An accurate control method and system for a pulse-type electric control valve

Abstract

The present invention relates to an accurate control method and system for a pulse-type electric control valve, comprising the following steps: obtaining the deviation of the quantity to be regulated in the current cycle; performing PID calculation based on the deviation of the quantity to be regulated in the current cycle to obtain the valve position increment in the current cycle; performing conversion based on the valve position increment in the current cycle to obtain the pulse time increment; performing calculation based on the pulse time increment to obtain the output pulse width in the current cycle; generating the current on / off command according to the output pulse width in the current cycle; and controlling the pulse-type electric control valve according to the current on / off command. The present invention combines the characteristics of the pulse-type electric control valve and the PID control characteristics, and through the corresponding conversion and processing of the valve position and the pulse time, enables the pulse-type electric control valve to achieve accurate control similar to that of a pneumatic control valve, and avoids frequent valve actions through the action limit function, increases the service life of the equipment, and improves the stability, accuracy and rapidity of the regulation system related to the pulse-type electric control valve.

Description

Technical Field

[0001] The present invention relates to the field of automatic control of nuclear power plants, and more specifically, to an accurate control method and system for a pulse-type electric control valve. Background Art

[0002] In order to reduce the regular discharge of the containment and save the time for treating waste gas during major repairs in some third-generation nuclear power units, pneumatic control valves are no longer used inside the reactor containment, but electric control valves with adjustable pulse control (hereinafter referred to as pulse-type electric control valves) are adopted. Their control methods are quite different from those of traditional pneumatic control valves.

[0003] The main difference between a pulse-type electric control valve and a switch-type electric control valve is that the pulse width of the switch command of the pulse-type electric control valve is adjustable, and its control interface diagram is as Figure 1 shown. Currently, DCS is first used in third-generation nuclear power to control pulse-type electric control valves. Hardware devices such as DCS mechanical I / O interfaces, electrical panels, electric heads, and valves are all standard devices, and the control of pulse-type electric control valves is realized through DCS software.

[0004] In the existing technology group of pulse-type electric control valve control, when the control valve is in the automatic mode, the deviation e of the measured variable (e is the difference between the measured value and the set value of the measured variable) is operated through an incremental PID module to calculate the incremental output △u of the valve.

[0005] Positive action process control (that is, when the deviation of the measured variable is greater than 0, the command of the actuator increases, and when the deviation of the measured variable is less than 0, the command of the actuator decreases). If △u is greater than the threshold value X, an open command is output according to the minimum pulse; if △u is less than the threshold value -X, a close command is output according to the minimum pulse. In order to ensure the regulation accuracy, X is generally set to 0.

[0006] Negative action process control (that is, when the deviation of the measured variable is greater than 0, the command of the actuator decreases, and when the deviation of the measured variable is less than 0, the command of the actuator increases. If △u is greater than the threshold value X, a close command is output according to the minimum pulse; if △u is less than the threshold value -X, an open command is output according to the minimum pulse.

[0007] The regulation dead zone is set through the incremental PID controller module. The comparison threshold value X of the incremental output △u of the valve is generally set to 0, or set to a value close to 0 such as 0.01. Otherwise, the valve will only act when the measured variable is under a large disturbance, resulting in a large regulation lag or the consequence of being unable to regulate.

[0008] Although the existing technical solution can complete the adjustment function, since the pulse-type electric control valve is different from the pneumatic control valve in that the valve position increment is related to the command length (i.e., the pulse time), the existing technical solution cannot perform valve position control according to the incremental PID output, resulting in the problem of frequent opening and closing actions of the valve. Frequent opening and closing actions of the valve will cause the electric motor to heat up and even be damaged due to excessive temperature. Therefore, the problems of adjustment performance and accuracy cannot be solved, and the characteristics of instantaneity and high speed of the proportional action are also lost. It takes a long time, has low precision, and poor stability. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide an accurate control method and system for a pulse-type electric control valve in view of the defects of the existing technology.

[0010] The technical solution adopted by the present invention to solve its technical problems is to construct an accurate control method for a pulse-type electric control valve, including the following steps:

[0011] Obtain the deviation of the quantity to be adjusted in the current cycle;

[0012] Perform PID calculation according to the deviation of the quantity to be adjusted in the current cycle to obtain the valve position increment in the current cycle;

[0013] Convert according to the valve position increment in the current cycle to obtain the pulse time increment;

[0014] Calculate based on the pulse time increment to obtain the output pulse width in the current cycle;

[0015] Generate the current open / close command according to the output pulse width in the current cycle;

[0016] Control the pulse-type electric control valve according to the current open / close command.

[0017] In the accurate control method for the pulse-type electric control valve of the present invention, the performing PID calculation according to the deviation of the quantity to be adjusted in the current cycle to obtain the valve position increment in the current cycle includes:

[0018] Perform PID calculation using an incremental PID controller according to the deviation of the quantity to be adjusted in the current cycle to obtain the valve position increment in the current cycle.

[0019] In the accurate control method for the pulse-type electric control valve of the present invention, the converting according to the valve position increment in the current cycle to obtain the pulse time increment includes:

[0020] Determine the relationship between the valve position and the stroke time of the pulse-type electric control valve;

[0021] Convert according to the relationship between the valve position and the stroke time to obtain the pulse time increment.

[0022] In the precise control method of the pulse-type electric control valve according to the present invention, determining the relationship between the valve position and the stroke time of the pulse-type electric control valve includes:

[0023] Controlling the pulse-type electric control valve to open from fully closed to fully open;

[0024] Collecting the opening degree and opening time of the pulse-type electric control valve during the opening process from fully closed to fully open;

[0025] Controlling the pulse-type electric control valve to close from fully open to fully closed;

[0026] Collecting the opening degree and closing time of the pulse-type electric control valve during the closing process from fully open to fully closed;

[0027] Obtaining the relationship between the valve position and the stroke time of the pulse-type electric control valve according to the opening degree during the opening process, the opening time, the opening degree during the closing process, and the closing time.

[0028] In the precise control method of the pulse-type electric control valve according to the present invention, the relationship between the valve position and the stroke time of the pulse-type electric control valve includes: a non-linear relationship and a linear relationship; the non-linear relationship includes: a forward conversion relationship and a negative conversion relationship.

