A protection circuit and air conditioner thereof

Abstract

This application relates to a protection circuit and an air conditioner thereof. The protection circuit includes a switch signal receiving circuit, a logic gate circuit, and a latching circuit. A high-pressure switch is configured to disconnect when the high-pressure side pressure of the air conditioning system is detected to be greater than or equal to a preset pressure; the switch signal receiving circuit is configured to output a first signal when the high-pressure switch is disconnected; the logic gate circuit is configured to output a high-level signal based on the first signal; the latching circuit is configured to output a protection current based on the high-level signal output by the logic gate circuit, wherein the protection current is less than the minimum drive current of the compressor. This application can more reliably control the compressor to stop running and reduce the risk of pipe rupture.

Description

Technical Field

[0001] This application relates to the field of air conditioning control technology, and in particular to a protection circuit and an air conditioner thereof. Background Technology

[0002] In air conditioning operation control, to prevent compressor overheating and damage, the air conditioner needs to monitor the refrigerant pressure in the system pipeline in real time. Generally, this is monitored via a high-pressure switch. When the system refrigerant pressure is normal, the high-pressure switch is closed; when the system refrigerant pressure is too high, the high-pressure switch is open. Correspondingly, when the control chip detects that the high-pressure switch is open based on its output signal, the control chip controls the compressor to stop running.

[0003] However, software detection and control within the control chip can fail, potentially leading to compressor shutdown. The compressor's high speed operation will continue to increase pipe pressure, raising the risk of pipe rupture. This risk is even higher in large air conditioning systems.

[0004] Therefore, how to reliably control the compressor to stop operating and reduce the risk of pipeline rupture when the refrigerant pressure in the system pipeline is too high remains an urgent problem to be solved. Utility Model Content

[0005] This application provides a protection circuit and its air conditioner to solve the technical problem that the compressor cannot be reliably controlled to stop running when the refrigerant pressure in the system pipeline is too high, thus increasing the risk of pipeline rupture.

[0006] In a first aspect, some embodiments provide protection circuitry, including: a switch signal receiving circuit, a logic gate circuit, and a latch circuit;

[0007] The input terminal of the switch signal receiving circuit is configured to be connected to one end of the high-pressure switch, and the other end of the high-pressure switch is connected to the first power supply.

[0008] The logic gate circuit has one input connected to the output of the switch signal receiving circuit and the other input connected to a second power supply; the second power supply is configured to provide a high-level signal.

[0009] The latch circuit has one input terminal connected to the output terminal of the logic gate circuit, and another input terminal connected to the output terminal of the control chip configured to control the operation of the compressor; the output terminal is connected to the compressor power module.

[0010] The high-pressure switch is configured as follows:

[0011] Disconnect if the high-pressure side pressure of the air conditioning system is detected to be greater than or equal to the preset pressure;

[0012] The switch signal receiving circuit is configured as follows:

[0013] The first signal is output when the high-pressure switch is disconnected.

[0014] The logic gate circuit is configured as follows:

[0015] Based on the first signal, output a high-level signal;

[0016] The latch circuit is configured as follows:

[0017] Based on the high-level signal output by the logic gate circuit, a protection current is output, wherein the protection current is less than the minimum drive current of the compressor.

[0018] In one embodiment, when the logic gate is an AND gate, the switch signal receiving circuit includes: an optocoupler; the optocoupler includes a diode and a transistor;

[0019] The positive terminal of the diode is the input terminal of the switch signal receiving circuit, and the negative terminal is connected to the third power supply; the voltage provided by the third power supply is less than the voltage provided by the first power supply.

[0020] The collector of the transistor is the output terminal of the switching signal receiving circuit, the collector is connected to the fourth power supply, and the emitter is connected to the fifth power supply; the voltage provided by the fifth power supply is less than the voltage provided by the fourth power supply.

[0021] The diode is configured as follows:

[0022] Cut off when the high-pressure switch is disconnected;

[0023] When the diode is off, the voltage level signal at the collector of the transistor is a high-level signal provided by the fourth power supply and serves as the first signal.

[0024] In one embodiment, when the logic gate is a NAND gate, the switching signal receiving circuit includes: an optocoupler and a level adjustment circuit; the optocoupler includes a diode and a transistor;

[0025] The positive terminal of the diode is the input terminal of the switch signal receiving circuit, and the negative terminal is connected to the third power supply; the voltage provided by the third power supply is less than the voltage provided by the first power supply.

[0026] The collector of the transistor is the output terminal of the switching signal receiving circuit, the collector is connected to the fourth power supply, and the emitter is connected to the fifth power supply; the voltage provided by the fifth power supply is less than the voltage provided by the fourth power supply.

[0027] The level adjustment circuit has a control terminal connected to the collector of the transistor and also connected to a fourth power supply; a first terminal connected to the fourth power supply and a second terminal connected to a fifth power supply; the first terminal is the output terminal of the switch signal receiving circuit.

[0028] The diode is configured as follows:

[0029] Cut off when the high-pressure switch is disconnected;

[0030] The level adjustment circuit is configured as follows:

[0031] When the diode is off, the voltage provided by the fourth power supply triggers the connection to the fifth power supply;

[0032] When the fifth power supply is connected, the level signal at the first terminal is a low-level signal provided by the fifth power supply and serves as the first signal.

