Switching power supply protection circuits, control methods, switching power supplies and electrical equipment

Abstract

This application relates to switching power supply protection circuits, control methods, switching power supplies, and electrical equipment, belonging to the technical field of switching power supply protection circuits. In this application, the switching circuit module is configured such that one end of the bus current on / off control side of the switching circuit module is connected to the DC bus, and the other end is connected to the bus capacitor and DC / DC conversion circuit of the switching power supply. When the bus current on / off control side of the switching circuit module is disconnected, an open circuit is formed between the DC bus and both the bus capacitor and the DC / DC conversion circuit. Under this configuration, when the controller determines, based on the sampled voltage, that the bus voltage exceeds the upper limit of the preset normal voltage range, it controls the bus current on / off control side of the switching circuit module to disconnect. Overvoltage DC current will not be supplied to the bus capacitor and DC / DC conversion circuit of the switching power supply, thereby achieving overvoltage protection for the bus capacitor and DC / DC conversion circuit of the switching power supply.

Description

Technical Field

[0001] This application belongs to the field of switching power supply protection circuit technology, specifically relating to switching power supply protection circuits, control methods, switching power supplies and electrical equipment. Background Technology

[0002] Switching power supplies are widely used in electrical equipment. Typically, switching power supplies have built-in over- or under-voltage protection circuits, which function to protect against over- or under-voltage conditions.

[0003] Please see Figure 1 , Figure 1 This is a schematic diagram of a switching power supply circuit in the related art, based on an embodiment. Figure 1 In the diagram, the control terminal of controller U1 is connected to the DC / DC conversion circuit to control the on / off state of the DC / DC conversion circuit. Here, DC represents direct current, and the DC / DC conversion circuit is used to convert the input A-volt DC to B-volt DC. Controller U1 uses a voltage sampling circuit (… Figure 1 The DC bus sampling voltage is obtained through R1, R2 and Rcs. When overvoltage or undervoltage is determined based on the DC bus sampling voltage, the DC / DC conversion circuit is controlled to disconnect. Figure 1 In the switching power supply circuit shown, since the control terminal of the controller U1 is connected to the DC / DC conversion circuit, if the DC bus in the switching power supply circuit is over-voltaged, the bus capacitor C1 and some electronic components in the DC / DC conversion circuit will actually receive over-voltage DC current. Over-voltage DC current may cause the bus capacitor C1 and some electronic components in the DC / DC conversion circuit to break down, thereby causing damage to the switching power supply itself. Summary of the Invention

[0004] Therefore, this application provides a switching power supply protection circuit, control method, switching power supply, and electrical equipment, which helps to solve the problem that if the DC current on the DC bus is over-voltaged when the switching power supply protection circuit is connected to the DC / DC conversion circuit, the bus capacitor of the switching power supply and some electronic components in the DC / DC conversion circuit may be damaged.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] In a first aspect, this application provides a switching power supply protection circuit, comprising:

[0007] Voltage sampling circuit module, switching circuit module, and controller;

[0008] The voltage sampling circuit module is used to obtain the sampled voltage of the DC bus of the switching power supply and send the sampled voltage to the controller, wherein the sampled voltage can characterize the bus voltage of the DC bus;

[0009] The output terminal of the controller is connected to the signal input terminal of the switching circuit module;

[0010] One end of the bus current on / off control side of the switching circuit module is connected to the DC bus, and the other end of the bus current on / off control side of the switching circuit module is connected to the bus capacitor and DC / DC conversion circuit of the switching power supply. When the bus current on / off control side of the switching circuit module is disconnected, the DC bus forms an open circuit with the bus capacitor and the DC / DC conversion circuit respectively. When the bus current on / off control side of the switching circuit module is on, the DC bus forms a closed circuit with the bus capacitor and the DC / DC conversion circuit respectively.

[0011] Furthermore, the bus current on / off control side of the switching circuit module is normally disconnected.