[0029] In the precise control method of the pulse-type electric control valve according to the present invention, if the relationship between the valve position and the stroke time of the pulse-type electric control valve is a non-linear relationship, then converting according to the relationship between the valve position and the stroke time to obtain the pulse time increment includes:

[0030] Judging the positive and negative of the valve position increment in the current cycle;

[0031] If the valve position increment in the current cycle is positive, then converting using the forward conversion relationship to obtain the pulse time increment;

[0032] If the valve position increment in the current cycle is negative, then converting using the negative conversion relationship to obtain the pulse time increment.

[0033] In the precise control method of the pulse-type electric control valve according to the present invention, if the relationship between the valve position and the stroke time of the pulse-type electric control valve is a linear relationship, then converting according to the relationship between the valve position and the stroke time to obtain the pulse time increment includes:

[0034] Converting according to the linear relationship between the valve position and the stroke time to obtain the pulse time increment.

[0035] In the precise control method of the pulse-type electric control valve according to the present invention, calculating based on the pulse time increment to obtain the output pulse width of the current cycle includes:

[0036] Obtaining the on / off command status of the previous cycle;

[0037] If there is an on command in the previous cycle, calculate using the first calculation formula to obtain the output pulse width of the current cycle;

[0038] If there is an off command in the previous cycle, calculate using the second calculation formula to obtain the output pulse width of the current cycle;

[0039] If there is no on command and off command in the previous cycle, the output pulse width of the current cycle is equal to the output pulse width of the previous cycle, or calculate the output pulse width of the current cycle based on the pulse time increment using the third calculation formula.

[0040] In the precise control method of the pulse-type electric control valve according to the present invention, the first calculation formula satisfies:

[0041] Tout(k) = Tout(k - 1) - Tcp + △T;

[0042] Wherein, Tout(k - 1) is the output pulse width compensated in the previous cycle, Tout(k) is the output pulse width of the current cycle, Tcp is the operation cycle, and △T is the pulse time increment.

[0043] In the precise control method of the pulse-type electric control valve according to the present invention, the second calculation formula satisfies:

[0044] Tout(k) = Tout(k - 1) + Tcp + △T;

[0045] Wherein, Tout(k - 1) is the output pulse width compensated in the previous cycle, Tout(k) is the output pulse width of the current cycle, Tcp is the operation cycle, and △T is the pulse time increment.

[0046] In the precise control method of the pulse-type electric control valve according to the present invention, the third calculation formula satisfies:

[0047] T out (k) = T out (k - 1) + △T;

[0048] Wherein, T out (k - 1) is the output pulse width compensated in the previous cycle, T out (k) is the output pulse width of the current cycle, and △T is the pulse time increment.

[0049] In the precise control method of the pulse-type electric control valve according to the present invention, the method further includes:

[0050] Compensating the output pulse width of the current cycle.

[0051] In the precise control method of the pulse-type electric control valve according to the present invention, the compensating the output pulse width of the current cycle includes:

[0052] Obtaining the current on / off command and judging the current on / off command;

[0053] If the current on / off command is an on command, judging whether there is an on command in the previous cycle;

[0054] If there is no on command in the previous cycle, judging whether the nearest command to the current on / off command is an on command;

[0055] If the nearest command to the current on / off command is an on command, performing a same-direction pulse width compensation on the output pulse width of the current cycle.

[0056] In the precise control method of the pulse-type electric control valve according to the present invention, the compensating the output pulse width of the current cycle further includes:

[0057] If the current on / off command is an off command, judging whether there is an off command in the previous cycle;

[0058] If there is no off command in the previous cycle, judging whether the nearest command to the current on / off command is an off command;

[0059] If the nearest command to the current on / off command is an off command, performing a same-direction pulse width compensation on the output pulse width of the current cycle.

[0060] In the precise control method of the pulse-type electric control valve according to the present invention, the compensating the output pulse width of the current cycle includes:

[0061] Obtaining the current on / off command and judging the current on / off command;

[0062] If the current on / off command is an on command, judging whether there is an on command in the previous cycle;

[0063] If there is no on command in the previous cycle, judging whether the nearest command to the current on / off command is an off command;

[0064] If the nearest command to the current on / off command is an off command, performing a reverse pulse width compensation on the output pulse width of the current cycle.

[0065] In the precise control method of the pulse-type electric control valve according to the present invention, the compensation for the output pulse width of the current cycle includes:

[0066] If the current on / off command is an off command, it is judged whether there is an off command in the previous cycle;

[0067] If there is no off command in the previous cycle, it is judged whether the nearest command to the current on / off command is an on command;

[0068] If the nearest command to the current on / off command is an on command, reverse pulse width compensation is performed on the output pulse width of the current cycle.

[0069] In the precise control method of the pulse-type electric control valve according to the present invention, the generation of the current on / off command according to the output pulse width of the current cycle includes:

[0070] Judge the absolute value of the output pulse width of the current cycle;

[0071] If the absolute value of the output pulse width of the current cycle is greater than the minimum pulse width limit value and the output pulse width of the current cycle is greater than 0, it is judged whether the previous cycle is an on command;

[0072] If the previous cycle is an on command, the current on / off command is an on command;

[0073] If there is no on command in the previous cycle, it is judged whether the positive / negative interval time and the same-direction interval time meet the on command condition;

[0074] If the positive / negative interval time and the same-direction interval time meet the on command condition, the current on / off command is an on command.

[0075] In the precise control method of the pulse-type electric control valve according to the present invention, the on command condition includes: the timing time of the on command timer is greater than the same-direction interval time, and the timing time of the off command timer is greater than the positive / negative interval time.

[0076] In the precise control method of the pulse-type electric control valve according to the present invention, the generation of the current on / off command according to the output pulse width of the current cycle further includes:

[0077] If the absolute value of the output pulse width of the current cycle is greater than the minimum pulse width limit value and the output pulse width of the current cycle is less than 0, it is judged whether the previous cycle is an off command;

[0078] If the previous cycle is an off command, the current on / off command is an off command;

[0079] If there is no command in the previous cycle, it is judged whether the positive / negative interval time and the same-direction interval time meet the off command condition;

[0080] If the positive-negative interval time and the same-direction interval time satisfy the off-instruction condition, the current on / off instruction is an off instruction.

