Valve opening calculation control method of intelligent valve positioner using electromagnetic induction

Abstract

The invention discloses a valve opening calculation control method of an intelligent valve positioner using electromagnetic induction, which comprises the following steps of: carrying out self-calibration on a non-contact angle sensor, carrying out reference point calibration on a feedback rod connected with the valve positioner, enabling the feedback rod to be parallel to the top surface of the valve positioner, and taking the position of the calibrated feedback rod as a reference line; the valve positioner is installed on the adjusting valve; the method comprises the following steps: debugging, recording signal AD values of two endpoints of an angle sensor, receiving a control signal by a valve positioner to adjust a valve position to obtain an actual valve position AD value of the sensor, calculating an actual valve position percentage according to an opening degree calculation method of the valve positioner, and comparing the actual valve position percentage with a set valve position percentage, and the percentage of the actual valve position is adjusted to be within the dead zone range of the percentage of the set valve position. The non-contact type magnetic induction angle sensor is adopted, and an existing method for calculating the opening degree of the valve through a traditional contact type potentiometer can be replaced.

Description

Technical Field

[0001] The present invention relates to the field of valve positioners, and in particular to a valve opening calculation and control method of an intelligent valve positioner using electromagnetic induction. Background Art

[0002] The intelligent valve positioner is a key control instrument for regulating valves, consisting of a signal processing unit and a valve position feedback unit (hereinafter referred to as the valve position feedback unit). The signal processing unit receives an external 4-20mA setpoint signal and, based on the valve's current position sampling signal provided by the valve position feedback unit, calculates and outputs a drive electrical signal. This signal is then converted by the I / P conversion unit into a corresponding pneumatic signal to drive the regulating valve. Changes in the regulating valve position are then sensed by the valve position feedback unit, which then collects the valve position signal in real time and feeds it back to the signal processing unit for processing. The accuracy of this processing directly determines the linear precision of the valve positioning. Currently, the mainstream calculation of valve opening is obtained by converting the value obtained using a traditional contact potentiometer.

[0003] Smart valve positioners currently use conductive plastic angular displacement sensors to measure the rotation angle of the feedback rod. These sensors operate based on the principle of resistor voltage division. A constant voltage source is connected across the sensor's sensitive resistor. The sensor generates output by moving a brush along a guide rail of the conductive plastic resistor. The brush's movement corresponds to the measured displacement, and the output voltage is linearly related to the angular displacement, thus measuring the rotation angle of the feedback rod. However, frequent movement of the brush along the guide rail of the conductive plastic resistor during use causes wear, shortening the sensor's lifespan, reducing measurement accuracy, and increasing manufacturing costs. Summary of the Invention

[0004] The present invention provides a valve opening calculation and control method of an intelligent valve positioner using electromagnetic induction, which adopts a non-contact magnetic induction angle sensor and can replace the existing method of calculating valve opening using a traditional contact potentiometer.

[0005] A valve opening calculation and control method using an intelligent valve positioner with electromagnetic induction adopts a regulating valve, including: a valve actuator, a valve positioner, a feedback rod and a latch;

[0006] The feedback rod is installed on the valve positioner;

[0007] A first slide groove is installed on the valve stem of the valve actuator;

[0008] A second sliding groove is provided in the middle of the feedback rod;

[0009] One end of the latch is installed in the first sliding groove, and the other end of the latch is installed in the second sliding groove of the feedback lever;

[0010] The valve positioner comprises: a housing, a magnetic induction angle sensor installed in the housing, and a positioner shaft, wherein the shaft in the magnetic induction angle sensor is connected to the positioner shaft via a gear, and the feedback lever is installed on the positioner shaft;

[0011] The valve opening calculation and control method comprises the following steps:

[0012] 1) The magnetic induction angle sensor performs self-calibration and records signal parameters;

[0013] 2) Install the magnetic induction angle sensor into the valve positioner housing and the feedback lever onto the valve positioner shaft. Calibrate the reference point of the feedback lever so that the feedback lever is parallel to the top surface of the valve positioner. Use the position of the horizontally calibrated feedback lever as the reference line and record the AD values of the sine and cosine signals of the angle sensor at that position: pos_ref_sin and pos_ref_cos.

[0014] 3) Install the valve positioner on the valve actuator, ensure that the top surface of the valve positioner is perpendicular to the valve stem, use the valve positioner self-tuning, and record the sine signal and cosine signal AD values of the magnetic induction angle sensor at the minimum valve position: pos_min_sin, pos_min_cos and the sine signal and cosine signal AD values of the magnetic induction angle sensor at the maximum valve position: pos_max_sin, pos_max_cos.

[0015] 4) After the valve positioner completes self-tuning, it receives a control signal to adjust the valve position, collects the sine and cosine AD values of the magnetic induction angle sensor at the current valve position: pos_sin, pos_cos, calculates the actual valve position percentage based on the valve positioner's opening calculation method, compares the actual valve position percentage with the set valve position percentage, and adjusts the actual valve position percentage to within the dead zone of the set valve position percentage.