[0012] Furthermore, the switching circuit module includes: an electronic switch tube and a relay; wherein, the driving terminal of the electronic switch tube serves as the signal input terminal of the switching circuit module and is connected to the output terminal of the controller, and the on / off side of the electronic switch tube is connected to the coil side of the relay;

[0013] The relay on / off side serves as the bus current on / off control side of the switching circuit module, with one end connected to the DC bus and the other end connected to the bus capacitor and the DC / DC conversion circuit.

[0014] Furthermore, the electronic switch is a transistor or a MOSFET.

[0015] Furthermore, the switching circuit module also includes:

[0016] A freewheeling diode and a capacitor are connected in parallel with the coil side of the relay, respectively.

[0017] Furthermore, the switching circuit module also includes a protection resistor connected in series between the output terminal of the controller and the signal input terminal of the switching circuit module.

[0018] Furthermore, the sampling circuit includes: two voltage divider resistors forming a series circuit, one end of the series circuit being connected to the DC bus of the switching power supply, the other end of the series circuit being grounded, and the sampling signal input terminal of the controller being connected to the line between the two voltage divider resistors.

[0019] Furthermore, the switching power supply protection circuit also includes a display module, which is connected to the controller.

[0020] Secondly, this application provides a control method for a switching power supply protection circuit, the method being applied to a controller of the switching power supply protection circuit according to any one of the first aspects, the method comprising:

[0021] The voltage sampling circuit module receives the sampled voltage, wherein the sampled voltage can characterize the bus voltage of the DC bus;

[0022] Based on the sampled voltage, it is determined whether the bus voltage exceeds the upper limit of the preset normal voltage range. If it does, a first control signal is sent to the switching circuit module to disconnect the bus current on / off control side of the switching circuit module, so that the DC bus is disconnected from the bus capacitor of the switching power supply and the DC / DC conversion circuit respectively.

[0023] Furthermore, the method also includes:

[0024] When the bus voltage is determined to be within the normal voltage range based on the sampled voltage, a second control signal is sent to the switching circuit module to turn on the bus current on / off control side of the switching circuit module, so that the DC bus can form a path between the bus capacitor of the switching power supply and the DC / DC conversion circuit respectively.

[0025] Furthermore, the method also includes:

[0026] When the bus voltage is determined to be lower than the lower limit of the normal voltage range based on the sampled voltage, the first control signal is sent to the switching circuit module to disconnect the bus current on / off control side of the switching circuit module, so that the DC bus is disconnected from the bus capacitor of the switching power supply and the DC / DC conversion circuit respectively.

[0027] Furthermore, the method also includes:

[0028] When it is determined that the bus voltage does not exceed the normal voltage range, the control display module displays the first display information, which is used to indicate that the input voltage of the switching power supply is normal.

[0029] When it is determined that the bus voltage exceeds the upper limit of the normal voltage range, the control display module displays second display information, which is used to indicate that the input voltage of the switching power supply is overvoltage.

[0030] When it is determined that the bus voltage exceeds the lower limit of the normal voltage range, the control display module displays third display information, which is used to indicate that the input voltage of the switching power supply is undervoltage.

[0031] Thirdly, this application provides a switching power supply, including the switching power supply protection circuit as described in any one of the first aspects, and the switching power supply protection circuit control method as described in any one of the second aspects.

[0032] Fourthly, this application provides an electrical device including the switching power supply described in the third aspect.

[0033] Furthermore, the electrical equipment includes an air conditioner.

[0034] The application employs the above technical solution and has at least the following beneficial effects:

[0035] The switching power supply protection circuit provided in this application has a switching circuit module configured such that one end of the bus current on / off control side of the switching circuit module is connected to the DC bus, and the other end is connected to the bus capacitor and DC / DC conversion circuit of the switching power supply. When the bus current on / off control side of the switching circuit module is open, an open circuit is formed between the DC bus and the bus capacitor and the DC / DC conversion circuit, respectively. When the bus current on / off control side of the switching circuit module is on, a closed circuit is formed between the DC bus and the bus capacitor and the DC / DC conversion circuit, respectively. Under this configuration, when the controller determines that the bus voltage exceeds the upper limit of the preset normal voltage range based on the sampled voltage, it controls the bus current on / off control side of the switching circuit module to open, thus forming an open circuit between the DC bus of the switching power supply and the bus capacitor and the DC / DC conversion circuit, preventing overvoltage DC current from being supplied to the bus capacitor and DC / DC conversion circuit of the switching power supply, thereby achieving overvoltage protection for the bus capacitor and DC / DC conversion circuit of the switching power supply.

