Multi-channel solenoid valve coil current monitoring system

Abstract

The invention relates to the technical field of current monitoring, and discloses a multi-channel electromagnetic valve coil current monitoring system, which comprises closed-loop Hall sensors arranged on two sides of an electromagnetic valve coil in a sleeving manner, and the closed-loop Hall sensors are connected with a control unit. The control unit comprises an operational amplifier circuit electrically connected with the closed-loop Hall sensor and a power supply circuit used for driving the closed-loop Hall sensor, the operational amplifier circuit is connected with an analog-to-digital conversion circuit, the analog-to-digital conversion circuit is connected with a digital filter circuit, the digital filter circuit is connected with an MODBUS slave station module, and the MODBUS slave station module is connected with the power supply circuit. The MODBUS slave station module is in communication connection with the MODBUS master station; according to the invention, while limited AI analog quantity channels are not occupied, real-time monitoring of the coil current of the key electromagnetic valve is realized.

Description

Technical Field

[0001] This application relates to the field of current monitoring technology, specifically a multi-channel solenoid valve coil current monitoring system. Background Technology

[0002] Gas turbine power plants have many important solenoid valves, such as natural gas ESD solenoid valves, safety shut-off valves, and trip solenoid valves. Loss of power to these solenoid valves can lead to unscheduled unit shutdowns. Currently, solenoid valve status monitoring relies solely on manual periodic checks of coil resistance. Many solenoid valves are in a continuously energized state during unit operation. As the equipment's service life increases, the insulation layer of the solenoid valve coil's enameled wire will carbonize. Outdoor solenoid valves may become damp, reducing their insulation performance, leading to increased current in the circuit, increased coil heat generation, and accelerated thermal aging of the solenoid valve coil. Furthermore, some solenoid valves are located in special geographical locations, making it inconvenient to access them during unit operation. Therefore, it is impossible to directly measure the coil resistance with a multimeter during unit operation. Existing technology uses a clamp-on ammeter to confirm the circuit current and calculates the current coil resistance based on the known supply voltage. Alternatively, a wideband current transformer (CT) can be installed in the circuit, with the solenoid valve coil directly passing through the CT core hole and fixed in place. This signal is then converted into a 4-20mA signal by a transmitter and input to the control system's AI analog input channel for monitoring.

[0003] However, the existing technology that uses a clamp meter to measure the current of the solenoid valve coil cannot achieve continuous monitoring of the solenoid valve current because it relies on manual labor. The method of using current transformers and transmitters requires each solenoid valve to be equipped with a current transformer and transmitter and to lay shielded cables, which occupies a limited number of analog input channels. Summary of the Invention

[0004] The purpose of this application is to provide a multi-channel solenoid valve coil current monitoring system that enables real-time monitoring of the current of a critical solenoid valve coil without occupying a limited number of AI analog input channels.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The present invention discloses a multi-channel solenoid valve coil current monitoring system, comprising a closed-loop Hall sensor sleeved on both sides of the solenoid valve coil, wherein the closed-loop Hall sensor is connected to a control unit, the control unit comprising an operational amplifier circuit electrically connected to the closed-loop Hall sensor and a power supply circuit for driving the closed-loop Hall sensor, the operational amplifier circuit being connected to an analog-to-digital converter circuit, the analog-to-digital converter circuit being connected to a digital filter circuit, the digital filter circuit being connected to a MODBUS slave module, and the MODBUS slave module being communicatively connected to a MODBUS master station.

[0007] Furthermore, the closed-loop Hall sensor includes a discrete first magnetic core and a second magnetic core. Both the first magnetic core and the second magnetic core are provided with matching ends. The first magnetic core and the second magnetic core form a closed magnetic circuit through end engagement. The second magnetic core is provided with an air gap. The Hall element is inserted into the air gap. The second magnetic core is wound with a compensation winding. Both the Hall element and the compensation winding are electrically connected to the control unit.

[0008] Furthermore, the ends of the first and second magnetic cores are mutually matched toothed structures.