[0016] The present invention includes: performing self-calibration on a non-contact angle sensor, calibrating a reference point of a feedback rod connected to a valve positioner, making the feedback rod parallel to the top surface of the valve positioner, and using the position of the calibrated feedback rod as a reference line; installing the valve positioner on a regulating valve; performing debugging, recording AD values of two endpoint signals of the angle sensor, the valve positioner receiving a control signal to adjust the valve position, obtaining the actual valve position AD value of the sensor, calculating the actual valve position percentage according to an opening calculation method of the valve positioner, comparing the actual valve position percentage with the set valve position percentage, and adjusting the actual valve position percentage to within a dead zone range of the set valve position percentage.

[0017] The first slide groove connected to the valve stem of the valve actuator is a U-shaped slide groove;

[0018] The second sliding groove of the feedback rod is a strip-shaped sliding groove.

[0019] The feedback rod is provided with a spring buckle for clamping the strip-shaped slide groove.

[0020] The valve stem of the valve actuator is perpendicular to the top surface of the valve positioner.

[0021] In step 1), the magnetic induction angle sensor performs self-calibration processing and records signal parameters, specifically including:

[0022] The magnetic induction angle sensor uses tunnel magnetoresistance technology and has an angular range of 360°. The magnetic induction angle sensor outputs two voltage signals with sine and cosine relationships with the magnetic field angle. The rotating shaft of the magnetic induction angle sensor is installed on the sensor self-calibration platform. When the rotating shaft of the sensor self-calibration platform rotates more than 360°, the peak and trough values of the sine and cosine signals are calculated and recorded.

[0023] In step 4), the actual valve position percentage is calculated according to the valve positioner opening calculation method, specifically including:

[0024] 1) The sensor angle value calculation formula is as follows:

[0025] sin_peak=(sensor_sin_max-sensor_sin_min) / 2;

[0026] cos_peak=(sensor_cos_max-sensor_cos_min) / 2;

[0027] sin_offset=(sensor_sin_max+sensor_sin_min) / 2;

[0028] cos_offset=(sensor_cos_max+sensor_cos_min) / 2;

[0029] sin_value=(sin_data-sin_offset) / sin_peak;

[0030] cos_value=(cos_data-cos_offset) / cos_peak;

[0031] angle_value=atan2(sin_value,cos_value)*180 / pi;

[0032] If angle_value<0, add 360° to angle_value as the final calculated angle value;

[0033] In the formula, sensor_sin_max and sensor_sin_min are the peak and trough AD values of the sine signal of the magnetic induction angle sensor, sensor_cos_max and sensor_cos_min are the peak and trough AD values of the cosine signal of the magnetic induction angle sensor, sin_data and cos_data are the AD values of the current sine and cosine signals of the magnetic induction angle sensor, and pi is the circumference of a circle.

[0034] 2) Set sin_data = pos_ref_sin, cos_data = pos_ref_cos, and substitute into the sensor angle value calculation formula in step 1) to obtain the reference point position sensor angle value angle_ref;

[0035] 3) Set sin_data = pos_min_sin, cos_data = pos_min_cos, and substitute into the sensor angle value calculation formula in step 1) to obtain the minimum position sensor angle value angle_min;

[0036] 4) Set sin_data = pos_max_sin, cos_data = pos_max_cos, and substitute into the sensor angle value calculation formula in step 1) to obtain the maximum position sensor angle value angle_max;

[0037] 5) Substitute sin_data = pos_sin and cos_data = pos_cos into the sensor angle calculation formula in step 1) to obtain the current position sensor angle value angle_pos;

[0038] 6) Swing angle at minimum position ref_angle_min = (angle_min - angle_ref) / angle_ratio;

[0039] Swing angle at maximum position ref_angle_max = (angle_max - angle_ref) / angle_ratio;

[0040] Actual position swing angle ref_angle_pos = (angle_pos - angle_ref) / angle_ratio;

[0041] Among them, angle_ratio is the transmission gear ratio of the angle sensor and the positioner spindle;

[0042] The minimum valve position distance from the reference line is S_angle_min: S_angle_min = tan(pi / 180*ref_angle_min);

[0043] The distance of the maximum valve position from the reference line is S_angle_max: S_angle_max = tan(pi / 180*ref_angle_max);

[0044] The distance between the actual valve position and the reference line is S_angle_pos: S_angle_pos = tan(pi / 180*ref_angle_pos);

[0045] Actual valve position percentage pos_percent: pos_percent = (S_angle_pos - S_angle_min) / (S_angle_max - S_angle_min).

[0046] The electromagnetic induction angle sensor comprises: an electromagnetic induction angle sensor housing, an electromagnetic induction angle sensor shaft, an induction magnet, an induction chip for detecting changes in the magnetic field of the induction magnet, and a circuit board.

[0047] One end of the electromagnetic induction angle sensor shaft is installed in the electromagnetic induction angle sensor housing and connected to the induction magnet, and the other end of the electromagnetic induction angle sensor shaft is installed outside the electromagnetic induction angle sensor housing and connected to the driven gear.