[0036] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0037] 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.

[0038] Figure 1 This is a schematic diagram of a switching power supply circuit in the related art, according to an embodiment;

[0039] Figure 2 This is a schematic diagram of a switching power supply protection circuit according to an exemplary embodiment;

[0040] Figure 3 This is a schematic diagram illustrating a switching power supply protection circuit control method according to an exemplary embodiment;

[0041] Figure 4 This is a block diagram illustrating an air conditioner according to an exemplary embodiment. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] Please see Figure 2 , Figure 2 This is a schematic diagram of a switching power supply protection circuit according to an exemplary embodiment, such as... Figure 2 As shown, the switching power supply protection circuit 21 includes:

[0044] Voltage sampling circuit module 211, switching circuit module 212, and controller 213;

[0045] The voltage sampling circuit module 211 is used to obtain the sampled voltage of the DC bus of the switching power supply and send the sampled voltage to the controller 213, wherein the sampled voltage can characterize the bus voltage of the DC bus. Figure 2 VIN represents the bus voltage.

[0046] The output terminal of the controller 213 is connected to the signal input terminal of the switching circuit module 212;

[0047] One end of the bus current on / off control side of the switching circuit module 212 is connected to the DC bus, and the other end of the bus current on / off control side of the switching circuit module 212 is connected to the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply. When the bus current on / off control side of the switching circuit module 212 is disconnected, the DC bus forms an open circuit with the bus capacitor 22 and the DC / DC conversion circuit 23 respectively. When the bus current on / off control side of the switching circuit module 212 is on, the DC bus forms a closed circuit with the bus capacitor 22 and the DC / DC conversion circuit 23 respectively.

[0048] Specifically, in this application, the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply 2 are connected to the DC bus of the switching power supply 2 through the bus current on / off control side of the switching circuit module 212. The voltage sampling circuit module 211 samples the DC bus voltage. The sampled voltage has a fixed proportional relationship with the bus voltage VIN on the DC bus. Therefore, the sampled voltage can characterize the bus voltage VIN of the DC bus. The voltage sampling circuit module 211 sends the sampled voltage to the controller 213. The controller 213 can determine whether the bus voltage VIN exceeds the upper limit of the preset normal voltage range based on the sampled voltage. When it is determined that the bus voltage VIN exceeds the upper limit of the normal voltage range, ... This indicates an overvoltage at the power input. In this case, the trigger controller 213 controls the bus current switching control side of the switching circuit module 212 to disconnect, thus creating an open circuit between the DC bus of the switching power supply 2 and the bus capacitor 22 and the DC / DC conversion circuit 23. The overvoltage DC current will not be supplied to the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply 2. Therefore, the overvoltage on the DC bus will not affect the bus capacitor 22 and the DC / DC conversion circuit 23, thereby preventing the overvoltage on the DC bus from causing some electronic components of the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply 2 to be damaged. This achieves overvoltage protection for the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply 2.

[0049] Please refer to Figure 2 In one embodiment, the bus current on / off control side of the switching circuit module 212 is normally disconnected.

[0050] Specifically, the bus current on / off control side of the switching circuit module 212 is normally disconnected. In this way, when the switching power supply 2 is initially powered on, the bus capacitor 22 and the DC / DC conversion circuit 23 do not receive DC input from the DC bus. After judging the bus voltage VIN of the DC bus, it is decided whether to turn on the bus current on / off control side of the switching circuit module 212, that is, whether to energize the bus capacitor 22 and the DC / DC conversion circuit 23. This can avoid the problem of overvoltage breakdown of some components in the bus capacitor 22 and the DC / DC conversion circuit 23 at the initial power-on of the DC bus.