[0009] Furthermore, the MODBUS slave module is connected to the MODBUS master station via an RS485 bus.

[0010] Compared with the prior art, the beneficial effects of this application are:

[0011] This invention employs a closed-loop Hall sensor, which compensates for the magnetic field generated by the measured current by using a compensating current to maintain a closed magnetic circuit with zero magnetic flux. A transverse potential difference, or Hall voltage, is generated in the Hall element, the magnitude of which is proportional to the magnetic field strength. The current in the solenoid valve is indirectly measured by detecting changes in the magnetic field. The GE 9FB gas turbine hardware supports MODBUS protocol communication, sending the output of the closed-loop Hall sensor to a hardware channel that supports MODBUS protocol communication. This achieves real-time monitoring of the current in the key solenoid valve coil without occupying the limited AI analog signal channels. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0013] Figure 1 This is a circuit structure block diagram of this application;

[0014] Figure 2 This is the circuit schematic of the amplifier circuit of this application;

[0015] Figure 3 This is a schematic diagram of the closed-loop Hall sensor of this application;

[0016] Figure 4 yes Figure 3 Side view.

[0017] Reference numerals: First magnetic core 1; Second magnetic core 2; Compensation winding 3; Hall element 4; Control unit 5. Detailed Implementation

[0018] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0019] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the layers related to the present invention and are not drawn according to the actual number, shape and size of the layers in the actual implementation. In the actual implementation, the form, number and proportion of each layer can be arbitrarily changed, and the layer layout may also be more complex.

[0020] Numerous details are explored in the following description to provide a more thorough explanation of embodiments of the invention; however, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details.

[0021] Please see Figure 1 and Figure 2 A multi-channel solenoid valve coil current monitoring system includes closed-loop Hall sensors sleeved on both sides of the solenoid valve coil. The closed-loop Hall sensors are connected to a control unit 5. The control unit 5 includes an operational amplifier circuit electrically connected to the closed-loop Hall sensors and a power supply circuit for driving the closed-loop Hall sensors. The operational amplifier circuit is connected to an analog-to-digital converter circuit. The analog-to-digital converter circuit is connected to a digital filter circuit. The digital filter circuit is connected to a MODBUS slave module. The MODBUS slave module is communicatively connected to a MODBUS master station.

[0022] Please see Figure 3 The closed-loop Hall sensor includes a discrete first magnetic core 1 and a second magnetic core 2. Both the first magnetic core 1 and the second magnetic core 2 are provided with matching ends. The first magnetic core 1 and the second magnetic core 2 form a closed magnetic circuit through end engagement. The second magnetic core 2 is provided with an air gap. A Hall element 4 is inserted into the air gap. A compensation winding 3 is wound around the second magnetic core 2. Both the Hall element 4 and the compensation winding 3 are electrically connected to the control unit 5.

[0023] Please see Figure 4 The ends of the first magnetic core 1 and the second magnetic core 2 are mutually matched toothed structures.

[0024] Please see Figure 1The MODBUS slave module communicates with the MODBUS master station via an RS485 bus.

