Refrigerant monitoring control circuit, control method and refrigeration equipment

Abstract

The application discloses a refrigerant monitoring control circuit, a control method and a refrigeration equipment, and relates to the technical field of energy saving and safety control of refrigeration equipment. The refrigerant monitoring control circuit comprises a timer circuit, a controller, a power supply control circuit, a refrigerant sensor, a power supply protection circuit and a load control circuit. The timer circuit periodically outputs a wake-up signal, the controller turns on the power supply of the refrigerant sensor in response to the wake-up signal, turns off the power supply after completing the current monitoring according to the comparison result of the refrigerant concentration and the preset alarm threshold, or keeps the power supply and outputs a load linkage control signal; and the power supply protection circuit performs current limiting, overvoltage clamping and fuse protection on the power supply circuit. The application can consider refrigerant leakage monitoring, refrigeration equipment safety linkage and low-power consumption operation, and improves the power supply safety of the refrigerant monitoring circuit.

Description

Technical Field

[0001] This invention relates to the field of energy-saving and safety control technology for refrigeration equipment, specifically to a refrigerant monitoring and control circuit, control method, and refrigeration equipment. Background Technology

[0002] With the development of refrigeration technology and environmental protection requirements, environmentally friendly refrigerants such as R290 and R454B, which are flammable, are increasingly being used in refrigeration equipment such as air conditioners, cold storage refrigeration units, refrigerated truck temperature control systems, and water chillers. Correspondingly, how to promptly detect refrigerant leaks and reduce the safety risks associated with leaks has become a crucial issue to consider during the operation of energy-efficient refrigeration and air conditioning equipment.

[0003] Refrigerant sensors can detect the refrigerant concentration in or around refrigeration equipment and provide the results to the control system. The control system uses the refrigerant concentration to determine if there is a leak or abnormality, thus providing a basis for alarms, shutdowns, or other safety procedures.

[0004] Existing refrigerant monitoring systems primarily focus on whether refrigerant concentration can be continuously detected. To ensure detection response, the refrigerant sensor and its peripheral circuitry typically need to maintain an operational state for an extended period. This increases the additional power consumption generated by the refrigerant monitoring function and also increases the cumulative operating time of the refrigerant sensor.

[0005] For refrigeration equipment that needs to operate for extended periods, the refrigerant concentration detected by the refrigerant sensor is likely to be within a safe range most of the time. If the refrigerant sensor continues to operate for extended periods during this period, it is not conducive to further reducing the operating energy consumption of the auxiliary monitoring section of the refrigeration equipment, nor is it conducive to the low-power design of energy-efficient refrigeration and air conditioning equipment.

[0006] Meanwhile, the refrigerant sensor itself requires a corresponding power supply circuit to provide operating voltage. Power supply circuits may experience overcurrent, overvoltage, or short circuits due to power fluctuations, device malfunctions, or circuit abnormalities. Power supply abnormalities can not only affect the refrigerant concentration detection results but may also cause abnormal heating of the refrigerant sensor and its peripheral components.

[0007] When using environmentally friendly refrigerants that are flammable, refrigerant leaks and power supply abnormalities may occur simultaneously. Therefore, refrigerant monitoring systems need to pay attention not only to whether the refrigerant concentration exceeds the safe range, but also to the safety and reliability of the refrigerant sensor power supply circuit under different abnormal conditions.

[0008] Existing refrigerant monitoring equipment may be installed as a standalone detection device outside of the refrigeration unit, requiring additional power supply, installation space, and communication interfaces. The coordination between refrigerant detection results and the operational controls of the compressor, fan, electronic expansion valve, and overall power supply is limited, hindering the timely activation of corresponding equipment linkages after a refrigerant leak is detected.

[0009] Some refrigerant sensors employ electrochemical detection principles. During long-term use, the electrode surface of electrochemical sensors may be affected by environmental contamination or adsorbed impurity ions, causing changes in the electrode reaction state and consequently affecting the accuracy and long-term stability of refrigerant concentration detection.

[0010] In the above situations, it is usually necessary to inspect, calibrate, or replace the refrigerant sensor, which not only increases the maintenance workload of the refrigeration equipment but may also affect the continuous availability of the refrigerant monitoring function.

[0011] Therefore, existing refrigerant monitoring technologies still have room for improvement in terms of operating power consumption under normal conditions, continuous tracking after refrigerant leakage, load linkage of refrigeration equipment, sensor power supply safety, and long-term maintenance of electrochemical sensors. A refrigerant monitoring and control solution that can balance energy-saving operation and safe monitoring is needed. Summary of the Invention

[0012] The present invention aims to at least solve the problems of existing refrigerant monitoring technologies, which are difficult to simultaneously achieve low power consumption operation under normal conditions, continuous monitoring after refrigerant leakage, load linkage of refrigeration equipment, power supply safety of refrigerant sensors, and long-term electrode maintenance.

[0013] To solve the above-mentioned technical problems, the present invention provides a refrigerant monitoring and control circuit, a control method, and a refrigeration device.

[0014] In a first aspect, the present invention provides a refrigerant monitoring and control circuit, including a timer circuit, a controller, a power supply control circuit, a refrigerant sensor, a power supply protection circuit, and a load control circuit.

[0015] The output terminal of the timer circuit, the signal output terminal of the refrigerant sensor, and the input terminal of the load control circuit are respectively connected to the controller.

[0016] The power supply control circuit is located in the power supply loop between the power supply and the power supply terminal of the refrigerant sensor, and the controlled terminal of the power supply control circuit is connected to the controller.

[0017] The power supply protection circuit is connected to both the power supply circuit and the controller.

[0018] The timer circuit is used to output a wake-up signal to the controller according to a preset period.

[0019] The controller is used to respond to the wake-up signal to control the power supply control circuit to turn on, obtain the refrigerant concentration detected by the refrigerant sensor, and compare the refrigerant concentration with a preset alarm threshold.

[0020] When the refrigerant concentration is lower than the preset alarm threshold, the controller controls the power supply control circuit to shut down after completing the current monitoring.

[0021] When the refrigerant concentration reaches or exceeds the preset alarm threshold, the controller controls the power supply control circuit to remain on and outputs a load linkage control signal through the load control circuit.

[0022] The power supply protection circuit is used to provide current limiting protection, overvoltage clamping protection, and fuse protection for the power supply circuit.

[0023] Furthermore, the power supply control circuit includes a P-channel enhancement-mode MOSFET, an NPN transistor, a base current limiting resistor, and a pull-up resistor.

[0024] The source of the P-channel enhancement-mode MOS transistor is connected to the power supply side of the power supply circuit, the drain is connected to the power supply terminal of the refrigerant sensor, and the gate is connected to the collector of the NPN transistor.

[0025] The emitter of the NPN transistor is grounded, and the base is connected to the controller through the base current-limiting resistor.

[0026] The pull-up resistor is connected between the source and gate of the P-channel enhancement-mode MOS transistor.

[0027] Furthermore, the power supply protection circuit includes a fuse, a current limiting element, and a voltage clamping element.

[0028] Along the power supply direction of the power supply circuit, the fuse, the current limiting element, the power supply control circuit, and the refrigerant sensor are connected in sequence.

[0029] The voltage clamping element is connected between the power supply terminal of the refrigerant sensor and ground.

[0030] Furthermore, the power supply protection circuit also includes an overvoltage detection circuit, which includes a voltage sampling unit, a threshold providing unit, a voltage comparison unit, and a delay unit.

[0031] The voltage sampling unit is connected to the power supply terminal of the refrigerant sensor. The voltage sampling unit and the threshold providing unit are respectively connected to the voltage comparison unit. The voltage comparison unit is connected to the controller through the delay unit.

[0032] The threshold providing unit is used to provide a threshold protection voltage, the voltage comparison unit is used to compare the power supply voltage of the refrigerant sensor with the threshold protection voltage, and the delay unit is used to perform delay processing on the overvoltage detection result output by the voltage comparison unit.

[0033] Furthermore, the power supply protection circuit also includes a controlled conduction element and a drive current limiting element.

[0034] The first conducting terminal of the controlled conducting element is connected to the node between the fuse element and the current limiting element, the second conducting terminal is grounded, and the controlled terminal is connected to the fuse trigger output terminal of the controller through the driving current limiting element.

[0035] The controller is used to output a fuse trigger signal through the fuse trigger output terminal when the overvoltage fault flag signal output by the overvoltage detection circuit continues to reach the software confirmation time, so as to control the controlled conducting element to conduct, so that the current flowing through the fuse element bypasses the current limiting element and melts the fuse element.

[0036] Furthermore, the load control circuit includes multiple control output terminals, which are respectively connected to the compressor, indoor fan, outdoor fan, electronic expansion valve, and main contactor for power supply of the whole machine.

[0037] The load control circuit is used to control the compressor to stop, the indoor fan and the outdoor fan to run at high speed, and the electronic expansion valve to close according to the load linkage control signal.

[0038] The load control circuit is also used to control the main contactor of the whole unit power supply to disconnect when the refrigerant concentration reaches or exceeds the high-risk threshold, and the high-risk threshold is higher than the preset alarm threshold.

[0039] Furthermore, the refrigerant sensor is an electrochemical sensor, and the refrigerant sensor has a working electrode, a counter electrode, and a reference electrode that are led out to the outside of the refrigerant sensor.

[0040] Furthermore, the refrigerant monitoring and control circuit also includes an electrode maintenance circuit, which includes a reverse current source and an analog switch.

[0041] The controlled terminal of the analog switch is connected to the controller, and the analog switch is disposed between the reverse current source and the working electrode and the counter electrode.

[0042] The analog switch is used to disconnect the reverse current source from the working electrode and the counter electrode during refrigerant concentration monitoring, and to connect the reverse current source between the working electrode and the counter electrode during electrode maintenance.

[0043] In a second aspect, the present invention provides a refrigerant monitoring and control method, implemented based on the refrigerant monitoring and control circuit described in the first aspect, comprising: Receive the wake-up signal output by the timer circuit according to a preset period; In response to the wake-up signal, the power supply control circuit is turned on, and the refrigerant concentration detected by the refrigerant sensor is obtained; The refrigerant concentration is compared with a preset alarm threshold. When the refrigerant concentration is lower than the preset alarm threshold, the power supply control circuit is turned off after the current monitoring is completed. When the refrigerant concentration reaches or exceeds the preset alarm threshold, the power supply control circuit is kept on, so that the refrigerant sensor can continuously monitor and output a load linkage control signal. During the refrigerant concentration monitoring process, the power supply protection circuit provides current limiting protection, overvoltage clamping protection, and fuse protection for the power supply circuit.

[0044] Further, the control of the power supply control circuit to be turned on and the acquisition of the refrigerant concentration detected by the refrigerant sensor includes: The power supply control circuit is turned on to power on the refrigerant sensor; Maintain the refrigerant sensor powered on for a preset stable duration; After the preset stabilization period ends, the refrigerant concentration is obtained.

[0045] Furthermore, when the refrigerant concentration reaches or exceeds the preset alarm threshold, the refrigerant sensor enters a continuous monitoring state.

[0046] In the continuous monitoring state, when the refrigerant concentration is continuously lower than the recovery threshold for a preset recovery time, the power supply control circuit is turned off, causing the refrigerant sensor to exit the continuous monitoring state and resume waking up the refrigerant sensor according to the preset cycle.

[0047] The recovery threshold is lower than the preset alarm threshold.

[0048] Furthermore, the output load linkage control signal includes: Controls the compressor to stop, controls the indoor and outdoor fans to run at high speed, and controls the electronic expansion valve to close; When the refrigerant concentration reaches or exceeds the high-risk threshold, the main contactor for power supply to the entire unit is disconnected, and the high-risk threshold is higher than the preset alarm threshold.

[0049] Furthermore, the overpressure detection process includes: Obtain the power supply voltage of the refrigerant sensor; The overvoltage detection result is obtained by comparing the supply voltage with the threshold protection voltage. The overvoltage detection results are then subjected to a time delay. When the supply voltage continuously exceeds the threshold protection voltage for a period of time until the hardware delay is reached, an overvoltage fault flag signal is output.

[0050] Furthermore, the fuse protection includes: Receive the overvoltage fault flag signal and perform software delay confirmation on the overvoltage fault flag signal; When the overvoltage fault flag signal continues for the software confirmation duration, a fuse trigger signal is output to control the controlled conducting element to conduct. The current flowing through the fuse element bypasses the current limiting element and flows to ground, thereby melting the fuse element and cutting off the power supply circuit of the refrigerant sensor.