[0051] Please refer to Figure 2 In one embodiment, the switching circuit module 212 includes: an electronic switch Q and a relay KA;

[0052] The driving end of the electronic switch Q serves as the signal input end of the switch circuit module 212 and is connected to the output end of the controller 213. The on / off side of the electronic switch Q is connected to the coil side of the relay KA.

[0053] The relay KA on / off side serves as the bus current on / off control side of the switching circuit module 212, with one end connected to the DC bus and the other end connected to the bus capacitor 22 and the DC / DC conversion circuit 23.

[0054] Specifically, in practical applications, the electronic switch Q can be a transistor or a MOSFET. Please refer to [link / reference needed]. Figure 2 , Figure 2 The diagram shows that the electronic switch Q is an NPN transistor.

[0055] Taking the normally open side of relay KA as an example, the on / off side of electronic switch Q and the coil side of relay KA form a series circuit. One end of this series circuit is connected to 12V DC power, and the other end is grounded. Controller 213 sends a first control signal (a low-level signal) to switch circuit module 212, causing the on / off side of electronic switch Q to be cut off, that is, the on / off side of switch circuit module 212 is open. Since the on / off side of electronic switch Q and the coil side of relay KA are connected in series, when the on / off side of switch circuit module 212 is open, the coil side of relay KA is in a disabled state, and the on / off side of relay KA remains open. Thus, an open circuit is formed between the DC bus and bus capacitor 22 and DC / DC conversion circuit 23, respectively. The controller 213 sends a second control signal (a high-level signal) to the switching circuit module 212, which turns on the on / off side of the electronic switch Q. Since the on / off side of the electronic switch Q is connected in series with the coil side of the relay KA, when the on / off side of the switching circuit module 212 is turned on, the coil side of the relay KA is in an enabled state, which turns on the on / off side of the relay KA, allowing the power input on the DC bus to be conducted to the bus capacitor 22 and the DC / DC conversion circuit 23, and the switching power supply 2 works normally.

[0056] Please refer to Figure 2 In one embodiment, the switching circuit module 212 further includes:

[0057] A freewheeling diode D1 and a capacitor C1 are connected in parallel with the coil side of the relay KA.

[0058] Specifically, the coil of relay KA is an inductor. When the coil of relay KA is energized, it stores energy. When the electronic switch Q is turned off, the coil releases energy, causing an impact on the electronic switch Q. By connecting a freewheeling diode D1 in parallel with the coil side of relay KA, the freewheeling diode D1 absorbs the energy released by the coil when the electronic switch Q is turned off. Capacitor C1 is connected in parallel with the coil side of relay KA to filter the induced electromotive force (EMF) generated when the coil is switched on and off, preventing the induced EMF generated by the coil from being too high and causing breakdown of the electronic switch Q connected to the coil.

[0059] Please refer to Figure 2 In one embodiment, the switching circuit module 212 further includes a protection resistor R1, which is connected in series between the output terminal of the controller 213 and the signal input terminal of the switching circuit module 212.

[0060] Specifically, Figure 2 As shown, the base of the NPN transistor is connected to the output terminal of the controller 213 through a protection resistor R1, which provides current limiting protection for the NPN transistor.

[0061] Please refer to Figure 2 In one embodiment, the sampling circuit includes two voltage divider resistors (R2 and R3), which form a series circuit. One end of the series circuit is connected to the DC bus of the switching power supply 2, and the other end of the series circuit is grounded. The sampling signal input terminal of the controller 213 is connected to the line between the two voltage divider resistors.

[0062] Specifically, the bus voltage VIN is often higher than the sampling input voltage required by the controller 213. The sampling signal input terminal of the controller 213 cannot be directly connected to the DC bus. The sampling circuit of this application uses series voltage divider resistors (R2 and R3) to form a voltage divider voltage as the sampling voltage. A fixed proportional relationship is formed between the voltage divider voltage and the bus voltage VIN. The bus voltage VIN can be calculated by sampling the voltage divider.

