Transient current suppression circuit and electric equipment

Abstract

The utility model discloses a transient current suppression circuit and electric equipment. The transient current suppression circuit is applied to electric equipment, the electric equipment comprises a rectifier bridge and a bus capacitor, an NTC resistor is arranged between a positive terminal of the rectifier bridge and a positive terminal of a power supply, and the transient current suppression circuit comprises a current detection module used for generating a current feedback signal based on direct current bus current; the input end of the processing module is connected with the current detection module, the output end of the processing module is connected with the control end of the protection switch, and the processing module is used for obtaining a direct-current bus current value based on the current feedback signal and controlling the on-off state of the protection switch according to the direct-current bus current value so as to control whether the current flows through the NTC resistor or not; and the protection switch and the NTC resistor are arranged in parallel. According to the utility model, the NTC resistor can be prevented from heating, so that surrounding electronic components are prevented from being influenced, and the reliability of electric equipment is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic power, in particular to a transient current suppression circuit and electrical equipment. Background Art

[0002] In today's industry, higher requirements are placed on electrical equipment (such as air conditioners). While ensuring the original performance, they need to be more miniaturized and lightweight. This means that the PCB board area of the control circuit of the electrical equipment is smaller and the components are more compact.

[0003] In existing electrical equipment, NTC resistors are used to suppress transient currents during the startup process. When the temperature of the NTC resistor rises, the heat will radiate to the surrounding area, causing the temperature of surrounding components to also rise. Especially in miniaturized electrical equipment, the compact layout of electronic components will cause the temperature of other components to rise more significantly, causing some electronic components, especially current-sensitive devices, to overheat, greatly increasing the risk of electronic component failure. In addition, under harsh harmonic voltage conditions, large induced currents will be generated, resulting in an increased probability of failure of the bus capacitor and a significant reduction in the reliability of the electrical equipment.

[0004] In the prior art, when the temperature of an NTC resistor in an electrical device rises, heat is radiated to the surrounding area, causing the temperature of surrounding components to also rise and thus fail. Currently, no effective solution has been proposed. Utility Model Content

[0005] The present invention provides a transient current suppression circuit and an electrical device in an embodiment to solve the problem in the prior art that when the temperature of an NTC resistor in an electrical device rises, heat is radiated to the surroundings, causing the temperature of surrounding components to also rise and thus fail.

[0006] To solve the above technical problems, the present invention provides a transient current suppression circuit, which is applied to an electrical device. The electrical device includes a rectifier bridge and a bus capacitor. An NTC resistor is provided between the positive terminal of the rectifier bridge and the positive terminal of the power supply. The transient current suppression circuit includes:

[0007] A current detection module, configured to generate a current feedback signal based on the DC bus current;

[0008] a processing module, whose input end is connected to the current detection module and whose output end is connected to the control end of the protection switch, wherein the processing module is configured to obtain a DC bus current value based on the current feedback signal, and control the on / off state of the protection switch according to the DC bus current value, thereby controlling whether the current flows through the NTC resistor;

[0009] The protection switch is arranged in parallel with the NTC resistor.

[0010] Furthermore, the current detection module includes:

[0011] a current sensor, mounted on the DC bus and configured to generate a sampling signal based on the DC bus current;

[0012] The detection unit is used to obtain the sampling signal and process the sampling signal to obtain the current feedback signal.

[0013] Furthermore, the protection switch is a relay, the positive pole of the coil of the relay is connected to the voltage source, the negative pole of the coil is connected to the processing module, the first contact of the relay is connected to the positive terminal of the power supply, and the second contact of the relay is connected to the positive terminal of the rectifier bridge.

[0014] Furthermore, the positive electrode of the detection unit in the current detection module is connected to the voltage source.

[0015] The utility model also provides an electrical device, comprising the above-mentioned transient current suppression circuit.

[0016] Furthermore, the electrical equipment further includes:

[0017] A filtering protection module, wherein the positive terminal on its input side is connected to the neutral line of the power grid, the negative terminal on its input side is connected to the live line of the power grid, the positive terminal on its output side is connected to the positive terminal of the rectifier bridge through the NTC resistor, and the negative terminal on its output side is connected to the negative terminal of the rectifier bridge.

[0018] Furthermore, the electrical equipment includes at least one of the following: a refrigerator, an air conditioner, a water heater, a washing machine, and an electric rice cooker.

[0019] By applying the technical solution of the present invention, the on / off state of the protection switch 30 is controlled according to the DC bus current value, thereby controlling whether the current flows through the NTC resistor. When the DC bus current value is high, the protection switch connected in parallel with the NTC resistor is controlled to be opened, thereby controlling the current to flow through the NTC resistor and performing transient current suppression. When the DC bus current value returns to normal, the protection switch connected in parallel with the NTC resistor is controlled to be closed, short-circuiting the NTC resistor. The current flows through the protection switch instead of the NTC resistor, thereby preventing the NTC resistor from heating. In summary, it is possible to achieve the transient current suppression effect of the NTC resistor while preventing the NTC resistor from heating, thereby preventing the impact on surrounding electronic components and improving the reliability of electrical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural diagram of an existing transient current suppression circuit;

[0021] Figure 2 1 is a structural diagram of a transient current suppression circuit according to an embodiment of the present utility model;

[0022] Figure 3 2 is a structural diagram of an electrical device according to an embodiment of the present utility model. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0024] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates otherwise, and "a plurality" generally includes at least two.