[0051] Furthermore, the refrigerant monitoring and control method also includes: In response to a manual maintenance trigger signal, or when the cumulative power-on time of the refrigerant sensor reaches a preset maintenance time, the acquisition of the refrigerant concentration is suspended. The analog switch is controlled to connect the reverse current source between the working electrode and the counter electrode, and the reverse current source is controlled to output multiple reverse micro-current pulses; After the reverse micro-current pulse is output, the analog switch is controlled to disconnect the reverse current source, maintain the power supply to the refrigerant sensor, and shield the sampling data of the refrigerant sensor within the preset electrode recovery time. After the preset electrode recovery time has elapsed, the shielding of the sampling data is removed, and the refrigerant concentration is reacquired.

[0052] Thirdly, the present invention provides a refrigeration device, including a refrigeration system, a controlled load, and the refrigerant monitoring and control circuit described in the first aspect.

[0053] The controlled load includes at least one of a compressor, an indoor fan, an outdoor fan, an electronic expansion valve, and a main contactor for power supply to the entire unit.

[0054] The refrigerant monitoring and control circuit is used to detect the refrigerant concentration in the environment where the refrigeration equipment is located, and to control the operating status of the controlled load according to the refrigerant concentration.

[0055] Compared with the prior art, the present invention has at least the following beneficial effects: (1) By periodically waking up the controller through the timer circuit and using the power supply control circuit to supply power to the refrigerant sensor on demand, the continuous power consumption of the refrigerant sensor when the refrigerant concentration is within the safe range can be reduced; when the refrigerant concentration exceeds the standard, the refrigerant sensor is kept powered and load linkage is executed, which can take into account both energy-saving operation and continuous monitoring after leakage anomaly.

[0056] (2) High-side power supply control is implemented by using a P-channel enhancement-type MOSFET and level conversion is performed by an NPN transistor, which can achieve reliable switching while maintaining the ground reference of the refrigerant sensor; the pull-up resistor can also reduce the situation where the refrigerant sensor is accidentally powered on when the controller is not initialized.

[0057] (3) The fuse, current limiting and voltage clamping elements form fuse, current limiting and voltage clamping protection respectively, so that the refrigerant sensor power supply circuit can cope with different types of power supply abnormalities and improve the redundancy of power supply protection.

[0058] (4) By using a voltage sampling unit, a threshold providing unit, a voltage comparison unit and a delay unit to perform hardware detection on the power supply voltage of the refrigerant sensor, continuous overvoltage can be identified without relying on the controller to generate a comparison reference, and misjudgment caused by instantaneous voltage interference can be reduced.

[0059] (5) After the controlled conducting element is turned on, a fuse current path is formed that bypasses the current limiting element. This can avoid the current limiting element from limiting the fuse current, so that the fuse element can reliably fuse under severe power supply failure, and realize the physical isolation of the refrigerant sensor power supply circuit.

[0060] (6) The load control circuit controls the compressor, indoor fan, outdoor fan, electronic expansion valve and main contactor of the whole machine power supply according to the refrigerant concentration. It can implement graded linkage according to the risk of refrigerant leakage, and improve the leakage safety control capability of refrigeration equipment.

[0061] (7) The working electrode, counter electrode and reference electrode of the refrigerant sensor are led out to the outside to provide an electrical connection basis for normal refrigerant concentration detection and electrode maintenance, and to facilitate the cooperation between the electrochemical refrigerant sensor and the external detection circuit and maintenance circuit.

[0062] (8) The analog switch disconnects the reverse current source during normal monitoring and connects the reverse current source between the working electrode and the counter electrode during electrode maintenance, which can reduce the impact of the electrode maintenance circuit on normal concentration detection.

[0063] (9) The refrigerant monitoring and control method combines periodic wake-up, sensor power supply, concentration acquisition, threshold comparison, continuous monitoring, load linkage and power supply protection to form a complete low-power refrigerant monitoring and safety control process.

[0064] (10) Acquiring the refrigerant concentration after the refrigerant sensor has been powered on for a preset stable time can reduce the impact of the transient output of the refrigerant sensor at the initial power-on stage on the concentration judgment and improve the reliability of the periodic monitoring results.

[0065] (11) By setting a recovery threshold lower than the preset alarm threshold and combining it with the preset recovery time to determine whether to exit continuous monitoring, hysteresis control can be formed to reduce the frequent switching of monitoring status caused by the fluctuation of refrigerant concentration near the alarm threshold.

[0066] (12) Based on the preset alarm threshold and high-risk threshold, different levels of load linkage can be implemented, and the machine can be shut down, ventilated, valve closed and whole machine power cut-off control can be performed respectively when the refrigerant concentration reaches different risk levels.

[0067] (13) Hardware delay processing is performed on the overvoltage detection results to filter out voltage spikes with short durations and output an overvoltage fault flag signal when the power supply voltage continuously exceeds the threshold protection voltage.

[0068] (14) The controller performs software delay confirmation of the overvoltage fault flag signal and outputs the fuse trigger signal after confirming the continuous severe overvoltage, which can further reduce the situation of permanent fuse protection being falsely triggered.

[0069] (15) By applying a reverse microcurrent pulse between the working electrode and the counter electrode, the electrodes of the electrochemical refrigerant sensor can be maintained; after maintenance, the power supply is kept on and the sampling data is shielded within the preset electrode recovery time, which can reduce the impact of maintenance transients on the refrigerant concentration judgment.

[0070] (16) Applying the refrigerant monitoring and control circuit to refrigeration equipment can enable refrigerant concentration detection, low power supply, safety protection and controlled load linkage to participate in the operation of refrigeration equipment, which is conducive to improving the monitoring safety and operational reliability of energy-saving refrigeration and air conditioning equipment. Attached Figure Description

[0071] Figure 1 A schematic diagram of the circuit structure of the refrigerant monitoring and control circuit provided in an embodiment of the present invention; Figure 2 This is a flowchart illustrating the refrigerant monitoring and control method provided in an embodiment of the present invention.

[0072] Explanation of reference numerals in the attached figures: 1—Timer circuit; 2—Controller; 3—Refrigerant sensor; 4—Reverse current source; 5—Voltage Comparison Unit; VCC – Power supply; GND - Earth; MCU – Controller; F1—Fuse element; R1—Current limiting element; R2—Pull-up resistor; Rb—Basic limiting current resistance; Rg—Drive current limiting element; Q1—P-channel enhancement-mode MOSFET; Q2—NPN transistor; Q3—Controlled conduction element; Z1—Voltage clamping element; S1—Overvoltage fault indicator signal; S2—Load linkage control signal; S3—Manual maintenance trigger signal; S4—Threshold protection voltage; S5—Fuse trigger signal.

[0073] Figure 1 In the diagram, the s, g, and d terminals of Q1 represent the source, gate, and drain of the P-channel enhancement-mode MOSFET Q1, respectively; the c, b, and e terminals of Q2 represent the collector, base, and emitter of the NPN transistor Q2, respectively; and the a, k, and g terminals of Q3 represent the first conducting terminal, the second conducting terminal, and the controlled terminal of the controlled conducting element Q3, respectively. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0075] Where there is no conflict, the following embodiments and the technical features thereof can be combined with each other. For those skilled in the art, without departing from the concept of the present invention, the corresponding circuit parameters and control parameters can be adaptively set according to the actual refrigeration equipment, refrigerant type, and working requirements of the refrigerant sensor 3.

[0076] In this embodiment, "connection" can be a direct electrical connection or an indirect electrical connection formed through intermediate devices that implement corresponding signal transmission, power supply control, or load driving functions. Conventional drive, isolation, or interface circuits that do not change the signal meaning and control relationship will not be described in detail.

[0077] In this embodiment, the refrigerant concentration can be the concentration value directly output by the refrigerant sensor 3, or it can be the concentration value calculated by the controller 2 based on the electrical signal output by the refrigerant sensor 3. Preset alarm thresholds, high-risk thresholds, recovery thresholds, preset cycles, and various preset durations can all be pre-stored in the controller 2 and set according to the refrigerant type and the safety requirements of the refrigeration equipment.

[0078] In this embodiment, the controller 2 can be a microcontroller (MCU). Signal S1 is an overvoltage fault indicator signal, signal S2 is a load linkage control signal, and signal S3 is a manual maintenance trigger signal, used to trigger an electrode maintenance process through manual button or touch input, and control the reverse current source 4 to output a reverse microcurrent pulse in manual trigger mode; signal S4 corresponds to the threshold protection voltage, and signal S5 is a fuse trigger signal. Each signal undertakes a different detection or control function.

[0079] By distinguishing the above signals, we can avoid logical conflicts caused by refrigerant leakage linkage control and power supply fault fuse control sharing the same control signal. It is also beneficial to verify the working status of refrigerant monitoring path, load linkage path and power supply protection path separately.

[0080] Example 1 This embodiment provides a refrigerant monitoring and control circuit. (Refer to...) Figure 1 The refrigerant monitoring and control circuit includes a timer circuit 1, a controller 2, a power supply control circuit, a refrigerant sensor 3, a power supply protection circuit, and a load control circuit.

[0081] The output of timer circuit 1 is connected to controller 2 and is used to output a wake-up signal to controller 2 according to a preset period. The signal output of refrigerant sensor 3 is connected to controller 2 and is used to provide the controller 2 with a detection signal corresponding to the refrigerant concentration.

[0082] The input terminal of the load control circuit is connected to the controller 2 to receive the load linkage control signal S2 output by the controller 2, and to perform linkage control on the controlled load of the refrigeration equipment according to the load linkage control signal S2.

[0083] The power supply control circuit is located in the power supply loop between the power supply and the power supply terminal of the refrigerant sensor 3, and the controlled terminal of the power supply control circuit is connected to the controller 2. The controller 2 controls the power supply control circuit to turn on or off, enabling the refrigerant sensor 3 to be powered on when refrigerant concentration monitoring is required, and to stop power supply after the corresponding monitoring is completed.

[0084] The power supply protection circuit is connected to both the power supply circuit and the controller 2, and is used to implement current limiting protection, overvoltage clamping protection, and fuse protection for the power supply circuit of the refrigerant sensor 3. By configuring multiple protection methods on the power supply path of the refrigerant sensor 3, minor overcurrent, power supply overvoltage, and continuous severe faults can be dealt with respectively, reducing the possibility that power supply abnormalities will continue to affect the refrigerant sensor 3 when a single protection device fails.

[0085] The aforementioned connections create mutually supportive signal and power supply paths for the refrigerant monitoring and control circuit. Specifically, timer circuit 1 and refrigerant sensor 3 provide trigger or detection information to controller 2, which in turn outputs control information to the power supply control circuit, load control circuit, and power supply protection circuit, respectively.

[0086] By configuring concentration detection, sensor power supply, load linkage, and fault fuse on corresponding circuit paths, different control actions can have clear input criteria and execution targets. This facilitates unified coordination by controller 2 and also makes it easier to check the corresponding paths during circuit maintenance.

[0087] Under normal periodic monitoring conditions, timer circuit 1 outputs a wake-up signal according to a preset cycle. Controller 2 responds to the wake-up signal, enters the monitoring working state, and controls the power supply control circuit to turn on, so that the power supply can supply power to refrigerant sensor 3.

[0088] After being powered on, the refrigerant sensor 3 detects the refrigerant in the environment. Once the refrigerant sensor 3 meets the sampling conditions, the controller 2 acquires the refrigerant concentration and compares it with a preset alarm threshold.

[0089] When the refrigerant concentration falls below a preset alarm threshold, controller 2 shuts off the power supply control circuit after completing the current monitoring. Afterward, controller 2 and refrigerant sensor 3 can re-enter a state awaiting the next wake-up.

[0090] By employing the aforementioned method of periodic wake-up, on-demand power supply, and power-off upon completion of monitoring, it is unnecessary for the refrigerant sensor 3 to be continuously powered on. This reduces the ineffective power consumption of the refrigerant sensor 3 and its peripheral circuits when the refrigerant concentration is within a safe range, and also reduces the cumulative power-on time of the refrigerant sensor 3.

[0091] The power supply period for refrigerant sensor 3 is mainly concentrated within the time range required for power-on stabilization and effective sampling. During the periodic waiting phase, the operating current of refrigerant sensor 3 is no longer continuously consumed. Therefore, the monitoring function is still executed repeatedly according to the preset cycle, while the effective working duty time of refrigerant sensor 3 can be reduced accordingly.

[0092] Reducing the cumulative power-on time also helps to reduce the time that the refrigerant sensor 3 is in the working bias state for a long time, so that the low power consumption control not only affects the overall energy consumption of the machine, but also works in conjunction with the long-term use of the refrigerant sensor 3.