[0033] In one embodiment, the level adjustment circuit includes: resistor R1, resistor R2, resistor R3 and level adjustment transistor; the sum of the resistance values ​​of resistor R1 and resistor R2 is greater than the resistance value of resistor R3.

[0034] Resistor R1 is connected at one end to the fourth power source and at one end to resistor R3;

[0035] Resistor R2 has one end connected to the other end of resistor R1 and to the collector of the transistor in the optocoupler; the other end is connected to the control terminal of the level-adjusting transistor.

[0036] Resistor R3 is connected to the fourth power supply at one end and to the collector of the level-regulating transistor at the other end.

[0037] The level-adjusting transistor has its emitter connected to the fifth power supply and also to the emitter of the transistor in the optocoupler.

[0038] In one embodiment, the high-pressure switch is further configured to:

[0039] The system closes when the high-pressure side pressure of the air conditioning system is detected to be lower than the preset pressure.

[0040] The switch signal receiving circuit is further configured to:

[0041] When the high-pressure switch is closed, a second signal is output; the second signal and the first signal are opposite level signals.

[0042] The logic gate circuit is further configured as follows:

[0043] Based on the second signal, a low-level signal is output;

[0044] The latch circuit is further configured as follows:

[0045] Based on the low-level signal output by the logic gate circuit and the drive signal output by the control chip when the second signal is detected, the level signal at the output of the control latch circuit follows the drive signal, which is used to drive the compressor to run.

[0046] In one embodiment, the protection circuit further includes the control chip;

[0047] The control chip is also configured to:

[0048] Upon detecting the first signal, a low-level signal is output.

[0049] In one embodiment, the protection circuit further includes:

[0050] Resistor R4 is connected at one end to the output terminal of the switch signal receiving circuit and at the other end to the input terminal of the control chip.

[0051] In one embodiment, the latch circuit includes: a latch and a pull-down circuit;

[0052] The latch has one input terminal connected to the output terminal of the logic gate circuit, and the other input terminal configured to be connected to the output terminal of the control chip.

[0053] The pull-down circuit has one end connected to the output of the latch and the compressor power module; the other end is connected to the sixth power supply, which provides a voltage lower than that provided by the second power supply.

[0054] In one embodiment, the protection circuit further includes:

[0055] Resistor R5 is connected at one end to the high-pressure switch and at the other end to the input terminal of the switch signal receiving circuit.

[0056] Secondly, this application provides an air conditioner including the protection circuit described in the first aspect.

[0057] In the above embodiment, the high-pressure switch disconnects when the high-pressure side pressure of the air conditioning system is detected to be greater than or equal to a preset pressure. Correspondingly, the switch signal receiving circuit outputs a first signal when the high-pressure switch is disconnected. The logic gate circuit outputs a high-level signal based on the first signal, and the latch circuit outputs a protection current based on the high-level signal. This protection current is less than the minimum drive current of the compressor. Furthermore, another input terminal of the latch circuit is connected to the output terminal of a control chip configured to control the operation of the compressor, and the output terminal of the latch circuit is connected to the compressor power module.

[0058] Because the signal output from the control chip is input to the latch circuit, and the latch circuit outputs a protective current whenever it receives a high-level signal from the logic gate circuit, even if the control chip cannot effectively stop the compressor from running when the high-pressure side of the air conditioning system is too high, the compressor will still stop because the protective current output by the protection circuit cannot drive the compressor to run. This improves the reliability of compressor shutdown and reduces the risk of pipe rupture. Furthermore, the control chip outputs a low-level signal to the latch circuit after software detection, thus achieving dual hardware and software protection. Attached Figure Description

[0059] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 A schematic diagram of the circuit structure for compressor shutdown control in related technologies;

[0061] Figure 2 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 1 ;

[0062] Figure 3 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 2 ;

[0063] Figure 4 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 3 ;

[0064] Figure 5 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 4 ;

[0065] Figure 6 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 6 ;

[0066] Figure 7 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 7 ;

[0067] Figure 8 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 8 ;

[0068] Figure 9Schematic diagram of the protection circuit provided in some embodiments of this application Figure 9 ;

[0069] Figure 10 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 10 ;

[0070] Figure 11 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 10 one;

[0071] Figure 12 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 10 two;

[0072] Figure 13 Schematic diagram of the protection circuit provided in some embodiments of this application Figure 10 three;

[0073] Figure 14 This is a schematic diagram of the monitoring circuit provided in some embodiments of this application;

[0074] Figure 15 The circuit structure diagram of an air conditioner provided in some embodiments of this application is shown. Detailed Implementation

[0075] To make the objectives, implementation methods and advantages of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the described exemplary embodiments are only some embodiments of this application, and not all embodiments.

[0076] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0077] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclusively include, for example, a product or device that includes a series of components is not necessarily limited to those that are explicitly listed, but may include other components that are not explicitly listed or that are inherent to such product or device.

[0078] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0079] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0080] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0081] In air conditioning operation control, to prevent compressor overheating and damage, the air conditioner needs to monitor the refrigerant pressure in the system piping in real time. If the refrigerant pressure in the system piping is too high, the compressor should be stopped immediately to reduce the risk of piping rupture. Please refer to [link / reference needed]. Figure 1 (The high-pressure switch is shown as S1 in the figure.) Related technologies use a high-pressure switch to monitor the refrigerant pressure in the system piping. If the refrigerant pressure in the system piping is too high, the high-pressure switch disconnects. Correspondingly, when the control chip detects that the high-pressure switch is disconnected, it shuts off the compressor drive output to stop the compressor. However, this method of controlling the compressor to stop by the control chip is too simplistic and may suffer from software detection failures, resulting in ineffective compressor shutdown. The high speed of the compressor will still cause the piping pressure to continue to increase, raising the risk of piping rupture. This risk is even higher in large air conditioning systems.