[0025] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0026] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[0027] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[0028] Optional embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0029] Example 1

[0030] Figure 1 The structure diagram of the existing transient current suppression circuit is as follows: Figure 1 As shown, NTC resistors are currently used to suppress transient currents during startup. In the initial startup state, the NTC resistor has a high resistance value, which can achieve current limiting and suppress transient currents during startup. As the startup process progresses, the temperature of the NTC resistor increases and its resistance decreases. After startup is complete, the resistance of the NTC resistor is reduced to a minimum and will not affect the normal operation of the electrical equipment. As the temperature of the NTC resistor rises, heat will radiate to the surrounding area, causing the temperature of surrounding components to also increase. Especially in miniaturized electrical equipment, the compact layout of electronic components will cause other components to heat up more significantly, causing some electronic components, especially current-sensitive devices, to overheat, greatly increasing the risk of electronic component failure. In addition, under severe harmonic voltage conditions, large induced currents will be generated, increasing the failure probability of bus capacitors and significantly reducing the reliability of electrical equipment.

[0031] In view of the problem in the prior art that when the temperature of the NTC resistor in the electrical equipment rises, the heat will radiate to the surroundings, causing the temperature of the surrounding components to also rise and then fail, this embodiment provides a transient current suppression circuit, which is applied to the electrical equipment, such as the above-mentioned Figure 1 As shown, the electrical equipment includes a rectifier bridge and a bus capacitor C, and an NTC resistor is set between the positive terminal of the rectifier bridge and the positive terminal of the power supply. Figure 2 FIG. 1 is a structural diagram of a transient current suppression circuit according to an embodiment of the present utility model, as shown in FIG. Figure 2 As shown, the transient current suppression circuit includes: a current detection module 10, which is used to generate a current feedback signal based on the DC bus current; a processing module 20, whose input end is connected to the current detection module 10, and whose output end is connected to the control end of the protection switch 30, the processing module 20 is used to obtain the DC bus current value based on the current feedback signal, and control the opening and closing state of the protection switch 30 according to the DC bus current value, thereby controlling whether the current flows through the NTC resistor; the protection switch 30 is set in parallel with the NTC resistor.

[0032] The transient current suppression circuit of this embodiment controls the on / off state of the protection switch 30 based on the DC bus current value, thereby controlling whether the current flows through the NTC resistor. When the DC bus current value is high, the protection switch connected in parallel with the NTC resistor is controlled to be open, thereby controlling the current to flow through the NTC resistor and suppressing the transient current. When the DC bus current value returns to normal, the protection switch connected in parallel with the NTC resistor is controlled to be closed, short-circuiting the NTC resistor. The current flows through the protection switch instead of the NTC resistor, thereby preventing the NTC resistor from heating. In summary, it is possible to achieve the transient current suppression effect of the NTC resistor while preventing the NTC resistor from heating, thereby preventing the impact on surrounding electronic components and improving the reliability of electrical equipment.

[0033] To isolate the current input side from the induced current side, a current sensor 101 is used to detect the DC bus current. Therefore, the current detection module 10 includes a current sensor 101101, which is mounted on the DC bus and generates a sampling signal based on the DC bus current. Current sensor 101 can use a Hall effect element. Because the sampling signal may have low signal strength or contain noise, the current detection module 10 also includes a detection unit 102, which is used to obtain the sampling signal, amplify the sampling signal, and filter it to obtain a current feedback signal.

[0034] In order to achieve automatic control of the protection switch, in some embodiments of the present invention, the above-mentioned protection switch is a relay, the positive pole of the coil of the relay is connected to the voltage source, the negative pole of the coil of the relay is connected to the processing module 20, the first contact of the relay is connected to the positive terminal of the power supply, and the second contact of the relay is connected to the positive terminal of the rectifier bridge.

[0035] In other embodiments of the present invention, the protection switch may also be a controllable switch, such as a MOS tube, an IGBT switch tube, etc.

[0036] The detection unit 102 requires power input to work properly. In order to save components and reduce circuit complexity, the detection unit 102 can share a power supply with the above-mentioned protection switch, and the positive pole of the detection unit 102 in the current detection module is connected to the voltage source.

