus network, comprising:

[0025] The redundant communication network connects servo card 1 and servo card 2, and adopts dual networks. Network A is an RS422 full-duplex differential network with a speed of up to 2.5 Mbps; Network B is a CAN bus network with a speed of up to 1 Mbps. The dual network is in master-slave mode, with RS422 as the master network and CAN network as the backup network. When the master network fails, it will switch to the backup network to work.

[0026] In conjunction with the first aspect, in the eighth implementation of the first aspect of this application, the servo chassis includes a backplane and sockets corresponding to the dual servo cards, comprising:

[0027] The servo chassis is used to house dual servo cards and consists of an electromagnetic shielded chassis, a backplane terminal block, and a card rail assembly. The servo chassis has a backplane inside, which is a printed circuit board with sockets corresponding to the dual servo cards soldered on it. All servo module sockets are soldered on the backplane. External wiring is connected through the terminal blocks on the backplane.

[0028] Compared with the prior art, the beneficial effects of this utility model are:

[0029] 1. It adopts a dual-servo card independent architecture, which gets rid of the mode of single card controlling dual LVDT signals, and realizes dual cards to independently process LVDT signals, avoiding the risk of single point of failure.

[0030] 2. When an abnormal signal is detected, the system automatically switches to a servo card with a normal signal to ensure the continuity and stability of valve operation.

[0031] 3. Achieve synchronous display of dual LVDT opening values, calculate the opening difference, and adjust the alarm threshold according to the current valve opening. Attached Figure Description

[0032] Figure 1 This is a diagram of the redundant servo card independent control system architecture of a DEH redundant system based on a dual servo card independent control architecture according to this utility model.

[0033] Figure 2 This is an automatic verification flowchart of a DEH redundancy system based on a dual-servo card independent control architecture according to this utility model.

[0034] Figure 3 This is a schematic diagram of the redundant servo chassis of a DEH redundant system based on a dual servo card independent control architecture according to this utility model.

[0035] Figure 4 This is a schematic diagram of the servo valve coil wiring of a DEH redundant system based on a dual servo card independent control architecture according to this utility model. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0037] Example: Figures 1-4 As shown, this utility model provides a technical solution.

[0038] like Figure 1 The diagram shows a redundant servo card independent control system architecture for a DEH redundant system based on a dual servo card independent control architecture. This invention provides a DEH redundant system based on a dual servo card independent control architecture, comprising:

[0039] After implementing the dual redundancy upgrade project for servo cards, each hydraulic motor is equipped with two linear variable differential transformers (LVDTs) to acquire LVDT1 and LVDT2 signals respectively. Each hydraulic motor is also equipped with two servo cards, servo card 1 and servo card 2, which receive signals from the two LVDTs, process them in parallel, and output control voltages U1 and U2. The difference between the control voltages U1 and U2 output by the two servo cards is compared in real time, and the voltage with the higher amplitude is selected as the final output U. out The tolerance threshold Δth is set to 0.5V by default. When the difference between the control voltages U1 and U2 output by the two servo cards exceeds the set tolerance threshold Δth, it is determined that there is a signal abnormality in one of the servo cards, including distortion, fluctuation or loss. The control logic will automatically switch to control the servo card with normal signal alone.

[0040] The dual servo cards synchronously acquire LVDT opening data S1 and S2 from both servo cards via independent communication channels, displaying the raw values ​​in real time at the operator station; they also calculate the LVDT opening difference between the two branches in real time, triggering an alarm when the difference exceeds the dynamic threshold Δalarm; the dynamic threshold Δalarm is based on the valve's current average opening S... avg Adjustments are made when S avg When the stroke is less than 50% of the valve's maximum stroke, the alarm threshold is set to 0.3mm; when S avg When the threshold is greater than or equal to 50%, the alarm threshold is raised to 0.5mm;

[0041] Data synchronization transmission: The dual servo cards send the original LVDT opening value to the operator station via an independent communication channel. Difference calculation and alarm: The difference in opening between the two LVDTs is calculated in real time and an alarm is triggered. The formula is:

[0042] ;

[0043] Where S1 is the measured opening of LVDT1, S2 is the measured opening of LVDT2, and ΔS is the opening difference;

[0044] Dynamic threshold adjustment sets tiered alarm thresholds based on the valve stroke range, using the following formula:

[0045] ;

[0046] Where Δalarm is the dynamic threshold, S avg This represents the average valve opening.

[0047] like Figure 2 An automatic verification flowchart of a DEH redundancy system based on a dual-servo card independent control architecture is shown. This invention provides a DEH redundancy system based on a dual-servo card independent control architecture, comprising:

[0048] When the servo module performs automatic verification, it outputs a closing command to drive the valve to the fully closed position. During this process, the integral action of the PI controller will generate a servo drive bias current, specifically an integral saturation phenomenon. After confirming the integral saturation state, a preset delay period is maintained to ensure the valve is fully closed, and the fully closed position value of the LVDT is recorded. After completing the closing direction verification, the servo module outputs an opening command to move the valve to the fully open position. At this time, the PI integral action will also generate a drive bias current. After another delay to confirm that the valve is fully open, the fully open value of the LVDT is recorded. At the same time, the fully closed and fully open values ​​of the LVDT obtained during the verification process are written into the FRAM memory. During the automatic verification process, the integral time constant must be kept non-zero.

[0049] like Figure 3 The diagram shows the outline of a redundant servo chassis for a DEH redundant system based on a dual-servo-card independent control architecture. This invention provides a DEH redundant system based on a dual-servo-card independent control architecture, comprising:

[0050] The front panel of the chassis has a total of 14 slots. The leftmost slot is for the Bluetooth wireless communication card, and the rightmost slot is empty and does not support card insertion. The remaining 12 slots are arranged in groups of two adjacent card slots from left to right, for a total of 6 groups. For example, the second and third slots are the first group, the fourth and fifth slots are the second group, and so on. The second to eighth slots are for redundant servo modules that have been inserted, and the ninth to thirteenth slots are reserved slots for cards that have not been inserted.