[0082] Based on this, this application provides a protection circuit and an air conditioner thereof. The protection circuit includes a switch signal receiving circuit, a logic gate circuit, and a latching circuit. A high-pressure switch disconnects when it detects that the high-pressure side pressure of the air conditioning system is greater than or equal to a preset pressure. Correspondingly, the switch signal receiving circuit outputs a first signal when the high-pressure switch is disconnected, the logic gate circuit outputs a high-level signal based on the first signal, and the latching circuit outputs a protection current based on the high-level signal. This protection current is less than the minimum drive current of the compressor. Furthermore, another input terminal of the latching circuit is connected to the output terminal of a control chip configured to control the operation of the compressor, and the output terminal of the latching circuit is connected to the compressor power module.

[0083] Because the signal output from the control chip is input to the latch circuit, and the latch circuit outputs a protective current whenever it receives a high-level signal from the logic gate circuit, even if the control chip cannot effectively stop the compressor from running when the high-pressure side of the air conditioning system is too high, the compressor will still stop because the protective current output by the protection circuit cannot drive the compressor to run. This improves the reliability of compressor shutdown and reduces the risk of pipe rupture. Furthermore, the control chip outputs a low-level signal to the latch circuit after software detection, thus achieving dual hardware and software protection.

[0084] The following description further illustrates the concept through examples.

[0085] In some embodiments, please refer to Figure 2 The circuit structure shown includes a switch signal receiving circuit 100, a logic gate circuit 200, and a latch circuit 300.

[0086] In one embodiment, the input terminal of the switch signal receiving circuit 100 is configured to be connected to one end of the high-pressure switch 20, and the other end of the high-pressure switch 20 is connected to a first power supply 11. The voltage provided by the first power supply 11 can be 5V. When the high-pressure switch 20 is closed, the switch signal receiving circuit 100 receives the voltage provided by the first power supply 11, thereby determining that the high-pressure switch 20 is in a closed state. When the high-pressure switch 20 is open, the switch signal receiving circuit 100 no longer receives the voltage provided by the first power supply 11, thereby determining that the high-pressure switch 20 is in an open state.

[0087] The high-pressure switch 20 is configured to disconnect when the detected high-pressure side pressure of the air conditioning system is greater than or equal to a preset pressure. Correspondingly, the switch signal receiving circuit 100 is configured to output a first signal when the high-pressure switch 20 disconnects. This first signal can be a level signal, either a low-level signal or a high-level signal.

[0088] The switch signal receiving circuit 100 may include a transistor. The control terminal of the transistor is the input terminal of the switch signal receiving circuit 100, the collector is connected to power supply 1, and the emitter is connected to power supply 2. The voltage provided by power supply 1 is greater than the voltage provided by power supply 2. The collector of the transistor serves as the output terminal of the switch signal receiving circuit 100. When the high-pressure switch 20 is closed, the transistor conducts to power supply 2, and the output terminal of the switch signal receiving circuit 100 outputs a low-level signal (which can also be understood as a pull-down voltage). When the high-pressure switch 20 is open, the transistor is open, and the output terminal of the switch signal receiving circuit 100 outputs a high-level signal (which can also be understood as a pull-up voltage).

[0089] In one embodiment, one input of the logic gate 200 is connected to the output of the switch signal receiving circuit 100, and the other input is connected to a second power supply 12, which is configured to provide a high-level signal. The voltage provided by the second power supply 12 can be 5V. The output of the logic gate 200 is connected to one input of the latch circuit 300. The logic gate 200 can be an AND gate or a NAND gate. In the case where the switch signal receiving circuit 100 includes a transistor 112, the logic gate 200 is an AND gate.

[0090] The logic gate 200 is configured to output a high-level signal based on a first signal. That is, when the high-pressure switch 20 is open, the logic gate 200 outputs a high-level signal. Referring to Table 1 below, when the logic gate 200 is an AND gate, the switch signal receiving circuit 100 needs to output a high-level first signal when the high-pressure switch 20 is open. Combined with the high-level signal provided by the second power supply 12, this causes the logic gate 200 to output a high-level signal to indicate that the high-pressure switch 20 is open. Referring to Table 2 below, when the logic gate 200 is a NAND gate, the switch signal receiving circuit 100 needs to output a low-level first signal when the high-pressure switch 20 is open. Combined with the high-level signal provided by the second power supply 12, this causes the logic gate 200 to output a high-level signal to indicate that the high-pressure switch 20 is open.

[0091] The truth table for AND gate circuits is shown in Table 1. 0 represents low level, and 1 represents high level.

[0092] Table 1

[0093]

[0094] The truth table for NAND gates is shown in Table 2. 0 represents a low level, and 1 represents a high level.

[0095] Table 2

[0096]

[0097] The response speed of the AND gate circuit is around 11 nanometers, which is fast and helps to quickly protect the compressor 23.