[0093] The timer circuit 1 can be a programmable timer. In one specific embodiment, the timer circuit 1 continues to perform low-power timing when the controller 2 and the refrigerant sensor 3 are in a non-monitoring state, and sends a wake-up signal to the controller 2 when a preset period is reached.

[0094] Timer circuit 1 can independently complete the periodic timing, so controller 2 does not need to maintain high-frequency operation to perform software timing. This setting helps to further reduce the power consumption during the periodic waiting phase and makes the wake-up time independent of whether the refrigerant sensor 3 is powered on.

[0095] The periodic triggering provided by timer circuit 1 also allows each monitoring process to have a relatively clear start time. Each time controller 2 receives a wake-up signal, it executes power supply, waiting, sampling, and judgment in a predetermined order, which helps to maintain control consistency between different monitoring cycles.

[0096] The preset cycle can be set according to the monitoring response requirements of the refrigeration equipment. For example, timer circuit 1 can output a wake-up signal at intervals of approximately 30 seconds, or it can be set to other time intervals that can meet the requirements of refrigerant leakage monitoring, depending on the actual usage scenario.

[0097] The preset period is used to determine the start time between adjacent monitoring processes, while the stabilization time of the refrigerant sensor 3 after each power-on is used to determine the effective sampling time in this monitoring process. By setting the preset period and preset stabilization time respectively, the power consumption during the waiting phase can be reduced, and the detection results can be avoided when the refrigerant sensor 3 has not yet met the effective sampling conditions.

[0098] In this embodiment, the refrigerant sensor 3 can be an electrochemical sensor. When the electrochemical sensor is powered on again after a power outage, the electrodes need to undergo a polarization process. Therefore, after the power supply control circuit is turned on, the controller 2 maintains the refrigerant sensor 3 powered on for a preset stable time before acquiring the refrigerant concentration.

[0099] In one specific implementation, the preset stabilization time can be set to 30 to 45 seconds. The controller 2 can use the end of the preset stabilization time as a sampling condition that allows reading the refrigerant concentration, without having to rely solely on the ambiguous "sensor stabilization" as the control basis.

[0100] In other words, this embodiment uses the completion of a pre-set stabilization time as the criterion for allowing sampling. After the preset stabilization period ends, the controller 2 reads the detection signal used to determine the refrigerant concentration according to the predetermined sampling rules, so that the monitoring sequence has a clear time basis, which facilitates the execution of the control program and on-site debugging.

[0101] By using time-based conditions to define the sampling start point, controller 2 does not need to separately set up an unclear state identification process after each power-on. Refrigerant sensors 3 of the same model can perform sampling according to the same preset stabilization duration, thereby improving the repeatability of the periodic monitoring process.

[0102] When the refrigerant concentration detected by controller 2 reaches or exceeds the preset alarm threshold, controller 2 determines that there is an abnormal refrigerant leak in the current environment. At this time, controller 2 will not shut off the power supply control circuit after the monitoring is completed, but will instead keep the power supply control circuit on, so that refrigerant sensor 3 enters continuous monitoring mode.

[0103] In continuous monitoring mode, controller 2 can continuously acquire refrigerant concentration to track whether the refrigerant concentration continues to rise or gradually decreases. Compared to immediately disconnecting the power supply to refrigerant sensor 3 after detecting excessive concentration, this setting can retain concentration change information after the leakage anomaly occurs, providing continuous detection basis for load linkage and recovery judgment.

[0104] Periodic monitoring and continuous monitoring correspond to normal and abnormal leakage environments, respectively. By switching between these two states based on refrigerant concentration, power consumption can be reduced under normal conditions, while ensuring continuous acquisition of concentration changes is prioritized under abnormal conditions.

[0105] Therefore, low-power control does not shorten the power-on time of refrigerant sensor 3 in all cases, but rather dynamically selects the power supply method based on the refrigerant concentration judgment result. This control logic can prevent the low-power target from weakening the continuous monitoring capability after a leakage anomaly occurs.

[0106] When the controller 2 determines that the refrigerant concentration has reached or exceeded the preset alarm threshold, it also outputs a load linkage control signal S2 through the load control circuit. The continuous monitoring of the refrigerant sensor 3 and the load linkage of the refrigeration equipment are triggered by the same refrigerant concentration judgment result, thus forming a closed loop from concentration detection, anomaly judgment to safety control.

[0107] The power supply control circuit includes a P-channel enhancement-mode MOSFET Q1, an NPN transistor Q2, a base current-limiting resistor Rb, and a pull-up resistor R2. The P-channel enhancement-mode MOSFET Q1 is located at the high end of the power supply circuit and is used to control the forward power supply path of the refrigerant sensor 3.

[0108] The source of the P-channel enhancement-mode MOSFET Q1 is connected to the power supply side of the power supply circuit, the drain is connected to the power supply terminal of the refrigerant sensor 3, and the gate is connected to the collector of the NPN transistor Q2. The emitter of the NPN transistor Q2 is grounded, and the base is connected to the power supply control output terminal of the controller 2 through the base current limiting resistor Rb.

[0109] Pull-up resistor R2 is connected between the source and gate of P-channel enhancement-mode MOSFET Q1. Therefore, when NPN transistor Q2 is not turned on, pull-up resistor R2 pulls the gate potential of P-channel enhancement-mode MOSFET Q1 up to near its source potential, keeping P-channel enhancement-mode MOSFET Q1 off.

[0110] When controller 2 needs to power on refrigerant sensor 3, the power supply control output terminal of controller 2 outputs a high level. This high level acts on the base of NPN transistor Q2 through the base current limiting resistor Rb, causing NPN transistor Q2 to conduct.

[0111] After the NPN transistor Q2 is turned on, its collector potential is pulled down, which in turn lowers the gate potential of the P-channel enhancement-mode MOSFET Q1. The source potential of the P-channel enhancement-mode MOSFET Q1 is higher than its gate potential, and its gate-source voltage meets the turn-on condition. The power supply then supplies power to the refrigerant sensor 3 through the P-channel enhancement-mode MOSFET Q1.

[0112] When controller 2 needs to stop supplying power to refrigerant sensor 3, controller 2 stops providing the control level to turn on the base of NPN transistor Q2. After NPN transistor Q2 is turned off, pull-up resistor R2 pulls the gate of P-channel enhancement-mode MOSFET Q1 back up to the source potential, turning off P-channel enhancement-mode MOSFET Q1.

[0113] Therefore, the default state of the P-channel enhancement-type MOSFET Q1 is determined by the pull-up resistor R2 to be the off state, while the on state requires the controller 2, the base current limiting resistor Rb, and the NPN transistor Q2 to form an effective drive. This setting allows the "stop output control level" to correspond to the refrigerant sensor 3 being de-energized.

[0114] Even if controller 2 has not completed port initialization when the cooling device is first powered on, as long as NPN transistor Q2 is not effectively driven, pull-up resistor R2 can still keep P-channel enhancement-mode MOSFET Q1 off. This reduces the possibility of unexpected power supply actions during the initialization phase.

[0115] Using an NPN transistor Q2 to convert the output level of controller 2 can accommodate situations where there is a voltage difference between the I / O port voltage of controller 2 and the supply voltage of refrigerant sensor 3. This driving method allows controller 2 to reliably control the high-side P-channel enhancement-mode MOSFET Q1 with its own logic level without directly bearing the voltage from the supply side of refrigerant sensor 3.

[0116] Placing the P-channel enhancement-mode MOSFET Q1 in the forward power supply path of the refrigerant sensor 3 also ensures that the grounding path of the refrigerant sensor 3 is not interrupted during power supply control. This helps maintain the consistency of the signal reference potential between the refrigerant sensor 3 and the controller 2, reducing the impact on the detection signal or communication level caused by switching the grounding path.

[0117] The separation of the forward power supply path from the ground reference path ensures that power supply control primarily alters whether the refrigerant sensor 3 receives operating power, without additionally changing the ground potential referenced by the detection signal. This connection method facilitates clear coordination between power supply control actions and signal acquisition actions.

[0118] Pull-up resistor R2 is also used to reliably cut off the P-channel enhancement-mode MOSFET Q1 when the controller 2 has not yet completed initialization, the output of the controller 2 is in a high-impedance state, or the NPN transistor Q2 is turned off. This can reduce the possibility of the refrigerant sensor 3 being mistakenly powered on or repeatedly powered on when the refrigeration equipment is powered on.

[0119] The base current limiting resistor Rb is used to limit the current flowing into the base of the NPN transistor Q2. By setting the base current limiting resistor Rb, the current to the I / O port of controller 2 and the base of the NPN transistor Q2 can be limited while ensuring reliable conduction of the NPN transistor Q2.

[0120] For example, the P-channel enhancement-mode MOSFET Q1 can be an AO3401 or SI2301, and the NPN transistor Q2 can be an MMBT3904 or S8050. The base current limiting resistor Rb can be approximately 4.7kΩ, and the pull-up resistor R2 can be selected in the range of 10kΩ to 100kΩ.

[0121] The device models and resistance values ​​described above are only for illustrating one feasible circuit configuration and do not constitute a limitation of the present invention. In practical applications, devices with corresponding electrical parameters can be selected based on the power supply voltage, the operating current of the refrigerant sensor 3, and the output capability of the controller 2.

[0122] When selecting components, the main principles are to maintain the high-side on / off function of the P-channel enhancement-mode MOSFET Q1, the level shifting function of the NPN transistor Q2, the driving current-limiting function of the base current-limiting resistor Rb, and the default shutdown function of the pull-up resistor R2. This allows for adaptation to different power supply conditions without changing the power supply control logic.

[0123] The power supply protection circuit includes a fuse F1, a current limiting element R1, and a voltage clamping element Z1. Along the power supply direction of the power supply circuit, the fuse F1, the current limiting element R1, the power supply control circuit, and the refrigerant sensor 3 are connected in sequence.

[0124] The voltage clamping element Z1 is connected between the power supply terminal of the refrigerant sensor 3 and ground. This connection allows the voltage clamping element Z1 to directly limit the voltage at the power supply terminal of the refrigerant sensor 3, reducing the direct impact of excessively high voltage caused by power supply surges or power supply faults on the refrigerant sensor 3.

[0125] The current-limiting element R1 is positioned between the fuse F1 and the power supply control circuit to increase the equivalent impedance and limit the current flowing to the refrigerant sensor 3 when an overcurrent occurs in the power supply circuit. The current-limiting element R1 can be a self-recovering current-limiting element with a positive temperature coefficient.

[0126] In one specific embodiment, the current limiting element R1 is a PTC self-resetting protection device. When the refrigerant sensor 3 is working normally, the current limiting element R1 maintains a low resistance value, which does not affect the normal power supply to the refrigerant sensor 3; when the current flowing through the power supply circuit increases abnormally, the temperature of the current limiting element R1 rises and its resistance increases, thereby limiting the abnormal current.

[0127] Current limiting protection can limit the current before the abnormal current reaches a level that requires permanent disconnection of the power supply circuit. For minor overcurrents that can recover as the abnormality disappears, the current limiting element R1 can reduce unnecessary permanent blowouts and provide recoverable protection for the refrigerant sensor 3 and its power supply components.

[0128] The voltage clamping element Z1 can be a Zener diode. When the voltage at the power supply terminal of the refrigerant sensor 3 exceeds the clamping voltage of the voltage clamping element Z1, the voltage clamping element Z1 is turned on, limiting the voltage at the power supply terminal of the refrigerant sensor 3 within a set range.

[0129] The current generated when the voltage clamping element Z1 is turned on can also be limited by the current limiting element R1. Through the cooperation of the voltage clamping element Z1 and the current limiting element R1, abnormal voltage and abnormal current generated by the clamping path can be suppressed simultaneously, reducing the situation where overvoltage energy continues to act on the refrigerant sensor 3.

[0130] Fuse F1 is used to physically disconnect the power supply circuit in the event of a persistent severe fault. Unlike the recoverable on / off control of the power supply control circuit, fuse F1 creates irreversible electrical isolation after it blows. It must be replaced after the fault has been cleared and maintenance completed before it can be put back into service.

[0131] The aforementioned current limiting, clamping, and fuse protections provide protection against different degrees of abnormality. The current limiting element R1 is used to limit overcurrent, the voltage clamping element Z1 is used to limit the voltage at the power supply terminal, and the fuse element F1 is used to ultimately cut off the power supply path under continuous severe faults, thereby improving the redundancy of power supply protection.

[0132] The current-limiting element R1 and the voltage clamping element Z1 primarily limit abnormal current or voltage while the power supply circuit remains connected, while the fuse element F1 disconnects the power supply connection after a serious fault is confirmed. The protection result of these three elements is jointly determined by the nature and duration of the abnormal quantity.

