Circuit for inhibiting starting impact current of alternating current input, control system and air conditioner

Abstract

The utility model discloses a circuit for suppressing starting impact current of alternating current input, a control system and an air conditioner, and belongs to the field of impact current suppression. The circuit for restraining the alternating current input starting impact current is applied to an air conditioner outdoor unit and sequentially comprises a plug connector, an anti-surge unit, a thermistor, an EMI filtering unit and a rectifier bridge, wherein the plug connector is provided with a live wire, a zero wire and a ground wire. The air conditioner outdoor unit is powered on from the air conditioner indoor unit through the plug connector, the plug connector is connected with the anti-surge unit, and the thermistor is arranged between the anti-surge unit and the EMI filtering unit, so that a capacitive load in the EMI filtering unit is located behind the thermistor, large current generated at the moment of power-on can be effectively restrained, the current specification of components in a circuit is reduced, and the service life of the circuit is prolonged. Component cost and size can be reduced, and wiring is facilitated.

Description

Technical Field

[0001] This utility model relates to the field of inrush current suppression technology, and in particular, to a circuit, control system, and air conditioner for suppressing AC input starting inrush current. Background Technology

[0002] A large current typically appears at the moment the AC input power is turned on; this is known as the inrush current. This is mainly because the power input circuit contains a capacitive load. The input capacitor is essentially short-circuited at the moment of power-on, resulting in a very large current during the brief instant of power-on. The inrush current is much greater than the nominal rated current of the circuit design; therefore, relays, fuses, and other components in the input circuit must be selected with stronger current surge resistance.

[0003] Existing technologies typically address excessive starting inrush current by adding a soft-start circuit inside the power supply. This not only increases costs but also raises the after-sales failure rate due to the device topology. Utility Model Content

[0004] To overcome the shortcomings of the prior art, this utility model provides a circuit, control system and air conditioner for suppressing AC input inrush current, so as to solve the problem that the existing technology generally solves the problem of excessive inrush current by adding a soft start circuit inside the power supply. This not only increases the cost, but also increases the after-sales failure rate due to the device topology.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] In a first aspect, a circuit for suppressing AC input inrush current is provided, which is applied to an outdoor unit of an air conditioner. The circuit includes, in sequence, a connector provided with a live wire, a neutral wire and a ground wire, a surge protection unit, a thermistor, an EMI filter unit and a rectifier bridge.

[0007] The connector is connected to the indoor unit of the air conditioner and is powered.

[0008] The connector is connected to the surge protection unit;

[0009] The thermistor is disposed between the surge protection unit and the EMI filter unit;

[0010] The EMI filter unit is connected to the rectifier bridge;

[0011] The rectifier bridge is connected to the load.

[0012] Furthermore, an outdoor unit switch is connected in parallel across the two ends of the thermistor;

[0013] At the instant the outdoor unit is powered on, the outdoor unit switch is turned off so that the thermistor can suppress the inrush current.

[0014] After the outdoor unit is powered on, the outdoor unit switch is closed to allow current to flow through the outdoor unit switch.

[0015] Furthermore, the outdoor unit switch is a relay.

[0016] Furthermore, the surge protection unit includes a first varistor, a second varistor, and a discharge tube;

[0017] One end of the first varistor is connected to the live wire, and the other end is connected to the neutral wire;

[0018] One end of the second varistor is connected to the live wire, and the other end is connected to one end of the discharge tube;

[0019] The other end of the discharge tube is connected to the ground wire.

[0020] Furthermore, the EMI filtering unit includes a common-mode inductor, a capacitor module, and a resistor module.

[0021] Furthermore, the capacitor module includes multiple capacitors;

[0022] The multiple capacitors are symmetrically arranged across the common-mode inductor.

[0023] Furthermore, the capacitor module includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, and a sixth capacitor, and the resistor module includes a first resistor and a second resistor;

[0024] The first capacitor, the third capacitor, and the fourth capacitor are disposed before the common mode inductor, and the second capacitor, the fifth capacitor, and the sixth capacitor are disposed after the common mode inductor;

[0025] One end of the first capacitor is connected to the live wire, and the other end is connected to the neutral wire;

[0026] The second capacitor has one end connected to the live wire and the other end connected to the neutral wire;

[0027] One end of the third capacitor is connected to the live wire, and the other end is connected to the ground wire;

[0028] One end of the fourth capacitor is connected to the neutral wire, and the other end is connected to the ground wire;

[0029] One end of the fifth capacitor is connected to the neutral wire, and the other end is connected to the ground wire through the first resistor. One end of the sixth capacitor is connected to the live wire, and the other end is connected to the ground wire through the second resistor.

