Power factor correction circuit and household appliance

Abstract

The embodiment of the application discloses a power factor correction circuit and a household appliance, and belongs to the electronic technical field, and the circuit comprises a first surge protection unit, a power factor correction module and a second surge protection unit; the first surge protection unit is configured to clamp a surge voltage at a preset voltage threshold value in the case of receiving the surge voltage, and output the clamped surge voltage to the power factor correction module; the second surge protection unit is configured to be turned on in the case that the reverse electromotive force output by the power factor correction module is greater than the operating voltage of the second surge protection unit, so as to clamp the reverse electromotive force generated by the power factor correction module at the operating voltage. The application can reduce the risk that the rectifier bridge and other devices in the power factor correction module are broken down by the reverse electromotive force in the case of the surge voltage, and thus the effect of improving the safety of the power factor correction circuit is achieved.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and to, but is not limited to, a power factor correction circuit and a household appliance. Background Technology

[0002] With the rapid development of electronic technology, various household appliances have become commonplace in people's lives, such as air conditioners, washing machines, and refrigerators. However, these household appliances are susceptible to harmonic interference from the mains power supply. Therefore, these appliances are generally equipped with power factor correction (PFC) circuits to correct the power factor.

[0003] In related technologies, surge voltages of several thousand volts may occur during lightning strikes or when an air switch is closed. However, the withstand voltage of a rectifier bridge is typically 1000V. Therefore, appropriate surge protection devices are required for the PFC circuit. For example, a varistor can be connected in parallel between the two input terminals of the PFC circuit to clamp the surge voltage below a safe threshold. However, since PFC circuits generally also include reactors, when the clamped surge voltage is applied to the reactor, the reactor will generate a high back electromotive force. This means the reverse voltage across the rectifier bridge may exceed its withstand voltage. Therefore, technicians typically connect a new varistor in parallel between the input terminals of the rectifier bridge to clamp the reverse voltage.

[0004] However, even with a new varistor added before the rectifier bridge, the related technical solution still carries the risk that the clamping voltage of the new varistor may exceed the withstand voltage of the rectifier bridge. In other words, this solution carries a significant risk of the rectifier bridge being damaged by high reverse voltage in the event of a surge voltage. Utility Model Content

[0005] In view of this, the power factor correction circuit and household appliance provided in this application embodiment can reduce the risk of reverse electromotive force breakdown of components such as the rectifier bridge in the power factor correction module under the condition of surge voltage, thereby improving the safety of the power factor correction circuit. The power factor correction circuit and household appliance provided in this application embodiment are implemented as follows:

[0006] A first aspect of this application provides a power factor correction circuit for use in household appliances; the circuit includes: a first surge protection unit, a power factor correction module, and a second surge protection unit;

[0007] The first surge protection unit is connected to the power factor correction module, and the first surge protection unit is used to input surge voltage; the first surge protection unit is configured to: clamp the surge voltage at a preset voltage threshold when the surge voltage is received, and output the clamped surge voltage to the power factor correction module.

[0008] The power factor correction module is also connected to the second surge protection unit, and the power factor correction module is also used to connect to the electrical load; the power factor correction module is configured to: when receiving the clamped surge voltage input from the first surge protection unit, convert the clamped surge voltage, and output a reverse electromotive force to the second surge protection unit based on the converted surge voltage;

[0009] The second surge protection unit is configured to turn on when the back electromotive force is greater than the operating voltage of the second surge protection unit, so as to clamp the back electromotive force generated by the power factor correction module to the operating voltage.

[0010] Optionally, the power factor correction module includes: a first rectifier bridge, a first reactor, and a first electrolytic capacitor;

[0011] The first end and the second end of the first rectifier bridge are respectively connected to the first surge protection unit, the third end of the first rectifier bridge is respectively connected to the first end of the first reactor and the first end of the second surge protection unit, the fourth end of the first rectifier bridge is connected to the first plate of the first electrolytic capacitor, and the fourth end of the first rectifier bridge is also used to connect the electrical load.

[0012] The second end of the first reactor is connected to the second plate of the first electrolytic capacitor and the second end of the second surge protection unit, respectively, and the second end of the first reactor is also used to connect the electrical load.

[0013] Optionally, the second surge protection unit includes: a first discharge tube;

[0014] The first end of the first discharge tube is connected to the first end of the first reactor, and the second end of the first discharge tube is connected to the second end of the first reactor;

[0015] The first discharge tube is configured to conduct when the reverse electromotive force is greater than the operating voltage of the first discharge tube, so as to clamp the reverse electromotive force generated by the power factor correction module to the operating voltage.