[0133] This configuration retains the ability to handle minor anomalies while providing irreversible isolation for persistent severe anomalies. Therefore, it eliminates the need to immediately replace fuse F1 when any short-term fluctuations occur, and avoids relying solely on recoverable current limiting when a severe fault persists.

[0134] In one specific parameter configuration, the normal supply voltage of the refrigerant sensor 3 is 5.0V ± 0.25V, the normal operating current is no greater than 50mA, and the absolute maximum withstand voltage is no greater than 6.0V. The device parameters of the power supply protection circuit can be set around the above-mentioned safe power supply range.

[0135] The holding current of the current limiting element R1 can be set to approximately 60mA, and its operating current can be set to approximately 100mA. When the current reaches the range of 80mA to 100mA, the resistance of the current limiting element R1 increases with the temperature rise to limit the current in the power supply circuit to below 150mA.

[0136] By making the holding current of the current-limiting element R1 slightly higher than the normal operating current of the refrigerant sensor 3, the possibility of the current-limiting element R1 malfunctioning due to fluctuations in the normal operating current can be reduced. At the same time, the operating current is lower than the abnormal current level that may cause continuous damage to the refrigerant sensor 3, thus leaving an operating range for overcurrent protection.

[0137] This parameter relationship allows the current-limiting element R1 to maintain its power supply capability within the normal operating range and enhances its limiting effect within the abnormal current range. Therefore, there is a distinguishable current boundary between normal power supply and abnormal protection.

[0138] The clamping voltage of the voltage clamping element Z1 can be selected as 5.6V, and the rated power can be selected as 0.5W. This clamping voltage is higher than the normal power supply limit of the refrigerant sensor 3 and lower than the absolute maximum withstand voltage of the refrigerant sensor 3, so as to form a protection margin between normal power supply and abnormal overvoltage.

[0139] By setting the clamping voltage outside the normal power supply range, the frequent conduction of the voltage clamping element Z1 under normal power supply fluctuations can be reduced. By keeping the clamping voltage below the maximum withstand voltage of the refrigerant sensor 3, voltage limiting can be achieved before the supply voltage reaches a level that could damage the refrigerant sensor 3.

[0140] The rated current of the fuse element F1 can be selected as 150mA. This rated current is higher than the normal operating current of the refrigerant sensor 3 and can serve as the final fuse current limit in the event of a sustained severe short circuit.

[0141] The above values ​​illustrate the correspondence between the power supply protection parameters and the safe power supply range of the refrigerant sensor 3. For refrigerant sensors 3 with different power supply voltages or operating currents, the current limiting element R1, voltage clamping element Z1, and fuse element F1 can be selected accordingly according to the same parameter matching principle.

[0142] Therefore, the parameters of each protection device are not set in isolation, but are jointly determined based on the normal power supply range, allowable tolerance range, and final fuse requirements of the refrigerant sensor 3. This parameter coordination helps to reduce conflicts between protection zones or situations where the normal operating range is too narrow.

[0143] The power supply protection circuit also includes an overvoltage detection circuit. The overvoltage detection circuit includes a voltage sampling unit, a threshold providing unit, a voltage comparison unit, and a delay unit.

[0144] The voltage sampling unit is connected to the power supply terminal of the refrigerant sensor 3 and is used to acquire the actual power supply voltage of the refrigerant sensor 3. The threshold providing unit is used to provide a threshold protection voltage S4 corresponding to the allowable power supply voltage.

[0145] The voltage sampling unit and the threshold providing unit are respectively connected to the voltage comparison unit 5. The voltage comparison unit 5 is used to compare the sampling voltage corresponding to the power supply voltage of the refrigerant sensor 3 with the reference voltage corresponding to the threshold protection voltage S4, and output the overvoltage detection result.

[0146] The overvoltage detection targets the actual voltage applied to the power supply terminal of refrigerant sensor 3, rather than just detecting the nominal output of the power supply. This allows the impact of the power supply control circuit and power line on the actual power supply status to be reflected in the overvoltage detection results.

[0147] In one specific embodiment, the voltage sampling unit includes a voltage divider network composed of resistors R3 and R4. The non-inverting input terminal of the voltage comparison unit 5 is connected to the sampling voltage formed by the voltage divider of the refrigerant sensor 3 power supply voltage through resistors R3 and R4, and the inverting input terminal is connected to the threshold protection voltage S4.

[0148] The threshold providing unit may include a TL431 reference voltage source and a corresponding resistor divider network to generate a hardware-fixed reference voltage. The threshold protection voltage S4 may correspond to a protection threshold of approximately 5.5V at the power supply terminal of the refrigerant sensor 3.

[0149] By employing a hardware reference source to provide the threshold protection voltage S4, overvoltage comparison can be made independent of the controller 2 generating a reference voltage in real time via software or a digital-to-analog converter port. Even if the controller 2's program malfunctions, the overvoltage detection circuit can still detect the supply voltage of the refrigerant sensor 3 based on the hardware reference.

[0150] Therefore, the comparison benchmark for overvoltage detection is separated from the software operating state of controller 2. Controller 2 is mainly responsible for receiving the overvoltage fault flag signal S1 and performing subsequent confirmation, while whether the voltage exceeds the threshold protection voltage S4 is first determined by the hardware comparison relationship.

[0151] The delay unit is connected between the voltage comparison unit 5 and the controller 2, and is used to delay the overvoltage detection result output by the voltage comparison unit 5. The delay unit may include an RC delay circuit composed of resistor R5 and capacitor C1.

[0152] In one specific implementation, the time constant of the RC delay circuit is approximately 100 milliseconds. The overvoltage detection circuit only outputs a valid overvoltage fault flag signal S1 when the overvoltage detection result continues to reach the corresponding hardware delay duration.

[0153] Hardware delay can filter out instantaneous spikes and short-duration interference signals generated when the power supply is powered on, reducing the possibility of false triggering of fuse protection due to short-term voltage fluctuations. For persistent real overvoltages, the delay unit retains the corresponding overvoltage fault flag after the delay period ends.

[0154] The output of the overvoltage detection circuit is connected to the overvoltage detection input of controller 2. The S1 signal used by the output of the overvoltage detection circuit and the input of controller 2 is the same signal network, and S1 represents the overvoltage fault flag signal output from the overvoltage detection circuit to controller 2.

[0155] After receiving a valid overvoltage fault flag signal S1, controller 2 can perform a software delay confirmation. In one specific embodiment, controller 2 continuously times the overvoltage fault flag signal S1 for 200 milliseconds. Only when S1 continues to reach the software confirmation duration is an irreversible serious fault determined to exist in the power supply circuit.

[0156] Hardware delay and software confirmation are performed sequentially. Overvoltage interference lasting less than approximately 100 milliseconds is filtered out by the hardware delay unit; overvoltage lasting longer than the hardware delay duration makes S1 valid, and controller 2 then performs software confirmation of the valid S1 for approximately 200 milliseconds.

[0157] By combining hardware delay and software verification, both transient interference can be suppressed and sustained overvoltage can be reliably identified. This combination also ensures that the final fuse trip requires independent hardware detection and software verification, reducing the possibility of a single transient signal directly triggering a permanent fuse trip.

[0158] The hardware delay occurs before the overvoltage fault flag signal S1 is generated, while the software confirmation occurs after controller 2 receives S1; the two are sequentially linked. This hierarchical confirmation method ensures that each stage has clearly defined inputs and outputs, facilitating the verification of hardware filtering and software judgment based on actual power supply interference conditions.

[0159] Meanwhile, the hardware delay does not depend on the execution of controller 2, while software verification can be performed in conjunction with the fault handling procedure of controller 2. These two verification methods complement each other, which helps improve the reliability of continuous overvoltage detection.

[0160] The power supply protection circuit also includes a controlled conducting element Q3 and a driving current limiting element Rg. The controlled conducting element Q3 can be a thyristor, and the driving current limiting element Rg can be a resistor connected in series between the controller 2 and the controlled terminal of the controlled conducting element Q3.

[0161] The first conducting terminal of the controlled conducting element Q3 is connected to the node between the fuse element F1 and the current limiting element R1, the second conducting terminal is grounded, and the controlled terminal is connected to the fuse trigger output terminal of the controller 2 through the driving current limiting element Rg. When a thyristor is used, the first conducting terminal is the anode, the second conducting terminal is the cathode, and the controlled terminal is the gate.

[0162] It should be noted that the connection point between the controlled conducting element Q3 and the power supply circuit is located after the fuse element F1 and before the current limiting element R1. This connection position allows the fuse current path formed after the controlled conducting element Q3 is turned on to bypass the current limiting element R1.

[0163] When controller 2 confirms that the overvoltage fault flag signal S1 has been continuously for the software confirmation duration, controller 2 outputs a fuse trigger signal S5 through the fuse trigger output terminal. The fuse trigger signal S5 is driven by the current limiting element Rg and applied to the controlled terminal of the controlled conducting element Q3, causing the controlled conducting element Q3 to conduct.

[0164] In one specific implementation, the fuse trigger signal S5 can be a high-level pulse of 3.3V or 5V, with a pulse width of 100 milliseconds to 200 milliseconds. The resistance value of the driving current limiting element Rg can be selected in the range of 100Ω to 1kΩ to limit the drive current flowing into the gate of the controlled conducting element Q3.

[0165] The current path after the controlled conducting element Q3 is turned on is as follows: the power supply flows into the controlled conducting element Q3 through the fuse element F1, and then flows to ground through the controlled conducting element Q3. Since the controlled conducting element Q3 is connected between the fuse element F1 and the current limiting element R1, the current does not pass through the current limiting element R1.

[0166] This current-breaking path ensures that the current-limiting element R1 does not restrict the current used to fuse element F1. The current flowing through fuse element F1 quickly exceeds its rated current, causing fuse element F1 to physically melt and disconnecting the power supply circuit to the refrigerant sensor 3.

[0167] Normal power supply current reaches refrigerant sensor 3 through fuse element F1 and current limiting element R1, while the fuse trigger current flows directly to ground through fuse element F1 and controlled conducting element Q3. By distinguishing the two current paths, current limiting element R1 can normally perform the current limiting function of sensor power supply, without hindering the final fuse trip.

[0168] The controlled-conduction element Q3 is connected to the fuse current path only when the controller 2 outputs the fuse trigger signal S5, and remains non-conductive during normal monitoring. Therefore, the controlled-conduction branch will not shunt the power supply current of the refrigerant sensor 3 under normal circumstances.

[0169] By using the controlled conducting element Q3 to actively form a fuse branch, the power supply can be cut off after the controller 2 confirms a severe overvoltage. It can also form a final physical isolation by using the fuse element F1 when the power supply control circuit itself breaks down and cannot be shut off by normal control.

[0170] After fuse F1 blows, the power supply circuit for refrigerant sensor 3 remains disconnected until maintenance personnel troubleshoot and replace fuse F1. This irreversible disconnection method helps prevent serious power supply failures from affecting refrigerant sensor 3 again after repeated restarts of the refrigeration equipment.

[0171] Maintaining the disconnected state after the fuse blows also provides maintenance personnel with a clear fault handling point. The refrigerant sensor 3 will only regain power supply after the cause of the power supply abnormality has been investigated and the blown component F1 has been replaced, thus avoiding repeated restoration of operation without maintenance.

[0172] Signal S5 is used only to trigger the controlled conductive element Q3, and signal S2 is used only for load linkage control in the event of refrigerant leakage. Setting them as different control outputs can prevent the fuse pulse from being mistakenly sent to the load control circuit, and can also prevent the load linkage signal from accidentally triggering the fuse branch.

[0173] Therefore, although both the refrigerant leakage abnormality and the sensor power supply abnormality are processed by the controller 2, they form different fault response paths respectively. The refrigerant leakage abnormality mainly changes the operating state of the controlled load, while the power supply abnormality mainly cuts off the fault power supply path of the refrigerant sensor 3.

[0174] The load control circuit has a plurality of control output terminals, which are respectively connected to the compressor, the indoor fan, the outdoor fan, the electronic expansion valve and the main power contactor of the whole unit. The load control circuit can provide corresponding drive control to different controlled loads according to the load linkage control signal S2 output by the controller 2.

[0175] When the refrigerant concentration reaches or exceeds the preset alarm threshold, the controller 2 outputs the load linkage control signal S2. The load control circuit controls the compressor to stop according to the load linkage control signal S2, controls the indoor fan and the outdoor fan to operate at high speed, and controls the electronic expansion valve to close.