[0063] Please see Figure 2 In one embodiment, the switching power supply protection circuit 21 further includes a display module 214, which is connected to the controller 213.

[0064] Specifically, the display module 214 can be, but is not limited to, an OLED display module. The display module 214 shows the current status of the protection circuit, providing users with intuitive prompts. For example, when the bus current switching control side of the switching circuit module 212 is disconnected, the display module 214 shows the specific operating status, allowing users to accurately understand whether it is overvoltage protection or undervoltage protection.

[0065] Please see Figure 3 , Figure 3 This is a schematic diagram illustrating a control method for a switching power supply protection circuit according to an exemplary embodiment. The method is applied to the controller of the switching power supply protection circuit provided in this application, and includes:

[0066] Step S31: Receive the sampled voltage sent by the voltage sampling circuit module, wherein the sampled voltage can characterize the bus voltage of the DC bus;

[0067] Step S32: Determine whether the bus voltage exceeds the upper limit of the preset normal voltage range based on the sampled voltage. If it does, send a first control signal to the switching circuit module to disconnect the bus current on / off control side of the switching circuit module, so that the DC bus is disconnected from the bus capacitor of the switching power supply and the DC / DC conversion circuit respectively.

[0068] In the hardware scheme of the switching power supply protection circuit of this application, the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply 2 are connected to the DC bus of the switching power supply 2 through the bus current on / off control side of the switching circuit module 212. Under this setting, when the bus current on / off control side of the switching circuit module 212 is disconnected, the DC bus of the switching power supply 2 can form an open circuit with the bus capacitor 22 and the DC / DC conversion circuit 23 respectively. Overvoltage DC current will not be delivered to the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply 2, thereby realizing overvoltage protection for the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply 2.

[0069] Based on the hardware scheme of the switching power supply protection circuit of this application, the control method described above uses a voltage sampling circuit module 211 to sample the DC bus voltage. The sampled voltage and the bus voltage VIN on the DC bus have a fixed proportional relationship. Therefore, the sampled voltage can characterize the bus voltage VIN of the DC bus. The voltage sampling circuit module 211 sends the sampled voltage to the controller 213. The controller 213 can determine whether the bus voltage VIN exceeds the upper limit of the preset normal voltage range based on the sampled voltage. When it is determined that the bus voltage VIN exceeds the upper limit of the normal voltage range, it indicates that the power input is overvoltage. In this case, the controller 213 sends a signal to the switching circuit module 212. The first control signal is used to control the bus current on / off control side of the switching circuit module 212 to disconnect, so that the DC bus of the switching power supply 2 forms an open circuit between the bus capacitor 22 and the DC / DC conversion circuit 23 respectively. The overvoltage DC current will not be delivered to the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply 2. Therefore, the overvoltage occurring on the DC bus will not affect the bus capacitor 22 and the DC / DC conversion circuit 23, thereby avoiding the possibility that the overvoltage on the DC bus may cause some electronic components of the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply 2 to be damaged by breakdown. This achieves overvoltage protection for the bus capacitor 22 and the DC / DC conversion circuit 23 of the switching power supply 2.

[0070] Furthermore, in one embodiment, the method further includes:

[0071] When the bus voltage is determined to be within the normal voltage range based on the sampled voltage, a second control signal is sent to the switching circuit module to turn on the bus current on / off control side of the switching circuit module, so that the DC bus can form a path between the bus capacitor of the switching power supply and the DC / DC conversion circuit respectively.

[0072] Specifically, if the controller 213 determines that the bus voltage VIN is within the normal voltage range based on the sampled voltage, it indicates that the bus voltage VIN on the DC bus is the voltage at which the electrical equipment can work normally. In this case, the controller 213 sends a second control signal to the switching circuit module 212. This second control signal is used to control the conduction of the bus current on / off control side of the switching circuit module 212, so that the DC bus of the switching power supply 2 forms a path between the bus capacitor 22 and the DC / DC conversion circuit 23 respectively. The power input on the DC bus is conducted to the bus capacitor 22 and the DC / DC conversion circuit 23, and the switching power supply 2 works normally.