[0016] Optionally, the power factor correction module includes: a second rectifier bridge, a second reactor, a switching transistor, a diode, a second electrolytic capacitor, a sampling resistor, and a detection unit;

[0017] The first and second ends of the second rectifier bridge are respectively connected to the first surge protection unit, the third end of the second rectifier bridge is respectively connected to the first end of the second reactor, and the fourth end of the second rectifier bridge is respectively connected to the first end of the sampling resistor and the first end of the detection unit.

[0018] The second terminal of the second reactor is connected to the first terminal of the switching transistor and the positive terminal of the diode, respectively;

[0019] The negative terminal of the diode is connected to the first plate of the second electrolytic capacitor, and the negative terminal of the diode is also used to connect to the electrical load.

[0020] The second end of the sampling resistor is connected to the second terminal of the switching transistor, the second plate of the second electrolytic capacitor, and the second end of the detection unit J, respectively. The second end of the sampling resistor is also used to connect to the electrical load.

[0021] The third terminal of the switching transistor is used to input a control signal, and the switching transistor is configured to turn on or off under the action of the control signal.

[0022] The second surge protection unit is connected in parallel with the second reactor, or the second surge protection unit is connected in parallel with the second reactor and the diode.

[0023] Optionally, the second surge protection unit includes: a second discharge tube;

[0024] The first end of the second discharge tube is connected to the first end of the second reactor, and the second discharge tube is connected to the second end of the second reactor;

[0025] The second discharge tube is configured to turn on when the reverse electromotive force is greater than the operating voltage of the second discharge tube, so as to clamp the reverse electromotive force generated by the power factor correction module to the operating voltage.

[0026] Optionally, the second surge protection unit includes: a second discharge tube and a voltage-resistant diode;

[0027] The first end of the second discharge tube is connected to the first end of the second reactor, the second discharge tube is connected to the positive terminal of the voltage-resistant diode, and the negative terminal of the voltage-resistant diode is connected to the negative terminal of the diode.

[0028] The second discharge tube is configured to turn on when the reverse electromotive force is greater than the operating voltage of the second discharge tube, so as to clamp the reverse electromotive force generated by the power factor correction module to the operating voltage.

[0029] Optionally, the power factor correction module further includes: a filter capacitor;

[0030] The filter capacitor is connected between the third and fourth terminals of the first rectifier bridge in the power factor correction module; or,

[0031] The filter capacitor is connected between the third and fourth terminals of the second rectifier bridge in the power factor correction module.

[0032] Optionally, the first surge protection unit includes: a varistor;

[0033] The first end of the varistor is connected to the first end of the power factor correction module, and the second end of the varistor is connected to the second end of the power factor correction module.

[0034] Furthermore, the first and second ends of the varistor are respectively used to input the surge voltage.

[0035] Optionally, the first surge protection unit further includes: a common-mode filter and a thermistor;

[0036] The first terminal of the common-mode filter is connected to the first terminal of the varistor, the second terminal of the common-mode filter is connected to the second terminal of the varistor, the third terminal of the common-mode filter is connected to the first terminal of the thermistor, and the fourth terminal of the common-mode filter is connected to the second terminal of the power factor correction module.

[0037] The second terminal of the thermistor is connected to the first terminal of the power factor correction module;

[0038] The first surge protection unit also includes: a fuse, a first protection capacitor and / or a second protection capacitor;

[0039] The first end of the fuse is used to input the surge voltage, and the second end of the fuse is connected to the first end of the varistor;

[0040] The first protection capacitor is connected between the first and second terminals of the common-mode filter device.

[0041] The second protection capacitor is connected between the third and fourth terminals of the common-mode filter device.

[0042] A second aspect of the embodiments of this application also provides a household appliance, which includes at least any of the power factor correction circuits provided in the first aspect.

[0043] A third aspect of the embodiments of this application also provides an air conditioner, the air conditioner comprising at least:

[0044] A refrigerant circulation loop includes a compressor, a condenser, and an evaporator connected in sequence, and the refrigerant circulation loop is used to circulate refrigerant in the refrigerant circulation loop.

[0045] An indoor fan is used to rotate and drive the airflow in the room.