[0051] like Figure 4 A schematic diagram of the servo valve coil wiring of a DEH redundant system based on a dual servo card independent control architecture is shown. This utility model provides a DEH redundant system based on a dual servo card independent control architecture, comprising:

[0052] This servo module is suitable for servo valves with redundant coils, with a drive current of ±40mA. TBSn_A2 is the lower row terminal of slot A, and TBSn_B2 is the lower row terminal of slot B. The two redundant servo modules in slots A and B respectively drive one coil of the servo valve.

[0053] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A DEH redundant system based on a dual-servo-card independent control architecture, characterized in that, include: The servo module, used to control dual servo cards, includes a signal acquisition unit, an automatic verification unit, a servo bias unit, a fault determination unit, and a servo wiring unit. The signal acquisition unit includes a linear variable differential transformer (LVDT); the servo bias unit includes servo bias input terminals and a hardware gate-off circuit; the fault determination unit includes a fault logic determination circuit and status indicator lights; and the servo wiring unit includes servo valve coil wiring, valve position feedback signal wiring, given command wiring, wired AC LVDT wiring, digital input type signal (DI) wiring, and digital output type (DO) wiring. Dual servo cards, including servo card 1 and servo card 2; Redundant communication networks, including RS422 full-duplex differential networks and CAN bus networks; The servo chassis includes a backplane and sockets for the dual servo cards.

2. The DEH redundancy system based on a dual-servo card independent control architecture according to claim 1, characterized in that, The signal acquisition unit includes a linear variable differential transformer (LVDT), comprising: Each hydraulic motor is equipped with two linear variable differential transformers (LVDTs) to collect LVDT1 and LVDT2 signals respectively. It is compatible with 6-wire AC LVDT and 4-20mA DC LVDT, and includes an LVDT excitation signal generator and a secondary coil signal acquisition channel. For the 6-wire AC LVDT, it is used to detect broken wires, loose iron cores, and whether the machine is operating in the linear region; the 4-20mA DC LVDT supports broken wire detection.

3. The DEH redundancy system based on a dual-servo card independent control architecture according to claim 1, characterized in that, The automatic verification unit includes: The automatic verification unit includes verification logic control and FRAM ferroelectric memory. The verification logic control generates verification instructions, and the FRAM ferroelectric memory stores the valve's fully open and fully closed values.

4. The DEH redundancy system based on a dual-servo card independent control architecture according to claim 1, characterized in that, The servo bias unit includes a servo bias input terminal and a hardware gate circuit, including: When the servo bias input terminal is active, both the microprocessor MPU and the hardware gate-closing circuit output the maximum gate-closing signal, forcing the valve to close. Specifically, this ensures the valve closes when either the MPU or the hardware gate-closing circuit fails.

5. A DEH redundancy system based on a dual-servo card independent control architecture according to claim 1, characterized in that, The fault determination unit includes a fault logic determination circuit and a status indicator light, including: The fault logic determination circuit connects to each functional unit to diagnose faults. When a fault is determined in the servo module, the fault relay output terminal of the control module is activated to send a fault signal to the outside. The status indicator is used to display the module's operating status and fault type.

6. A DEH redundancy system based on a dual-servo card independent control architecture according to claim 1, characterized in that, The servo wiring unit includes servo valve coil wiring, valve position feedback signal wiring, given command wiring, ACLVDT wiring, digital input type signal DI wiring, and digital output type signal DO wiring, including: The servo valve coil wiring is used to connect the two redundant coils of the servo valve; the valve position feedback signal wiring connects to the LVDT to receive the output valve position feedback signal; the given command wiring consists of two independent 4-20mA standard signal wirings, connected to servo card 1 and servo card 2 respectively; the wired AC LVDT wiring is used to connect the primary coil and two secondary coils of the LVDT; the digital input type signal DI wiring is a dry contact wiring; the digital output type signal DO wiring is a relay contact output, with the relay contact capacity being 250V AC 5A and 30V DC 5A for resistive loads and 250V AC 1.5A and 30V DC 1.5A for inductive loads.

7. A DEH redundancy system based on a dual-servo card independent control architecture according to claim 1, characterized in that, The dual servo cards, including servo card 1 and servo card 2, include: Each hydraulic motor is equipped with two servo cards, namely servo card 1 and servo card 2, which receive signals from the dual LVDTs of the hydraulic motor, process them in parallel, and output control voltages U1 and U2.

8. A DEH redundancy system based on a dual-servo card independent control architecture according to claim 1, characterized in that, The redundant communication network includes an RS422 full-duplex differential network and a CAN bus network, comprising: The redundant communication network connects servo card 1 and servo card 2, and adopts dual networks. Network A is an RS422 full-duplex differential network with a speed of up to 2.5 Mbps; Network B is a CAN bus network with a speed of up to 1 Mbps. The dual network is in master-slave mode, with RS422 as the master network and CAN network as the backup network. When the master network fails, it will switch to the backup network to work.

9. A DEH redundancy system based on a dual-servo card independent control architecture according to claim 1, characterized in that, The servo chassis includes a backplane and sockets corresponding to the dual servo cards, including: The servo chassis is used to house dual servo cards and consists of an electromagnetic shielded chassis, a backplane terminal block, and a card rail assembly. The servo chassis has a backplane inside, which is a printed circuit board with sockets corresponding to the dual servo cards soldered on it. All servo module sockets are soldered on the backplane. External wiring is connected through the terminal blocks on the backplane.

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