[0176] Controlling the compressor to stop and the electronic expansion valve to close can reduce the continuous operation of the refrigeration system under the abnormal state of refrigerant leakage. Controlling the indoor fan and the outdoor fan to operate at high speed can enhance air flow to dilute and diffuse the refrigerant in the leakage area, and reduce the risk of continuous accumulation of local refrigerant concentration.

[0177] When the refrigerant concentration further reaches or exceeds the high-risk threshold, the controller 2 controls the main power contactor of the whole unit to disconnect through the load control circuit. The high-risk threshold is higher than the preset alarm threshold, so that graded linkage control can be implemented according to the risk level corresponding to the refrigerant concentration.

[0178] The graded linkage makes different concentration intervals correspond to different control intensities. The preset alarm threshold is used to trigger the linkage of the compressor, the fans and the electronic expansion valve, and the high-risk threshold is used to trigger the disconnection of the main power contactor of the whole unit, so as to avoid applying exactly the same control result to all abnormal concentrations.

[0179] When the refrigerant concentration reaches the preset alarm threshold but has not yet reached the high-risk threshold, the ventilation operation of the fans can be maintained, so as to use the existing loads of the refrigeration equipment for dilution. Disconnecting the main power contactor of the whole unit after the refrigerant concentration reaches the high-risk threshold can further isolate the electrical loads of the whole unit under a higher risk state.

[0180] In the continuous monitoring state, the controller 2 continuously acquires the refrigerant concentration. When the refrigerant concentration is continuously lower than the recovery threshold for a preset recovery duration, the controller 2 determines that the refrigerant leakage abnormality has been eliminated, and exits the continuous monitoring state.

[0181] The recovery threshold is lower than the preset alarm threshold to create a hysteresis between the alarm entry condition and the alarm exit condition. In one specific embodiment, the recovery threshold can be set to 90% of the preset alarm threshold, and the preset recovery duration can be set to 60 seconds.

[0182] Setting a recovery threshold and preset recovery time can prevent frequent switching between the power supply state and load control state of refrigerant sensor 3 when the refrigerant concentration fluctuates around the preset alarm threshold. Controller 2 only resumes periodic monitoring when the refrigerant concentration remains at a low level for a certain period, thereby improving the stability of control state transitions.

[0183] The recovery decision includes both concentration and duration conditions; continuous monitoring is not immediately terminated if only one condition is met. This dual-condition decision reduces the likelihood of a single instantaneous low-concentration sample directly altering the monitoring status.

[0184] After controller 2 exits continuous monitoring, it controls the power supply control circuit to shut down once the current monitoring is completed and the recovery conditions are met. Subsequently, timer circuit 1 wakes up controller 2 and refrigerant sensor 3 again according to a preset cycle, restoring the system to a low-power cycle of "timed wake-up—concentration detection—safety judgment—power off after monitoring."

[0185] The refrigerant sensor 3 can be a three-electrode electrochemical sensor with a working electrode WE, a counter electrode CE, and a reference electrode RE. The working electrode WE, the counter electrode CE, and the reference electrode RE are all led out to the outside of the refrigerant sensor 3 for connection with the detection circuit and the electrode maintenance circuit.

[0186] The refrigerant sensor 3 can determine the refrigerant concentration based on the microcurrent signal generated by the redox reaction of the refrigerant on the electrode surface. The specific detection target, detection range, and output characteristics can be determined according to the technical parameters of the selected three-electrode electrochemical sensor.

[0187] For example, a suitable three-electrode electrochemical sensor can be selected based on the refrigerant to be detected, the detection range, the external electrode connection method, and the application requirements of the refrigeration equipment. The selected refrigerant sensor 3 should have an externally connectable working electrode WE, a counter electrode CE, and a reference electrode RE, and should be compatible with the detection circuit and electrode maintenance circuit of this embodiment.

[0188] In one optional detection circuit, during normal detection, a constant potential bias circuit is connected between the working electrode WE and the reference electrode RE, and a micro-current amplification and sampling circuit is connected between the working electrode WE and the counter electrode CE. The micro-current amplification and sampling circuit amplifies and samples the micro-current generated by the electrode reaction and provides the corresponding detection signal to the controller 2.

[0189] The above-described normal detection circuit is only used to illustrate one external connection method for the three-electrode electrochemical sensor. In actual implementation, the corresponding constant potential and sampling circuit can be configured according to the interface requirements of the selected refrigerant sensor 3, as long as the refrigerant concentration can be obtained under normal monitoring conditions and the reverse current source 4 is connected between the working electrode WE and the counter electrode CE under maintenance conditions.

[0190] Three electrodes are led out to the outside of the refrigerant sensor 3, allowing the normal detection circuit and the electrode maintenance circuit to be connected to the corresponding electrodes without altering the internal physical structure of the refrigerant sensor 3. This provides an external electrical connection basis for the implementation of the electrode maintenance function.

[0191] The refrigerant monitoring and control circuit may also include an electrode maintenance circuit. The electrode maintenance circuit includes a reverse current source 4 and an analog switch, the controlled terminal of which is connected to the controller 2.

[0192] An analog switch is positioned between the reverse current source 4 and the working electrode WE and the counter electrode CE, used to switch between the normal monitoring path and the electrode maintenance path according to the control of the controller 2. The reverse current source 4 is not directly connected to the power supply terminal of the refrigerant sensor 3, but is used to apply maintenance current to the electrodes of the refrigerant sensor 3.

[0193] During refrigerant concentration monitoring, the analog switch disconnects the reverse current source 4 from the working electrode WE and the counter electrode CE, preventing the reverse current source 4 from participating in normal concentration detection. This disconnection reduces the impact of the maintenance circuit on normal electrode bias and micro-current sampling.

[0194] Normal monitoring and electrode maintenance states are isolated by an analog switch, ensuring that the reverse current source 4 is connected to the electrode only during maintenance. This allows for both detection and maintenance functions to be configured on the same refrigerant sensor 3, while maintaining clear distinction between the operating periods of the two functions.

[0195] When electrode maintenance is required, controller 2 first pauses the acquisition of refrigerant concentration, and then controls the analog switch to connect the reverse current source 4 between the working electrode WE and the counter electrode CE. The positive terminal of the reverse current source 4 is connected to the counter electrode CE, and the negative terminal is connected to the working electrode WE, so as to form a reverse micro-current pulse relative to the normal detection state.

[0196] After prolonged use, contaminants or impurity ions may adsorb onto the electrode surface of the refrigerant sensor 3, affecting electrode response and detection accuracy. Applying a short-duration reverse microcurrent pulse can promote the detachment of impurity ions adsorbed on the electrode surface, thereby maintaining the electrode.

[0197] Because the reverse microcurrent pulse acts directly between the working electrode WE and the counter electrode CE, rather than on the power supply terminal of the refrigerant sensor 3, electrode maintenance can be completed without changing the overall power supply voltage of the refrigerant sensor 3. Using microcurrent and short pulses also reduces the possibility of over-stimulating the electrodes during maintenance.

[0198] In one specific implementation, the amplitude of the reverse microcurrent pulse is 1 μA to 5 μA, and the width of a single pulse is 50 milliseconds. Each maintenance trigger can continuously output 3 to 5 reverse microcurrent pulses, with an interval of 100 milliseconds between adjacent pulses.

[0199] The pulse amplitude, pulse width, number of pulses, and pulse interval mentioned above collectively determine the amount of reverse stimulation applied to the electrodes during a single maintenance procedure. By using multiple short pulses spaced apart from each other, the electrodes can receive intermittent reverse stimulation, avoiding the application of reverse current continuously for extended periods.

[0200] In contrast to a continuous application of reverse current, multiple short pulses are spaced apart by a time interval. This pulse configuration allows for a clear and repeatable output rhythm during a single maintenance process while meeting the requirements for reverse electrode maintenance.

[0201] Electrode maintenance can be triggered by the manual maintenance trigger signal S3. On-site maintenance personnel generate the manual maintenance trigger signal S3 by pressing a button or touching a screen. The manual maintenance trigger signal S3 is used to control the reverse current source 4 and trigger an electrode maintenance process.

[0202] The manual triggering method allows maintenance personnel to proactively perform maintenance when they deem it necessary, such as during equipment inspection, sensor calibration, or electrode maintenance. The reverse current source 4 responds to the manual maintenance trigger signal S3 by outputting a reverse micro-current pulse according to preset pulse parameters. The controller 2 then coordinates to pause sampling, switch analog circuits, and resume timing, reducing operational differences that occur when directly applying current to the sensor electrodes manually.

[0203] Electrode maintenance can also be automatically triggered by controller 2 based on the cumulative power-on time of refrigerant sensor 3. Controller 2 records the power-on time of refrigerant sensor 3 in each periodic monitoring and continuous monitoring, and accumulates the corresponding power-on time.

[0204] In one specific implementation, when the cumulative power-on time of the refrigerant sensor 3 reaches 168 hours, the controller 2 automatically triggers an electrode maintenance cycle. Timing maintenance based on cumulative power-on time rather than natural time ensures that the maintenance trigger condition corresponds to the actual usage level of the refrigerant sensor 3.

[0205] Manual triggering and cumulative power-on duration triggering can respectively meet the needs of on-site active maintenance and controller 2 periodic maintenance. The two triggering methods share the same pulse output and recovery process, which can avoid different electrode maintenance results due to different triggering sources.

[0206] Regardless of whether manual or automatic triggering is used, controller 2 suspends refrigerant concentration sampling during the application of a reverse microcurrent pulse. This avoids misinterpreting the transient electrode response caused by the maintenance pulse as a change in the ambient refrigerant concentration.

[0207] After the reverse micro-current pulse output is completed, controller 2 controls the analog switch to disconnect the reverse current source 4 while maintaining power supply to the refrigerant sensor 3. The refrigerant sensor 3 then enters the electrode recovery process after the reverse current source 4 is disconnected.

[0208] In one specific implementation, the controller 2 is set with a preset electrode recovery time of 2 to 3 minutes. During the preset electrode recovery time, the controller 2 blocks the sampling data from the refrigerant sensor 3 and does not use the sampling data during this period to determine refrigerant leakage.

[0209] The preset electrode recovery time here is a defined time condition. After the preset electrode recovery time ends, controller 2 removes the shielding of the sampling data and reacquires the refrigerant concentration without needing to separately determine the sensor recovery status at the boundary where quantization is not performed.

[0210] Using a preset electrode recovery time also allows the data shielding phase to have a defined start and end time. Controller 2 can directly start the recovery timing based on the end time of the maintenance pulse, and automatically resume the use of the sampled data after the timing is completed.

[0211] By maintaining power to the refrigerant sensor 3 after maintenance, the electrodes can re-establish the polarization state required for detection under predetermined operating conditions. By shielding the sampling data during the preset electrode recovery time, the transient impact of the maintenance pulse on the refrigerant concentration determination process can be reduced.

[0212] After re-acquiring the refrigerant concentration, controller 2 continues to perform normal judgment according to the preset alarm threshold. When the re-acquiring refrigerant concentration is lower than the preset alarm threshold, controller 2 can continue to perform periodic monitoring; when the re-acquiring refrigerant concentration reaches or exceeds the preset alarm threshold, controller 2 enters continuous monitoring mode and performs load linkage control.

[0213] Therefore, the electrode maintenance process does not cancel the safety assessment of refrigerant leak monitoring. After maintenance, the sampling data is reintegrated into the original concentration assessment process after a specified shielding period, thus creating a seamless control process between the electrode maintenance function and the refrigerant monitoring function.

[0214] In this embodiment, the refrigerant monitoring and control circuit, under normal conditions, uses timer circuit 1, controller 2 and power supply control circuit to achieve periodic power-on monitoring of refrigerant sensor 3; when the refrigerant concentration exceeds the standard, continuous monitoring and load linkage are achieved through continuous power supply and load control circuit.

[0215] Meanwhile, the power supply protection circuit, through current limiting element R1, voltage clamping element Z1, overvoltage detection circuit, fuse element F1, and controlled conduction element Q3, provides protection for the power supply circuit of refrigerant sensor 3 from recoverable limitation to irreversible disconnection. The electrode maintenance circuit maintains the electrodes of refrigerant sensor 3 through reverse micro-current pulses.

[0216] The aforementioned components address the control of refrigerant sensor 3 in three aspects: operating power consumption, abnormal power supply, and long-term use. These components are coordinated by controller 2, enabling refrigerant concentration monitoring, equipment load linkage, power supply safety protection, and sensor electrode maintenance to be implemented collaboratively within the same control circuit.

[0217] Among them, the timer circuit 1 and the power supply control circuit solve the problem of when to make the refrigerant sensor 3 work, the refrigerant sensor 3 and the load control circuit solve the problem of how to monitor and link according to the concentration results, and the power supply protection circuit and the electrode maintenance circuit respectively handle abnormal power supply and long-term use status.