[0030] Furthermore, it also includes: fuses;

[0031] The fuse is positioned before the surge protection unit;

[0032] The fuse is located on the live wire.

[0033] Secondly, a control system is provided, comprising:

[0034] The circuit described above;

[0035] The mains power line is connected to the connector in the circuit via the indoor unit switch and the indoor / outdoor unit connection line.

[0036] When the indoor unit switch is closed, the mains power line supplies power to the connector;

[0037] When the indoor unit switch is off, the mains power line does not supply power to the connector.

[0038] Thirdly, an air conditioner is provided, comprising: a control system as described above.

[0039] The application employs the above technical solution and has at least the following beneficial effects:

[0040] This application provides a circuit, control system, and air conditioner for suppressing AC input inrush current. The circuit for suppressing AC input inrush current is applied to the outdoor unit of the air conditioner and includes, in sequence, a connector with live, neutral, and ground wires, a surge protection unit, a thermistor, an EMI filter unit, and a rectifier bridge. The outdoor unit receives power from the indoor unit via the connector. The surge protection unit is connected after the connector. The thermistor is positioned between the surge protection unit and the EMI filter unit. This arrangement places the capacitive load within the EMI filter unit after the thermistor, effectively suppressing the large current generated at power-on. This reduces the current rating of components in the circuit, lowers component costs and size, and facilitates wiring. Attached Figure Description

[0041] 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.

[0042] Figure 1 This is a schematic diagram of a circuit structure for suppressing AC input inrush current provided by an embodiment of the present invention;

[0043] Figure 2 This is a circuit schematic diagram of an embodiment of the present invention for suppressing AC input inrush current;

[0044] Figure 3This is a circuit diagram of a control system provided in an embodiment of the present invention.

[0045] K1 - Indoor unit switch, CN1 - Connector, L - Live wire, N - Neutral wire, E - Ground wire, FU1 - Fuse, K2 - Outdoor unit switch, RT1 - Thermistor, RV1 - First varistor, RV2 - Second varistor, TVS1 - Discharge tube, C1 - First capacitor, C2 - Second capacitor, C3 - Third capacitor, C4 - Fourth capacitor, C5 - Fifth capacitor, C6 - Sixth capacitor, L1 - Common mode inductor, R1 - First resistor, R2 - Second resistor, G1 - Rectifier bridge. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this utility model will be described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of 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.

[0047] Reference Figure 1 and Figure 2 This utility model provides a circuit for suppressing AC input inrush current, applied to an air conditioner outdoor unit. The circuit includes, in sequence: a connector CN1 with a live wire L, a neutral wire N and a ground wire E, a surge protection unit, a thermistor RT1, an EMI filter unit and a rectifier bridge G1.

[0048] The connector CN1 is connected to the indoor unit of the air conditioner and is powered.

[0049] The connector CN1 is connected to the surge protection unit;

[0050] The thermistor RT1 is disposed between the surge protection unit and the EMI filter unit;

[0051] The EMI filter unit is connected to the rectifier bridge G1;

[0052] The rectifier bridge G1 is connected to the load. The specific form of the rectifier bridge G1 is not specifically limited in this application and can be set according to actual needs.

[0053] Among them, the thermistor RT1 is a PTC resistor or an NTC resistor. PTC resistors are positive temperature coefficient resistors, and their main characteristic is that the higher the temperature, the greater the resistance.

[0054] This application uses thermistor RT1 as a PTC resistor as an example for further explanation. Figure 2 As shown, an outdoor unit switch K2 is connected in parallel across the thermistor RT1;

[0055] At the instant the outdoor unit is powered on, the outdoor unit switch K2 is turned off so that the thermistor RT1 can suppress the inrush current.

[0056] After the outdoor unit is powered on, the outdoor unit switch K2 is closed to allow current to flow through the outdoor unit switch K2.

[0057] In a preferred implementation of this application, the outdoor unit switch K2 is a relay. Strong and weak currents are isolated to ensure safety.

[0058] As a preferred implementation of this application, the surge protection unit includes a first varistor RV1, a second varistor RV2, and a discharge tube TVS1;

[0059] One end of the first varistor RV1 is connected to the live wire L, and the other end is connected to the neutral wire N;

[0060] One end of the second varistor RV2 is connected to the live wire L, and the other end is connected to one end of the discharge tube TVS1;

[0061] The other end of the discharge tube TVS1 is connected to the ground wire E.