[0046] A return air temperature sensor is used to detect the return air temperature of the air conditioner;

[0047] Any of the power factor correction circuits provided in the first aspect above;

[0048] And a controller connected to the power factor correction circuit.

[0049] The power factor correction circuit and household appliance provided in this application embodiment are achieved by incorporating a first surge protection unit, a power factor correction module, and a second surge protection unit within the power factor correction circuit. Specifically, the first surge protection unit is connected to the power factor correction module, and the first surge protection unit is used to input surge voltage. The power factor correction module is also connected to the second surge protection unit, and the power factor correction module is also used to connect an electrical load.

[0050] The first surge protection unit is configured to: clamp the surge voltage to a preset voltage threshold upon receiving the surge voltage, and output the clamped surge voltage to the power factor correction module.

[0051] The power factor correction module is configured to: upon receiving the clamped surge voltage input from the first surge protection unit, convert the clamped surge voltage and output a reverse electromotive force to the second surge protection unit based on the converted surge voltage.

[0052] The second surge protection unit is configured to turn on when the reverse electromotive force is greater than the operating voltage of the second surge protection unit, so as to clamp the reverse electromotive force generated by the power factor correction module to the operating voltage.

[0053] As can be seen from the circuit's operating principle, when a surge occurs, the first surge protection unit clamps the surge voltage to a preset voltage threshold that is lower than the original surge voltage level. This clamped surge voltage is then output to the power factor correction module. Because the clamped surge voltage is lower than the original surge voltage level, the power factor correction module can convert the clamped surge voltage to a level that is also lower than the original surge voltage. This protects the power factor correction module to some extent and reduces the back electromotive force (EMF) generated by the module. Furthermore, if the back EMF exceeds the operating voltage of the second surge protection unit, the second surge protection unit quickly enters a low-impedance state to form a low-impedance discharge path. This rapidly dissipates the energy of the surge voltage and / or the back EMF, clamping the back EMF to the operating voltage. Since this operating voltage is less than or equal to the power factor correction module's withstand voltage, damage to the components within the power factor correction module by the back EMF can be minimized.

[0054] In this way, the risk of reverse electromotive force breakdown of components such as the rectifier bridge in the power factor correction module can be reduced in the event of surge voltage, thereby improving the safety of the power factor correction circuit and at least partially solving the technical problems mentioned in the background art. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments 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.

[0056] Figure 1 A schematic diagram of the structure of the first power factor correction circuit provided in the embodiments of this application;

[0057] Figure 2 This is a schematic diagram of the structure of the second power factor correction circuit provided in the embodiments of this application;

[0058] Figure 3 A schematic diagram of the structure of the third power factor correction circuit provided in the embodiments of this application;

[0059] Figure 4 This is a schematic diagram of the structure of the fourth power factor correction circuit provided in the embodiments of this application;

[0060] Figure 5 A schematic diagram of the structure of the fifth power factor correction circuit provided in the embodiments of this application;

[0061] Figure 6 A schematic diagram of the sixth power factor correction circuit provided in the embodiments of this application;

[0062] Figure 7 This is a schematic diagram of the structure of the seventh power factor correction circuit provided in the embodiments of this application. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the specific technical solutions of this application will be further described in detail below with reference to the accompanying drawings of the embodiments of this application. The following embodiments are used to illustrate this application, but are not intended to limit the scope of this application.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0065] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0066] It should be noted that the terms "first, second, third" used in the embodiments of this application are used to distinguish similar or different objects and do not represent a specific order of objects. It can be understood that "first, second, third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0067] In related technologies, surge voltages of several thousand volts may occur during lightning strikes or when an air circuit breaker is closed. However, the withstand voltage of a rectifier bridge is typically 1000V. Therefore, appropriate surge protection devices are required for the PFC circuit. For example, a varistor can be connected in parallel between the two input terminals of the PFC circuit to clamp the surge voltage below a safe threshold. However, since PFC circuits generally also include reactors, when the clamped surge voltage is applied to the reactor, the reactor will generate a high back electromotive force. This means the reverse voltage across the rectifier bridge may exceed its withstand voltage. Therefore, technicians typically connect a new varistor in parallel between the input terminals of the rectifier bridge to clamp the reverse voltage.

[0068] However, even with a new varistor added before the rectifier bridge, the related technical solution still carries the risk that the clamping voltage of the new varistor may exceed the withstand voltage of the rectifier bridge. In other words, this solution carries a significant risk of the rectifier bridge being damaged by high reverse voltage in the event of a surge voltage.

