A control system and method for main command contact position of hydraulic machine backup protection taking water head into account

Abstract

The present invention discloses a control system and method for the position of a main command contact for backup protection of a water turbine taking water head into consideration. The system includes a relay, wherein the relay piston rod is connected to a guide vane control ring connecting rod; the main command contact push rod is fixed directly below the connection between the relay piston rod and the guide vane control ring connecting rod and cooperates with a screw slide control mechanism. During control, the position data is first calibrated and the position given is calculated, and then the position loop control, speed loop control and current loop control are performed in sequence, and finally the parameters are adjusted in sequence from the inner loop to the outer loop; the problem that the installation position of the no-load main command contact in the prior art is difficult to determine and calibrate, and the problem that the no-load main command contact cannot be adjusted in real time with changes in water head, thereby causing abnormal operation or damage of the equipment is solved; the position of the main command contact can be accurately adjusted in real time according to the water head, and there is no need to mark the position when the main command contact is disassembled for overhaul of the unit. When the installation is restored, the installation position is automatically calibrated, which greatly improves work efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of no-load opening master contact, and in particular to a water machine backup protection master contact position control system and method taking water head into account. Background Art

[0002] The no-load opening master contact is a local component that indicates the no-load opening status of the unit. It is often used in the hydraulic turbine backup protection circuit as a judgment condition for tripping the CCB or GCB switch and de-exciting the system. The hydraulic turbine backup protection circuit is a critical component in the protection system of a hydro-turbine generator set. Its primary function is to provide an additional safety measure to prevent equipment damage and ensure personnel safety when an abnormality occurs in the unit's LCU (local control unit). The hydraulic turbine backup protection circuit is a hard-wired circuit. When the temperature of the three bearing shells of the unit is too high or the unit is overspeeding, the hydraulic turbine backup protection circuit is triggered to drop the rapid door, actuating the emergency shutdown solenoid valve and the emergency pressure regulating valve to close the guide vanes. When the guide vane opening is reduced to the no-load opening, the no-load opening master contact is activated, tripping the CCB or GCB switch, de-exciting the system, and achieving a safe shutdown of the unit.

[0003] In the prior art, a master contact bracket is fixed to the ground below the main servomotor piston rod, on which is mounted a no-load opening master contact. This contact uses a travel switch to output a switching signal. A push rod is fixed below the connection between the servomotor piston rod and the control ring, with the front end of the push rod tilted upward by approximately 30°. When the guide vanes are opened, the servomotor piston rod drives the push rod forward. When the guide vane opening is greater than the no-load opening, the push rod and the travel switch are no longer in contact, and the no-load opening master contact signal is reset. When the guide vanes are closed, the servomotor piston rod drives the push rod backward. When the guide vane opening is less than the no-load opening, the push rod squeezes the travel switch, and the no-load opening master contact signal is activated.

[0004] The shortcomings of the prior art are as follows:

[0005] 1. The no-load opening is negatively correlated with the unit's operating head. When the head increases, the no-load opening decreases, and when the head decreases, the no-load opening increases. The existing no-load opening master contact is fixed in a bracket, making it impossible to adjust the installation position in real time based on changes in head. After the water turbine backup protection process is activated, if the installation position is greater than the no-load opening, the CCB or GCB switch will trip prematurely, causing a rapid increase in the unit speed and, in severe cases, equipment damage. If the installation position is less than the no-load opening, the CCB or GCB switch will trip later, causing the unit to operate at reverse power.

[0006] 2. During unit overhaul, the control loop, main relay, master contact, and their brackets are removed. During restoration, the installation positions are difficult to determine and verify. Therefore, a head-based master contact position control system and method for backup protection of a turbine is needed to address this issue. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a water turbine backup protection master contact position control system and method taking water head into account, aiming to solve the problems in the prior art that the installation position of the no-load master contact is difficult to determine and calibrate, and the no-load master contact cannot be adjusted in real time with changes in water head, thereby causing abnormal operation or damage to the equipment.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A control system for the position of a master contact for backup protection of a hydraulic turbine taking water head into account comprises a servo, wherein the servo piston rod is connected to a guide vane control ring connecting rod; when pressurized oil flows through the servo opening chamber, the guide vanes are opened, and when pressurized oil flows through the servo closing chamber, the guide vanes are closed; a master contact push rod is fixed directly below the connection between the servo piston rod and the guide vane control ring connecting rod and cooperates with a lead screw slide control mechanism to perform linear displacement motion following the servo piston rod.