[0062] When a surge voltage enters the outdoor unit's main board, the resistance values ​​of the first varistor RV1 and the second varistor RV2 decrease rapidly, dissipating most of the surge energy through the discharge tube TVS1 until the voltage drops to the safe operating voltage, at which point the resistance values ​​of the first varistor RV1 and the second varistor RV2 return to their nominal values.

[0063] In a preferred implementation of this application, the EMI filtering unit includes a common-mode inductor L1, a capacitor module, and a resistor module.

[0064] The common-mode inductor L1 typically consists of two coils of identical size and number of turns symmetrically wound on a magnetic core, forming a bidirectional, two-wire structure. Its main function is to suppress common-mode interference signals, i.e., interference signals that act simultaneously on two signal lines. The common-mode inductor L1 has important applications in switching power supplies, frequency converters, UPS power supplies, and other equipment, effectively filtering out these interference signals and ensuring stable equipment operation.

[0065] The capacitor module includes multiple capacitors;

[0066] The multiple capacitors are symmetrically arranged across the common-mode inductor L1.

[0067] For example, the capacitor module includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a sixth capacitor C6, and the resistor module includes a first resistor R1 and a second resistor R2.

[0068] The first capacitor C1, the third capacitor C3, and the fourth capacitor C4 are disposed before the common mode inductor L1, and the second capacitor C2, the fifth capacitor C5, and the sixth capacitor C6 are disposed after the common mode inductor L1.

[0069] The first capacitor C1 is connected to the live wire L at one end and to the neutral wire N at the other end.

[0070] The second capacitor C2 is connected to the live wire L at one end and to the neutral wire N at the other end.

[0071] One end of the third capacitor C3 is connected to the live wire L, and the other end is connected to the ground wire E;

[0072] The fourth capacitor C4 is connected to the neutral line N at one end and to the ground line E at the other end.

[0073] One end of the fifth capacitor C5 is connected to the neutral line N, and the other end is connected to the ground line E through the first resistor R1.

[0074] One end of the sixth capacitor C6 is connected to the live wire L, and the other end is connected to the ground wire E through the second resistor R2.

[0075] The reason why the fifth capacitor C5 is connected to ground E through the first resistor R1 and the sixth capacitor C6 is connected to ground E through the second resistor R2 is to enhance the filtering effect.

[0076] Among them, the first capacitor C1 is a safety X capacitor, the second capacitor C2 is a safety X capacitor, the third capacitor C3 is a safety Y capacitor, the fourth capacitor C4 is a safety Y capacitor, the fifth capacitor C5 is a safety Y capacitor, and the sixth capacitor C6 is a safety Y capacitor.

[0077] Compared to conventional capacitors, safety capacitors possess superior insulation properties and high-voltage resistance, effectively isolating high-voltage power supplies from low-voltage signals in high-voltage AC operating environments, preventing electric shock and leakage. Safety capacitors do not pose a hazard to human health even after failure, ensuring personal safety. They are primarily used in power-supply electronic instruments and equipment, especially in areas where spark discharge occurs, such as switches and contacts, absorbing pulse interference and reducing electromagnetic interference. Safety capacitors are classified into X capacitors and Y capacitors; X capacitors suppress differential-mode interference, while Y capacitors suppress common-mode interference.

[0078] In addition, it also includes: Fuse FU1;

[0079] The fuse FU1 is positioned before the surge protection unit;

[0080] The fuse FU1 is installed on the live wire L.

[0081] Fuse FU1 is an overcurrent protection device on the outdoor unit's main board. It will be triggered and blown when a large current passes through it, thus protecting the circuit.

[0082] In the existing technical solution, the thermistor RT1 is placed after the EMI filter unit and before the rectifier bridge G1. This solution can suppress the large current generated by the capacitive load after the thermistor RT1 when it is powered on. However, since there is also a capacitive load in the EMI filter unit and it is located after the thermistor RT1, a large instantaneous current will be generated at the moment of power-on due to the charging effect of the capacitive load in the EMI filter unit. Components such as fuses still need to be selected with high current specifications, which has the disadvantages of high component cost and large component size, which restricts the routing of motherboard.

[0083] This invention connects the PTC resistor RT1 and the outdoor unit switch K2 circuit in series between the surge protection circuit and the EMI circuit. When the indoor unit relay K1 is activated, the outdoor unit switch K2 is not activated. Current flows through the PTC resistor RT1 to charge the safety capacitors C1, C2, C3, and C4. The current-limiting effect of the PTC resistor RT1 effectively suppresses the inrush current, allowing smaller components such as the fuse FU1 to be used, thus achieving cost reduction and efficiency improvement.

