Power supply system with power-on overcurrent protection circuit and air conditioning system

Abstract

The utility model discloses a power supply system with a power-on over-current protection circuit and an air conditioning system, and the power supply system with the power-on over-current protection circuit comprises a power factor correction circuit and a bus capacitor which are carried on a live wire and a zero wire which are used for providing electric energy. The power factor correction circuit is used for adjusting the voltage on the live wire and supplying power to the bus capacitor, and the bus capacitor can supply power to a load connected with the bus capacitor. The thermistor and the power factor correction circuit are connected in series on the live wire together, the voltage detection circuit is used for detecting electrical parameters on the live wire, and the switch control circuit is used for adjusting the access state of the thermistor according to the electrical parameters. Compared with the prior art, the circuit can accurately control the connection and disconnection of the thermistor, thereby solving the problem that a unit is shut down due to faults when the power-on interval is short.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to a power supply system and an air conditioning system with a power-on overcurrent protection circuit. Background Art

[0002] With the rapid development of existing air-conditioning technology and the improvement of people's quality of life, the country has certain standards for harmonic currents. Most air-conditioning outdoor units will use power factor correction circuits to solve related problems. However, since the circuit parameters of the components on the unit are set during the design process, it is necessary to add some protection measures such as overvoltage maintenance and overcurrent detection to the relevant circuits to ensure the safe operation of the unit. At this time, the mutual cooperation between the circuits of each module is required to ensure the stable and reliable operation of the unit.

[0003] In order to solve the problem of excessive current at power-on, the unit will add an NTC / PTC resistor to the live wire of the power supply to suppress the instantaneous surge current at power-on. After the unit is powered on, a relay is used to short-circuit the NTC / PTC resistor. However, this method has a defect. In special cases, the power is restored soon after the community power outage. Since the power of the rear bus capacitor has not been fully released, the relay is not disconnected at the moment of power-on, and the NTC / PTC resistor is not connected to the network, resulting in excessive instantaneous surge current, causing the PFC current detection of the unit to be too large, causing the unit to report a fault and shut down; even worse, excessive current damages semiconductor components in the circuit.

[0004] Therefore, how to design a power supply system and air conditioning system with a power-on overcurrent protection circuit to solve the problem of false overcurrent protection faults of the unit is a technical problem that needs to be solved urgently in the industry. Utility Model Content

[0005] In view of the problem in the prior art that at the moment of power-on, the relay is not disconnected and the NTC / PTC resistor is not connected to the network, resulting in an instantaneous excessive surge current, causing the PFC current detection of the unit to be too large, causing the unit to report a fault and shut down, the utility model proposes a power supply system and an air-conditioning system with a power-on overcurrent protection circuit.

[0006] The technical solution of the utility model is to propose a power supply system with a power-on overcurrent protection circuit, including a power factor correction circuit and a bus capacitor mounted on a live wire and a neutral wire for providing electric energy, wherein the power factor correction circuit is used to adjust the voltage on the live wire and supply power to the bus capacitor, and the bus capacitor can supply power to a load connected thereto, and also includes a thermistor connected in series with the power factor correction circuit on the live wire, a voltage detection circuit for detecting electrical parameters on the live wire, and a switch control circuit for adjusting the access state of the thermistor according to the electrical parameters.

[0007] Furthermore, it also includes a switching power supply connected to the bus capacitor and capable of drawing power from the bus capacitor;

[0008] The voltage detection circuit and the switch control circuit are mounted on the same main control chip, and the main control chip is connected to the switch power supply for power supply.

[0009] Further, the electrical parameter is voltage;

[0010] When the voltage on the live wire is not zero, the switch control circuit controls the thermistor to be short-circuited;

[0011] When the voltage on the live wire is zero, the switch control circuit controls the thermistor to be normally connected.

[0012] Furthermore, the voltage detection circuit includes: a resistor R1, a resistor R2, a resistor R3, a diode D1, and an optical coupler U1;

[0013] The positive electrode of the diode D1 is connected to the live wire, the negative electrode of the diode D1 is connected in series with the resistor R3 and then connected to the first end of the control end of the optocoupler U1, and the second end of the control end of the optocoupler U1 is connected to the neutral wire;

[0014] One end of the resistor R2 is connected to a power supply, the other end of the resistor R2 is connected to the first end of the controlled end of the optical coupler U1, the second end of the controlled end of the optical coupler U1 is connected to the detection pin of the main control chip, and one end of the resistor R1 is connected to the second end of the controlled end of the optical coupler U1 and the detection pin of the main control chip.