[0081] In the precise control method of the pulse-type electric control valve of the present invention, the off-instruction condition includes: the timing time of the off-instruction timer is greater than the same-direction interval time and the timing time of the on-instruction timer is greater than the positive-negative interval time.

[0082] In the precise control method of the pulse-type electric control valve of the present invention, the method further includes:

[0083] Before judging the absolute value of the output pulse width of the current cycle:

[0084] Judge whether the length of the output pulse width of the current cycle is greater than the minimum pulse width limit value;

[0085] If the length of the output pulse width of the current cycle is greater than the minimum pulse width limit value, execute the step of judging the absolute value of the output pulse width of the current cycle.

[0086] In the precise control method of the pulse-type electric control valve of the present invention, the method further includes:

[0087] Receive input parameters;

[0088] Set the characteristic parameters of the pulse-type electric control valve according to the input parameters.

[0089] The present invention also provides a precise control system for a pulse-type electric control valve, including:

[0090] An acquisition module for acquiring the deviation of the quantity to be adjusted in the current cycle;

[0091] A valve position increment output module for performing PID calculation according to the deviation of the quantity to be adjusted in the current cycle to obtain the valve position increment in the current cycle;

[0092] A pulse time conversion module for converting according to the valve position increment in the current cycle to obtain a pulse time increment;

[0093] A pulse output calculation module for calculating based on the pulse time increment to obtain the output pulse width in the current cycle;

[0094] A switch instruction generation module for generating a current on / off instruction according to the output pulse width in the current cycle;

[0095] A control module for controlling the pulse-type electric control valve according to the current on / off instruction.

[0096] In the precise control system of the pulse-type electric control valve according to the present invention, the acquisition module and the valve position increment output module are built into an incremental PID controller.

[0097] In the precise control system of the pulse-type electric control valve according to the present invention, there is also included:

[0098] A pulse setting module, configured to receive input parameters and set characteristic parameters of the pulse-type electric control valve according to the input parameters.

[0099] Implementing the precise control method and system of the pulse-type electric control valve of the present invention has the following beneficial effects: including the following steps: obtaining the deviation of the quantity to be adjusted in the current cycle; performing PID calculation according to the deviation of the quantity to be adjusted in the current cycle to obtain the valve position increment in the current cycle; performing conversion according to the valve position increment in the current cycle to obtain the pulse time increment; performing calculation based on the pulse time increment to obtain the output pulse width in the current cycle; generating the current on / off instruction according to the output pulse width in the current cycle; controlling the pulse-type electric control valve according to the current on / off instruction. The present invention combines the characteristics of the pulse-type electric control valve and the PID control characteristics, and through the corresponding conversion and processing of the valve position and the pulse time, enables the pulse-type electric control valve to achieve precise control similar to that of a pneumatic control valve, and avoids frequent valve actions through the action limit function, increases the service life of the equipment, and improves the stability, accuracy and rapidity of the relevant adjustment system of the pulse-type electric control valve. Description of the Drawings

[0100] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0101] Figure 1 is a schematic diagram of the control hardware interface of the existing pulse-type electric control valve;

[0102] Figure 2 is a schematic flowchart of the precise control method of the pulse-type electric control valve provided by an embodiment of the present invention;

[0103] Figure 3 is a schematic diagram of the forward conversion relationship of the pulse-type electric control valve provided by an embodiment of the present invention;

[0104] Figure 4 is a schematic diagram of the negative conversion relationship of the pulse-type electric control valve provided by an embodiment of the present invention;

[0105] Figure 5 is a schematic diagram of the principle of generating on / off instructions provided by an embodiment of the present invention;

[0106] Figure 6 is a schematic diagram of the principle of the precise control system of the pulse-type electric control valve provided by an embodiment of the present invention. Detailed Embodiments

[0107] In order to have a clearer understanding of the technical features, objectives and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0108] Based on the nodes of the pneumatic control valve and the pulse-type electric control valve, the present invention transforms the PID control of the valve command into the PID control of the pulse time, so that the pulse-type electric control valve can achieve precise control similar to that of the pneumatic control valve.

[0109] Specifically, referring to Figure 2 , it is a schematic flowchart of an optional embodiment of the precise control method for the pulse-type electric control valve provided by the present invention.

[0110] As Figure 2 shown, the precise control method for the pulse-type electric control valve includes the following steps:

[0111] Step S201, obtain the deviation of the quantity to be adjusted in the current period.

[0112] Optionally, in the embodiments of the present invention, the deviation of the quantity to be adjusted in the current period refers to the difference between the set value and the measured value. Its specific parameters are determined according to the application scenario. For example, when the adjustment parameter is flow rate, the deviation of the quantity to be adjusted in the current period is the difference between the flow rate set value and the flow rate in the current period; when the adjustment parameter is valve position, the deviation of the quantity to be adjusted in the current period is the difference between the valve position set value and the valve position in the current period. Similarly, when the adjustment parameter is liquid level, temperature, etc., it is the corresponding difference. Among them, the measured value can be obtained by monitoring with the corresponding monitoring tools (or devices, sensors, etc.) required for the adjusted parameter, and the present invention does not make specific limitations.

[0113] Step S202, perform PID calculation according to the deviation of the quantity to be adjusted in the current period to obtain the valve position increment in the current period.

[0114] In some embodiments, performing PID calculation according to the deviation of the quantity to be adjusted in the current period to obtain the valve position increment in the current period includes: performing PID calculation using an incremental PID controller according to the deviation of the quantity to be adjusted in the current period to obtain the valve position increment in the current period.

[0115] In the embodiments of the present invention, an incremental PID controller can be used for PID calculation to obtain the corresponding valve position increment. Specifically, the incremental PID controller is widely used in the digital instrument control system, and the controller parameters, dead zone setting, and positive / negative action setting are all set through interfaces on the controller itself. The actual actuator of the pulse-type electric control valve is a motor and a gear, and the output of the control quantity is the increment relative to the previous control quantity, that is, the valve position increment. For the retention of the previous cycle PID output, that is, the valve position, the pulse-type electric control valve realizes the retention of the valve position through the mechanism structure. Therefore, in the embodiments of the present invention, the algorithm adopted by the incremental PID controller of the pulse-type electric control valve is as follows:

[0116] u(k) = Δu(k)(1).