[0048] The sensor chip is mounted on the circuit board. The circuit board includes:

[0049] a first resistor and a second resistor connected in series;

[0050] a first operational amplifier, wherein a non-inverting input terminal of the first operational amplifier is connected between the first resistor and the second resistor;

[0051] a first capacitor connected to the power input terminal of the first operational amplifier and grounded;

[0052] a third resistor and a fourth resistor, both of which are connected to the inverting input terminal and the output terminal of the first operational amplifier;

[0053] a first differential amplifier circuit connected to the third resistor;

[0054] a second differential amplifier circuit connected to the fourth resistor;

[0055] A magnetic field sensing chip, wherein the output ends of the magnetic field sensing chip are both connected to the first differential amplifier circuit and the second differential amplifier circuit.

[0056] The first differential amplifier circuit includes:

[0057] a fifth resistor and a sixth resistor connected to the third resistor;

[0058] a second capacitor connected in parallel with the fifth resistor and grounded;

[0059] a second operational amplifier, wherein a positive input terminal of the second operational amplifier is connected to the sixth resistor, and a power input terminal of the second operational amplifier is connected in parallel with a third capacitor and is grounded;

[0060] a ninth resistor and a tenth resistor connected to the magnetic field sensing chip, the ninth resistor being connected to the positive input terminal of the second operational amplifier, and the tenth resistor being connected to the negative input terminal of the second operational amplifier;

[0061] a thirteenth resistor, the thirteenth resistor being connected in parallel to the positive input terminal and the output terminal of the second operational amplifier;

[0062] A sixth capacitor is connected in parallel with the thirteenth resistor.

[0063] a fifteenth resistor connected to the output terminal of the second operational amplifier;

[0064] a seventh capacitor connected in parallel with the fifteenth resistor and grounded.

[0065] The second differential amplifier circuit includes:

[0066] connecting a seventh resistor and an eighth resistor to the fourth resistor;

[0067] a fourth capacitor connected in parallel with the seventh resistor and grounded;

[0068] a third operational amplifier, wherein a positive input terminal of the third operational amplifier is connected to the eighth resistor, and a power input terminal of the second operational amplifier is connected in parallel with a fifth capacitor and grounded;

[0069] an eleventh resistor and a twelfth resistor connected to the magnetic field sensing chip, the eleventh resistor being connected to the positive input terminal of the second operational amplifier, and the twelfth resistor being connected to the negative input terminal of the second operational amplifier;

[0070] a fourteenth resistor, the fourteenth resistor being connected in parallel to the positive input terminal and the output terminal of the second operational amplifier;

[0071] an eighth capacitor, the eighth capacitor being connected in parallel with the fourteenth resistor;

[0072] a sixteenth resistor connected to the output terminal of the third operational amplifier;

[0073] a ninth capacitor connected in parallel with the sixteenth resistor and grounded.

[0074] The advantages of the above circuit design are that it can amplify varying AC signals and phase-shift the output signal to center it at two-thirds of the power supply input voltage. This facilitates the amplification of the two voltage signals for magnetic field sensing, and the digital-to-analog conversion of these signals into digital AD values, which are more accurate.

[0075] Compared with the prior art, the present invention has the following advantages:

[0076] This design is based on the principle of magnetic induction. The magnet and sensor chip are non-contact, completely eliminating wear caused by the frequent movement of brushes in the mechanical structure. This improves the sensor's service life. The non-contact design also prevents wear on the sensor caused by vibration during field use of the intelligent valve positioner. This ensures sensor precision. Compared to conductive plastic angular displacement sensors, this invention offers lower cost and higher accuracy and linearity.

[0077] The opening algorithm of the present invention can completely replace the opening algorithm of conventional contact potentiometers, and avoids the problem of increased basic error and hysteresis due to long-term wear of the internal mechanical structure of conventional contact potentiometers. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 This is a schematic diagram of the disassembled structure of the electromagnetic induction angle sensor of the present invention;

[0079] Figure 2 This is a schematic diagram of the structure of the electromagnetic induction angle sensor driven by the main shaft of the positioner of the present invention through gears;

[0080] Figure 3 This is the output voltage waveform of the electromagnetic induction angle sensor of the present invention;

[0081] Figure 4 Schematic diagram of the structure of the regulating valve in the present invention;

[0082] Figure 5 Schematic diagram of the structure of the regulating valve in the present invention;

[0083] Figure 6 Schematic diagram of the structure of the valve positioner in the present invention;

[0084] Figure 7 It is the sensor self-calibration fixture in the present invention;

[0085] Figure 8 This is the principle diagram of the positioner opening algorithm;

[0086] Figure 9 Calibrate the reference point position of the positioner feedback rod;

[0087] Figure 10 This is the overall schematic diagram of the positioner and valve;

[0088] Figure 11 This is a circuit diagram of the circuit board of the electromagnetic induction angle sensor in the present invention. DETAILED DESCRIPTION

[0089] The present invention is further described in detail below with reference to the accompanying drawings.

[0090] The transmission structure of the intelligent valve positioner with electromagnetic induction angle sensor can be divided into the following three parts. Through the transmission of these three parts, the movement of the valve is converted into the rotation of the induction magnet.