[0015] Between the detection pins of the main control chip, the other end of the resistor R1 is grounded.

[0016] Furthermore, the switch control circuit includes: a resistor R4, a transistor Q1, and a relay K1;

[0017] The collector of the transistor Q1 is connected to the second end of the control end of the relay K1, the base of the transistor Q1 is connected in series with the resistor R4 and then connected to the driving pin of the main control chip, the emitter of the transistor Q1 is grounded, and the first end of the control end of the relay K1 is connected to a power supply;

[0018] The controlled end of the relay K1 is connected to both ends of the thermistor.

[0019] Furthermore, when the detection pin of the main control chip is at a high level, the driving pin of the main control chip is at a high level;

[0020] When the detection pin of the main control chip is at a low level, the driving pin of the main control chip is at a low level.

[0021] Furthermore, the thermistor is an NTC resistor or a PTC resistor.

[0022] Furthermore, it also includes a filter circuit which is arranged at the front stage of the power factor correction circuit and mounted between the live wire and the neutral wire.

[0023] Furthermore, it also includes a rectifier circuit which is arranged at the front stage of the power factor correction circuit and mounted between the live wire and the neutral wire.

[0024] The utility model also provides an air conditioning system, which comprises a power supply system of the overcurrent protection circuit.

[0025] Compared with the prior art, the utility model has at least the following beneficial effects:

[0026] The utility model is provided with a voltage detection circuit, and the voltage detection circuit is mounted on the live wire. By detecting the voltage of the live wire, it is possible to more intuitively and accurately know whether the load is powered on and working. At the same time, in conjunction with the switch control circuit provided in the utility model, it is possible to control whether the thermistor is connected or not. This ensures that when the load is operating normally, the thermistor is short-circuited to avoid power loss caused by the thermistor, and when the load is powered on, the thermistor can be accurately connected to suppress surge current at the moment of power-on. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 It is a logic block diagram of the utility model as a whole;

[0029] Figure 2 This is a circuit topology diagram related to thermistor control of the utility model;

[0030] Figure 3 It is a circuit topology diagram of the voltage detection circuit in the utility model;

[0031] Figure 4 It is a connection diagram of the switch control circuit and the thermistor in the utility model. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the utility model, rather than implying that each embodiment of the utility model must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0034] The principle and structure of the present utility model are described in detail below with reference to the accompanying drawings and embodiments.

[0035] In order to solve the problem of excessive current at power-on, the unit will add an NTC / PTC resistor to the live wire of the power supply to suppress the instantaneous surge current at power-on. After the unit is powered on, a relay is used to short-circuit the NTC / PTC resistor. However, this method has a defect, that is, when the power is cut off and powered on in a short period of time, since the energy of the rear bus capacitor has not been fully released, the relay is not disconnected at the moment of power-on, and the NTC / PTC resistor is not connected to the network, resulting in excessive instantaneous surge current, causing the PFC current detection of the unit to be too large, causing the unit to report a fault and shut down; what's more, the excessive current damages the semiconductor components in the circuit.

[0036] In view of the above problems, the design idea of ​​the utility model is to set up a detection circuit for detecting the voltage on the live wire, so as to more accurately know whether the load is powered on and working, and cooperate with the switch control circuit to control the access of the thermistor, so as to suppress the surge current at the moment of power-on, and avoid the problem of excessive PFC current detection causing the unit to report a fault and shut down.

[0037] Specifically, the power supply system with a power-on overcurrent protection circuit proposed in the utility model includes a power factor correction circuit and a bus capacitor mounted on a live wire and a neutral wire for providing electrical energy. The power factor correction circuit is used to adjust the voltage on the live wire and supply power to the bus capacitor. The bus capacitor can supply power to the load connected thereto. It also includes a thermistor connected in series with the power factor correction circuit on the live wire, a voltage detection circuit for detecting electrical parameters on the live wire, and a switch control circuit for adjusting the access state of the thermistor according to the electrical parameters.