[0117] Wherein, in the formula, △u(k) satisfies:

[0118]

[0119] Wherein, in formula (2), K p is the proportionality coefficient, K i is the integral gain, T i is the integral time, K D is the derivative gain, CP is the operation period, e(k) is the controlled variable deviation, e(k - 1) is the controlled variable deviation, △u p (k) is the proportional increment, △u I (k) is the integral increment, △u D (k) is the derivative increment.

[0120] Therefore, after obtaining the controlled variable deviation of the current cycle, the valve position increment of the current cycle of the pulse-type electric control valve can be obtained according to formula (1) and formula (2).

[0121] Step S203: Convert according to the valve position increment of the current cycle to obtain the pulse time increment.

[0122] In some embodiments, converting according to the valve position increment of the current cycle to obtain the pulse time increment includes: determining the relationship between the valve position and the stroke time of the pulse-type electric control valve; converting according to the relationship between the valve position and the stroke time to obtain the pulse time increment.

[0123] Further, determining the relationship between the valve position and the stroke time of the pulse-type electric control valve includes: controlling the pulse-type electric control valve to open from fully closed to fully open; collecting the opening degree and opening time of the pulse-type electric control valve during the opening process from fully closed to fully open; controlling the pulse-type electric control valve to close from fully open to fully closed; collecting the opening degree and closing time of the pulse-type electric control valve during the closing process from fully open to fully closed; and obtaining the relationship between the valve position and the stroke time of the pulse-type electric control valve based on the opening degree during the opening process, the opening time, the opening degree during the closing process, and the closing time.

[0124] Optionally, in the embodiments of the present invention, the relationship between the valve position and the stroke time of the pulse-type electric control valve includes: a non-linear relationship and a linear relationship; the non-linear relationship includes: a positive conversion relationship and a negative conversion relationship.

[0125] Among them, as Figure 3 shown, it is a schematic diagram of the valve position stroke curve during the opening process of the pulse-type electric control valve (positive conversion relationship), and as Figure 4 shown, it is a schematic diagram of the valve position stroke curve during the closing process of the pulse-type electric control valve (negative conversion relationship).

[0126] Specifically, when the pulse-type electric control valve is opened from fully closed to fully open (i.e., the open command always exists, and the time when the valve position is fully closed is 0 s), by monitoring the opening degree (opening degree during the opening process) and opening time of the pulse-type electric control valve during the opening process, the corresponding relationship between the valve position and time as Figure 3 shown can be obtained. It can be expressed by the mathematical formula as: y = f open (x), where x is the valve position percentage and y is the time (unit: ms). When the pulse-type electric control valve is closed from fully open to fully closed (the close command always exists, and the time when the valve position is fully open is 0 s), by monitoring the opening degree (closing process opening degree) and closing time of the pulse-type electric control valve during the closing process, the corresponding relationship between the valve position and time as Figure 4 shown can be obtained. It can be expressed by the mathematical formula as: y = f close (x), where x is the valve position percentage and y is the time (unit: ms).

[0127] In some embodiments, if the relationship between the valve position and the stroke time of the pulse-type electric control valve is a non-linear relationship, then converting according to the relationship between the valve position and the stroke time to obtain the pulse time increment includes: judging the positive and negative of the valve position increment of the current cycle; if the valve position increment of the current cycle is positive, then using the positive conversion relationship for conversion to obtain the pulse time increment; if the valve position increment of the current cycle is negative, then using the negative conversion relationship for conversion to obtain the pulse time increment.

[0128] Specifically, when the relationship between the valve position and the stroke time of the pulse-type electric control valve is a non-linear relationship,

[0129] If the valve position increment of the current cycle output by the incremental PID controller is received, first, judge the valve position increment of the current cycle. If the valve position increment of the current cycle is positive, the valve position increment of the current cycle and the pulse time increment satisfy a positive conversion relationship, that is:

[0130] ΔT = f open (Δu + P) - f open (P) (P is the current valve position) (3).

[0131] If the valve position increment of the current cycle is negative, the valve position increment of the current cycle and the pulse time increment satisfy a negative conversion relationship, that is:

[0132] ΔT = f close (Δu + P) - f close (P) (P is the current valve position) (4).

[0133] Among them, in formulas (3) and (4), △u is the valve position increment.

[0134] In some embodiments, if the relationship between the valve position and the stroke time of the pulse-type electric control valve is a linear relationship, then convert according to the relationship between the valve position and the stroke time to obtain the pulse time increment, including: convert according to the linear relationship between the valve position and the stroke time to obtain the pulse time increment.

[0135] Specifically, for the pulse-type electric control valve, when the relationship between the valve position and the stroke time is a linear relationship, although there are slight differences between the closing process and the starting process, it can be approximately considered that T open = T close = T run , so the conversion relationship between the valve position increment △u and the pulse time increment △T can be approximately:

[0136]

[0137] It can be seen from formula (5) that for the pulse-type electric control valve with a linear valve position stroke curve, the pulse time increment △T is only related to the valve position increment △u.

[0138] Step S204: Calculate based on the pulse time increment to obtain the output pulse width of the current cycle.

[0139] In some embodiments, calculations are performed based on the pulse time increment to obtain the output pulse width of the current cycle, including: obtaining the on / off instruction status of the previous cycle; if there is an on instruction in the previous cycle, the first calculation formula is used for calculation to obtain the output pulse width of the current cycle; if there is an off instruction in the previous cycle, the second calculation formula is used for calculation to obtain the output pulse width of the current cycle; if there is neither an on instruction nor an off instruction in the previous cycle, the output pulse width of the current cycle is equal to the output pulse width of the previous cycle, or the output pulse width of the current cycle is calculated based on the pulse time increment using the third calculation formula.

[0140] Among them, the first calculation formula satisfies:

[0141] T out (k) = T out (k - 1) - T cp + ΔT (6).