[0010] Preferably, the screw slide control mechanism includes a bracket, a base plate is connected above the bracket, a guide rail is connected to the upper surface of the base plate, and the guide rail is slidably connected to the movable plate; a main command contact is connected to the upper surface of the movable plate, the bottom of the movable plate is threadedly connected to the screw rod, one end of the screw rod is connected to the output end of the servo motor to realize screw rod transmission, and the screw slide control mechanism controls the main command contact to move to a given position according to the current operating head of the unit; the bracket is fixed on the ground of the waterwheel room.

[0011] The controller further calculates the position reference based on the unit's current operating head and receives encoder data to control the position and speed loops. The servo driver controls the current loop and outputs control signals to the servo motor. The servo motor receives the driver's control signals to rotate forward and reverse, pushing the master contact on the moving plate forward and backward via the leadscrew.

[0012] The above-mentioned method for controlling the position of the main command contact of the hydraulic turbine backup protection taking into account the water head comprises the following steps:

[0013] S1, perform position data calibration, and standardize the encoder data to 0-10000, corresponding to the guide vane opening 0-100%;

[0014] S2, calculate the position given ;

[0015] S3, uses the proportional controller as the position controller to perform position loop control;

[0016] S4, uses the proportional-integral controller as the speed controller to perform speed loop control;

[0017] S5, using the servo drive as a current controller to perform current loop control;

[0018] S6, from the inner loop to the outer loop, perform parameter tuning in the order of current loop, speed loop, and position loop.

[0019] Preferably, in step S1, the encoder data is normalized to 0-10000, and the corresponding formula for the guide vane opening of 0-100% is expressed as:

[0020] ;

[0021] in, is the position data after per unit, X(t) The original code value output by the encoder; fully close the guide vane to control the movement of the main contact; when the main contact is squeezed by the push rod, the original code value collected by the encoder is ; Fully open the guide vane to control the movement of the main contact. When the main contact is squeezed by the push rod, the original code value collected by the encoder is .

[0022] Preferably, in step S2, in the position calibration mode, the position given is calculated include:

[0023] Fully close the guide vane, position given Equal to the manually set value , until the master contact is actuated, the position feedback Assign value to position given At this time, the negative feedback deviation is equal to 0, the servo motor maintains the current position unchanged, and the original code value output by the encoder is X(t) Assign to ;

[0024] Fully open guide vanes, given position Equal to the manually set value , until the master contact is actuated, the position feedback Assign value to position given At this time, the negative feedback deviation is equal to 0, the servo motor maintains the current position unchanged, and the original code value output by the encoder is X(t) Assign to By detecting the state of the master contact and switching the position given value, the position calibration data can be realized. , Automatic collection of .

[0025] Preferably, in step S2, in automatic control mode, the position given is calculated include:

[0026] If the unit is not connected to the grid, the position is given Equal to position feedback , the negative feedback deviation is equal to 0, and the servo motor maintains its current position;

[0027] If the unit has been connected to the grid, collect the unit's current operating head data H , through the head no-load opening curve Calculate the no-load opening corresponding to the current water head Y ; Then according to the no-load opening relay stroke curve Calculate the relay stroke value corresponding to the current operating head, that is, .

[0028] Preferably, in step S3, the position loop control method is:

[0029] The position controller is a proportional controller, input:

[0030] ;

[0031] Output:

[0032] ;

[0033] in Given the position With position feedback The difference, is the speed setting, which serves as the input of the speed loop. is the proportional control coefficient.

[0034] Preferably, the speed loop control method is:

[0035] The speed controller is a proportional-integral controller, with the following input:

[0036] ;

[0037] Output:

[0038] ;

[0039] in Speed ​​given With speed feedback The difference, is the output of the speed controller and serves as the input of the current loop; is the proportional control coefficient, is the integral control coefficient.

[0040] Preferably, the current loop control method is:

[0041] The servo drive acts as a current controller, using proportional integral control and current feedback The servo drive output current is collected from the Hall element inside the servo drive; input:

[0042] ;

[0043] right After proportional-integral operation, the voltage signal that drives the servo motor to rotate is output; The output of the speed controller With current feedback The difference.