[0038] See also Figure 1 , which is the overall logic block diagram of the utility model, the power factor correction circuit is also the attached Figure 1The "PFC" in the figure refers to the bus capacitor. Figure 1 The DC bus in the diagram is the load. Figure 1 The "compressor and other loads" in the above text are thermistors. Figure 1 The "NTC / PTC resistor" in the voltage detection circuit is also the Figure 1 The "voltage detection" in the switch control circuit is also the attached Figure 1 , then select Switch Access.

[0039] From this attachment Figure 1 It can be seen that the thermistor is directly connected in series with the live wire, one side of the switch control circuit is connected to both ends of the thermistor, and when the switch corresponding to the switch control circuit is closed, the thermistor can be short-circuited;

[0040] One side of the voltage detection circuit is directly connected to the live wire, and it can directly obtain whether the load is powered on and working. If the load is working normally, the voltage on the live wire must not be 0, and the voltage detection circuit can detect a high-level signal. Conversely, when the load is powered off, the voltage on the live wire is 0, and the voltage detection circuit can detect a low-level signal.

[0041] Therefore, based on this setting, the working principle of the utility model can be:

[0042] The working state of the load is accurately determined through the voltage detection circuit. When the voltage on the detected live wire is not zero and stabilizes, it indicates that the load is working normally. At this time, the thermistor needs to be short-circuited through the switch control circuit to avoid the loss caused by the thermistor.

[0043] When it is detected that the voltage on the live wire is zero, it indicates that the load is not working at this time. In order to avoid a large surge current generated when power is turned on, it is necessary to connect the thermistor normally through the switch control circuit to suppress the surge current at the moment of power-on and avoid the problem of excessive PFC current detection causing the unit to report a fault and shut down.

[0044] The power supply system with power-on overcurrent protection circuit proposed by the utility model further includes a switching power supply connected to a bus capacitor and capable of drawing power from the bus capacitor;

[0045] The voltage detection circuit and the switch control circuit are mounted on the same main control chip, and the main control chip is connected to a switch power supply for power supply.

[0046] See also Figure 1 , the switching power supply is also attached Figure 1 The "switching power supply" in the main control chip is also attached Figure 1 "MCU Control System" in Appendix Figure 1 The parts in the dotted box belong to the main control chip;

[0047] From this attachment Figure 1 It can be clearly seen that after the bus capacitor obtains electrical energy from the live wire, the electrical energy is divided into two parts. The first part is provided to the load, and the second part is provided to the DC power supply. The DC power supply can perform voltage conversion and convert the voltage into various subsequent low-voltage control circuits.

[0048] Here, the purpose of setting a switching power supply is to avoid the need to set up an additional power supply, and to directly draw power from the bus capacitor, thereby avoiding the waste of electric energy. At the same time, since the working voltage of the main control chip is different from the voltage on the bus capacitor, it may cause damage to the main control chip. After setting up the switching power supply, the voltage on the bus capacitor can be converted into the working voltage of the main control chip, thus avoiding the occurrence of the above problems.

[0049] Furthermore, the electrical parameter in the present invention is voltage;

[0050] The control logic of the utility model is:

[0051] When the voltage on the live wire is not zero, the switch control circuit controls the thermistor to be short-circuited;

[0052] Here, when the voltage on the live wire is not zero, it indicates that the load is working normally at this time, so at this time it is necessary to short-circuit the thermistor through the switch control circuit to avoid the loss caused by the thermistor;

[0053] When the voltage on the live wire is zero, the switch control circuit controls the thermistor to be normally connected;

[0054] Here, when the voltage on the live wire is zero, it indicates that the load is not working at this time. Therefore, in order to avoid a large surge current generated when power is turned on, it is necessary to connect the thermistor normally through the switch control circuit to suppress the surge current at the moment of power-on and avoid the problem of excessive PFC current detection causing the unit to report a fault and shut down.

[0055] See also Figure 2 and Figure 3 , the voltage detection circuit of the utility model includes: a resistor R1, a resistor R2, a resistor R3, a diode D1, and an optical coupler U1;

[0056] The positive electrode of the diode D1 is connected to the live wire, the negative electrode of the diode D1 is connected in series with the resistor R3 and then connected to the first end of the control end of the optocoupler U1, and the second end of the control end of the optocoupler U1 is connected to the neutral wire;

[0057] One end of the resistor R2 is connected to a power supply, the other end of the resistor R2 is connected to the first end of the controlled end of the optocoupler U1, the second end of the controlled end of the optocoupler U1 is connected to the detection pin of the main control chip, one end of the resistor R1 is connected between the second end of the controlled end of the optocoupler U1 and the detection pin of the main control chip, and the other end of the resistor R1 is grounded.