[0142] Among them, T out (k - 1) is the output pulse width compensated in the previous cycle, T out (k) is the output pulse width of the current cycle, T cp is the operation cycle, and ΔT is the pulse time increment. For the above three variables, if it is a positive number, it represents on, and if it is a negative number, it represents off. This formula is used for the case where the previous cycle has an on instruction, and T out (k - 1) is a positive number.

[0143] The second calculation formula satisfies:

[0144] T out (k) = T out (k - 1) + T cp + ΔT (7).

[0145] Among them, T out (k - 1) is the output pulse width compensated in the previous cycle, T out (k) is the output pulse width of the current cycle, T cp is the operation cycle, and ΔT is the pulse time increment. For the above three variables, if it is a positive number, it represents on, and if it is a negative number, it represents off. This formula is used for the case where the previous cycle has an off instruction, indicating that T out (k - 1) is a negative number.

[0146] The third calculation formula satisfies:

[0147] T out (k) = T out (k - 1) + ΔT (8).

[0148] Among them, T out (k - 1) is the output pulse width compensated in the previous cycle, T out(k) is the output pulse width of the current cycle, and △T is the pulse time increment.

[0149] Specifically, the incremental pulse output of the pulse-type electric control valve needs to drive the valve to open and close through the rotation of the motor. Therefore, it takes time, and the pulse time increment △T obtained in one operation cycle cannot be completely output to the electric head. Therefore, in the embodiments of the present invention, by accumulating the pulse width and compensating the operation cycle, the output pulse width of the current cycle is obtained, that is:

[0150] When there is an open command in the previous cycle, the output pulse width of the current cycle can be calculated based on formula (6); when there is a close command in the previous cycle, the output pulse width of the current cycle can be calculated based on formula (7); in other cases: the output pulse width of the current cycle is equal to the output pulse width compensated in the previous cycle (i.e., T out (k - 1) = T out (k)), or the output pulse width of the current cycle is calculated based on formula (8).

[0151] Furthermore, in the stage where the open and close commands are triggered to start (such as changing from 0 to 1), in order to make the correspondence between the pulse width and the valve opening more accurate, the present invention can take into account the error of the electric head commutation rotation of the pulse-type electric control valve and the delay of the hardware interface, and compensate the calculated output pulse width of the current cycle.

[0152] Specifically, compensating the output pulse width of the current cycle includes: obtaining the current open / close command and judging the current open / close command; if the current open / close command is an open command, judging whether there is an open command in the previous cycle; if there is no open command in the previous cycle, judging whether the nearest command to the current open / close command is an open command; if the nearest command to the current open / close command is an open command, compensating the output pulse width of the current cycle in the same direction. If the current open / close command is a close command, judging whether there is a close command in the previous cycle; if there is no close command in the previous cycle, judging whether the nearest command to the current open / close command is a close command; if the nearest command to the current open / close command is a close command, compensating the output pulse width of the current cycle in the same direction.

[0153] That is, if the current open / close command is an open command, there is no open command in the previous cycle, and the nearest command output is an open command, then compensate the output pulse width of the current cycle in the same direction (i.e., the compensated output pulse width is: T out +T sy ), where T sy is the same-direction pulse width compensation value. If the current open / close command is a close command, there is no close command in the previous cycle, and the nearest command output is a close command, then compensate the output pulse width of the current cycle in the same direction (i.e., the compensated output pulse width is: T out -Tsy ). (T out If it is a positive number, it means open; T out A negative number indicates off. Same direction pulse width compensation T sy is a value greater than or equal to 0. If T sy 0 means no same-direction pulse width compensation.)

[0154] Further, compensating the output pulse width of the current cycle includes: obtaining the current on / off instruction and judging the current on / off instruction; if the current on / off instruction is an on instruction, judging whether there is an on instruction in the previous cycle; if there is no on instruction in the previous cycle, judging whether the most recent instruction with the current on / off instruction is an off instruction; if the most recent instruction with the current on / off instruction is an off instruction, performing reverse pulse width compensation on the output pulse width of the current cycle. If the current on / off instruction is an off instruction, judging whether there is a related instruction in the previous cycle; if there is no related instruction in the previous cycle, judging whether the most recent instruction with the current on / off instruction is an on instruction; if the most recent instruction with the current on / off instruction is an on instruction, performing reverse pulse width compensation on the output pulse width of the current cycle.

[0155] That is, if the current on / off instruction is an on instruction, and there is no on instruction in the previous cycle, and the most recent instruction output is an off instruction, then the output pulse width of the current cycle is reversely compensated (that is, the compensated output pulse width is: T out +T op ), where T op is the reverse pulse width compensation value. If the current on / off instruction is the off instruction, and the previous cycle has no instructions, and the most recent instruction output is the on instruction, then the output pulse width of the current cycle is reversed for pulse width compensation (i.e. the compensated output pulse width is: T out -T op ). It should be noted that when T sy and T op When set to 0, it means no compensation. (T out If it is a positive number, it means open; T out A negative number indicates off. Reverse pulse width compensation T op is a value greater than or equal to 0. If T op 0 means no reverse pulse width compensation.)

[0156] The most recent instruction output can be determined by comparing the timing values ​​of the on instruction timer and the off instruction timer. If the timing value of the on instruction timer is greater than the timing value of the off instruction timer, the instruction of the previous cycle is an off instruction; if the timing value of the off instruction timer is greater than the timing value of the on instruction timer, the instruction of the previous cycle is an on instruction.

[0157] Step S205: Generate a current on / off instruction according to the output pulse width of the current cycle.

[0158] In some embodiments, generating the current on / off instruction according to the output pulse width of the current cycle includes: judging the absolute value of the output pulse width of the current cycle; if the output pulse width T of the current cycle out is greater than the minimum pulse width limit value T min , then judge whether the previous cycle is an on instruction; if the previous cycle is an on instruction, the current on / off instruction is an on instruction; if there is no on instruction in the previous cycle, then judge whether the positive / negative interval time and the same-direction interval time meet the on instruction condition; if the positive / negative interval time and the same-direction interval time meet the on instruction condition, the current on / off instruction is an on instruction. (T out is a positive number, indicating on; T out is a negative number, indicating off. The minimum pulse width limit value T min is a value greater than 0. Generally, to avoid frequent valve operation, T min is not set to 0.)