[0218] The components are not simply arranged in parallel, but are interconnected through the input-output relationship of controller 2 and the power supply and detection process of refrigerant sensor 3. This forms a complete closed-loop operation from periodic start-up, effective detection, threshold judgment, load control to protection and maintenance.

[0219] Example 2 like Figure 2 As shown, this embodiment provides a refrigerant monitoring and control method, which can be implemented based on the refrigerant monitoring and control circuit described in Embodiment 1. The method specifically includes the following steps.

[0220] Step 1: Receive the wake-up signal output by timer circuit 1 according to the preset period.

[0221] When the refrigerant concentration is within a safe range and continuous monitoring has not yet begun, timer circuit 1 continues to perform periodic timing. After the preset period is reached, timer circuit 1 outputs a wake-up signal to controller 2, and controller 2 enters the current refrigerant concentration monitoring process from the waiting state.

[0222] The preset cycle can be pre-set according to the refrigerant type, operating environment, and monitoring response requirements of the refrigeration equipment. For example, a wake-up signal can be output at a cycle of approximately 30 seconds, or other cycles that meet the refrigerant monitoring requirements can be used.

[0223] In this step, a wake-up event is generated by timer circuit 1, so that controller 2 and refrigerant sensor 3 do not need to remain operational between adjacent monitoring processes. This method distinguishes between monitoring time and waiting time, which helps reduce continuous power consumption when the refrigerant concentration is within a safe range.

[0224] Each wake-up signal corresponds to a new monitoring process, eliminating the need for controller 2 to continuously poll whether the monitoring time has been reached during the waiting phase. This allows the periodic timing task to be separated from the refrigerant concentration sampling task.

[0225] Step 2: In response to the wake-up signal, the power supply control circuit is turned on, and the refrigerant concentration detected by the refrigerant sensor 3 is obtained.

[0226] After receiving the wake-up signal, controller 2 controls its power supply control output terminal to output a control level for turning on the power supply control circuit. This control level drives NPN transistor Q2 to conduct through the base current limiting resistor Rb. NPN transistor Q2 pulls down the gate potential of P-channel enhancement-mode MOSFET Q1, thus turning on P-channel enhancement-mode MOSFET Q1.

[0227] After the power supply control circuit is turned on, the power supply is supplied to the refrigerant sensor 3 through the fuse element F1, the current limiting element R1, and the P-channel enhancement-mode MOSFET Q1. The refrigerant sensor 3 is powered on and begins to detect the refrigerant in the environment.

[0228] The controller 2 maintains the refrigerant sensor 3 powered on for a preset stabilization period. In one specific embodiment, the preset stabilization period is 30 to 45 seconds. After the preset stabilization period ends, the controller 2 acquires the detection signal output by the refrigerant sensor 3 and determines the refrigerant concentration.

[0229] By setting the preset stabilization time as a specific control parameter, time can be allowed for electrode polarization after the electrochemical sensor is powered on. Controller 2 then reads the concentration after this time has elapsed, which reduces the impact of cold-start transient signals on concentration determination.

[0230] The preset stabilization duration and the preset period of timer circuit 1 are used to control different stages. The former is used to limit the sampling waiting time after each power-on, and the latter is used to limit the time between adjacent wake-up events in the periodic monitoring state, so that periodic scheduling and effective sampling each have a clear time basis.

[0231] The output of this step is the refrigerant concentration used in this monitoring. This refrigerant concentration serves as the common input for subsequent threshold comparisons, monitoring status switching, and load linkage. This ensures that different subsequent control actions are based on the same monitoring result.

[0232] Step 3: Compare the refrigerant concentration with the preset alarm threshold, and control the power supply status of the refrigerant sensor 3 according to the comparison result.

[0233] When the refrigerant concentration is lower than the preset alarm threshold, controller 2 determines that the current monitoring result is within a safe range. After completing this monitoring, controller 2 stops outputting the control level that would turn on the NPN transistor Q2.

[0234] When NPN transistor Q2 is turned off, pull-up resistor R2 pulls the gate of P-channel enhancement-mode MOSFET Q1 to its source potential, turning off P-channel enhancement-mode MOSFET Q1 and stopping power supply to refrigerant sensor 3. Timer circuit 1 continues timing, waiting for the next cycle to wake up.

[0235] By promptly shutting off the power supply to the refrigerant sensor 3 based on safety monitoring results, the power-on time of the refrigerant sensor 3 can be concentrated in the stage required for actual sampling. This retains the periodic refrigerant concentration check while reducing invalid operation between checks.

[0236] When the refrigerant concentration reaches or exceeds the preset alarm threshold, controller 2 determines that the current environment has entered an abnormal refrigerant leakage state. Controller 2 keeps the P-channel enhancement-mode MOSFET Q1 on, so that the refrigerant sensor 3 is continuously powered and enters continuous monitoring mode.

[0237] Once in continuous monitoring mode, controller 2 no longer waits for the next cycle wake-up to read the refrigerant concentration, but instead continuously acquires the detection results from refrigerant sensor 3. This allows for tracking of refrigerant concentration changes after an alarm, providing continuous data to determine whether the risk continues to escalate and whether recovery conditions are met.

[0238] In continuous monitoring mode, when the refrigerant concentration remains below the recovery threshold for a preset recovery time, controller 2 exits continuous monitoring mode. The recovery threshold is lower than the preset alarm threshold, allowing different concentration conditions to be used for entering and exiting continuous monitoring.

[0239] For example, the recovery threshold is 90% of the preset alarm threshold, and the preset recovery time is 60 seconds. Only when the refrigerant concentration remains below this recovery threshold for 60 seconds will the controller 2 control the power supply control circuit to shut down and resume periodic monitoring.

[0240] The hysteresis formed by the recovery threshold can reduce repeated state switching caused by small changes in refrigerant concentration near the preset alarm threshold. The preset recovery time further eliminates short-term concentration drops, allowing controller 2 to resume low-power operation only after confirming that the abnormality has been continuously resolved.

[0241] Step 3 thus establishes the state transition rules between periodic monitoring and continuous monitoring. Entering continuous monitoring uses a preset alarm threshold, while exiting continuous monitoring uses a lower recovery threshold and duration, ensuring that the two transition directions are distinguishable from each other.

[0242] Step 4: When the refrigerant concentration reaches or exceeds the preset alarm threshold, output load linkage control signal S2.

[0243] Controller 2 controls the compressor to stop, the indoor and outdoor fans to run at high speed, and the electronic expansion valve to close via the load control circuit. These actions simultaneously inhibit the continued operation of the refrigeration system and enhance airflow, thereby reducing the risk of continued refrigerant leakage or accumulation in localized areas.

[0244] When the refrigerant concentration reaches or exceeds the high-risk threshold, controller 2 also controls the main contactor of the whole unit's power supply to disconnect through the load control circuit. The high-risk threshold is higher than the preset alarm threshold, thus forming a further power-off control corresponding to the risk level of the refrigerant concentration.

[0245] By setting preset alarm thresholds and high-risk thresholds, load linkage can be made not limited to a single complete power-off action. When the refrigerant concentration reaches the alarm level, the combined control of the compressor, fan, and electronic expansion valve is executed first. When a higher risk level is reached, the main contactor for cutting off the power supply to the entire unit is then cut off, which is beneficial for achieving graded safety control.

[0246] Step 4 converts the refrigerant concentration judgment result obtained in Step 3 into the actual action of the controlled load of the refrigeration equipment. Refrigerant monitoring thus goes beyond simply acquiring concentration information; it further develops into a control output capable of altering the operating state of the refrigeration equipment.

[0247] The load linkage control signal S2 and the fuse trigger signal S5 are independent of each other. The load linkage control signal S2 is triggered by excessive refrigerant concentration, while the fuse trigger signal S5 is triggered by continuous overvoltage in the power supply circuit. The triggering conditions and controlled objects of the two are different.

[0248] Step 5: During the refrigerant concentration monitoring process, the power supply circuit of the refrigerant sensor 3 is protected against current limiting, overvoltage clamping, and fuse failure through the power supply protection circuit.

[0249] During the power-on period of the refrigerant sensor 3, the current-limiting element R1 remains in the power supply circuit. When the power supply current increases abnormally, the current-limiting element R1 increases its resistance to limit the current flowing to the refrigerant sensor 3, thus providing recoverable protection against minor overcurrent or short-term abnormalities.

[0250] When the voltage at the power supply terminal of refrigerant sensor 3 exceeds the clamping voltage of voltage clamping element Z1, voltage clamping element Z1 conducts, limiting the power supply terminal voltage to near the allowable range of refrigerant sensor 3. Current limiting element R1 simultaneously limits the current in the clamping path, so that voltage limiting and current limiting work together.

[0251] During overvoltage detection, the voltage sampling unit acquires the power supply voltage of the refrigerant sensor 3 and provides the corresponding sampling voltage to the voltage comparison unit 5. The threshold providing unit provides the threshold protection voltage S4 to the voltage comparison unit 5.

[0252] Voltage comparison unit 5 compares the sampled voltage with the threshold protection voltage S4 to obtain the overvoltage detection result. The delay unit performs hardware delay processing on the overvoltage detection result. When the supply voltage continuously exceeds the threshold protection voltage S4 for the hardware delay time, the overvoltage detection circuit outputs an overvoltage fault flag signal S1.

[0253] In one specific implementation, the hardware delay duration is approximately 100 milliseconds. This hardware delay is used to filter power-on spikes and short-duration voltage disturbances, preventing the permanent fuse protection from tripping directly due to short-term interference.

[0254] After receiving the overvoltage fault flag signal S1, controller 2 performs a software-delayed confirmation of the overvoltage fault flag signal S1. In one specific embodiment, the software confirmation time is approximately 200 milliseconds.

[0255] When the overvoltage fault flag signal S1 persists for the software confirmation duration, controller 2 determines that the current limiting protection and overvoltage clamping protection have failed to eliminate the current abnormality, or that there is a serious fault in the power supply circuit. Controller 2 then outputs a fuse trigger signal S5 from the fuse trigger output terminal.

[0256] The fuse trigger signal S5 controls the controlled conducting element Q3 to conduct via the driving current limiting element Rg. After the controlled conducting element Q3 conducts, the current flows from the power supply through the fuse element F1 and the controlled conducting element Q3 to ground, bypassing the current limiting element R1.

[0257] The current flowing through fuse F1 exceeds its rated current, causing fuse F1 to blow. After fuse F1 blows, the power supply path between the power supply and the refrigerant sensor 3 is physically cut off.

[0258] The processing chain, consisting of hardware overvoltage comparison, hardware delay, software confirmation, and controlled fuse tripping, can first identify persistent overvoltage and then execute irreversible disconnection. This processing chain can suppress malfunctions caused by transient interference and isolate the refrigerant sensor 3 from the faulty power supply when a serious anomaly persists.

[0259] Step 5 can be executed synchronously during each power-on of the refrigerant sensor 3, without waiting for the refrigerant concentration comparison to complete before initiating protection. This allows the power supply protection to cover different operating stages, including power-on stabilization, concentration sampling, and continuous monitoring.

[0260] Step 6: When the preset maintenance conditions are met, maintain the electrodes of the refrigerant sensor 3.

[0261] Preset maintenance conditions may include generating a manual maintenance trigger signal S3, or the cumulative power-on time of the refrigerant sensor 3 reaching a preset maintenance time. For example, the preset maintenance time may be 168 hours.

[0262] When the preset maintenance conditions are met, controller 2 pauses acquiring refrigerant concentration and controls the analog switch to connect the reverse current source 4 between the working electrode WE and the counter electrode CE. In manual triggering mode, the manual maintenance trigger signal S3 is used to control the reverse current source 4 to output multiple reverse micro-current pulses; in automatic triggering mode, controller 2 controls the reverse current source 4 to output multiple reverse micro-current pulses.

[0263] In one specific implementation, each reverse microcurrent pulse has an amplitude of 1 μA to 5 μA and a width of 50 milliseconds. Three to five pulses are output for each maintenance cycle, with an interval of 100 milliseconds between adjacent pulses.

[0264] Pausing concentration sampling during the application of the reverse microcurrent pulse can prevent electrode responses caused by maintenance current from affecting refrigerant concentration judgment. Using multiple short-duration microcurrent pulses can limit the disturbance to the electrode's operating state caused by a single maintenance while providing reverse stimulation to the electrode.

[0265] After the reverse micro-current pulse output is completed, controller 2 controls the analog switch to disconnect the reverse current source 4 and maintains power supply to the refrigerant sensor 3. Controller 2 shields the sampling data of the refrigerant sensor 3 for a preset electrode recovery time.