[0084] The circuit for suppressing AC input inrush current provided in this application embodiment is applied to an air conditioner outdoor unit. It sequentially includes a connector with live, neutral, and ground wires, a surge protection unit, a thermistor, an EMI filter unit, and a rectifier bridge. The outdoor unit receives power from the indoor unit via the connector, which is connected to the surge protection unit. The thermistor is positioned between the surge protection unit and the EMI filter unit, so that the capacitive load within the EMI filter unit is located after the thermistor. This effectively suppresses the large current generated at power-on, reducing the current rating of components in the circuit, thereby reducing component cost and size, and facilitating wiring. This circuit addresses the problem of excessive inrush current at power-on of the inverter controller. It suppresses the starting current without increasing cost, allowing for smaller specifications for relays, fuses, and other components in the AC input circuit, thus meeting overall cost reduction requirements.

[0085] Based on the same inventive concept, embodiments of this application also provide a control system, such as... Figure 3 As shown, it includes:

[0086] like Figure 2 The circuit shown;

[0087] The mains power line is connected to the connector CN1 in the circuit via the indoor unit switch K1 and the indoor / outdoor unit connection line.

[0088] When the indoor unit switch K1 is closed, the mains power line supplies power to the connector CN1;

[0089] When the indoor unit switch K1 is turned off, the mains power line does not supply power to the connector CN1.

[0090] The indoor unit switch K1 controls whether the outdoor unit is powered. The indoor and outdoor units are connected by a 3.5-meter connecting cable. The fuse FU1 is an overcurrent protection device on the outdoor unit's main board, which will be triggered and blown when a large current passes through.

[0091] In the surge protection unit, the first varistor RV1 is located between the live wire and the neutral wire, and the second varistor RV2 is connected to the live wire at one end and to the discharge tube TVS1 at the other end. The other end of the discharge tube TVS1 is connected to the ground wire. When a surge voltage enters the outdoor unit's main board, the resistance values ​​of the first and second varistors decrease rapidly, dissipating most of the surge energy through the discharge tube TVS1 until the voltage drops to the safe operating voltage. At this point, the resistance values ​​of the first and second varistors return to their nominal values.

[0092] PTC resistor RT1 is a positive temperature coefficient resistor, whose main characteristic is that the higher the temperature, the greater the resistance. The high-voltage terminal of the outdoor unit switch K2 is connected in parallel with PTC resistor RT1. After the outdoor unit is normally powered on, the outdoor unit switch K2 is energized. At this time, the current does not pass through PTC resistor RT1, but through the outdoor unit switch K2.

[0093] Safety capacitor C1 is located between the live wire and the neutral wire, safety capacitor C3 is located between the live wire and the ground wire, and safety capacitor C4 is located between the neutral wire and the ground wire. These three components are located between the common mode inductor L1 and the PTC resistor.

[0094] Safety capacitors C2, C5, and C6 are symmetrically distributed after the corresponding common-mode inductor. To enhance the filtering effect, safety capacitors C5 and C6 are connected in series with the first resistor R1 and the second resistor R2. The EMI circuit is then connected to a rectifier bridge G1 to convert AC to DC and supply power to the subsequent load.

[0095] This circuit differs from the conventional solution. In the conventional solution, the PTC resistor RT1 and the outdoor unit switch K2 are placed after the EMI filter circuit and before the rectifier bridge. In this solution, when the indoor unit switch K1 is energized, a large instantaneous current will be generated due to the charging effect of capacitive loads such as safety capacitors C1, C3, and C4. The relay K1 and fuse FU1 need to be selected with high current specifications, which has the disadvantages of high component cost and large component size, which restricts the routing of the motherboard.

[0096] To overcome the shortcomings of conventional solutions, this invention connects the PTC resistor RT1 and the outdoor unit switch K2 circuit in series between the surge protection circuit and the EMI circuit. When the indoor unit switch K1 is activated, the outdoor unit switch K2 is not activated. Current flows through the PTC resistor RT1 to charge the safety capacitors C1, C2, C3, and C4. The current-limiting effect of the PTC resistor RT1 effectively suppresses the inrush current, allowing smaller components to be used for the relay K1 and fuse FU1, thus achieving cost reduction and efficiency improvement.