[0098] In one embodiment, one input of the latch circuit 300 is connected to the output of the logic gate circuit 200, and the other input of the latch circuit 300 is configured to be connected to the output of the control chip 21. The output of the latch circuit 300 is connected to the compressor power module 22. The compressor power module 22 (i.e., the compressor power IPM (Intelligent Power Module)) is connected to the compressor 23. The control chip 21 is configured to control the operation of the compressor 23. Specifically, it controls the compressor 23 to operate normally when the high-pressure switch 20 is closed, and controls the compressor 23 to stop operating based on software detection when the high-pressure switch 20 is open. The control chip 21 can output a low-level signal when the high-pressure switch 20 is open. The input of the control chip 21 (i.e., the detection port) can be connected to the output of the switch signal receiving circuit 100, and the high-pressure switch 20 is determined to be open upon detection of a first signal.

[0099] The latch circuit 300 is configured to output a protection current based on the high-level signal output by the logic gate circuit 200. This protection current is less than the minimum drive current of the compressor 23. In other words, the protection current cannot drive the compressor 23 to operate; instead, it will cause the compressor 23 to stop operating. It should be noted that this protection current refers to the current input to the compressor power module. The minimum drive current, after being converted and output by the compressor function module, becomes the minimum current capable of driving the compressor.

[0100] The latch circuit 300 may include a latch 310 and other devices, such as resistors, with one end of the resistor connected to the output of the latch 310 and the other end connected to the compressor power module 22.

[0101] The truth table of latch 310 is shown in Table 3. 0 represents low level, 1 represents high level. X represents an uncertain state, and Z represents a high impedance state. The input signal G represents the signal output by logic gate 200. It can be seen that when logic gate 200 outputs a high-level signal, that is, when one input of latch 300 receives a high-level signal, the output of latch 310 will always be in a high impedance state, regardless of the level of the signal input to the other input of latch 300.

[0102] Table 3

[0103]

[0104] The latch circuit 300 may also include other components, which are not limited in this embodiment.

[0105] In the above embodiment, the high-pressure switch 20 disconnects when the high-pressure side pressure of the air conditioning system is detected to be greater than or equal to a preset pressure. Correspondingly, the switch signal receiving circuit 100 outputs a first signal when the high-pressure switch 20 is disconnected. The logic gate circuit 200 outputs a high-level signal based on the first signal, and the latch circuit 300 outputs a protection current based on the high-level signal. This protection current is less than the minimum drive current of the compressor 23. Furthermore, another input terminal of the latch circuit 300 is connected to the output terminal of the control chip 21 configured to control the operation of the compressor 23, and the output terminal of the latch circuit 300 is connected to the compressor power module 22.

[0106] Since the signal output by the control chip 21 is input to the latch circuit 300, and the latch circuit 300 will output a protective current as long as it receives a high-level signal from the logic gate circuit 200, even if the control chip 21 cannot effectively control the compressor 23 to stop running when the high-pressure side pressure of the air conditioning system is too high, the compressor 23 will still stop running because the protective current output by the protection circuit 10 cannot drive the compressor 23 to run. This improves the reliability of the compressor 23 stopping operation and reduces the risk of pipe bursting. Furthermore, the control chip 21 outputs a low-level signal to the latch circuit 300 after software detection, thus achieving dual hardware and software protection.

[0107] In some embodiments, please refer to Figure 3 The circuit structure shown is an AND gate circuit with one input terminal A as shown in the figure and another input terminal B as shown in the figure, and the output port Y as shown in the figure.

[0108] When the logic gate 200 is an AND gate, the switch signal receiving circuit 100 includes an optocoupler 110. The optocoupler 110 includes a diode 111 and a transistor 112.

[0109] The anode of diode 111 is the input terminal of the switch signal receiving circuit 100, and the cathode is connected to the third power supply 13. The voltage provided by the third power supply 13 is lower than the voltage provided by the first power supply 11. The third power supply 13 can be ground. Diode 111 can be an optocoupler 110 diode 111.

[0110] The collector of transistor 112 is the output terminal of the switch signal receiving circuit 100, and the collector is connected to the fourth power supply 14, while the emitter is connected to the fifth power supply 15. The voltage provided by the fifth power supply 15 is lower than the voltage provided by the fourth power supply 14. The voltage provided by the fourth power supply 14 can be 5V, and the fifth power supply 15 can be ground. Transistor 112 can be an optocoupler 110 transistor 112.

[0111] The diode 111 is configured to be cut off when the high-pressure switch 20 is open. When diode 111 is cut off, the voltage level signal at the collector of the transistor 112 is a high-level signal provided by the fourth power supply 14 and serves as the first signal. That is, when diode 111 is cut off, the first signal is provided by the fourth power supply 14. Since logic gate 200 is an AND gate, it outputs a high-level signal when the first signal is high. Referring to the above description, when logic gate 200 outputs a high-level signal, the compressor 23 stops operating.

[0112] In the above embodiments, the use of optocoupler 110 can isolate interference signals, preventing them from negatively impacting other devices and indirectly improving the accuracy of compressor 23 control. Furthermore, optocoupler 110 can achieve nanosecond-level response, for example, turning on or off in approximately 600 nanoseconds, enabling faster control of compressor 23 to stop operation.

[0113] In some embodiments, please refer to Figure 4 The circuit structure is shown. When the logic gate circuit 200 is a NAND gate circuit, the switch signal receiving circuit 100 includes an optocoupler 110 and a level adjustment circuit 120.