[0044] Preferably, in step S6, the parameter setting method is:

[0045] Start from the inner loop to the outer loop, first adjust the current loop, then adjust the speed loop, and finally adjust the position loop;

[0046] The current loop has the fastest response speed. Use the default parameters inside the servo drive or fine-tune the proportional control coefficient and integral control coefficient according to actual conditions.

[0047] The speed loop responds faster than the position loop. The proportional control coefficient and the integral control coefficient are appropriately adjusted, and the optimal parameters are selected as the final values ​​with the goal of fast dynamic response and high system stability.

[0048] The position loop response speed should be slower than the speed loop. The proportional control coefficient should be properly adjusted and the parameter that does not cause speed oscillation should be selected as the final value.

[0049] After the three closed-loop parameters are determined, the position setting is manually set to test the dynamic response capability and stability of the control system. The parameters are fine-tuned according to the test results until the dynamic response capability and stability indicators of the system meet the set values.

[0050] The beneficial effects of the present invention are as follows:

[0051] The present invention can accurately adjust the position of the master contact in real time according to the water head. After the water machine backup process is started, it can avoid the unit overspeed or reverse power events caused by inaccurate master contact position. There is no need to mark the position when disassembling the master contact for overhauling the unit. When restoring the installation, the installation position is automatically checked, which greatly improves work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the overall structure of the system of the present invention;

[0053] Figure 2 It is a structural diagram of the screw slide control mechanism of the system of the present invention;

[0054] Figure 3 This is a logic block diagram of the components of the no-load opening master contact position control system of the present invention;

[0055] Figure 4 This is a block diagram of the no-load opening master contact position control principle of the present invention;

[0056] The reference numerals in the figure are: relay 1, guide vane control ring connecting rod 2, main command contact push rod 3, screw slide control mechanism 4, bracket 401, base plate 402, guide rail 403, moving plate 404, main command contact 405, servo motor 406, and screw 407. DETAILED DESCRIPTION

[0057] Example 1:

[0058] like Figure 1 As shown, a no-load opening master contact 405 position control system taking water head into account includes a relay 1, the relay 1 piston rod of the relay 1 is connected to the guide vane control ring connecting rod 2; when the relay 1 opens the cavity and passes pressurized oil, the guide vane opens; when the relay 1 closes the cavity and passes pressurized oil, the guide vane closes; the master contact push rod 3 is fixed just below the connection between the relay 1 piston rod and the guide vane control ring connecting rod 2, cooperates with the screw slide control mechanism 4, and follows the relay 1 piston rod to perform linear displacement movement.

[0059] like Figure 2 As shown, the screw slide control mechanism 4 includes a bracket 401, a base plate 402 is connected above the bracket 401, the upper surface of the base plate 402 is connected to a guide rail 403, and the guide rail 403 is slidably connected to the movable plate 404; the upper surface of the movable plate 404 is connected to a main command contact 405, the bottom of the movable plate 404 is threadedly connected to a screw rod 407, and the screw rod 407 is connected to the output end of the servo motor 406 when the screw rod 407 is disconnected to realize the transmission of the screw rod 407, and the screw slide control mechanism 4 controls the main command contact 405 to move to a given position according to the current operating head of the unit; the bracket 401 is fixed on the ground of the waterwheel room.

[0060] The controller further calculates the position reference based on the unit's current operating head and receives encoder data to control the position and velocity loops. The servo driver controls the current loop and outputs control signals to servo motor 406. Servo motor 406 receives the servo driver's control signals to rotate forward and reverse, pushing master contact 405 on movable plate 404 forward and backward via the leadscrew.

[0061] Example 2:

[0062] like Figure 3 , Figure 4 As shown, a method for controlling the position of the no-load opening master contact 405 taking into account the water head includes the following steps:

[0063] S1, perform position data calibration, and standardize the encoder data to 0-10000, corresponding to the guide vane opening 0-100%;

[0064] S2, calculate the position given ;

[0065] S3, uses the proportional controller as the position controller to perform position loop control;

[0066] S4, uses the proportional-integral controller as the speed controller to perform speed loop control;

[0067] S5, using the servo drive as a current controller to perform current loop control;

[0068] S6, from the inner loop to the outer loop, perform parameter tuning in the order of current loop, speed loop, and position loop.