[0058] Here, the power supply is also the Figure 2 and attached Figure 3 The VCC in the figure can also be powered by the switching power supply mentioned above;

[0059] The detection pin is also the Figure 2 and attached Figure 3 MCU-VCD pin in.

[0060] The following is combined with Figure 2 And attached Figure 3 , the working principle of the voltage detection circuit in the utility model is introduced:

[0061] When the voltage on the live line is not zero:

[0062] At this time, the current flowing out of the live wire can flow into the first end of the control end of the optocoupler U1 after passing through the diode D1 and the resistor R3 in sequence, and then flow to the neutral line through the second end of the control end of the optocoupler U1, forming a loop. At this time, the control end of the optocoupler U1 is normally powered on, and it can turn on the controlled end of the optocoupler U1. Since the first end of the controlled end of the optocoupler U1 is connected to a power supply, after the controlled end of the optocoupler U1 is turned on by its control end, the current flowing out of the power supply will flow into the first end of the controlled end of the optocoupler U1 after passing through the resistor R2, and then flow out from the second end of the controlled end of the optocoupler U1, and pass through the resistor R1 to the ground;

[0063] At this time, since the detection pin of the main control chip is connected between the second end of the controlled end of the optocoupler U1 and the resistor R1, the voltage on the detection pin is pulled up to the divided voltage of the resistor R1, which is a high level;

[0064] When the voltage on the live line is zero:

[0065] At this time, no current flows out of the live wire. After passing through the diode D1 and the resistor R3, the current flowing into the first end of the control end of the optocoupler U1 is 0, and then flows to the neutral line through the second end of the control end of the optocoupler U1, forming a loop. At this time, no current flows through the control end of the optocoupler U1, and it is in a power-off state. At this time, although the first end of the controlled end of the optocoupler U1 is connected to a power supply, after the controlled end of the optocoupler U1 cannot be turned on by its control end, the current flowing out of the power supply flows into the first end of the controlled end of the optocoupler U1 after passing through the resistor R2, but cannot flow out from the second end of the controlled end of the optocoupler U1. At this time, the current flowing through the resistor R1 is 0;

[0066] At this time, since the detection pin of the main control chip is connected between the second end of the controlled end of the optocoupler U1 and the resistor R1, the voltage on the detection pin is pulled down to the divided voltage of the resistor R1, which is a low level;

[0067] In summary, it can be seen that in the present invention, when the voltage on the live wire is not zero, the voltage detected by the detection pin is a high level;

[0068] In the utility model, when the voltage on the live wire is zero, the voltage detected by the detection pin is a low level.

[0069] Here, the role of the diode D1 is rectification. Since the voltage on the live line is AC, and the diode D1 has the unidirectional conduction characteristic, it can only flow the current in the same direction of the AC, that is, rectify the AC into DC to provide it to the optocoupler U1.

[0070] The resistor R3 acts as a current limiting resistor. For the AC power carried by the live wire, it is generally 220V or 380V. Even if it is converted into DC power, it is still too high for the working voltage of the optocoupler U1. Therefore, the resistor R3 needs to be set for current limiting to prevent the optocoupler U1 from being damaged by excessive voltage.

[0071] The resistor R1 acts as a pull-down resistor. When the controlled end of the optocoupler U1 is not conducting, the voltage on the resistor R1 is 0. The detection pin is connected to the resistor R1, and its voltage will be pulled down to a low level, that is, the voltage detected by the detection pin is a low level.

[0072] The resistor R2 acts as a pull-up resistor. When the controlled end of the optocoupler U1 is turned on, the resistor R2 is powered on, and it provides voltage to the detection pin through the controlled end of the optocoupler U1, pulling the level of the detection pin to a high level, that is, the voltage detected by the detection pin is a high level;

[0073] The function of the optocoupler U1 is isolation, which is used to separate the high-voltage circuit at the control end of the optocoupler U1 from the low-voltage circuit at the controlled end of the optocoupler U1, thereby preventing the low-voltage circuit at the controlled end of the optocoupler U1 from being damaged by excessive voltage on the live line.