[0266] For example, the preset electrode recovery time is 2 to 3 minutes. After the preset electrode recovery time is completed, the controller 2 removes the shielding of the sampling data and reacquires the refrigerant concentration.

[0267] Using a clearly preset electrode recovery time as the recovery sampling condition avoids using unquantized sensor states as program judgment conditions. This method is easy to execute directly in the control program and also allows for adjustment of the corresponding time based on the recovery characteristics of different sensor models.

[0268] Step 6 returns to the concentration acquisition and threshold comparison process used in steps 2 and 3 after resuming sampling. Electrode maintenance therefore has clearly defined entry and exit conditions, and does not form a sampling decision path independent of the normal monitoring process.

[0269] Steps 1 through 6 together constitute the complete process of the refrigerant monitoring and control method. Periodic wake-up and on-demand power supply are used to reduce power consumption under normal operating conditions; threshold comparison and continuous monitoring are used to maintain concentration tracking in the event of refrigerant leakage; load linkage is used to implement safety control of refrigeration equipment; and power supply protection and electrode maintenance are used to improve power supply safety and maintain the long-term detection capability of refrigerant sensor 3, respectively.

[0270] The above steps are not required to be executed completely sequentially in all cases. For example, power supply protection can be performed continuously during the power-on monitoring of the refrigerant sensor 3; electrode maintenance is performed after pausing normal sampling when preset maintenance conditions are met. As long as the triggering conditions and data connection relationships between each step remain unchanged, the corresponding execution sequence is within the scope of this invention.

[0271] Overall, this method uses the wake-up signal as the periodic monitoring entry point, refrigerant concentration as the criterion for judging monitoring status and load linkage, power supply voltage as the criterion for power supply protection, and maintenance trigger conditions as the electrode maintenance entry point. Different inputs enter their respective processing flows, ensuring a clear logical relationship between the method steps.

[0272] Example 3 This embodiment provides a refrigeration device. The refrigeration device includes a refrigeration system, a controlled load, and the refrigerant monitoring and control circuit described in Embodiment 1.

[0273] The controlled loads may include compressors, indoor fans, outdoor fans, electronic expansion valves, and the main contactor for power supply to the entire unit. The load control output of the refrigerant monitoring and control circuit is connected to the corresponding controlled load to implement load linkage when the refrigerant concentration reaches the corresponding threshold.

[0274] The refrigerant monitoring and control circuit detects the refrigerant concentration in the environment where the refrigeration equipment is located through refrigerant sensor 3. When the refrigerant concentration is lower than the preset alarm threshold, the refrigerant monitoring and control circuit powers on refrigerant sensor 3 for monitoring according to a preset cycle, and then turns off the power supply to refrigerant sensor 3 after completing the current monitoring.

[0275] This operating mode eliminates the need for continuous power supply to the refrigerant sensor 3 during normal operation when no refrigerant leakage occurs for extended periods. This reduces the standby and operating power consumption of the refrigerant monitoring function and decreases the cumulative operating time of the refrigerant sensor 3.

[0276] When the refrigerant concentration reaches or exceeds the preset alarm threshold, the refrigerant monitoring and control circuit keeps the refrigerant sensor 3 powered and puts it into continuous monitoring mode. At the same time, the refrigerant monitoring and control circuit controls the compressor to stop, the indoor and outdoor fans to run at high speed, and the electronic expansion valve to close.

[0277] Through this linkage, the refrigeration equipment can stop its normal refrigeration cycle upon detecting a refrigerant leak and increase airflow using a fan. Therefore, the refrigerant monitoring results can not only generate alerts but also directly contribute to the safety control of the refrigeration equipment.

[0278] When the refrigerant concentration reaches or exceeds the high-risk threshold, the refrigerant monitoring and control circuit disconnects the main power contactor of the entire unit. This setting allows the refrigeration equipment to transition from load operation to complete power supply isolation based on different risk levels of refrigerant concentration.

[0279] When the refrigerant concentration remains below the recovery threshold for a preset recovery time, the refrigerant monitoring and control circuit exits continuous monitoring and resumes periodic monitoring. By setting a recovery threshold below the preset alarm threshold, the repeated shutdowns and restarts of the refrigeration equipment near the alarm boundary can be reduced.

[0280] The power supply circuit of refrigerant sensor 3 in the refrigeration equipment is equipped with a current limiting element R1, a voltage clamping element Z1, and a fuse element F1. When the power supply of refrigerant sensor 3 is abnormal, the refrigerant monitoring and control circuit can use the corresponding protection functions to limit the abnormal current and clamp the abnormal voltage, and blow the fuse element F1 after confirming that the overvoltage is continuous and severe.

[0281] The aforementioned power supply protection settings are particularly suitable for refrigeration equipment using slightly flammable refrigerants. By limiting the abnormal current and voltage of the refrigerant sensor 3 and its power supply circuit under fault conditions, the possibility of persistent abnormal heating of the circuit can be reduced, and the power supply safety of the refrigerant monitoring section itself can be enhanced.

[0282] The refrigerant sensor 3 in the refrigeration equipment can be a three-electrode electrochemical sensor. The refrigerant monitoring and control circuit can respond to the manual maintenance trigger signal S3, or apply a reverse micro-current pulse to the working electrode WE and the counter electrode CE when the cumulative power-on time reaches the preset maintenance time.

[0283] By configuring an electrode maintenance function in the refrigeration equipment, the existing controller 2 can automatically complete the electrode maintenance process without removing the refrigerant sensor 3 and then applying the maintenance current. After maintenance, the sampling data is shielded according to the preset electrode recovery time, and then the refrigerant concentration monitoring is restored, so that the maintenance function can be integrated with the daily operation of the refrigeration equipment.

[0284] The refrigeration equipment in this embodiment can be an air conditioner, a cold storage refrigeration unit, a refrigerated truck temperature control system, or a variable frequency chiller. All of the above refrigeration equipment can use a refrigerant monitoring and control circuit to periodically monitor and control any potential refrigerant leaks.

[0285] The refrigerant may include environmentally friendly refrigerants such as R290 and R454B, which are flammable. For refrigeration equipment that uses other refrigerants and requires leak monitoring, the refrigerant monitoring and control circuit of this embodiment can be configured according to the detection target and safety parameters of the refrigerant sensor 3.

[0286] By applying the refrigerant monitoring and control circuit to different refrigeration equipment, the overall control logic of periodic power supply, continuous monitoring, load linkage, power supply protection, and electrode maintenance can be reused. Different application scenarios are mainly adapted to the configuration of the controlled load and the three parameters of the refrigerant sensor without changing the basic technical concept of the invention.

[0287] Therefore, the refrigeration equipment implementation does not merely treat the refrigerant monitoring and control circuit as an additional detection component, but rather establishes a control relationship between this circuit and the controlled load of the refrigeration system. The refrigerant concentration detection results can directly participate in the adjustment of the refrigeration equipment's operating status, thereby achieving integrated monitoring and control.

[0288] Application Example 1 This application example illustrates the periodic monitoring process when the refrigerant concentration is within a safe range.

[0289] The refrigeration equipment operates normally, and timer circuit 1 counts according to a preset period. After the preset period is reached, timer circuit 1 outputs a wake-up signal to controller 2, and controller 2 responds to the wake-up signal by turning on the power supply control circuit.

[0290] When controller 2 outputs a high level, the NPN transistor Q2 is turned on via the base current-limiting resistor Rb. The NPN transistor Q2 pulls the gate of the P-channel enhancement-mode MOSFET Q1 low, turning on Q1 and supplying power to the refrigerant sensor 3.

[0291] Controller 2 keeps refrigerant sensor 3 powered on for 30 to 45 seconds, and acquires the refrigerant concentration after the preset stabilization period. If the refrigerant concentration is lower than the preset alarm threshold, controller 2 completes the monitoring and sequentially turns off NPN transistor Q2 and P-channel enhancement-mode MOSFET Q1.

[0292] After the refrigerant sensor 3 is de-energized, the timer circuit 1 continues to wait for the next preset cycle. This process is repeated cyclically, enabling the refrigeration equipment to periodically check the refrigerant concentration in the environment without requiring the refrigerant sensor 3 to be constantly powered on.

[0293] In this application example, each monitoring is performed after the refrigerant sensor 3 has undergone a defined power-on stabilization period. Therefore, periodic power outages do not directly cause the controller 2 to read the transient output immediately upon power-on. The timer circuit 1, in conjunction with the preset stabilization period, can create a clear connection between power consumption control and effective sampling.

[0294] In this cycle, each monitoring iteration repeats the same sequence of power-on, waiting, sampling, and power-off, allowing controller 2 to handle refrigerant monitoring under normal conditions with a unified process. When the refrigerant concentration does not reach the alarm condition, no additional load linkage is triggered, thus maintaining normal refrigeration operation.

[0295] Application Example 2 This application example illustrates the continuous monitoring and load linkage process after a refrigerant leak is detected.

[0296] Controller 2 acquires the refrigerant concentration during a single cycle of monitoring and determines whether the refrigerant concentration has reached or exceeded a preset alarm threshold. Controller 2 keeps the power supply control circuit connected, causing the refrigerant sensor 3 to switch from the current cycle monitoring state to continuous monitoring.

[0297] Controller 2 outputs a load linkage control signal S2 through the load control circuit to control the compressor to stop, the indoor and outdoor fans to run at high speed, and the electronic expansion valve to close. Refrigerant sensor 3 continuously monitors the refrigerant concentration, and controller 2 continuously tracks changes in the concentration.

[0298] If the refrigerant concentration continues to rise and reaches or exceeds the high-risk threshold, controller 2 will disconnect the main power contactor for the entire unit. Thus, the refrigeration equipment will implement different levels of load control based on the risk level of the refrigerant concentration.

[0299] If the refrigerant concentration gradually decreases, controller 2 will not immediately stop continuous monitoring when the refrigerant concentration just falls below the preset alarm threshold. Controller 2 will only determine that the recovery conditions are met when the refrigerant concentration remains below 90% of the preset alarm threshold for 60 seconds.

[0300] Once the recovery conditions are met, controller 2 exits continuous monitoring mode, shuts off the power supply to refrigerant sensor 3 after completing the corresponding monitoring, and restarts the periodic wake-up process of timer circuit 1. This recovery process can reduce frequent start-stop cycles caused by concentration fluctuations near the alarm threshold.

[0301] This application example forms a complete closed loop, from periodic monitoring to continuous monitoring, executing load linkage, continuously judging concentration, and resuming periodic monitoring. Each state transition is triggered by clearly defined concentration and time conditions.

[0302] Application Example 3 This application example illustrates the protection process when an abnormality occurs in the power supply circuit of refrigerant sensor 3.

[0303] When the refrigerant sensor 3 is powered on normally, the power supply current flows sequentially through the fuse element F1, the current limiting element R1, and the power supply control circuit before reaching the refrigerant sensor 3. The voltage clamping element Z1 is connected between the power supply terminal of the refrigerant sensor 3 and ground.

[0304] When a slight overcurrent occurs in the power supply circuit, the resistance of the current-limiting element R1 increases with the temperature rise, thus limiting the power supply current. If an abnormal voltage exceeding the clamping voltage occurs at the power supply terminal, the voltage clamping element Z1 conducts and limits the voltage at the power supply terminal of the refrigerant sensor 3.

[0305] Simultaneously, the overpressure detection circuit acquires the supply voltage of the refrigerant sensor 3 and compares the sampled voltage with the threshold protection voltage S4. Overpressure signals with a duration shorter than the hardware delay are filtered out by the RC delay circuit.

[0306] When the overvoltage persists for approximately 100 milliseconds, the overvoltage detection circuit outputs an overvoltage fault flag signal S1. Controller 2 receives S1 and then performs a software verification process for approximately 200 milliseconds.

[0307] If S1 remains valid during software verification, controller 2 outputs a fuse trigger signal S5. The fuse trigger signal S5 triggers the controlled conducting element Q3 to conduct via the current limiting element Rg.

[0308] After the controlled conducting element Q3 is turned on, the power supply, the fuse element F1, the controlled conducting element Q3, and the ground form a fusing current path. Since this path is led out from the node between the fuse element F1 and the current limiting element R1, the fusing current bypasses the current limiting element R1.

[0309] Fuse F1 blew under a current exceeding its rated current, permanently cutting off the power supply circuit for refrigerant sensor 3. The refrigerant monitoring and control circuit was only put back into operation after maintenance personnel resolved the power supply fault and replaced fuse F1.