[0069] Preferably, in step S1, the encoder data is normalized to 0-10000, and the corresponding formula for the guide vane opening of 0-100% is expressed as:

[0070] ;

[0071] in, is the position data after per unit, X(t) The original code value output by the encoder; fully close the guide vane to control the movement of the main contact 405; when the main contact 405 is squeezed by the push rod, the original code value collected by the encoder is ; Fully open the guide vane to control the movement of the main contact 405. When the main contact 405 is squeezed by the push rod, the original code value collected by the encoder is .

[0072] Preferably, in step S2, in the position calibration mode, the position given is calculated include:

[0073] Fully close the guide vane, position given Equal to the manually set value , until the main command contact 405 is actuated, the position feedback Assign value to position given At this time, the negative feedback deviation is equal to 0, the servo motor 406 maintains the current position unchanged, and the original code value output by the encoder is X(t) Assign to ;

[0074] Fully open guide vanes, given position Equal to the manually set value Until the main command contact 405 is actuated, the position feedback Assign value to position given At this time, the negative feedback deviation is equal to 0, the servo motor 406 maintains the current position unchanged, and the original code value output by the encoder is X(t) Assign to By detecting the state of the main command contact 405, the position given value is switched to realize the position calibration data , Automatic collection of .

[0075] Preferably, in step S2, in automatic control mode, the position given is calculated include:

[0076] If the unit is not connected to the grid, the position is given Equal to position feedback , the negative feedback deviation is equal to 0, and the servo motor 406 maintains the current position unchanged;

[0077] If the unit has been connected to the grid, collect the unit's current operating head data H , through the head no-load opening curve Calculate the no-load opening corresponding to the current water head Y ; Then according to the no-load opening relay 1 stroke curve Calculate the stroke value of relay 1 corresponding to the current running head, that is, .

[0078] Preferably, in step S3, the position loop control method is:

[0079] The position controller is a proportional controller, input:

[0080] ;

[0081] Output:

[0082] ;

[0083] in Given the position With position feedback The difference, is the speed setting, which serves as the input of the speed loop. is the proportional control coefficient.

[0084] Preferably, the speed loop control method is:

[0085] The speed controller is a proportional-integral controller, with the following input:

[0086] ;

[0087] Output:

[0088] ;

[0089] in Speed ​​given With speed feedback The difference, is the output of the speed controller and serves as the input of the current loop; is the proportional control coefficient, is the integral control coefficient.

[0090] Preferably, the current loop control method is:

[0091] The servo drive acts as a current controller, using proportional integral control and current feedback The servo drive output current is collected from the Hall element inside the servo drive; input:

[0092] ;

[0093] right After proportional-integral operation, the voltage signal that drives the servo motor to rotate is output; The output of the speed controller With current feedback The difference.

[0094] Preferably, in step S6, the parameter setting method is:

[0095] Start from the inner loop to the outer loop, first adjust the current loop, then adjust the speed loop, and finally adjust the position loop;

[0096] The current loop has the fastest response speed. Use the default parameters inside the servo drive or fine-tune the proportional control coefficient and integral control coefficient according to actual conditions.

[0097] The speed loop responds faster than the position loop. The proportional control coefficient and the integral control coefficient are appropriately adjusted, and the optimal parameters are selected as the final values ​​with the goal of fast dynamic response and high system stability.

[0098] The position loop response speed should be slower than the speed loop. The proportional control coefficient should be properly adjusted and the parameter that does not cause speed oscillation should be selected as the final value.

[0099] After the three closed-loop parameters are determined, the position setting is manually set to test the dynamic response capability and stability of the control system. The parameters are fine-tuned according to the test results until the dynamic response capability and stability indicators of the system meet the set values.