[0074] See also Figure 2 and Figure 4 , the switch control circuit in the utility model includes: a resistor R4, a transistor Q1, and a relay K1;

[0075] The collector of the transistor Q1 is connected to the second end of the control end of the relay K1, the base of the transistor Q1 is connected in series with the resistor R4 and then connected to the driving pin of the main control chip, the emitter of the transistor Q1 is grounded, and the first end of the control end of the relay K1 is connected to a power supply;

[0076] The controlled terminals of relay K1 are connected across the thermistor.

[0077] Here, the power supply also includes the Figure 2 and attached Figure 4The 12V power supply can also be realized by the switching power supply mentioned above;

[0078] The drive pin is also the Figure 2 and attached Figure 4 MCU-CTR pin in.

[0079] The following is combined with Figure 2 and attached Figure 4 , the working principle of the switch control circuit in the utility model is introduced:

[0080] When the drive pin is high:

[0081] The main control chip has detection and drive pins, which can adjust the voltage signal of the drive pin according to the voltage signal detected by the detection pin, so as to achieve the control effect of the switch control circuit. Since the base of the transistor Q1 is connected to the drive pin through the resistor R4, the base of the transistor Q1 is pulled up to a high level, and the emitter of the transistor Q1 is grounded, so that the emitter of the transistor Q1 is pulled down to a low level. At this time, the base voltage of the transistor Q1 is greater than the emitter voltage of the transistor Q1, and the transistor Q1 is turned on;

[0082] Since the first end of the control end of the relay K1 is connected to the power supply, the current flowing out of the power supply can flow in through the first end of the control end of the relay K1, flow out through the second end of the control end of the relay K1, and flow into the ground after passing through the collector and emitter of the transistor Q1, so that the control end of the relay K1 is normally powered on;

[0083] When the control end of relay K1 is powered on normally, it will close the switch of the controlled end of relay K1. Since the switch of the controlled end of relay K1 is connected in parallel to both ends of the thermistor, the switch of the controlled end of relay K1 is equivalent to short-circuiting the thermistor, that is, the thermistor is short-circuited at this time.

[0084] When the drive pin is low:

[0085] The main control chip has detection and drive pins, which can adjust the voltage signal of the drive pin according to the voltage signal detected by the detection pin, so as to achieve the control effect of the switch control circuit. Since the base of the transistor Q1 is connected to the drive pin through the resistor R4, the base of the transistor Q1 is pulled down to a low level, and the emitter of the transistor Q1 is grounded, so that the emitter of the transistor Q1 is pulled down to a low level. At this time, the base voltage of the transistor Q1 is not greater than the emitter voltage of the transistor Q1, and the transistor Q1 is cut off;

[0086] Since the first end of the control end of the relay K1 is connected to the power supply, the current flowing out of the power supply can flow in through the first end of the control end of the relay K1 and flow out through the second end of the control end of the relay K1, but cannot flow into the ground after passing through the collector and emitter of the transistor Q1, so the control end of the relay K1 cannot be powered on normally;

[0087] When the control end of relay K1 cannot be powered on normally, the controlled end of relay K1 will remain disconnected. Since the switch of the controlled end of relay K1 is connected in parallel to both ends of the thermistor, the switch of the controlled end of relay K1 will not affect the operation of the thermistor, that is, the thermistor is normally connected at this time.

[0088] In summary, in the present invention, when the driving pin is at a high level, the thermistor is controlled to be short-circuited;

[0089] The utility model controls the thermistor to be normally connected when the driving pin is at a low level.

[0090] Here, the resistor R4 functions as a current limiting resistor. Since the driving pin needs to send a high-level signal, in order to prevent the high voltage of the high-level signal from damaging the transistor Q1, the resistor R4 needs to be set for current limiting.