[0114] In one embodiment, the optocoupler 110 includes a diode 111 and a transistor 112. The anode of the diode 111 is the input terminal of the switch signal receiving circuit 100, and the cathode is connected to a third power supply 13; the voltage provided by the third power supply 13 is lower than the voltage provided by the first power supply 11. The collector of the transistor 112 is the output terminal of the switch signal receiving circuit 100, the collector is connected to a fourth power supply 14, and the emitter is connected to a fifth power supply 15; the voltage provided by the fifth power supply 15 is lower than the voltage provided by the fourth power supply 14. A description of the optocoupler 110 can be found in the above description and will not be repeated here.

[0115] In one embodiment, the control terminal of the level adjustment circuit 120 is connected to the collector of the transistor 112, and the control terminal is also connected to the fourth power supply 14. The first terminal of the level adjustment circuit 120 is connected to the fourth power supply 14, and the second terminal is connected to the fifth power supply 15. The first terminal of the level adjustment circuit 120 is the output terminal of the switch signal receiving circuit 100. The diode 111 is configured to be cut off when the high-pressure switch 20 is open. Correspondingly, the level adjustment circuit 120 is configured to be triggered by the voltage provided by the fourth power supply 14 to conduct to the fifth power supply 15 when the diode 111 is cut off. When the fifth power supply 15 is conducted, the level signal at the first terminal is a low-level signal provided by the fifth power supply 15 and serves as the first signal.

[0116] When the high-pressure switch 20 is open, the transistor 112 is not conducting. The control terminal of the level adjustment circuit 120 receives voltage 1 provided by the fourth power supply 14, and the first terminal receives voltage 2 provided by the fourth power supply 14. The voltage difference between voltage 2 and voltage 1 can turn on the level adjustment circuit 120 to the fifth power supply 15, thereby making the level signal at the first terminal a low-level signal provided by the fifth power supply 15.

[0117] Since the AND gate is a NAND gate, and the second power supply 12 provides a high-level signal, the AND gate can output a high-level signal when the first signal is low. Referring to the above description, when the AND gate outputs a high-level signal, the compressor 23 stops operating.

[0118] In one embodiment, the level adjustment circuit 120 may include at least one level adjustment transistor 112. When a level adjustment transistor 112 is included, the collector of the level adjustment transistor 112 is the first terminal of the level adjustment circuit 120, the emitter of the level adjustment transistor 112 is the second terminal of the level adjustment circuit 120, and the base of the level adjustment transistor 112 is the control terminal of the level adjustment circuit 120.

[0119] In the above embodiments, by setting the level adjustment circuit 120, a low-level signal can be output when the optocoupler 110 is disconnected, thereby adapting to the case where the logic AND gate circuit is a NAND gate circuit, making the structure of the protection circuit 10 more flexible and adaptable to more application scenarios.

[0120] In some embodiments, please refer to Figure 5 The circuit structure shown is a level adjustment circuit 120, which includes resistors R1, R2, and R3, and a level adjustment transistor 112.

[0121] Resistor R1 is connected at one end to the fourth power supply 14 and at one end to resistor R3. Resistor R2 is connected at one end to the other end of resistor R1 and to the collector of transistor 112 in optocoupler 110; the other end is connected to the control terminal of level-adjusting transistor 112. Resistor R3 is connected at one end to the fourth power supply 14 and at the other end to the collector of level-adjusting transistor 112.

[0122] The sum of the resistances of resistors R1 and R2 is greater than the resistance of resistor R3. For example, when the voltage supplied by the fourth power supply 14 is 5V, the resistance of resistor R1 can be around 4.7 kΩ, the resistance of resistor R2 can be around 1 kΩ, and the resistance of resistor R3 can be around 4.7 kΩ. The purpose of this arrangement is to make the level regulating transistor 112 conduct to the fifth power supply 15 under the action of the voltage difference.

[0123] The emitter of the level-adjusting transistor 112 is connected to the fifth power supply 15, and also to the emitter of the transistor 112 in the optocoupler 110. The number of level-adjusting transistors 112 can be one or more, and this embodiment does not limit this, as long as the above functions can be achieved.

[0124] In some embodiments, please refer to Figure 6 , Figure 7 and Figure 8 The circuit structure shown is as follows. The latch circuit 300 includes a latch 310 and a pull-down circuit 320.

[0125] One input of latch 310 is connected to the output of logic gate 200, and the other input is configured to be connected to the output of control chip 21. One end of pull-down circuit 320 is connected to the output of latch 310 and to compressor power module 22. The other end of pull-down circuit 320 is connected to a sixth power supply, the voltage of which is lower than the voltage provided by second power supply 12. This sixth power supply can be ground.

[0126] Referring to the above description, when logic gate 200 outputs a high-level signal, the output port of latch 310 is in a high-impedance state. After the signal output by latch 310 is affected by pull-down circuit 320, the output protection current is smaller, so the protection current cannot drive compressor 23 to run, and compressor 23 stops running, thus achieving the effect of protecting compressor 23.

[0127] In one embodiment, the pull-down circuit 320 may include a pull-down resistor, one end of which is connected to the output of the latch 310, and the other end is connected to a sixth power supply. The resistance value of the pull-down resistor may be 100 kiloohms. The number of pull-down resistors can be selected according to actual needs, and this embodiment does not limit it. The pull-down circuit 320 may also include other components, as long as they can achieve the above-mentioned related functions.

[0128] In the above embodiments, the latch 310 has a faster response speed, which can respond in about 500 nanoseconds, further improving the protection speed of the protection circuit 10 for the compressor 23.