[0310] In this application example, short-term interference, recoverable overcurrent, power supply overvoltage, and persistent severe faults are handled by corresponding limiting, clamping, detection confirmation, and fuse-breaking processes, respectively. These multiple protection processes work together to prevent all power supply anomalies from directly relying on controller 2 to shut down the P-channel enhancement-mode MOSFET Q1.

[0311] In particular, the controlled fuse branch bypasses the current-limiting element R1, allowing the recoverable current-limiting and irreversible fuses to use different current paths. This ensures the final disconnect capability after a serious fault is confirmed while retaining routine current-limiting protection.

[0312] Application Example 4 This application example illustrates the electrode maintenance process for a three-electrode electrochemical sensor.

[0313] In response to the manual maintenance trigger signal S3, or when the controller 2 detects that the refrigerant sensor 3 has accumulated 168 hours of power-on time, the refrigerant monitoring and control circuit enters the electrode maintenance process. The controller 2 suspends refrigerant concentration sampling to prevent the electrode response during the maintenance process from being involved in leak detection.

[0314] Controller 2 controls the analog switch to connect the reverse current source 4 between the counter electrode CE and the working electrode WE. The positive terminal of the reverse current source 4 is connected to the counter electrode CE, and the negative terminal is connected to the working electrode WE.

[0315] The reverse current source 4 outputs 3 to 5 reverse micro-current pulses according to preset parameters. The amplitude of each pulse is 1μA to 5μA, the pulse width is 50 milliseconds, and the interval between adjacent pulses is 100 milliseconds.

[0316] Reverse microcurrent pulses intermittently stimulate the electrode surface to promote the detachment of adsorbed impurity ions. Because both pulse amplitude and duration are limited, electrode maintenance can be performed while minimizing disruption to the electrode's normal detection capabilities.

[0317] After the pulse output is completed, controller 2 controls the analog switch to disconnect the reverse current source 4 and maintains power supply to the refrigerant sensor 3. Controller 2 shields the sampling data of the refrigerant sensor 3 within a preset electrode recovery time of 2 to 3 minutes, allowing the electrode to return to the working state required for detection while powered on.

[0318] After the preset electrode recovery time expires, controller 2 removes the data shield and reacquires the refrigerant concentration. If the reacquired refrigerant concentration is lower than the preset alarm threshold, normal monitoring continues; if the reacquired refrigerant concentration reaches or exceeds the preset alarm threshold, it enters continuous monitoring mode and executes load linkage control.

[0319] Therefore, the electrode maintenance process has clearly defined triggering conditions, pulse parameters, sampling pause conditions, and sampling resumption conditions. The maintenance process can be embedded into the refrigerant monitoring and control flow without allowing post-maintenance transient data to bypass normal refrigerant concentration judgment.

[0320] Both manual and automatic maintenance perform the same sampling pause, pulse output, timing resumption, and resampling process, ensuring consistent results for both field maintenance and periodic self-maintenance. This unified process facilitates the addition of electrode maintenance functionality without altering the basic operating mode of the normal detection circuit.

[0321] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A refrigerant monitoring and control circuit, characterized in that, include: The circuit consists of a timer circuit (1), a controller (2), a power supply control circuit, a refrigerant sensor (3), a power supply protection circuit, and a load control circuit. The output terminal of the timer circuit (1), the signal output terminal of the refrigerant sensor (3) and the input terminal of the load control circuit are respectively connected to the controller (2); The power supply control circuit is set on the power supply loop between the power supply and the power supply terminal of the refrigerant sensor (3), and the controlled terminal of the power supply control circuit is connected to the controller (2). The power supply protection circuit is connected to the power supply circuit and the controller (2) respectively; The timer circuit (1) is used to output a wake-up signal to the controller (2) according to a preset period; The controller (2) is used to respond to the wake-up signal to control the power supply control circuit to turn on, obtain the refrigerant concentration detected by the refrigerant sensor (3), and compare the refrigerant concentration with a preset alarm threshold; when the refrigerant concentration is lower than the preset alarm threshold, the controller controls the power supply control circuit to turn off after completing the current monitoring; when the refrigerant concentration reaches or exceeds the preset alarm threshold, the controller controls the power supply control circuit to remain on, and outputs a load linkage control signal through the load control circuit. The power supply protection circuit is used to provide current limiting protection, overvoltage clamping protection, and fuse protection for the power supply circuit.

2. The refrigerant monitoring and control circuit according to claim 1, characterized in that: The power supply control circuit includes a P-channel enhancement-mode MOSFET (Q1), an NPN transistor (Q2), a base current limiting resistor (Rb), and a pull-up resistor (R2). The source of the P-channel enhancement-mode MOS transistor (Q1) is connected to the power supply side of the power supply circuit, the drain is connected to the power supply terminal of the refrigerant sensor (3), and the gate is connected to the collector of the NPN transistor (Q2). The emitter of the NPN transistor (Q2) is grounded, and the base is connected to the controller (2) through the base current limiting resistor (Rb); the pull-up resistor (R2) is connected between the source and gate of the P-channel enhancement-mode MOS transistor (Q1).

3. The refrigerant monitoring and control circuit according to claim 1, characterized in that: The power supply protection circuit includes a fuse (F1), a current limiting element (R1), and a voltage clamping element (Z1). Along the power supply direction of the power supply circuit, the fuse element (F1), the current limiting element (R1), the power supply control circuit and the refrigerant sensor (3) are connected in sequence; The voltage clamping element (Z1) is connected between the power supply terminal of the refrigerant sensor (3) and ground.

4. The refrigerant monitoring and control circuit according to claim 3, characterized in that: The power supply protection circuit also includes an overvoltage detection circuit, which includes a voltage sampling unit, a threshold providing unit, a voltage comparison unit (5), and a delay unit; The voltage sampling unit is connected to the power supply terminal of the refrigerant sensor (3), the voltage sampling unit and the threshold providing unit are respectively connected to the voltage comparison unit (5), and the voltage comparison unit (5) is connected to the controller (2) through the delay unit; The threshold providing unit is used to provide a threshold protection voltage (S4), the voltage comparison unit (5) is used to compare the power supply voltage of the refrigerant sensor (3) with the threshold protection voltage (S4), and the delay unit is used to perform delay processing on the overvoltage detection result output by the voltage comparison unit (5).

5. The refrigerant monitoring and control circuit according to claim 4, characterized in that: The power supply protection circuit also includes a controlled conduction element (Q3) and a drive current limiting element (Rg). The first conducting terminal of the controlled conducting element (Q3) is connected to the node between the fuse element (F1) and the current limiting element (R1), the second conducting terminal is grounded, and the controlled terminal is connected to the fuse trigger output terminal of the controller (2) through the driving current limiting element (Rg); The controller (2) is used to output a fuse trigger signal (S5) through the fuse trigger output terminal when the overvoltage fault flag signal (S1) output by the overvoltage detection circuit continues to reach the software confirmation time, so as to control the controlled conducting element (Q3) to conduct, so that the current flowing through the fuse element (F1) bypasses the current limiting element (R1) and melts the fuse element (F1).

6. The refrigerant monitoring and control circuit according to claim 1, characterized in that: The load control circuit includes multiple control output terminals, which are respectively connected to the compressor, indoor fan, outdoor fan, electronic expansion valve, and main contactor for power supply of the whole machine; The load control circuit is used to control the compressor to stop, the indoor fan and the outdoor fan to run at high speed and the electronic expansion valve to close according to the load linkage control signal, and to control the main contactor of the whole unit power supply to disconnect when the refrigerant concentration reaches or exceeds the high-risk threshold, wherein the high-risk threshold is higher than the preset alarm threshold.

7. The refrigerant monitoring and control circuit according to claim 1, characterized in that: The refrigerant sensor (3) is an electrochemical sensor, and the refrigerant sensor (3) has a working electrode, a counter electrode and a reference electrode that are led out to the outside of the refrigerant sensor (3).

8. The refrigerant monitoring and control circuit according to claim 7, characterized in that: It also includes an electrode protection circuit, which includes a reverse current source (4) and an analog switch; The controlled terminal of the analog switch is connected to the controller (2), and the analog switch is disposed between the reverse current source (4) and the working electrode and the counter electrode; The analog switch is used to disconnect the reverse current source (4) from the working electrode and the counter electrode during refrigerant concentration monitoring, and to connect the reverse current source (4) between the working electrode and the counter electrode during electrode maintenance.

9. A refrigerant monitoring and control method, based on the refrigerant monitoring and control circuit according to any one of claims 1 to 8, characterized in that, include: Receive the wake-up signal output by the timer circuit (1) according to a preset period; In response to the wake-up signal, the power supply control circuit is turned on, and the refrigerant concentration detected by the refrigerant sensor (3) is obtained; The refrigerant concentration is compared with a preset alarm threshold. When the refrigerant concentration is lower than the preset alarm threshold, the power supply control circuit is turned off after the current monitoring is completed; when the refrigerant concentration reaches or exceeds the preset alarm threshold, the power supply control circuit is kept on so that the refrigerant sensor (3) can perform continuous monitoring and output a load linkage control signal. During the refrigerant concentration monitoring process, the power supply protection circuit provides current limiting protection, overvoltage clamping protection, and fuse protection for the power supply circuit.

10. A refrigerant monitoring and control method according to claim 9, characterized in that: The control circuit for power supply is turned on, and the refrigerant concentration detected by the refrigerant sensor (3) is obtained, including: The power supply control circuit is turned on to power on the refrigerant sensor (3); Maintain the refrigerant sensor (3) powered on for a preset stable duration; After the preset stabilization period ends, the refrigerant concentration is obtained.

11. The refrigerant monitoring and control method according to claim 9, characterized in that: When the refrigerant concentration reaches or exceeds the preset alarm threshold, the refrigerant sensor (3) is put into continuous monitoring mode; In the continuous monitoring state, when the refrigerant concentration is continuously lower than the recovery threshold for a preset recovery time, the power supply control circuit is turned off, so that the refrigerant sensor (3) exits the continuous monitoring state and resumes waking up the refrigerant sensor (3) according to the preset cycle, and the recovery threshold is lower than the preset alarm threshold.

12. The refrigerant monitoring and control method according to claim 9, characterized in that: The output load linkage control signal includes: Controls the compressor to stop, controls the indoor and outdoor fans to run at high speed, and controls the electronic expansion valve to close; When the refrigerant concentration reaches or exceeds the high-risk threshold, the main contactor for power supply to the entire unit is disconnected, and the high-risk threshold is higher than the preset alarm threshold.

13. The refrigerant monitoring and control method according to claim 9, characterized in that: The refrigerant monitoring and control method further includes an overpressure detection process, which includes: Obtain the power supply voltage of the refrigerant sensor (3); The supply voltage is compared with the threshold protection voltage (S4) to obtain the overvoltage detection result; The overvoltage detection results are then subjected to a time delay. When the supply voltage continuously exceeds the threshold protection voltage (S4) for a hardware delay period, an overvoltage fault flag signal (S1) is output.

14. The refrigerant monitoring and control method according to claim 13, characterized in that: The refrigerant monitoring and control circuit is the refrigerant monitoring and control circuit as described in claim 5; The fuse protection includes: Receive the overvoltage fault flag signal (S1) and perform software delay confirmation on the overvoltage fault flag signal (S1); When the overvoltage fault flag signal (S1) continues to reach the software confirmation time, a fuse trigger signal (S5) is output to control the controlled conducting element (Q3) to conduct; The current flowing through the fuse element (F1) bypasses the current limiting element (R1) and flows to ground, thereby melting the fuse element (F1) and cutting off the power supply circuit of the refrigerant sensor (3).

15. A refrigerant monitoring and control method according to claim 9, characterized in that, Also includes: The refrigerant monitoring and control circuit is the refrigerant monitoring and control circuit as described in claim 8; In response to the manual maintenance trigger signal (S3), or when the cumulative power-on time of the refrigerant sensor (3) reaches the preset maintenance time, the acquisition of the refrigerant concentration is suspended; The analog switch is controlled to connect the reverse current source (4) between the working electrode and the counter electrode, and the reverse current source (4) is controlled to output multiple reverse micro-current pulses; After the reverse micro-current pulse is output, the analog switch is controlled to disconnect the reverse current source (4), the refrigerant sensor (3) is kept powered, and the sampling data of the refrigerant sensor (3) is shielded within the preset electrode recovery time. After the preset electrode recovery time has elapsed, the shielding of the sampling data is removed, and the refrigerant concentration is reacquired.

16. A refrigeration device, characterized in that, It includes a refrigeration system, a controlled load, and the refrigerant monitoring and control circuit as described in any one of claims 1 to 8.

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