[0091] Combined with what has been pointed out above, the control logic that needs to be achieved is:

[0092] First: When the voltage on the detected live wire is not zero and stabilizes, it indicates that the load is working normally. At this time, the thermistor needs to be short-circuited through the switch control circuit to avoid the loss caused by the thermistor;

[0093] When the voltage on the detected live wire is not zero, according to the working logic of the voltage detection circuit described above, the level of the detection pin is high at this time;

[0094] When the thermistor is short-circuited, according to the working logic of the switch control circuit described above, the level of the drive pin is also high at this time;

[0095] Therefore, the control logic that the main control chip needs to achieve should be that when the detection pin of the main control chip is at a high level, the driving pin of the main control chip is also at a high level;

[0096] Second: When the voltage on the live wire is detected to be zero, it indicates that the load is not working at this time. In order to avoid the large surge current generated when power is turned on, it is necessary to connect the thermistor normally through the switch control circuit to suppress the surge current at the moment of power-on and avoid the problem of excessive PFC current detection, which causes the unit to report a fault and shut down.

[0097] When the voltage on the live wire is detected to be zero, according to the working logic of the voltage detection circuit described above, the level of the detection pin is low at this time;

[0098] When the thermistor is normally connected, according to the working logic of the switch control circuit described above, the level of the driving pin is also low at this time.

[0099] Combining the control logic of the first and second above, the control logic of the main control chip in the present invention should be:

[0100] When the detection pin of the main control chip is at a high level, the driving pin of the main control chip is at a high level;

[0101] When the detection pin of the main control chip is at a low level, the driving pin of the main control chip is at a low level.

[0102] Furthermore, the thermistor in the present invention adopts one of an NTC resistor or a PTC resistor.

[0103] See also Figure 2 Thermistor is also the attached Figure 2 "NTC / PTC" in.

[0104] Among them, NTC resistor is a type of thermistor, which belongs to the "negative temperature coefficient" thermistor. The specific working principle is: in the NTC thermistor, as the temperature of the metal oxide semiconductor increases, free electrons and holes move, causing current to flow and the resistance value to decrease.

[0105] That is, as the temperature increases, the resistance of its NTC thermistor decreases.

[0106] In addition, PTC resistor is also a type of thermistor, which belongs to the "positive temperature coefficient" thermistor. The specific working principle is: PTC thermistor is a polycrystalline ceramic with barium titanate as the main component and a small amount of rare earth elements (Kidoruigenso, meaning rare earth) used as a resistor. Barium titanate has the characteristics of ferroelectric materials, and its dielectric constant changes with temperature. When it is lower than the Curie point, due to the high dielectric constant and current flow, the electron movement is stable, that is, a low resistance value is displayed.

[0107] That is, as the temperature increases, the resistance of the PTC thermistor increases.

[0108] Here, NTC thermistors and PTC thermistors can play the role of protecting circuits such as fuses because they can be used under large currents, that is, they can suppress large surge currents.

[0109] Here, in order to ensure the reliability of the circuit, the thermistor not only has resistance requirements, but also power and temperature rise must be considered. The specific test should be based on the actual material parameters to ensure that the surge current after connecting the thermistor does not damage the components in the circuit, and the temperature rise of the thermistor itself cannot be too high and cannot exceed the maximum allowable power of the resistor.

[0110] See also Figure 1 The power supply system with power-on overcurrent protection circuit proposed by the utility model also includes: a filter circuit arranged in the front stage of the power factor correction circuit and mounted between the live wire and the neutral wire.

[0111] Here, the filter module is also attached Figure 1 In the "EMC module", since the filter module does not essentially participate in the control of whether the thermistor is connected, Figure 2 It is not shown in the figure, wherein the filtering module is mainly composed of common mode inductance and X capacitor, which is used to filter out other high-frequency interference in the live wire and the neutral wire.

[0112] See also Figure 1 The power supply system with power-on overcurrent protection circuit proposed by the utility model also includes: a rectifier circuit arranged in the front stage of the power factor correction circuit and mounted between the live wire and the neutral wire.

[0113] Here, the rectifier circuit is also attached Figure 2 The "rectifier bridge" in the attached Figure 2 The bridge rectifier is generally composed of four diodes connected in the first place, which can convert AC into DC by using the unidirectional conduction characteristics of the diodes themselves.

[0114] In the attached Figure 1 It can be seen that the bus capacitor is a "DC bus". Because the current on the live wire and the neutral wire is AC, it is necessary to set up the rectifier circuit to convert AC into DC for energy storage in the bus capacitor.