[0069] To address this, embodiments of this application provide a power factor correction circuit, which includes a first surge protection unit, a power factor correction module, and a second surge protection unit. Specifically, the first surge protection unit is connected to the power factor correction module, and the first surge protection unit is used to input surge voltage; the power factor correction module is also connected to the second surge protection unit, and the power factor correction module is also used to connect to an electrical load. Furthermore, the first surge protection unit is configured to: clamp the surge voltage to a preset voltage threshold upon receiving the surge voltage, and output the clamped surge voltage to the power factor correction module; the power factor correction module is configured to: convert the clamped surge voltage input from the first surge protection unit upon receiving the clamped surge voltage, and output a back electromotive force (EMF) to the second surge protection unit based on the converted surge voltage; the second surge protection unit is configured to: turn on when the back EMF is greater than its operating voltage, thereby clamping the back EMF generated by the power factor correction module to the operating voltage. In this way, the risk of reverse EMF breakdown of components such as the rectifier bridge in the power factor correction module can be reduced in the event of a surge voltage, thereby improving the safety of the power factor correction circuit.

[0070] This application uses a power factor correction circuit applied in household appliances as an example for illustration. However, it does not imply that this application's embodiments can only be applied to power factor correction in household appliances.

[0071] The power factor correction circuit provided in the embodiments of this application will be explained in detail below.

[0072] Figure 1 This application provides a schematic diagram of a power factor correction circuit. This circuit can be applied to household appliances, such as air conditioners, refrigerators, washing machines, microwave ovens, and any other possible devices. Moreover, the household appliance may include any control unit and / or processor with functions such as processing, control, identification, and calculation.

[0073] See Figure 1 This application provides a power factor correction circuit 100, which includes a first surge protection unit 101, a power factor correction module 102, and a second surge protection unit 103.

[0074] The first surge protection unit 101 is connected to the power factor correction module 102, and the first surge protection unit 101 is used to input surge voltage. The power factor correction module 102 is also connected to the second surge protection unit 103, and the power factor correction module 102 is also used to connect to the electrical load F.

[0075] The first surge protection unit 101 is configured to: clamp the surge voltage at a preset voltage threshold when the surge voltage is received, and output the clamped surge voltage to the power factor correction module 102.

[0076] The power factor correction module 102 is configured to: upon receiving the clamped surge voltage input from the first surge protection unit 101, convert the clamped surge voltage and output a reverse electromotive force to the second surge protection unit 103 based on the converted surge voltage.

[0077] The second surge protection unit 103 is configured to turn on when the reverse electromotive force is greater than the operating voltage of the second surge protection unit 103, so as to clamp the reverse electromotive force generated by the power factor correction module 102 to the operating voltage.

[0078] Optionally, the first surge protection unit 101 may include any device capable of voltage clamping, such as a varistor, a transient voltage suppressor (TVS), and / or a thyristor surge suppressor (TSS), etc. In addition to voltage clamping, the first surge protection unit 101 may also include filtering, current suppression, overcurrent protection, etc., among other possible functions. This application embodiment does not limit this aspect.

[0079] Optionally, the surge voltage may refer to the transient overvoltage that occurs when the circuit 100 is struck by lightning, when an inductive load is switched on or off, or when a large load is switched on or off; or, in a laboratory setting, the surge voltage may be output by a corresponding surge generator.

[0080] Typically, the surge voltage is quite high, generally exceeding the activation threshold of the first surge protection unit 101, and may even reach 5-20 times the rated current. For example, this surge voltage can be a differential-mode surge signal, transmitted through... Figure 1 The LN line shown is input into circuit 100.

[0081] Optionally, the voltage level of the preset voltage threshold can be determined by the parameters of the first surge protection unit 101. For example, the higher the varistor voltage of the first surge protection unit 101, the higher the voltage level of the preset voltage threshold; or, the greater the surge current flowing through the first surge protection unit 101, the higher the voltage level of the preset voltage threshold. Generally, the voltage level of the preset voltage threshold is lower than the voltage level of the surge voltage, and the preset voltage threshold can be a specific voltage value or a voltage range, such as between 1050V and 1100V. This application embodiment does not limit this.

[0082] Optionally, the voltage level of the clamped surge voltage is the preset voltage threshold.