[0091] 1. Transmission between the rotating shaft 13 and the induction magnet 12 in the electromagnetic induction angle sensor;

[0092] like Figure 1 As shown, the induction magnet 12 is interference-fitted in the rotating shaft 13 of the electromagnetic induction angle sensor. The rotating shaft 13 in the electromagnetic induction angle sensor rotates, driving the induction magnet 12 to rotate relative to the induction chip 11.

[0093] 2. Transmission between the positioner spindle 8 and the electromagnetic induction angle sensor:

[0094] like Figure 2 As shown, the driving gear 16 is fixed to the positioner main shaft 8 through the inner hole, and the driven gear 15 is fixed to the rotating shaft 13 in the electromagnetic induction angle sensor through the set screws on both sides.

[0095] 3. Transmission between valve and positioner

[0096] The main shaft 8 of the positioner rotates to drive the driving gear 16 to rotate. The two gears are engaged and the driven gear 15 rotates synchronously to drive the rotating shaft 13 in the electromagnetic induction angle sensor to rotate.

[0097] like Figure 1 、 Figure 2As shown, an intelligent valve positioner with an electromagnetic induction angle sensor includes: a positioner housing; a main shaft 8, one end of which is mounted inside the positioner housing and connected to a driving gear 16, and the other end of which is mounted outside the positioner housing; and an electromagnetic induction angle sensor mounted inside the positioner housing, with a driven gear 15 mounted on the electromagnetic induction angle sensor, which mates with the driving gear 16. The electromagnetic induction angle sensor includes: an electromagnetic induction angle sensor housing, an electromagnetic induction angle sensor shaft 13, a sensing magnet 12, a sensing chip 11 for detecting changes in the magnetic field of the sensing magnet 12, and a circuit board. One end of the electromagnetic induction angle sensor shaft 13 is mounted inside the electromagnetic induction angle sensor housing and connected to the sensing magnet 12, while the other end of the electromagnetic induction angle sensor shaft 13 is mounted outside the electromagnetic induction angle sensor housing and connected to the driven gear 15. The sensing chip 11 is mounted on the circuit board.

[0098] Principle of magnetic induction: An induction magnet 12 is placed on the surface of the induction chip 11. By rotating, the induction magnet 12 can generate a magnetic field in any direction parallel to the surface of the induction chip 11. When the induction magnet 12 rotates, the magnetic field angle changes, and at the same time, the output voltage waveform of the sensor is a sine and cosine curve. Figure 3 As shown, since the angle of rotation corresponds to a point in a quadrant of the chip's output sine and cosine curves, the relative angle of the magnet's rotation can be determined using software based on the curves stored in the positioner and the nonlinear characteristics of the correction curves and principle.

[0099] Utilizing the principle of magnetic induction, the induction magnet 12 is mounted on the magnetic induction angle sensor shaft 13, and the magnetic field sensing chip 11 is mounted on a circuit board. The induction magnet 12 and the sensing chip 11 are close to each other. Utilizing the principle of magnetic induction, the positioner spindle 8 rotates, driving the magnetic induction angle sensor shaft 13. When the magnetic induction angle sensor shaft 13 drives the induction magnet 12 to rotate, the sensing chip 11 outputs a related voltage signal value. This signal is then processed and corrected by the signal processing circuit and sent to the MCU on the positioner control circuit board. The MCU uses software to process and correct the signal to obtain the rotation angle of the induction magnet 12. Since the induction magnet 12 is mounted on the magnetic induction angle sensor shaft 13, the rotation angle of the magnetic induction angle sensor shaft 13 can be determined.

[0100] like Figure 2 As shown, the driving gear 16 is fixed to the positioner main shaft 8 through its inner hole, and the driven gear 15 is fixed to the electromagnetic induction angle sensor shaft 13 via set screws on both sides. Rotation of the positioner main shaft 8 drives the driving gear 16, and through meshing, the driven gear 15 rotates synchronously, driving the electromagnetic induction angle sensor shaft 13. This structure converts the transmission between the valve and the positioner into magnet rotation, and the magnetic induction chip can accurately calculate the magnet's rotation angle. This allows the valve's position to be calculated.

[0101] The transmission structure of the magnetic induction positioner converts the movement of the valve into the rotation of the induction magnet.

[0102] like Figure 4 、 Figure 5 、 Figure 6 As shown, the regulating valve includes a valve actuator and a valve positioner 1 coordinated with the valve actuator. The valve positioner 1 includes a housing 11. A magnetic induction angle sensor is provided in the valve positioner 1. The magnetic induction angle sensor is connected to a magnetic induction angle sensor shaft 13. The magnetic induction angle sensor shaft 13 is connected to the positioner main shaft 8 through gears (a driving gear 16 and a driven gear 15) and then to a feedback rod 2. A contact head 3 is provided at the end of the feedback rod 2. The feedback rod 2 has a strip hole. The contact head 3 is fixed in the strip hole of the feedback rod 2 by a bolt. The contact head 3 can be moved to a desired position for fixation according to actual conditions.