[0115] Based on the above power supply system with power-on overcurrent protection circuit, the utility model also proposes an air conditioning system, which has the power supply system with power-on overcurrent protection circuit mentioned above.

[0116] Compared with the prior art, the utility model has at least the following beneficial effects:

[0117] The utility model is provided with a voltage detection circuit, and the voltage detection circuit is mounted on the live wire. By detecting the voltage of the live wire, it is possible to more intuitively and accurately know whether the load is powered on and working. At the same time, in conjunction with the switch control circuit provided in the utility model, it is possible to control whether the thermistor is connected or not. This ensures that when the load is operating normally, the thermistor is short-circuited to avoid power loss caused by the thermistor, and when the load is powered on, the thermistor can be accurately connected to suppress surge current at the moment of power-on.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A power supply system with a power-on overcurrent protection circuit, comprising a power factor correction circuit and a bus capacitor mounted on a live wire and a neutral wire for providing electric energy, wherein the power factor correction circuit is used to adjust the voltage on the live wire and supply power to the bus capacitor, and the bus capacitor can supply power to a load connected thereto, characterized in that: It also includes a thermistor connected in series with the power factor correction circuit on the live wire, a voltage detection circuit for detecting electrical parameters on the live wire, and a switch control circuit for adjusting the access state of the thermistor according to the electrical parameters.

2. The power supply system with a power-on overcurrent protection circuit according to claim 1, characterized in that: It also includes a switching power supply connected to the bus capacitor and capable of drawing power from the bus capacitor; The voltage detection circuit and the switch control circuit are mounted on the same main control chip, and the main control chip is connected to the switch power supply for power supply.

3. The power supply system with power-on overcurrent protection circuit according to claim 2, characterized in that: The electrical parameter is voltage; When the voltage on the live wire is not zero, the switch control circuit controls the thermistor to be short-circuited; When the voltage on the live wire is zero, the switch control circuit controls the thermistor to be normally connected.

4. The power supply system with power-on overcurrent protection circuit according to claim 2, characterized in that: The voltage detection circuit includes: a resistor R1, a resistor R2, a resistor R3, a diode D1, and an optical coupler U1; The positive electrode of the diode D1 is connected to the live wire, the negative electrode of the diode D1 is connected in series with the resistor R3 and then connected to the first end of the control end of the optocoupler U1, and the second end of the control end of the optocoupler U1 is connected to the neutral wire; One end of the resistor R2 is connected to a power supply, the other end of the resistor R2 is connected to the first end of the controlled end of the optocoupler U1, the second end of the controlled end of the optocoupler U1 is connected to the detection pin of the main control chip, one end of the resistor R1 is connected between the second end of the controlled end of the optocoupler U1 and the detection pin of the main control chip, and the other end of the resistor R1 is grounded.

5. The power supply system with power-on overcurrent protection circuit according to claim 2, characterized in that: The switch control circuit includes: a resistor R4, a transistor Q1, and a relay K1; The collector of the transistor Q1 is connected to the second end of the control end of the relay K1, the base of the transistor Q1 is connected in series with the resistor R4 and then connected to the driving pin of the main control chip, the emitter of the transistor Q1 is grounded, and the first end of the control end of the relay K1 is connected to a power supply; The controlled end of the relay K1 is connected to both ends of the thermistor.

6. The power supply system with power-on overcurrent protection circuit according to claim 3, characterized in that: When the detection pin of the main control chip is at a high level, the driving pin of the main control chip is at a high level; When the detection pin of the main control chip is at a low level, the driving pin of the main control chip is at a low level.

7. The power supply system with a power-on overcurrent protection circuit according to claim 1, characterized in that: The thermistor is an NTC resistor or a PTC resistor.

8. The power supply system with a power-on overcurrent protection circuit according to claim 1, characterized in that: It also includes a filter circuit that is arranged at the front stage of the power factor correction circuit and mounted between the live wire and the neutral wire.

9. The power supply system with a power-on overcurrent protection circuit according to claim 1, characterized in that: It also includes a rectifier circuit which is arranged at the front stage of the power factor correction circuit and mounted between the live wire and the neutral wire.

10. An air conditioning system, characterized in that: The air conditioning system has a power supply system with a power-on overcurrent protection circuit as claimed in any one of claims 1 to 9.

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