[0129] In addition, it should be emphasized that in some embodiments, by combining the aforementioned optocoupler 110, logic gate circuit 200, and latch 310, the protection speed of compressor 23 can be increased to approximately 1.11 microseconds. In related technologies, software detection and protection of compressor 23 using control chip 21 requires a delay on the order of milliseconds (typically 100 milliseconds) before compressor 23 can be stopped. During this delay, compressor 23 continues to run at high speed, causing pipeline pressure to continuously increase, thereby increasing the risk of pipeline rupture. Therefore, compared to related technologies, the protection circuit 10 provided in this embodiment can control compressor 23 to stop running much faster, significantly reducing the risk of pipeline rupture.

[0130] In some embodiments, the high-pressure switch 20 is also configured to close when the high-pressure side pressure of the air conditioning system is detected to be less than a preset pressure. Referring to the description of the protection circuit 10 provided in any of the above embodiments, the protection circuit 10 can also control the compressor 23 to operate normally when the high-pressure switch 20 is closed. A detailed description follows.

[0131] The switch signal receiving circuit 100 is also configured to output a second signal when the high-pressure switch 20 is closed. The first signal and the second signal are opposite level signals. If the first signal is high, the second signal is low. If the first signal is low, the second signal is high.

[0132] The logic gate 200 is also configured to output a low-level signal based on a second signal. When the logic gate 200 is an AND gate, the second signal is low, causing the logic gate 200 to output a low-level signal. When the logic gate 200 is a NAND gate, the second signal is high, causing the logic gate 200 to output a low-level signal.

[0133] The latch circuit 300 is further configured to control the output level of the latch circuit 300 to follow the drive signal based on the low-level signal output by the logic gate circuit 200 and the drive signal output by the control chip 21 upon detecting the second signal. This drive signal is used to drive the compressor 23 to operate. The detection port of the control chip 21 can be connected to the output of the switch signal receiving circuit 100.

[0134] Referring to the above description, when the latch circuit 300 includes a latch 310, if one input receives a low-level signal from the logic gate circuit 200, the level signal output by the latch 310 follows the drive signal output by the control chip 21. For example, in Table 3, when input signal A is 0, the level signal output by the latch 310 is 0; when input signal A is 1, the level signal output by the latch 310 is 1. Thus, the control chip 21 can normally control the compressor 23 by outputting the input signal A.

[0135] In the above embodiment, when the high-pressure switch 20 is closed (the high-pressure side pressure of the air conditioning system is less than the preset pressure), the level signal output by the latch circuit 300 follows the drive signal output by the control chip 21, thereby enabling the control chip 21 to control the operation of the compressor 23 normally. The design of this protection circuit 10 does not affect the normal operation of the compressor 23, and can quickly protect the compressor 23 in the event of abnormal high-pressure side pressure, achieving two goals at once and demonstrating high practicality.

[0136] In some embodiments, please refer to Figure 9 and Figure 10 The circuit structure shown includes the aforementioned control chip 21 in the protection circuit 10. The control chip 21 is configured to output a drive signal upon detecting a second signal to drive the compressor 23 to operate normally. The control chip 21 is also configured to output a low-level signal upon detecting a first signal to provide secondary protection for the compressor 23.

[0137] The drive signal can include low-level signals and high-level signals, which are used to drive the compressor 23 to operate normally.

[0138] The detection port of the control chip 21 is connected to the output of the switch signal receiving circuit 100.

[0139] In the above embodiment, when the high pressure switch 20 is disconnected, the control chip 21 can output a low-level signal to provide secondary protection for the compressor 23, thereby achieving dual protection for the compressor 23 and improving the reliability of the compressor 23 protection.

[0140] In some embodiments, please also refer to Figure 11 The protection circuit 10 also includes a resistor R4. One end of the resistor R4 is connected to the output terminal of the switch signal receiving circuit 100, and the other end is connected to the input terminal of the control chip 21. The resistance value of the resistor R4 can be 1 kiloohm. The resistor R4 can include multiple resistors, which is not limited in this embodiment.

[0141] In the above embodiment, the resistor R4 can step down the signal output by the switch signal receiving circuit 100 to prevent the detection port of the control chip 21 from being damaged by high voltage. In addition, the resistor R4 can also reduce the influence of interference signals on the control chip 21, thereby improving the accuracy of the control chip 21 in identifying whether the high-pressure side pressure of the air conditioning system is abnormal, and further improving the accuracy of compressor 23 control.

[0142] In some embodiments, please refer to Figure 12 The circuit structure shown includes a protection circuit 10 that further comprises a resistor R5. One end of resistor R5 is connected to the high-pressure switch 20, and the other end is connected to the input terminal of the switch signal receiving circuit 100. The resistance value of resistor R5 can be 1 kiloohm. Resistor R5 can comprise multiple resistors; this embodiment does not limit the number of resistors.

[0143] In the above embodiment, the resistor R5 can limit the current of the signal output by the high-pressure switch 20, preventing the switch signal receiving circuit 100 from being damaged by high voltage. In addition, the resistor R5 can also reduce the influence of interference signals on the switch signal receiving circuit 100, thereby improving the accuracy of compressor 23 control.

[0144] For ease of understanding, combined with Figure 13 The circuit structure and two embodiments shown will be used to further explain the operating principle of the protection circuit 10.

[0145] First embodiment: The high-pressure side pressure of the air conditioning system is less than the preset pressure.