[0159] Optionally, the on instruction condition includes: the timing time of the on instruction timer is greater than the same-direction interval time, and the timing time of the off instruction timer is greater than the positive / negative interval time.

[0160] Further, generating the current on / off instruction according to the output pulse width of the current cycle further includes: if the output pulse width T of the current cycle out is less than -T min , then judge whether the previous cycle is an off instruction; if the previous cycle is an off instruction, the current on / off instruction is an off instruction; if there is no instruction in the previous cycle, then judge whether the positive / negative interval time and the same-direction interval time meet the off instruction condition; if the positive / negative interval time and the same-direction interval time meet the off instruction condition, the current on / off instruction is an off instruction. (T out is a positive number, indicating on; T out is a negative number, indicating off. The minimum pulse width limit value T min is a value greater than 0. Generally, to avoid frequent valve operation, T min is not set to 0.)

[0161] Optionally, the off instruction condition includes: the timing time of the off instruction timer is greater than the same-direction interval time and the timing time of the on instruction timer is greater than the positive / negative interval time.

[0162] Further, in the embodiments of the present invention, before judging the absolute value of the output pulse width of the current cycle: judge whether the length of the output pulse width of the current cycle is greater than the minimum pulse width limit value; if the length of the output pulse width of the current cycle is greater than the minimum pulse width limit value, then execute the step of judging the absolute value of the output pulse width of the current cycle. That is, in the embodiments of the present invention, the length of the output pulse width of the current cycle being greater than the minimum pulse width limit value is a prerequisite for generating an on instruction or an off instruction.

[0163] Specifically, as Figure 5 shown, when the length of the output pulse width in the current cycle is greater than the minimum pulse width limit value:

[0164] If the output pulse width in the current cycle is greater than 0 and the previous cycle is an open command, an open command is generated; if the output pulse width in the current cycle is greater than 0, there is no open command in the previous cycle, the timing time of the open command timer is greater than the forward and reverse interval time, and the timing time of the close command timer is greater than the same direction interval time, an open command is generated.

[0165] If the output pulse width in the current cycle is less than 0 and the previous cycle is a close command, a close command is generated; if the output pulse width in the current cycle is less than 0, there is no close command in the previous cycle, the timing time of the open command timer is greater than the forward and reverse interval time, and the timing time of the close command timer is greater than the same direction interval time, a close command is generated.

[0166] Among them, the timing of the open command timer is: starting from the disappearance of the open command for timing, and resetting when the open command is triggered. The timing of the close command timer is: starting from the disappearance of the close command for timing, and resetting when the close command is triggered.

[0167] In the embodiment of the present invention, by setting the forward and reverse interval time, the motor can be protected by using the forward and reverse interval time during the commutation rotation of the electric head. At the same time, in order to avoid frequent operation of the motor, in addition to setting the forward and reverse interval time, the same direction interval time can also be set to avoid frequent startup of the motor. It can be understood that if the same direction interval time is set to 0, it means that there is no interval time limit for the same direction rotation of the electric head of the pulse type electric control valve.

[0168] Further, in the embodiment of the present invention, the precise control method of the pulse type electric control valve further includes: receiving input parameters; setting the characteristic parameters of the pulse type electric control valve according to the input parameters. Among them, the input parameters can be set and input by engineering personnel according to the actual situation of on-site equipment through the human-machine interface, and thus the setting of the characteristic parameters of the pulse type electric control valve can be realized. Optionally, the characteristic parameters of the pulse type electric control valve include but are not limited to: the minimum pulse width limit value T min , the forward and reverse interval time T olag , the same direction time interval T slag , the controller operation cycle T cp , the total stroke time T run , the same direction pulse width compensation T sy , the reverse pulse width compensation T op and other parameters.

[0169] Among them, the minimum pulse width T min is the minimum pulse width received by the pulse type electric control valve. If the pulse length calculated through the previous links is greater than T min, the output instruction. The forward and reverse interval time T olag and the same-direction time interval T slag The setting is to prevent the electric head from operating frequently. Generally, the forward and reverse interval time T olag is set. If the same-direction time interval T slag is 0, it means that the same-direction action limit of the pulse-type electric control valve is not set. The controller operation period T cp is a characteristic of the digital instrument control system, and the total stroke time T run is a characteristic of the pulse-type electric control valve and can be obtained through on-site measurement. To further improve the regulation accuracy, the same-direction pulse width compensation T sy and the reverse pulse width compensation Top can be set. Considering the error of the electric head commutation rotation of the electric control valve and the delay of the hardware interface, the output pulse width is compensated to make the corresponding relationship between the pulse width and the valve opening more accurate.

[0170] Step S206, control the pulse-type electric control valve according to the current open / close instruction.

[0171] Reference Figure 6 , the schematic diagram of an optional embodiment of the precise control system of the pulse-type electric control valve provided by the present invention. Among them, the precise control system of the pulse-type electric control valve can be used to implement the precise control method of the pulse-type electric control valve disclosed in the embodiments of the present invention.

[0172] Specifically, as Figure 6 shown, the precise control system of the pulse-type electric control valve includes:

[0173] An acquisition module 601, configured to acquire the deviation of the quantity to be adjusted in the current period.

[0174] A valve position increment output module 602, configured to perform PID calculation according to the deviation of the quantity to be adjusted in the current period to obtain the valve position increment in the current period.

[0175] A pulse time conversion module 603, configured to perform conversion according to the valve position increment in the current period to obtain the pulse time increment.

[0176] A pulse output calculation module 604, configured to perform calculation based on the pulse time increment to obtain the output pulse width in the current period.

[0177] A switch instruction generation module 605, configured to generate the current open / close instruction according to the output pulse width in the current period.

[0178] A control module 606, configured to control the pulse-type electric control valve according to the current open / close instruction.

[0179] Among them, the acquisition module and the valve position increment output module are built in the incremental PID controller.

[0180] Further, as Figure 6 shown, the precise control system of the pulse-type electric control valve further includes: a pulse setting module 607, configured to receive input parameters and set characteristic parameters of the pulse-type electric control valve according to the input parameters. Among them, the parameters required by the pulse time conversion module 603, the pulse output calculation module 604, and the switch command generation module 605 can be provided by the pulse setting module 607.