[0103] A mounting block 5 is fixed to the valve stem 4 of the valve actuator, and the mounting block 5 is connected to a U-shaped slide 7;

[0104] The contact head 3 is slidably mounted in the slide groove of the U-shaped slide groove 7;

[0105] In the present invention, the contact head 3 is slidably installed in the slide groove of the U-shaped slide groove 7. When the valve actuator controls the valve stem 4 to move up and down to adjust the valve opening, the mounting block 5 and the U-shaped slide groove 7 fixed on the valve stem 4 will also move accordingly during the up and down movement of the U-shaped slide groove 7. During the up and down movement of the U-shaped slide groove 7, the contact head 3 installed in the slide groove of the U-shaped slide groove 7 will move in the slide groove of the U-shaped slide groove 7, and the feedback rod 2 drives the positioner main shaft 8 to rotate through the gear transmission. The magnetic induction angle sensor shaft 13 rotates, and the rotation angle is detected by the magnetic induction angle sensor. After calculation, it is converted into the opening of the valve stem 4.

[0106] A method for calculating and controlling the angle of an electromagnetically inductive intelligent valve positioner employs a regulating valve and includes: a valve actuator, a valve positioner, a feedback rod 2, and a latch (i.e., a contact head 3); the feedback rod 2 is mounted on the valve positioner; the latch (i.e., the contact head 3) is mounted on a U-shaped slot 7 connected to the valve stem 4 of the valve actuator; a slot (a strip-shaped slot) is provided in the middle of the feedback rod 2; one end of the latch is mounted in the U-shaped slot 7 connected to the valve stem 4 of the valve actuator; the other end of the latch is mounted in the slot of the feedback rod 2. The valve positioner includes a housing, a magnetic induction angle sensor mounted within the housing, and a positioner shaft 13. The shaft 13 of the magnetic induction angle sensor is connected to the positioner shaft 8 via a gear; the feedback rod 2 is mounted on the positioner main shaft 8. A spring clip is mounted on the feedback rod 2 to clamp the strip-shaped slot. The valve stem 4 of the valve actuator is perpendicular to the top surface of the valve positioner.

[0107] The magnetic induction angle sensor performs self-calibration and records signal parameters, including: the magnetic induction angle sensor uses tunnel magnetoresistive technology, the angle range is 360°, and the magnetic induction angle sensor outputs two voltage signals with a sine and cosine relationship with the magnetic field angle, such as Figure 3 As shown, the magnetic induction angle sensor's rotation axis is rotated more than 360°. The circuit board converts the two voltage signals induced by the magnetic field into digital signal AD values through digital-to-analog conversion, converts the sine signal and cosine signal respectively, and records the peak and trough AD values.

[0108] like Figure 3 and Figure 8 As shown, the opening calculation control method includes the following steps:

[0109] 1) The non-contact angle sensor performs self-calibration and records signal parameters. The non-contact angle sensor (i.e., magnetic induction angle sensor) uses tunnel magnetoresistance (TMR) technology. The angle range is 360°. The sensor outputs two voltage signals (e.g., Figure 3 Install the shaft of the magnetic induction angle sensor 18 to the fixture (as shown). Figure 7 The stepper motor 17 is mounted on the fixture and connected to the shaft via a gear mechanism. The sensor output signal is connected to a circuit board, and the signal value is collected by the circuit board's AD module. The stepper motor is started to rotate the shaft, and the sensor signal value is continuously collected during this process. When the shaft rotates more than 360°, the peak and trough values of the sine and cosine signals are calculated and recorded.

[0110] 2) Install the sensor and circuit board into the valve positioner housing. Install the feedback rod onto the valve positioner spindle. Use a calibration fixture (such as Figure 9 ) Calibrate the reference point position of feedback rod 2. Feedback rod 2 is parallel to the top surface of valve positioner 1. The position of feedback rod 2 after horizontal calibration is used as the reference line. The sine and cosine AD values of the angle sensor at this position are recorded: pos_ref_sin and pos_ref_cos.

[0111] 3) Install the valve positioner on the regulating valve, making sure the top surface of the valve positioner is perpendicular to the valve stem. The overall installation diagram is as follows Figure 10 Use the valve positioner self-tuning function to operate the valve switch action, record the sine signal and cosine signal AD value of the sensor at the minimum valve position: pos_min_sin, pos_min_cos and the sine signal and cosine signal AD value of the sensor at the maximum valve position: pos_max_sin, pos_max_cos.

[0112] 4) After the valve positioner completes auto-tuning, it receives a control signal to adjust the valve position and collects the AD values of the sensor's sine and cosine signals at the current valve position: pos_sin and pos_cos. The actual valve position percentage is calculated using the valve positioner's opening calculation method, compared with the set valve position percentage, and adjusted to within the deadband range of the set valve position percentage.

[0113] Sensor angle value calculation formula:

[0114] sin_peak=(sensor_sin_max-sensor_sin_min) / 2;

[0115] cos_peak=(sensor_cos_max-sensor_cos_min) / 2;

[0116] sin_offset=(sensor_sin_max+sensor_sin_min) / 2;

[0117] cos_offset=(sensor_cos_max+sensor_cos_min) / 2;

[0118] sin_value=(sin_data-sin_offset) / sin_peak;

[0119] cos_value=(cos_data-cos_offset) / cos_peak;

[0120] angle_value=atan2(sin_value,cos_value)*180 / pi;

[0121] If angle_value<0, angle_value=360+angle_value;

[0122] angle_value is the final calculated angle value.