[0073] Furthermore, in one embodiment, the method further includes:

[0074] When the bus voltage is determined to be lower than the lower limit of the normal voltage range based on the sampled voltage, the first control signal is sent to the switching circuit module to disconnect the bus current on / off control side of the switching circuit module, so that the DC bus is disconnected from the bus capacitor of the switching power supply and the DC / DC conversion circuit respectively.

[0075] Specifically, if the controller 213 determines that the bus voltage VIN exceeds the lower limit of the normal voltage range based on the sampled voltage, it indicates that the bus voltage VIN on the DC bus is undervoltage. In this case, the controller 213 also sends a first control signal to the switching circuit module 212, and controls the bus current switching control side of the switching circuit module 212 to disconnect, so that the DC bus of the switching power supply 2 forms an open circuit between the bus capacitor 22 and the DC / DC conversion circuit 23 respectively, thereby realizing undervoltage protection.

[0076] Furthermore, in one embodiment, the method further includes:

[0077] When it is determined that the bus voltage does not exceed the normal voltage range, the control display module displays the first display information, which is used to indicate that the input voltage of the switching power supply is normal.

[0078] When it is determined that the bus voltage exceeds the upper limit of the normal voltage range, the control display module displays second display information, which is used to indicate that the input voltage of the switching power supply is overvoltage.

[0079] When it is determined that the bus voltage exceeds the lower limit of the normal voltage range, the control display module displays third display information, which is used to indicate that the input voltage of the switching power supply is undervoltage.

[0080] The current status of the protection circuit is displayed by the display module 214, providing users with intuitive prompts. For example, when the bus current switching control side of the switching circuit module 212 is disconnected, without a display prompt function, the user only knows that the switching power supply is not working, but does not know whether it is due to overvoltage or undervoltage. Using the above solution, the display module 214 displays the specific working status, making it convenient for users to accurately understand whether it is overvoltage protection or undervoltage protection when the bus current switching control side of the switching circuit module 212 is disconnected.

[0081] Please see Figure 2 This application also provides a switching power supply 2, including the switching power supply protection circuit 21 provided in this application, and the switching power supply protection circuit control method provided in this application.

[0082] The switching power supply 2 and the corresponding control method of the protection circuit provided in this application have been described in the above-mentioned embodiments, and will not be repeated here.

[0083] Please see Figure 4 , Figure 4 This is a block diagram illustrating an electrical device according to an exemplary embodiment. The electrical device 4 includes a switching power supply 2 as described above.

[0084] In practical applications, the electrical equipment 4 includes, but is not limited to, electrical equipment that uses switching power supplies, such as air conditioners and refrigerators.

[0085] It is understood that the same or similar parts in the above embodiments can be referred to each other, and the contents not described in detail in some embodiments can be referred to the same or similar contents in other embodiments.

[0086] It should be noted that in the description of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "multiple" or "more" means at least two.

[0087] It should be understood that when an element is referred to as “fixed to” or “set on” another element, it may be directly on the other element or may be interposed with an intervening element; when an element is referred to as “connected to” another element, it may be directly connected to the other element or may be interposed with an intervening element. Furthermore, the term “connected” as used herein may include wireless connections; the word “and / or” as used includes any and all combinations of one or more of the associated listed items.

[0088] Any process or method description in the flowchart or otherwise herein can be understood as: representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0089] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0090] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0091] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0092] The storage media mentioned above can be read-only memory, disk, or optical disk, etc.