[0146] With normal pipeline pressure, the high-pressure switch 20S1 is closed. The 5V voltage (Vsw as shown in the figure) provided by the first power supply 11 passes through S1, and forms a conductive path through resistor R5 (current limiting resistor) and diode 111 inside optocoupler 110, forcing transistor 112 in optocoupler 110 to saturate and conduct. The conduction voltage (Vce) of transistor 112 in optocoupler 110 is 0.2V. Due to the saturation conduction of transistor 112 inside optocoupler 110, the collector of level regulating transistor 112 forms a loop through resistor R2 (current limiting resistor) and the base of level regulating transistor 112. Because the Vce conduction voltage of transistor 112 inside optocoupler 110 is insufficient, the circuit conduction current is also insufficient, and level regulating transistor 112 is in the cut-off state. The 5V voltage provided by the fourth power supply 14 passes through resistors R3 and R4 and finally connects to Vmcu (detection port of control chip 21, also known as signal input detection interface), forming a detection signal loop. The control chip 21 determines that the air conditioning system pipeline pressure is normal by judging that the input detection signal is high level.

[0147] The control chip 21 normally outputs the drive signal PWMin (PWMin is the drive signal output by the control chip 21 to the compressor power module 22). The drive signal PWMin is controlled by the latch 310 and the NAND gate X4, and finally output to the PWM port (i.e., the input drive port of the compressor power module 22). Referring to Tables 2 and 3 above, the NAND gate X4 controls the latch 310 to enable the output. The input port A of the NAND gate X4 is connected to the fourth power supply 14 (5V power supply) and resistor R3, and the input port B is connected to the second power supply 12 (5V power supply, high level). The state of input port B is 1 (high level), and the state of input port A is 1 (high level). Referring to Table 2, the output port Y of the NAND gate X4 is 0 (low level). The output port Y of the NAND gate X4 is connected to the input port G of the latch 310, the input port A of the latch 310 is connected to the output port PWMin of the control chip 21, and the output port Y of the latch 310 is connected to the input port PWM of the compressor power module 22. As shown in Table 3, when the level signal of the input port G of latch 310 is 0, the level signal of the output port Y follows the level signal of the input port A, and the compressor power module 22 is normally controlled by the software of control chip 21, and the compressor 23 operates normally.

[0148] Second embodiment: The high-pressure side pressure of the air conditioning system is greater than or equal to the preset pressure.

[0149] When the system pressure is too high, S1 disconnects. Resistor R5 (current-limiting resistor) and the internal diode 111 of optocoupler 110 do not form a conducting loop, forcing the internal transistor 112 of optocoupler 110 to turn off (disconnect). The voltage provided by the first power supply 11 forms a loop through resistors R1 and R2 and the level-regulating transistor 112, forcing the level-regulating transistor 112 to saturate and conduct. The saturation voltage drop of the level-regulating transistor 112 Vce is 0.2V. The Vce signal is connected to the VMCU port (signal input detection interface of control chip 21) through resistor R4, forming a detection loop. The control chip 21 software determines that the input detection signal is low. After internal processing, the PWMin port signal is finally turned off, and the output signal is low, completing the software control function. The software detection and judgment time is on the order of milliseconds.

[0150] The Vce conduction voltage of the level-regulating transistor 112 is simultaneously input to input port A of the NAND gate X4, and the voltage provided by the second power supply 12 is input to input port B. Referring to Table 2, the output port Y of the NAND gate X4 is 1 (high level), and the output terminal of the NAND gate X4 is connected to the input port G of the latch 310. Referring to Table 3, regardless of the level state of input port A (any level state), as long as input port G is 1 (high level), the output port Y of the latch 310 is forced to Z (high impedance state, pull-up resistor is on the order of megaohms, drive current is nanoamps, drive capability is insufficient to drive the compressor power module 22). Simultaneously, the Z signal passes through the pull-down resistor, and the output signal is reduced to 0.4V.

[0151] The optocoupler 110, level-regulating transistor 112, NAND gate X4, and latch 310 have a nanosecond-level delay. Before the software in the control chip 21 completes its logic judgment, the hardware circuit has already performed the logic judgment. The input port of the compressor power module 22 is in a high-impedance state, acting before the control signal from the software control chip 21, forcibly stopping the compressor 23. After the software judgment is completed, the software sets the PWMin port to a low level, thus completing the implementation of the dual hardware and software protection function.

[0152] The above is a description of the protection circuit 10. It should be noted that the protection circuit 10 may also include other components, but this embodiment does not limit this.

[0153] In some embodiments, please refer to Figure 14 The circuit structure is shown. This application also provides a monitoring circuit 30, including the protection circuit 10 as provided in any of the above embodiments, and further including a high-pressure switch 20, a first power supply 11, and a second power supply 12.

[0154] In some embodiments, please refer to Figure 15 The circuit structure is shown. This application also provides an air conditioner 40, which includes the protection circuit 10 provided in any of the above embodiments. The air conditioner 40 also includes the aforementioned high-pressure switch 20, control chip 21, compressor power module 22, and compressor 23, and may further include the aforementioned first power supply 11 and second power supply 12. The air conditioner 40 may also include other components, which are not limited in this embodiment.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0156] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better use the embodiments and various different variations of the embodiments suitable for specific application considerations.