[0123] In the formula, sensor_sin_max and sensor_sin_min are the peak and trough AD values of the sensor's sine signal. sensor_cos_max and sensor_cos_min are the peak and trough AD values of the sensor's cosine signal. sin_data and cos_data are the current AD values of the sensor's sine and cosine signals. pi is the circumference of a circle.

[0124] ●Let sin_data = pos_ref_sin, cos_data = pos_ref_cos, and substitute into the above formula to obtain the reference point position sensor angle value angle_ref.

[0125] ●Let sin_data = pos_min_sin, cos_data = pos_min_cos, and substitute into the above formula to obtain the minimum position sensor angle value angle_min.

[0126] ●Let sin_data = pos_max_sin, cos_data = pos_max_cos, and substitute into the above formula to obtain the maximum position sensor angle value angle_max.

[0127] ●Let sin_data = pos_sin, cos_data = pos_cos, and substitute into the above formula to obtain the current position sensor angle value angle_pos.

[0128] according to Figure 8 Calculate the swing angle of the feedback lever relative to the reference point:

[0129] Swing angle at minimum position ref_angle_min = (angle_min - angle_ref) / angle_ratio;

[0130] Swing angle at maximum position ref_angle_max = (angle_max - angle_ref) / angle_ratio;

[0131] Actual position swing angle ref_angle_pos = (angle_pos - angle_ref) / angle_ratio;

[0132] Among them, angle_ratio is the transmission gear ratio of the angle sensor and the positioner spindle;

[0133] The minimum valve position distance from the reference line:

[0134] S_angle_min=tan(pi / 180*ref_angle_min);

[0135] The maximum valve position distance from the reference line:

[0136] S_angle_max=tan(pi / 180*ref_angle_max);

[0137] Actual valve position distance from the reference line:

[0138] S_angle_pos=tan(pi / 180*ref_angle_pos);

[0139] Actual valve position percentage:

[0140] pos_percent=(S_angle_pos-S_angle_min) / (S_angle_max-S_angle_min).

[0141] like Figure 11As shown, the circuit board includes a first resistor R1 (10K) and a second resistor R2 (15K) connected in series with a 2.5V input voltage. A 1.5V voltage is divided and input to the positive input of a first operational amplifier U1. The negative input and output of the first operational amplifier U1 are connected to form a voltage follower circuit, thereby outputting a 1.5V high-impedance stable voltage. The 1.5V voltage is input to a third resistor R3 (15K) and a fourth resistor R4 (15K). The third resistor R3 (15K) is connected to a fifth resistor R5 (50K) and a sixth resistor R6 (180K). The fifth resistor R5 (50K) is connected in parallel to a second capacitor C2 and grounded. A sixth resistor R6 with a resistance of 180K is connected to the positive input of the second operational amplifier U2. A third capacitor C3 with a capacitance of 10pF is connected in parallel to the power input of the second operational amplifier U2 and grounded. A fourth resistor R4 with a resistance of 15K is connected to a seventh resistor R7 with a resistance of 50K and an eighth resistor R8 with a resistance of 180K. The seventh resistor R7 with a resistance of 50K is connected in parallel to the fourth capacitor C4 with a capacitance of 10pF and grounded. An eighth resistor R8 with a resistance of 180K is connected to the positive input of the third operational amplifier U3. A fifth capacitor C5 with a capacitance of 100nF is connected in parallel to the power input of the third operational amplifier U3 and grounded. The above circuit achieves a voltage phase shift of 1.2V for the operational amplifier. The magnetic field sensing chip U5 is connected to a ninth resistor R9 (75K), a tenth resistor R10 (75K), an eleventh resistor R11 (75K), and a twelfth resistor R12 (75K). The ninth resistor R9 is connected to the positive input of the second operational amplifier U2. The tenth resistor R10 is connected to the negative input of the second operational amplifier U2 and a thirteenth resistor R13 (180K). The thirteenth resistor R13 (180K) is connected in parallel with a sixth capacitor C6 (10pF). The thirteenth resistor R13 (180K) is connected to the output of the second operational amplifier U2 and a fifteenth resistor R15 (50Ω). The fifteenth resistor R15 (50Ω) is connected in parallel with a seventh capacitor C7 (5nF) and grounded. An eleventh resistor R11 (75K) is connected to the positive input of the third operational amplifier U3. A twelfth resistor R12 (75K) is connected to the negative input of the third operational amplifier U3 and a fourteenth resistor R14 (180K). This resistor is connected in parallel to an eighth capacitor C8 (10pF). A fourteenth resistor R14 (180K) is connected to the output of the third operational amplifier U3 and a sixteenth resistor R16 (50Ω). This resistor is connected in parallel to a ninth capacitor C9 (5nF) and grounded. The above circuit differentially amplifies the input signals Y+, Y-, X+, and X-.