[0025] In practical applications, please refer to Figures 1 to 4 When detecting the current in a solenoid valve coil, a closed-loop Hall sensor with a current rating twice that of the solenoid valve is selected. The first magnetic core 1 and the second magnetic core 2 are separated, and inserted from both sides of the coil of the solenoid valve being tested. The toothed structures of the first magnetic core 1 and the second magnetic core 2 mesh seamlessly, forming a closed magnetic circuit. The Hall element 4 is inserted into the air gap, ensuring the sensitive surface is perpendicular to the magnetic field direction, to measure and determine if the magnetic flux is zero. A magnetic field is generated through the compensation winding 3 electrically connected to the power supply circuit. To achieve zero magnetic flux in the core of the closed-loop Hall current sensor, the sensor converts the magnetic flux into an electrical signal and amplifies it. The compensation current is increased or decreased to make it equal in magnitude and opposite in direction to the magnetic field generated by the measured current, achieving mutual cancellation and forming a closed-loop system. The signal is then processed through calculation. The large circuit measures the voltage across the resistor, calculates the compensation current, and converts it to the current in the solenoid valve coil. The closed-loop Hall sensor overcomes the influence of the hysteresis loop of the open-loop Hall sensor, resulting in higher measurement accuracy and faster response. The voltage output signal of the operational amplifier circuit is sampled by a 16-bit ADC, filtered by a digital filter circuit, and then input to the MODBUS slave module. The MODBUS slave channel one outputs the current through a conversion formula, and channel two also outputs the current. The current is written to the alarm threshold through the 06 function code, and the overcurrent alarm is stored in the status register. A response frame is constructed, checked by CRC, and sent to the MODBUS master station via the RS485 bus. Each slave station has a corresponding address, and the master station can also be configured to prioritize access to certain slave stations, thereby prioritizing the confirmation of the status of important solenoid valves. This enables real-time continuous monitoring of multiple solenoid valves without occupying limited AI channels.

[0026] Please see Figure 2 When the magnetic field balance is disrupted, the sensitive Hall element 4 senses the magnetic field imbalance and generates a weak Hall potential V. h Because the potential is very small, this signal needs to be amplified. This invention uses the OPA2277 high-precision, low-noise operational amplifier circuit. The amplification factor is changed by altering the resistance; a resistor is connected between pins a and b of the OPA2277 to form a proportional amplifier circuit. This invention adjusts the amplification factor by adjusting the adjustable resistor connected to the capacitor.

[0027] This invention employs a closed-loop Hall sensor, which compensates for the magnetic field generated by the measured current by a compensating current, maintaining a closed magnetic circuit with zero magnetic flux. A transverse potential difference, i.e., Hall voltage, is generated in Hall element 4, the magnitude of which is proportional to the magnetic field strength. The current in the solenoid valve is indirectly measured by detecting changes in the magnetic field. The GE 9FB gas turbine hardware supports MODBUS protocol communication, sending the output of the closed-loop Hall sensor to a hardware channel that supports MODBUS protocol communication. This achieves real-time monitoring of the current in the key solenoid valve coil without occupying the limited AI analog signal channels.

[0028] In the above embodiments, although the invention has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. The embodiments of the invention are intended to cover all such substitutions, modifications, and variations falling within the broad scope of the appended claims.

[0029] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A multi-channel solenoid valve coil current monitoring system, characterized by: The closed loop Hall sensor is sleeved on both sides of the solenoid valve coil, and is connected with a control unit (5), the control unit (5) includes an operational amplifier circuit electrically connected with the closed loop Hall sensor and a power supply circuit for driving the closed loop Hall sensor, the operational amplifier circuit is connected with an analog-to-digital conversion circuit, the analog-to-digital conversion circuit is connected with a digital filter circuit, the digital filter circuit is connected with a MODBUS slave module, and the MODBUS slave module is in communication connection with a MODBUS master station.

2. A multi-channel solenoid valve coil current monitoring system according to claim 1, wherein, The closed loop Hall sensor includes a first magnetic core (1) and a second magnetic core (2), the first magnetic core (1) and the second magnetic core (2) are provided with matching end heads, the first magnetic core (1) and the second magnetic core (2) are engaged by the end heads to form a closed magnetic circuit, the second magnetic core (2) is provided with an air gap, a Hall element (4) is inserted in the air gap, and the second magnetic core (2) is wound with a compensation winding (3), and the Hall element (4) and the compensation winding (3) are electrically connected with the control unit (5).

3. A multi-channel solenoid valve coil current monitoring system according to claim 2, wherein, The end heads of the first magnetic core (1) and the second magnetic core (2) are tooth-shaped structures matched with each other.

4. A multi-channel solenoid valve coil current monitoring system according to claim 1, wherein, The MODBUS slave module is in communication connection with the MODBUS master station through an RS485 bus.

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