Claims

1. A hydraulic machine backup protection master contact position control system taking water head into account, characterized in that: It includes a servo, the servo piston rod is connected to the guide vane control ring connecting rod; the master contact push rod is fixed just below the connection between the servo piston rod and the guide vane control ring connecting rod and cooperates with the screw slide control mechanism to follow the servo piston rod to perform linear displacement movement; The screw slide control mechanism includes a bracket, a base plate is connected to the upper surface of the bracket, a guide rail is connected to the upper surface of the base plate, and the guide rail is slidably connected to the movable plate; a main command contact is connected to the upper surface of the movable plate, the bottom of the movable plate is threadedly connected to the screw, one end of the screw is connected to the output end of the servo motor to realize screw transmission, and the screw slide control mechanism controls the main command contact to move to a given position according to the current operating water head of the unit; the bracket is fixed to the ground of the waterwheel room; The control method of the main contact position control system for the water turbine backup protection taking water head into account comprises the following steps: S1, perform position data calibration, and standardize the encoder data to 0-10000, corresponding to the guide vane opening 0-100%; S2, calculate the position given ; S3, uses the proportional controller as the position controller to perform position loop control; S4, uses the proportional-integral controller as the speed controller to perform speed loop control; S5, using the servo drive as a current controller to perform current loop control; S6, from the inner loop to the outer loop, perform parameter tuning in the order of current loop, speed loop, and position loop.

2. A hydraulic machine backup protection master contact position control system taking water head into account according to claim 1, characterized in that: In step S1, the encoder data is normalized to 0-10000, and the corresponding formula for guide vane opening 0-100% is expressed as: ； in, is the position data after per unit, X(t) The original code value output by the encoder; fully close the guide vane to control the movement of the main contact; when the main contact is squeezed by the push rod, the original code value collected by the encoder is ; Fully open the guide vane to control the movement of the main contact. When the main contact is squeezed by the push rod, the original code value collected by the encoder is .

3. A hydraulic machine backup protection master contact position control system taking water head into account according to claim 2, characterized in that: In step S2, in the position calibration mode, calculate the position given include: Fully close the guide vane, position given Equal to the manually set value , until the master contact is actuated, the position feedback Assign value to position given At this time, the negative feedback deviation is equal to 0, the servo motor maintains the current position unchanged, and the original code value output by the encoder is X(t) Assign to ; Fully open guide vanes, given position Equal to the manually set value , until the master contact is actuated, the position feedback Assign value to position given At this time, the negative feedback deviation is equal to 0, the servo motor maintains the current position unchanged, and the original code value output by the encoder is X(t) Assign to .

4. A hydraulic machine backup protection master contact position control system taking water head into account according to claim 3, characterized in that: In step S2, in automatic control mode, calculate the position given include: If the unit is not connected to the grid, the position is given Equal to position feedback , the negative feedback deviation is equal to 0, and the servo motor maintains its current position; If the unit has been connected to the grid, collect the unit's current operating head data H , through the head no-load opening curve Calculate the no-load opening corresponding to the current water head Y ; Then according to the no-load opening relay stroke curve Calculate the relay stroke value corresponding to the current operating head, that is, .

5. A hydraulic machine backup protection master contact position control system taking water head into account according to claim 4, characterized in that: In step S3, the position loop control method is: The position controller is a proportional controller, input: ； Output: ； in Given the position With position feedback The difference, is the input of the speed loop, is the proportional control coefficient.

6. A hydraulic machine backup protection master contact position control system taking water head into account according to claim 5, characterized in that: In step S4, the speed loop control method is: The speed controller is a proportional-integral controller, with the following input: ； Output: ； in Speed ​​given With speed feedback The difference, is the input of the current loop; is the proportional control coefficient, is the integral control coefficient.

7. A hydraulic machine backup protection master contact position control system taking water head into account according to claim 6, characterized in that: In step S5, the current loop control method is: The servo drive acts as a current controller, using proportional integral control and current feedback The servo drive output current collected by the Hall element inside the servo drive; enter: ； right After proportional-integral operation, the voltage signal that drives the servo motor to rotate is output; The output of the speed controller With current feedback The difference.

8. The hydraulic machine backup protection master contact position control system taking water head into account according to claim 1 is characterized in that: In step S6, the parameter setting method is: The current loop uses the default parameters inside the servo drive or adjusts the proportional control coefficient and integral control coefficient according to actual conditions; The speed loop adjusts the proportional control coefficient and the integral control coefficient, and selects the optimal parameters as the final value with the goal of fast dynamic response and high system stability; The position loop adjusts the proportional control coefficient, and the parameters that meet the target are selected as the final value with the goal of preventing speed oscillation. After the three closed-loop parameters are determined, the position setting is manually set to test the dynamic response capability and stability of the control system. The parameters are adjusted according to the test results until the dynamic response capability and stability indicators of the system meet the set values.

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