[0097] The advantage of this solution is that it can effectively suppress the inrush current on the outdoor unit controller of the air conditioner without increasing the cost and quantity of circuit components, and also meet the cost reduction requirements of the indoor unit relay.

[0098] The control system provided in this application embodiment has a PTC connected in series before the capacitive load in the AC input circuit. The PTC is preceded by a surge protection circuit. Upon power-up, the relay does not engage, and current flows through the PTC to charge subsequent capacitive loads such as the X capacitor and electrolytic capacitor. This current is not excessively high due to the PTC's impedance effect. The relay engages only after the subsequent switching power supply and main chip power on and start up. At this time, the PTC is not in the circuit, reducing PTC heat generation and overall power consumption.

[0099] Based on the same inventive concept, this application provides an air conditioner, including: a control system as provided in the above embodiments.

[0100] The air conditioner provided in this application includes a control system as described in the above embodiments. When the indoor unit switch of the indoor unit is closed, the outdoor unit receives power from the indoor unit through a connector. A surge protection unit is connected after the connector. A thermistor is placed between the surge protection unit and the EMI filter unit. In this way, the capacitive load in the EMI filter unit is located after the thermistor, which can effectively suppress the large current generated at the moment of power-on, reduce the current specification of the components in the circuit, reduce the component cost and size, and facilitate wiring.

[0101] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0102] 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, "a plurality of" means at least two.

[0103] 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.

[0104] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof.

[0105] 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.

[0106] 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.

[0107] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0108] 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.

[0109] 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 circuit for suppressing AC input inrush current, characterized in that, Applied to an outdoor unit of an air conditioner, the circuit sequentially includes: a connector with a live wire, a neutral wire and a ground wire, a surge protection unit, a thermistor, an EMI filter unit and a rectifier bridge; The connector is connected to the indoor unit of the air conditioner and is powered. The connector is connected to the surge protection unit; The thermistor is disposed between the surge protection unit and the EMI filter unit; The EMI filter unit is connected to the rectifier bridge; The rectifier bridge is connected to the load.

2. The circuit according to claim 1, characterized in that: An outdoor unit switch is connected in parallel across the two ends of the thermistor; At the instant the outdoor unit is powered on, the outdoor unit switch is turned off so that the thermistor can suppress the inrush current. After the outdoor unit is powered on, the outdoor unit switch is closed to allow current to flow through the outdoor unit switch.

3. The circuit according to claim 2, characterized in that: The outdoor unit switch is a relay.

4. The circuit according to claim 1, characterized in that: The surge protection unit includes a first varistor, a second varistor, and a discharge tube; One end of the first varistor is connected to the live wire, and the other end is connected to the neutral wire; One end of the second varistor is connected to the live wire, and the other end is connected to one end of the discharge tube; The other end of the discharge tube is connected to the ground wire.

5. The circuit according to claim 1, characterized in that: The EMI filtering unit includes a common-mode inductor, a capacitor module, and a resistor module.

6. The circuit according to claim 5, characterized in that: The capacitor module includes multiple capacitors; The plurality of capacitors are symmetrically arranged across the common-mode inductor.

7. The circuit according to claim 6, characterized in that: The capacitor module includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, and a sixth capacitor; the resistor module includes a first resistor and a second resistor. The first capacitor, the third capacitor, and the fourth capacitor are disposed before the common mode inductor, and the second capacitor, the fifth capacitor, and the sixth capacitor are disposed after the common mode inductor; One end of the first capacitor is connected to the live wire, and the other end is connected to the neutral wire; The second capacitor has one end connected to the live wire and the other end connected to the neutral wire; One end of the third capacitor is connected to the live wire, and the other end is connected to the ground wire; One end of the fourth capacitor is connected to the neutral wire, and the other end is connected to the ground wire; One end of the fifth capacitor is connected to the neutral wire, and the other end is connected to the ground wire through the first resistor. One end of the sixth capacitor is connected to the live wire, and the other end is connected to the ground wire through the second resistor.

8. The circuit according to claim 1, characterized in that, Also includes: Fuse; The fuse is positioned before the surge protection unit; The fuse is located on the live wire.

9. A control system, characterized in that, include: The circuit as described in any one of claims 1-8; The mains power line is connected to the connector in the circuit via the indoor unit switch and the indoor / outdoor unit connection line. When the indoor unit switch is closed, the mains power line supplies power to the connector; When the indoor unit switch is off, the mains power line does not supply power to the connector.

10. An air conditioner, characterized in that, include: The control system as described in any one of claims 9.

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