[0181] The present invention combines the characteristics of pneumatic control valves and pulse-type electric control valves, and provides a precise control method and system for pulse-type electric control valves. By combining the characteristics of pulse-type electric control valves and PID control characteristics, through the corresponding conversion and processing of valve position and pulse time, the pulse-type electric control valve can achieve precise control similar to that of pneumatic control valves, and avoid frequent valve actions through an action limit function, increase the service life of the equipment, and improve the stability, accuracy, and rapidity of the regulation system related to the pulse-type electric control valve. Moreover, the precise control method and system of the pulse-type electric control valve can be applied to nuclear power plants, effectively improving the stability, accuracy, and rapidity of the regulation system related to the pulse-type electric control valve in nuclear power plants.

[0182] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0183] Those skilled in the art can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this article can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0184] The steps of the method or algorithm described in combination with the embodiments disclosed in this article can be directly implemented by hardware, a software module executed by a processor, or a combination of the two. The software module can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field.

[0185] The above embodiments are only used to illustrate the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and cannot limit the protection scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

Claims

1. An accurate control method for a pulse-type electric control valve, characterized in that, it includes the following steps: Obtain the deviation of the quantity to be regulated in the current cycle; Perform PID calculation according to the deviation of the quantity to be regulated in the current cycle to obtain the valve position increment in the current cycle; Perform conversion according to the valve position increment in the current cycle to obtain the pulse time increment; Perform calculation based on the pulse time increment to obtain the output pulse width in the current cycle; Generate the current on / off command according to the output pulse width in the current cycle; Control the pulse-type electric control valve according to the current on / off command; It also includes: compensating the output pulse width in the current cycle; Among them, the performing PID calculation according to the deviation of the quantity to be regulated in the current cycle to obtain the valve position increment in the current cycle includes: Perform PID calculation using an incremental PID controller according to the deviation of the quantity to be regulated in the current cycle to obtain the valve position increment in the current cycle; The performing conversion according to the valve position increment in the current cycle to obtain the pulse time increment includes: determining the relationship between the valve position and the stroke time of the pulse-type electric control valve; performing conversion according to the relationship between the valve position and the stroke time to obtain the pulse time increment; The determining the relationship between the valve position and the stroke time of the pulse-type electric control valve includes: controlling the pulse-type electric control valve to open from fully closed to fully open; collecting the opening degree and opening time of the pulse-type electric control valve during the opening process from fully closed to fully open; controlling the pulse-type electric control valve to close from fully open to fully closed; collecting the opening degree and closing time of the pulse-type electric control valve during the closing process from fully open to fully closed; obtaining the relationship between the valve position and the stroke time of the pulse-type electric control valve according to the opening degree during the opening process, the opening time, the opening degree during the closing process, and the closing time.

2. The accurate control method for a pulse-type electric control valve according to claim 1, characterized in that, the determining the relationship between the valve position and the stroke time of the pulse-type electric control valve includes: Controlling the pulse-type electric control valve to open from fully closed to fully open; Collecting the opening degree and opening time of the pulse-type electric control valve during the opening process from fully closed to fully open; Controlling the pulse-type electric control valve to close from fully open to fully closed; Collecting the opening degree and closing time of the pulse-type electric control valve during the closing process from fully open to fully closed; Obtaining the relationship between the valve position and the stroke time of the pulse-type electric control valve according to the opening degree during the opening process, the opening time, the opening degree during the closing process, and the closing time.

3. The accurate control method for a pulse-type electric control valve according to claim 1, characterized in that, the relationship between the valve position and the stroke time of the pulse-type electric control valve includes: a non-linear relationship and a linear relationship; the non-linear relationship includes: a positive conversion relationship and a negative conversion relationship.

4. The accurate control method for a pulse-type electric control valve according to claim 3, characterized in that, if the relationship between the valve position and the stroke time of the pulse-type electric control valve is a non-linear relationship, then the performing conversion according to the relationship between the valve position and the stroke time to obtain the pulse time increment includes: Judging the positive and negative of the valve position increment in the current cycle; If the valve position increment in the current cycle is positive, the forward conversion relationship is used for conversion to obtain the pulse time increment; If the valve position increment in the current cycle is negative, the reverse conversion relationship is used for conversion to obtain the pulse time increment.

5. The precise control method of the pulse-type electric control valve according to claim 3, characterized in that, if the relationship between the valve position and the stroke time of the pulse-type electric control valve is a linear relationship, the conversion is performed according to the relationship between the valve position and the stroke time, and obtaining the pulse time increment includes: Performing conversion according to the linear relationship between the valve position and the stroke time to obtain the pulse time increment.

6. The precise control method of the pulse-type electric control valve according to claim 1, characterized in that, the calculation based on the pulse time increment to obtain the output pulse width of the current cycle includes: Obtaining the on / off command status of the previous cycle; If there is an open command in the previous cycle, the first calculation formula is used for calculation to obtain the output pulse width of the current cycle; If there is a close command in the previous cycle, the second calculation formula is used for calculation to obtain the output pulse width of the current cycle; If there is no open command and no close command in the previous cycle, the output pulse width of the current cycle is equal to the output pulse width of the previous cycle, or the output pulse width of the current cycle is calculated based on the pulse time increment and using the third calculation formula.

7. The precise control method of the pulse-type electric control valve according to claim 6, characterized in that, the first calculation formula satisfies: T out T(k) = T out (k - 1)-T cp + △T; Among them, T out (k - 1) is the output pulse width after compensation in the previous cycle, T out (k) is the output pulse width in the current cycle, T cp is the operation cycle, and △T is the pulse time increment.

8. The precise control method of the pulse-type electric control valve according to claim 6, characterized in that, the second calculation formula satisfies: T out T(k) = T out (k - 1)+T cp + ΔT; Among them, T out (k - 1) is the output pulse width after compensation in the previous cycle, T out (k) is the output pulse width of the current cycle, T cp is the operation cycle, and △T is the pulse time increment.

9. The precise control method of the pulse-type electric control valve according to claim 6, characterized in that, the third calculation formula satisfies: T out T(k) = T out (k - 1)+ΔT; Among them, T out (k - 1) is the output pulse width after compensation in the previous cycle, T out (k) is the output pulse width of the current cycle, and △T is the pulse time increment.