[0142] like Figure 11As shown, U5 is a magnetic induction chip. When the magnet rotates, the 5th pin Y+ and 6th pin Y- of the magnetic induction chip U5 will output differential signals, and the 2nd pin X- and 3rd pin X+ will output differential signals. The X- and X+ signals are input to the operational amplifier U3 for differential amplification and then output the sinusoidal voltage signal OUT1. The Y- and Y+ signals are input to the operational amplifier U2 for differential amplification and then output the cosine voltage signal OUT2. The processed sinusoidal voltage signal OUT1 and cosine voltage signal OUT2 are Figure 3 The input main circuit board MCU uses software to process and correct the calculated rotation angle.

[0143] The advantages of the above circuit design are that it can amplify varying AC signals and phase-shift the output signal to center it at two-thirds of the power supply input voltage. This facilitates the amplification of the two voltage signals for magnetic field sensing, and the digital-to-analog conversion of these signals into digital AD values, which are more accurate.

[0144] The specific implementation methods described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A valve opening calculation and control method for an intelligent valve positioner using electromagnetic induction, characterized in that: A regulating valve is used, including: a valve actuator, a valve positioner, a feedback rod and a latch; The feedback rod is installed on the valve positioner; A first slide groove is installed on the valve stem of the valve actuator; A second sliding groove is provided in the middle of the feedback rod; One end of the latch is installed in the first sliding groove, and the other end of the latch is installed in the second sliding groove of the feedback lever; The valve positioner comprises: a housing, a magnetic induction angle sensor installed in the housing, and a positioner shaft, wherein the shaft in the magnetic induction angle sensor is connected to the positioner shaft via a gear, and the feedback lever is installed on the positioner shaft; The valve opening calculation and control method comprises the following steps: 1) The magnetic induction angle sensor performs self-calibration and records signal parameters; 2) Install the magnetic induction angle sensor into the valve positioner housing and the feedback lever onto the valve positioner shaft. Calibrate the reference point of the feedback lever so that the feedback lever is parallel to the top surface of the valve positioner. Use the position of the horizontally calibrated feedback lever as the reference line and record the AD values of the sine and cosine signals of the angle sensor at that position: pos_ref_sin and pos_ref_cos. 3) Install the valve positioner on the valve actuator, ensure that the top surface of the valve positioner is perpendicular to the valve stem, use the valve positioner self-tuning, and record the sine signal and cosine signal AD values of the magnetic induction angle sensor at the minimum valve position: pos_min_sin, pos_min_cos and the sine signal and cosine signal AD values of the magnetic induction angle sensor at the maximum valve position: pos_max_sin, pos_max_cos. 4) After the valve positioner completes self-tuning, it receives a control signal to adjust the valve position, collects the sine and cosine AD values of the magnetic induction angle sensor at the current valve position: pos_sin, pos_cos, calculates the actual valve position percentage based on the valve positioner's opening calculation method, compares the actual valve position percentage with the set valve position percentage, and adjusts the actual valve position percentage to within the dead zone of the set valve position percentage.

2. The valve opening calculation and control method of the intelligent valve positioner using electromagnetic induction according to claim 1, characterized in that: The valve stem of the valve actuator is perpendicular to the top surface of the valve positioner.

3. The valve opening calculation and control method of the intelligent valve positioner using electromagnetic induction according to claim 1, characterized in that: In step 1), the magnetic induction angle sensor performs self-calibration processing and records signal parameters, specifically including: The magnetic induction angle sensor uses tunnel magnetoresistance technology and has an angular range of 360°. The magnetic induction angle sensor outputs two voltage signals with sine and cosine relationships with the magnetic field angle. The rotating shaft of the magnetic induction angle sensor is installed on the sensor self-calibration platform. When the rotating shaft of the sensor self-calibration platform rotates more than 360°, the peak and trough values of the sine and cosine signals are calculated and recorded.