Claims

1. A protection circuit, characterized in that, include: Switch signal receiving circuit, logic gate circuit and latch circuit; The input terminal of the switch signal receiving circuit is configured to be connected to one end of the high-pressure switch, and the other end of the high-pressure switch is connected to the first power supply. The logic gate circuit has one input terminal connected to the output terminal of the switch signal receiving circuit and the other input terminal connected to the second power supply. The second power supply is configured to provide a high-level signal; The latch circuit has one input terminal connected to the output terminal of the logic gate circuit, and another input terminal connected to the output terminal of the control chip configured to control the operation of the compressor; the output terminal is connected to the compressor power module. The high-pressure switch is configured as follows: Disconnect if the high-pressure side pressure of the air conditioning system is detected to be greater than or equal to the preset pressure; The switch signal receiving circuit is configured as follows: The first signal is output when the high-pressure switch is disconnected. The logic gate circuit is configured as follows: Based on the first signal, output a high-level signal; The latch circuit is configured as follows: Based on the high-level signal output by the logic gate circuit, a protection current is output, wherein the protection current is less than the minimum drive current of the compressor.

2. The protection circuit of claim 1, wherein When the logic gate is an AND gate, the switching signal receiving circuit includes: an optocoupler; the optocoupler includes a diode and a transistor; The positive terminal of the diode is the input terminal of the switch signal receiving circuit, and the negative terminal is connected to the third power supply; the voltage provided by the third power supply is less than the voltage provided by the first power supply. The collector of the transistor is the output terminal of the switching signal receiving circuit, the collector is connected to the fourth power supply, and the emitter is connected to the fifth power supply; the voltage provided by the fifth power supply is less than the voltage provided by the fourth power supply. The diode is configured as follows: Cut off when the high-pressure switch is disconnected; When the diode is off, the voltage level signal at the collector of the transistor is a high-level signal provided by the fourth power supply and serves as the first signal.

3. The protection circuit of claim 1, wherein When the logic gate is a NAND gate, the switching signal receiving circuit includes: an optocoupler and a level adjustment circuit; the optocoupler includes a diode and a transistor. The positive terminal of the diode is the input terminal of the switch signal receiving circuit, and the negative terminal is connected to the third power supply; the voltage provided by the third power supply is less than the voltage provided by the first power supply. The collector of the transistor is the output terminal of the switching signal receiving circuit, the collector is connected to the fourth power supply, and the emitter is connected to the fifth power supply; the voltage provided by the fifth power supply is less than the voltage provided by the fourth power supply. The level adjustment circuit has a control terminal connected to the collector of the transistor and also connected to a fourth power supply; a first terminal connected to the fourth power supply and a second terminal connected to a fifth power supply; the first terminal is the output terminal of the switch signal receiving circuit. The diode is configured as follows: Cut off when the high-pressure switch is disconnected; The level adjustment circuit is configured as follows: When the diode is off, the voltage provided by the fourth power supply triggers the connection to the fifth power supply; When the fifth power supply is connected, the level signal at the first terminal is a low-level signal provided by the fifth power supply and serves as the first signal.

4. The protection circuit of claim 3, wherein, The level adjustment circuit includes: resistor R1, resistor R2, resistor R3 and level adjustment transistor; the sum of the resistance values ​​of resistor R1 and resistor R2 is greater than the resistance value of resistor R3. Resistor R1 is connected at one end to the fourth power source and at one end to resistor R3; Resistor R2 has one end connected to the other end of resistor R1 and to the collector of the transistor in the optocoupler; the other end is connected to the control terminal of the level-adjusting transistor. Resistor R3 is connected to the fourth power supply at one end and to the collector of the level-regulating transistor at the other end. The level-adjusting transistor has its emitter connected to the fifth power supply and also to the emitter of the transistor in the optocoupler.

5. The protection circuit according to claim 1, characterized in that, The high-pressure switch is also configured to: The system closes when the high-pressure side pressure of the air conditioning system is detected to be lower than the preset pressure. The switch signal receiving circuit is further configured to: When the high-pressure switch is closed, a second signal is output; the second signal and the first signal are opposite level signals. The logic gate circuit is further configured as follows: Based on the second signal, a low-level signal is output; The latch circuit is further configured as follows: Based on the low-level signal output by the logic gate circuit and the drive signal output by the control chip when the second signal is detected, the level signal at the output of the control latch circuit follows the drive signal, which is used to drive the compressor to run.

6. The protection circuit according to any one of claims 1 to 5, characterized in that, The protection circuit also includes: the control chip; The control chip is also configured to: Upon detecting the first signal, a low-level signal is output.

7. The protection circuit of claim 6, wherein, The protection circuit also includes: Resistor R4 is connected at one end to the output terminal of the switch signal receiving circuit and at the other end to the input terminal of the control chip.

8. The protection circuit according to any one of claims 1-5, characterized in that, The latching circuit includes: a latch and a pull-down circuit; A latch, one input terminal of which is connected to the output terminal of the logic gate circuit, and the other input terminal of which is configured to be connected to the output terminal of the control chip; The pull-down circuit has one end connected to the output of the latch and the compressor power module; the other end is connected to the sixth power supply, which provides a voltage lower than that provided by the second power supply.

9. The protection circuit according to any one of claims 1-5, characterized in that, The protection circuit also includes: Resistor R5 is connected at one end to the high-pressure switch and at the other end to the input terminal of the switch signal receiving circuit.

10. An air conditioner characterized by comprising: Includes the protection circuit as described in any one of claims 1-9.

Images