[0037] like Figure 2As shown, the transient current suppression circuit is mainly composed of modules such as an NTC resistor, a relay, a current sensor 101 and a detection unit 102 for processing the sampling signal of the current sensor. The L terminal of the transient current suppression circuit is simultaneously connected to the 1 terminal of the NTC resistor and the 4 terminal of the relay; the 3 terminal of the relay is connected to the 2 terminal of the NTC resistor, and together connected to the 2 terminal of the rectifier bridge; the N terminal of the electrical device is directly connected to the 3 terminal of the rectifier bridge, and the device connected to the L terminal constitutes the power input terminal; the lead wire from the 1 terminal of the output end of the rectifier bridge passes through the current sensor 101 and is connected to the V+ terminal of the electrical device, forming the positive output pole of the power supply; the 4 terminal of the rectifier bridge is directly connected to the V- terminal of the electrical device, forming the negative output pole of the power supply; the bus capacitor is connected in parallel between the 1 and 4 terminals of the rectifier bridge; for the current sensor 101, the current sensor 101 is connected to the a terminal of the detection unit 102, and then the output terminal b of the detection unit 102 is connected to the FB terminal of the processing module to form a feedback link; for the 1 terminal of the relay, it is directly connected to the SW terminal of the processing module to form a control terminal; the 2 terminal of the relay and the c terminal of the detection unit 102 are jointly connected to the VCC terminal to form a power supply circuit.

[0038] Example 2

[0039] This embodiment provides an electrical device, Figure 3 FIG. 1 is a structural diagram of an electrical device according to an embodiment of the present utility model, as shown in FIG. Figure 3 As shown, the electrical equipment includes a rectifier bridge and a bus capacitor, and also includes the transient current suppression circuit of the above embodiment, which is used to ensure the transient current suppression effect of the NTC resistor while avoiding heating of the NTC resistor, avoiding affecting surrounding electronic components, and improving the reliability of the electrical equipment.

[0040] Because electrical equipment is connected to the power grid, there will be harmonics or high currents in the power from the power grid, which will have an adverse effect on the subsequent circuits. In order to achieve filtering and prevent high currents, such as Figure 3 As shown, the electrical equipment also includes: a filtering protection module 40, the positive terminal on its input side is connected to the neutral line of the power grid, the negative terminal on its input side is connected to the live wire of the power grid, the positive terminal on its output side is connected to the positive terminal of the rectifier bridge through the NTC resistor, and the negative terminal on its output side is connected to the negative terminal of the rectifier bridge, which is used to filter out harmonics and large currents from the power grid.

[0041] like Figure 3As shown, the live wire and the neutral wire first pass through the filtering protection circuit 40, and then the positive and negative terminals L1 and N1 are connected to the terminals L and N respectively, and the terminals V+ and V- are connected to the load R for powering the load; the terminals SW, FB and VCC are respectively connected to different processing units inside the processing module 20, and the processing module 20 receives the level signal output by the FB terminal, processes the signal, and converts it into a current value to realize real-time monitoring of the current operation of the load; when a transient large current is detected, the processing module 20 can input a control signal to the SW terminal to control the relay to disconnect, so as to achieve the effect of suppressing the transient large current.

[0042] In some embodiments of the present invention, the electrical equipment includes at least one of the following: a refrigerator, an air conditioner, a water heater, a washing machine, and an electric rice cooker.

[0043] The circuit embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network elements. Some or all of these modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A transient current suppression circuit, applied to an electrical device, wherein the electrical device comprises a rectifier bridge and a bus capacitor, wherein an NTC resistor is provided between the positive terminal of the rectifier bridge and the positive terminal of the power supply, wherein: The transient current suppression circuit comprises: A current detection module, configured to generate a current feedback signal based on the DC bus current; a processing module, whose input end is connected to the current detection module and whose output end is connected to the control end of the protection switch, wherein the processing module is configured to obtain a DC bus current value based on the current feedback signal, and control the on / off state of the protection switch according to the DC bus current value, thereby controlling whether the current flows through the NTC resistor; The protection switch is arranged in parallel with the NTC resistor.

2. The circuit according to claim 1, wherein: The current detection module includes: a current sensor, mounted on the DC bus and configured to generate a sampling signal based on the DC bus current; The detection unit is used to obtain the sampling signal and process the sampling signal to obtain the current feedback signal.

3. The circuit according to claim 1, wherein: The protection switch is a relay, the positive pole of the coil of the relay is connected to the voltage source, the negative pole of the coil is connected to the processing module, the first contact of the relay is connected to the positive terminal of the power supply, and the second contact of the relay is connected to the positive terminal of the rectifier bridge.

4. The circuit according to claim 3, characterized in that The positive electrode of the detection unit in the current detection module is connected to the voltage source.

5. An electrical device, characterized in that: A transient current suppression circuit comprising the transient current suppression circuit according to any one of claims 1 to 4.

6. The electrical equipment according to claim 5, characterized in that: The electrical equipment also includes: A filtering protection module, wherein the positive terminal on its input side is connected to the neutral line of the power grid, the negative terminal on its input side is connected to the live line of the power grid, the positive terminal on its output side is connected to the positive terminal of the rectifier bridge through the NTC resistor, and the negative terminal on its output side is connected to the negative terminal of the rectifier bridge.

7. The electrical equipment according to claim 5, characterized in that: The electrical equipment includes at least one of the following: a refrigerator, an air conditioner, a water heater, a washing machine, and an electric rice cooker.

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