[0083] Optionally, the power factor correction module 102 can be either an active PFC module or a passive PFC module. Generally, the power factor correction module 102 may include at least any possible components such as a rectifier bridge, capacitor, and reactor to achieve the purpose of converting the input voltage and adjusting its power factor. The working principle of the power factor correction module 102 will not be explained here; the specific principle will be explained in detail later based on the circuit structure.

[0084] In this embodiment, the power factor correction module 102 is not only used to convert the clamped surge voltage, but also to adjust the normal operating voltage when the circuit 100 is working normally, that is, when the LN line inputs a normal operating voltage (e.g., converting the operating voltage from AC to DC, and / or adjusting the power factor of the operating voltage). This application embodiment does not limit this.

[0085] Optionally, the converted surge voltage is obtained by the power factor correction module 102 performing AC-DC conversion on the clamped surge voltage. The reverse electromotive force (EMF) is generally generated by the reactor in the power factor correction module 102 under the influence of the voltage output from the rectifier bridge; that is, the reverse EMF is generated by the reactor resisting the trend of current change. This application embodiment does not limit this aspect.

[0086] Optionally, the electrical load F can be any possible electrical load. For example, if the household appliance is an air conditioner, then the electrical load can be the power management module in the air conditioner, or any possible device such as the fan module, relay coil, CPU, or sensor in the air conditioner. This application does not limit this.

[0087] In this embodiment, the second surge protection unit 103 can maintain a high impedance state when the circuit 100 is working normally (the LN line is input with a normal operating voltage). At this time, the second surge protection unit 103 has almost no effect on the circuit 100. The second surge protection unit 103 can also quickly enter a low impedance state when a surge voltage occurs in the circuit 100 (the voltage across the second surge protection unit 103 exceeds the operating voltage) to form a low-impedance discharge path and quickly discharge the energy of the surge voltage and / or the reverse electromotive force. The second surge protection unit 103 can also automatically return to a high impedance state after the energy of the surge voltage and / or the reverse electromotive force has been discharged (that is, when the voltage across the second surge protection unit 103 is lower than the operating voltage).

[0088] Furthermore, the second surge protection unit 103 may include any possible device, such as a gas discharge tube (GDT), a transient voltage suppressor (TVS), and / or a thyristor surge suppressor (TSS). This application does not limit this.

[0089] In this embodiment, the operating voltage can be less than or equal to the withstand voltage of the power factor correction module 102 (such as the reverse withstand voltage of the rectifier in the power factor correction module 102). Generally, in order to improve safety, devices with operating voltages lower than the withstand voltage can be selected to form the second surge protection unit 103.

[0090] Optionally, the operating voltage can be determined by the physical characteristics of the second surge protection unit 103. Generally, when the power factor correction module 102 outputs the reverse electromotive force to the second surge protection unit 103, the reverse electromotive force is applied across the second surge protection unit 103. If the reverse electromotive force is greater than or equal to the operating voltage, the second surge protection unit 103 enters a low-impedance state and is turned on; if the reverse electromotive force is less than the operating voltage, the second surge protection unit 103 enters a high-impedance state and is turned off. This application does not limit this aspect.

[0091] It is worth noting that, in order to better explain the power factor correction circuit 100, the working principle of the circuit 100 will be briefly introduced below:

[0092] When circuit 100 is operating normally, a corresponding operating voltage is input to circuit 100 via the LN line. This operating voltage level generally meets the safety requirements of circuit 100, and the first surge protection unit 101 will not clamp the operating voltage. Therefore, the operating voltage can be directly input to the power factor correction module 102. The power factor correction module 102 can actively or passively convert the operating voltage to DC, then adjust the power factor of the DC, and finally output the adjusted voltage to the electrical load. In this way, the purpose of power factor correction can be achieved.

[0093] When a surge occurs in circuit 100, a surge voltage is input to circuit 100 via the LN line. This surge voltage is typically much higher than the operating voltage. In this case, the first surge protection unit 101 is triggered to clamp the surge voltage to a preset voltage threshold. The clamped surge voltage is then input to the power factor correction module 102, which converts the clamped surge voltage into a corresponding DC current. The power factor correction module 102 generally does not adjust the power factor of the clamped surge voltage. Based on this converted surge voltage, it outputs a corresponding reverse electromotive force (EMF) to the second surge protection unit 103. If the reverse EMF is greater than the operating voltage of the second surge protection unit 103, the second surge protection unit 103 enters a low-impedance state and conducts, forming a low-impedance discharge path to rapidly dissipate the energy of the surge voltage and / or the reverse EMF.