[0093] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0094] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A switching power supply protection circuit, characterized in that, include: Voltage sampling circuit module, switching circuit module, and controller; The voltage sampling circuit module is used to obtain the sampled voltage of the DC bus of the switching power supply and send the sampled voltage to the controller, wherein the sampled voltage can characterize the bus voltage of the DC bus; The output terminal of the controller is connected to the signal input terminal of the switching circuit module; One end of the bus current on / off control side of the switching circuit module is connected to the DC bus, and the other end of the bus current on / off control side of the switching circuit module is connected to the bus capacitor and DC / DC conversion circuit of the switching power supply. When the bus current on / off control side of the switching circuit module is disconnected, the DC bus forms an open circuit with the bus capacitor and the DC / DC conversion circuit respectively. When the bus current on / off control side of the switching circuit module is on, the DC bus forms a closed circuit with the bus capacitor and the DC / DC conversion circuit respectively. The switching circuit module includes an electronic switch tube and a relay; wherein, the driving end of the electronic switch tube serves as the signal input end of the switching circuit module and is connected to the output end of the controller, and the on / off side of the electronic switch tube is connected to the coil side of the relay. The relay on / off side serves as the bus current on / off control side of the switching circuit module, with one end connected to the DC bus and the other end connected to the bus capacitor and the DC / DC conversion circuit.

2. The switching power supply protection circuit according to claim 1, characterized in that, The bus current on / off control side of the switching circuit module is normally disconnected.

3. The switching power supply protection circuit according to claim 1, characterized in that, The electronic switch is a transistor or a MOSFET.

4. The switching power supply protection circuit according to claim 1, characterized in that, The switching circuit module also includes: A freewheeling diode and a capacitor are connected in parallel with the coil side of the relay, respectively.

5. The switching power supply protection circuit according to claim 1, characterized in that, The switching circuit module further includes a protection resistor connected in series between the output terminal of the controller and the signal input terminal of the switching circuit module.

6. The switching power supply protection circuit according to claim 1, characterized in that, The sampling circuit includes two voltage divider resistors that form a series circuit. One end of the series circuit is connected to the DC bus of the switching power supply, and the other end of the series circuit is grounded. The sampling signal input terminal of the controller is connected to the line between the two voltage divider resistors.

7. The switching power supply protection circuit according to claim 1, characterized in that, The switching power supply protection circuit also includes a display module, which is connected to the controller.

8. A control method for a switching power supply protection circuit, characterized in that, The method is applied to the controller of the switching power supply protection circuit according to any one of claims 1-7, and the method includes: The voltage sampling circuit module receives the sampled voltage, wherein the sampled voltage can characterize the bus voltage of the DC bus; Based on the sampled voltage, it is determined whether the bus voltage exceeds the upper limit of the preset normal voltage range. If it does, a first control signal is sent to the switching circuit module to disconnect the bus current on / off control side of the switching circuit module, so that the DC bus is disconnected from the bus capacitor of the switching power supply and the DC / DC conversion circuit respectively.

9. The method according to claim 8, characterized in that, The method further includes: When the bus voltage is determined to be within the normal voltage range based on the sampled voltage, a second control signal is sent to the switching circuit module to turn on the bus current on / off control side of the switching circuit module, so that the DC bus can form a path between the bus capacitor of the switching power supply and the DC / DC conversion circuit respectively.

10. The method according to claim 8, characterized in that, The method further includes: When the bus voltage is determined to be lower than the lower limit of the normal voltage range based on the sampled voltage, the first control signal is sent to the switching circuit module to disconnect the bus current on / off control side of the switching circuit module, so that the DC bus is disconnected from the bus capacitor of the switching power supply and the DC / DC conversion circuit respectively.

11. The method according to any one of claims 8-10, characterized in that, The method further includes: When it is determined that the bus voltage does not exceed the normal voltage range, the control display module displays the first display information, which is used to indicate that the input voltage of the switching power supply is normal. When it is determined that the bus voltage exceeds the upper limit of the normal voltage range, the control display module displays second display information, which is used to indicate that the input voltage of the switching power supply is overvoltage. When it is determined that the bus voltage exceeds the lower limit of the normal voltage range, the control display module displays third display information, which is used to indicate that the input voltage of the switching power supply is undervoltage.

12. A switching power supply, characterized in that, It includes the switching power supply protection circuit as described in any one of claims 1-7, and the switching power supply protection circuit control method as described in any one of claims 8-11.

13. An electrical appliance, characterized in that, Including the switching power supply as described in claim 12.

14. The electrical equipment according to claim 13, characterized in that, The electrical equipment includes an air conditioner.

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