4. The valve opening calculation and control method of the intelligent valve positioner using electromagnetic induction according to claim 1, characterized in that: In step 4), the actual valve position percentage is calculated according to the valve positioner opening calculation method, specifically including: 1) The sensor angle value calculation formula is as follows: sin_peak=(sensor_sin_max-sensor_sin_min) / 2; cos_peak=(sensor_cos_max-sensor_cos_min) / 2; sin_offset=(sensor_sin_max+sensor_sin_min) / 2; cos_offset=(sensor_cos_max+sensor_cos_min) / 2; sin_value=(sin_data-sin_offset) / sin_peak; cos_value=(cos_data-cos_offset) / cos_peak; angle_value=atan2(sin_value,cos_value)*180 / pi; If angle_value<0, add 360° to angle_value as the final calculated angle value; In the formula, sensor_sin_max and sensor_sin_min are the peak and trough AD values of the sine signal of the magnetic induction angle sensor, sensor_cos_max and sensor_cos_min are the peak and trough AD values of the cosine signal of the magnetic induction angle sensor, sin_data and cos_data are the AD values of the current sine and cosine signals of the magnetic induction angle sensor, and pi is the circumference of a circle. 2) Set sin_data = pos_ref_sin, cos_data = pos_ref_cos, and substitute into the sensor angle value calculation formula in step 1) to obtain the reference point position sensor angle value angle_ref; 3) Set sin_data = pos_min_sin, cos_data = pos_min_cos, and substitute into the sensor angle value calculation formula in step 1) to obtain the minimum position sensor angle value angle_min; 4) Set sin_data = pos_max_sin, cos_data = pos_max_cos, and substitute into the sensor angle value calculation formula in step 1) to obtain the maximum position sensor angle value angle_max; 5) Substitute sin_data = pos_sin and cos_data = pos_cos into the sensor angle calculation formula in step 1) to obtain the current position sensor angle value angle_pos; 6) Swing angle at minimum position ref_angle_min = (angle_min - angle_ref) / angle_ratio; Swing angle at maximum position ref_angle_max = (angle_max - angle_ref) / angle_ratio; Actual position swing angle ref_angle_pos = (angle_pos - angle_ref) / angle_ratio; Among them, angle_ratio is the transmission gear ratio of the angle sensor and the positioner spindle; The minimum valve position distance from the reference line is S_angle_min: S_angle_min = tan(pi / 180*ref_angle_min); The distance of the maximum valve position from the reference line is S_angle_max: S_angle_max = tan(pi / 180*ref_angle_max); The distance between the actual valve position and the reference line is S_angle_pos: S_angle_pos = tan(pi / 180*ref_angle_pos); Actual valve position percentage pos_percent: pos_percent = (S_angle_pos - S_angle_min) / (S_angle_max - S_angle_min).

5. The valve opening calculation and control method of the intelligent valve positioner using electromagnetic induction according to claim 1, characterized in that: The electromagnetic induction angle sensor comprises: an electromagnetic induction angle sensor housing, an electromagnetic induction angle sensor shaft, an induction magnet, an induction chip for detecting changes in the magnetic field of the induction magnet, and a circuit board.

6. The valve opening calculation and control method of the intelligent valve positioner using electromagnetic induction according to claim 5, characterized in that: One end of the electromagnetic induction angle sensor shaft is installed in the electromagnetic induction angle sensor housing and connected to the induction magnet, and the other end of the electromagnetic induction angle sensor shaft is installed outside the electromagnetic induction angle sensor housing and connected to the driven gear.

7. The valve opening calculation and control method of the intelligent valve positioner using electromagnetic induction according to claim 5, characterized in that: The sensing chip is mounted on the circuit board.

8. The valve opening calculation and control method of the intelligent valve positioner using electromagnetic induction according to claim 5, characterized in that: The circuit of the circuit board includes: a first resistor and a second resistor connected in series; a first operational amplifier, wherein a non-inverting input terminal of the first operational amplifier is connected between the first resistor and the second resistor; a first capacitor connected to the power input terminal of the first operational amplifier and grounded; a third resistor and a fourth resistor, both of which are connected to the inverting input terminal and the output terminal of the first operational amplifier; a first differential amplifier circuit connected to the third resistor; a second differential amplifier circuit connected to the fourth resistor; A magnetic field sensing chip, wherein the output ends of the magnetic field sensing chip are both connected to the first differential amplifier circuit and the second differential amplifier circuit.

9. The valve opening calculation and control method of the intelligent valve positioner using electromagnetic induction according to claim 5, characterized in that: The first differential amplifier circuit includes: a fifth resistor and a sixth resistor connected to the third resistor; a second capacitor connected in parallel with the fifth resistor and grounded; a second operational amplifier, wherein a positive input terminal of the second operational amplifier is connected to the sixth resistor, and a power input terminal of the second operational amplifier is connected in parallel with a third capacitor and is grounded; a ninth resistor and a tenth resistor connected to the magnetic field sensing chip, the ninth resistor being connected to the positive input terminal of the second operational amplifier, and the tenth resistor being connected to the negative input terminal of the second operational amplifier; a thirteenth resistor, the thirteenth resistor being connected in parallel to the positive input terminal and the output terminal of the second operational amplifier; A sixth capacitor is connected in parallel with the thirteenth resistor. a fifteenth resistor connected to the output terminal of the second operational amplifier; a seventh capacitor connected in parallel with the fifteenth resistor and grounded.

10. The valve opening calculation and control method of the intelligent valve positioner using electromagnetic induction according to claim 5, characterized in that: The second differential amplifier circuit includes: connecting a seventh resistor and an eighth resistor to the fourth resistor; a fourth capacitor connected in parallel with the seventh resistor and grounded; a third operational amplifier, wherein a positive input terminal of the third operational amplifier is connected to the eighth resistor, and a power input terminal of the second operational amplifier is connected in parallel with a fifth capacitor and grounded; an eleventh resistor and a twelfth resistor connected to the magnetic field sensing chip, the eleventh resistor being connected to the positive input terminal of the second operational amplifier, and the twelfth resistor being connected to the negative input terminal of the second operational amplifier; a fourteenth resistor, the fourteenth resistor being connected in parallel to the positive input terminal and the output terminal of the second operational amplifier; an eighth capacitor, the eighth capacitor being connected in parallel with the fourteenth resistor; a sixteenth resistor connected to the output terminal of the third operational amplifier; a ninth capacitor connected in parallel with the sixteenth resistor and grounded.

Images