10. The precise control method of the pulse-type electric control valve according to claim 1, characterized in that, the compensation for the output pulse width of the current cycle includes: Obtaining the current on / off command and judging the current on / off command; If the current on / off command is an open command, judge whether there is an open command in the previous cycle; If there is no open command in the previous cycle, judge whether the nearest command to the current on / off command is an open command; If the nearest command to the current on / off command is an open command, perform co-directional pulse width compensation on the output pulse width of the current cycle.

11. The precise control method of the pulse-type electric control valve according to claim 10, characterized in that, the compensation for the output pulse width of the current cycle further includes: If the current on / off command is a close command, judge whether there is a close command in the previous cycle; If there is no close command in the previous cycle, judge whether the nearest command to the current on / off command is a close command; If the nearest command to the current on / off command is a close command, perform co-directional pulse width compensation on the output pulse width of the current cycle.

12. The precise control method of the pulse-type electric control valve according to claim 1, characterized in that, the compensation for the output pulse width of the current cycle includes: Obtain the current on / off instruction and judge the current on / off instruction; If the current on / off instruction is an on instruction, judge whether there was an on instruction in the previous cycle; If there was no on instruction in the previous cycle, judge whether the most recent instruction from the current on / off instruction is an off instruction; If the most recent instruction from the current on / off instruction is an off instruction, perform reverse pulse width compensation on the output pulse width of the current cycle.

13. The precise control method of the pulse-type electric control valve according to claim 12, characterized in that, The compensation for the output pulse width of the current cycle includes: If the current on / off instruction is an off instruction, judge whether there was an off instruction in the previous cycle; If there was no off instruction in the previous cycle, judge whether the most recent instruction from the current on / off instruction is an on instruction; If the most recent instruction from the current on / off instruction is an on instruction, perform reverse pulse width compensation on the output pulse width of the current cycle.

14. The precise control method of the pulse-type electric control valve according to claim 1, characterized in that, The generation of the current on / off instruction according to the output pulse width of the current cycle includes: Judge the absolute value of the output pulse width of the current cycle; if the absolute value of the output pulse width of the current cycle is greater than the minimum pulse width limit value and the output pulse width of the current cycle is greater than 0, judge whether the previous cycle was an on instruction; If the previous cycle was an on instruction, the current on / off instruction is an on instruction; If there was no on instruction in the previous cycle, judge whether the positive and negative interval time and the same-direction interval time meet the on instruction condition; If the positive and negative interval time and the same-direction interval time meet the on instruction condition, the current on / off instruction is an on instruction.

15. The precise control method of the pulse-type electric control valve according to claim 14, characterized in that, The on instruction condition includes: the timing time of the on instruction timer is greater than the same-direction interval time, and the timing time of the off instruction timer is greater than the positive and negative interval time.

16. The precise control method of the pulse-type electric control valve according to claim 14, characterized in that, The generation of the current on / off instruction according to the output pulse width of the current cycle further includes: if the absolute value of the output pulse width of the current cycle is greater than the minimum pulse width limit value and the output pulse width of the current cycle is less than 0, judge whether the previous cycle was an off instruction; If the previous cycle was an off instruction, the current on / off instruction is an off instruction; If there was no instruction in the previous cycle, judge whether the positive and negative interval time and the same-direction interval time meet the off instruction condition; If the positive and negative interval time and the same-direction interval time meet the off instruction condition, the current on / off instruction is an off instruction.

17. The precise control method of the pulse-type electric control valve according to claim 14, characterized in that, The off instruction condition includes: the timing time of the off instruction timer is greater than the same-direction interval time and the timing time of the on instruction timer is greater than the positive and negative interval time.

18. The precise control method of the pulse-type electric control valve according to claim 16, characterized in that, The method further includes: Before judging the absolute value of the output pulse width of the current cycle: Determine whether the length of the output pulse width in the current cycle is greater than the minimum pulse width limit value; If the length of the output pulse width in the current cycle is greater than the minimum pulse width limit value, then perform the step of judging the absolute value of the output pulse width in the current cycle.

19. The precise control method of the pulse-type electric control valve according to any one of claims 1-18, characterized in that, the method further includes: receiving input parameters; setting the characteristic parameters of the pulse-type electric control valve according to the input parameters.

20. A precise control system of a pulse-type electric control valve, characterized in that, comprising: an acquisition module for acquiring the deviation of the quantity to be regulated in the current cycle; a valve position increment output module for performing PID calculation according to the deviation of the quantity to be regulated in the current cycle to obtain the valve position increment in the current cycle; compensating the output pulse width in the current cycle; performing PID calculation by using an incremental PID controller according to the deviation of the quantity to be regulated in the current cycle to obtain the valve position increment in the current cycle; a pulse time conversion module for converting according to the valve position increment in the current cycle to obtain a pulse time increment; the converting according to the valve position increment in the current cycle to obtain a pulse time increment includes: determining the relationship between the valve position and the stroke time of the pulse-type electric control valve; converting according to the relationship between the valve position and the stroke time to obtain the pulse time increment; the determining the relationship between the valve position and the stroke time of the pulse-type electric control valve includes: controlling the pulse-type electric control valve to open from fully closed to fully open; collecting the opening degree and opening time of the pulse-type electric control valve during the opening process from fully closed to fully open; controlling the pulse-type electric control valve to close from fully open to fully closed; collecting the opening degree and closing time of the pulse-type electric control valve during the closing process from fully open to fully closed; obtaining the relationship between the valve position and the stroke time of the pulse-type electric control valve according to the opening process opening degree, opening time, closing process opening degree and closing time; a pulse output calculation module for calculating based on the pulse time increment to obtain the output pulse width in the current cycle; a switch command generation module for generating a current on / off command according to the output pulse width in the current cycle; a control module for controlling the pulse-type electric control valve according to the current on / off command.

21. The precise control system of the pulse-type electric control valve according to claim 20, characterized in that, the acquisition module and the valve position increment output module are built in the incremental PID controller.

22. The precise control system of the pulse-type electric control valve according to claim 20, characterized in that, further comprising: a pulse setting module for receiving input parameters and setting the characteristic parameters of the pulse-type electric control valve according to the input parameters.

Images