[0094] In this way, the reverse electromotive force generated by the power factor correction module 102 can be clamped to the operating voltage.

[0095] In this embodiment, a first surge protection unit 101, a power factor correction module 102, and a second surge protection unit 103 are provided in the power factor correction circuit 100. Specifically, the first surge protection unit 101 is connected to the power factor correction module 102, and the first surge protection unit 101 is used to input surge voltage. The power factor correction module 102 is also connected to the second surge protection unit 103, and the power factor correction module 102 is also used to connect to the electrical load F.

[0096] The first surge protection unit 101 is configured to: clamp the surge voltage at a preset voltage threshold when the surge voltage is received, and output the clamped surge voltage to the power factor correction module 102.

[0097] The power factor correction module 102 is configured to: upon receiving the clamped surge voltage input from the first surge protection unit 101, convert the clamped surge voltage and output a reverse electromotive force to the second surge protection unit 103 based on the converted surge voltage.

[0098] The second surge protection unit 103 is configured to turn on when the reverse electromotive force is greater than the operating voltage of the second surge protection unit 103, so as to clamp the reverse electromotive force generated by the power factor correction module 102 to the operating voltage.

[0099] As can be seen from the working principle of circuit 100, when a surge occurs in circuit 100, the first surge protection unit 101 can clamp the surge voltage to a preset voltage threshold with a lower voltage level, so as to obtain the clamped surge voltage and output it to the power factor correction module 102. Because the voltage level of the clamped surge voltage is lower than the voltage level of the surge voltage, the power factor correction module 102 can convert the clamped surge voltage to obtain a surge voltage with a voltage level that is also lower than the surge voltage. This can protect the power factor correction module 102 to a certain extent and reduce the reverse electromotive force generated by the power factor correction module 102. Furthermore, when the reverse electromotive force is greater than the operating voltage of the second surge protection unit 103, the second surge protection unit 103 will quickly enter a low-impedance state to form a low-impedance discharge path. In this way, the energy of the surge voltage and / or the reverse electromotive force can be quickly discharged, and the reverse electromotive force can be clamped at the operating voltage. Since the operating voltage is less than or equal to the withstand voltage of the power factor correction module 102, the problem of the reverse electromotive force damaging the various devices in the power factor correction module 102 can be avoided as much as possible.

[0100] In this way, the risk of devices such as the rectifier bridge in the power factor correction module 102 being broken down by reverse electromotive force can be reduced in the event of surge voltage, thereby improving the safety of the power factor correction circuit 100.

[0101] In one possible implementation, see [link to relevant documentation]. Figure 2 The power factor correction module 102 includes: a first rectifier bridge BD1, a first reactor L1, and a first electrolytic capacitor E1.

[0102] The first and second ends of the first rectifier bridge BD1 are respectively connected to the first surge protection unit 101. The third end of the first rectifier bridge BD1 is respectively connected to the first end of the first reactor L1 and the first end of the second surge protection unit 103. The fourth end of the first rectifier bridge BD1 is connected to the first plate of the first electrolytic capacitor E1. The fourth end of the first rectifier bridge BD1 is also used to connect the electrical load F.

[0103] The second end of the first reactor L1 is connected to the second plate of the first electrolytic capacitor E1 and the second end of the second surge protection unit 103, and the second end of the first reactor L1 is also used to connect the electrical load F.

[0104] In this embodiment, the first rectifier bridge BD1 is used to convert the clamped surge voltage from alternating current to direct current to obtain the converted surge voltage. Generally, the first rectifier bridge BD1 can be composed of four diodes. This embodiment does not limit this.

[0105] In this embodiment, the first reactor L1 can be a passive reactor, which can serve as a power frequency choke. Generally, the first reactor L1 can be used to slow down the current rise rate, smooth rectified current spikes, and / or suppress characteristic harmonics. The first reactor L1 can generate the reverse electromotive force under the action of the converted surge voltage, and output the reverse electromotive force to both ends of the second surge protection unit 103.

[0106] In this embodiment, the first electrolytic capacitor E1 can absorb power frequency ripple to filter out low frequency pulses and maintain the continuity of load power supply in the zero-crossing range of the input voltage; in addition, the first electrolytic capacitor E1 can absorb transient energy in the event of a surge.

[0107] It is worth noting that the power factor correction module 102 provided in this embodiment is a passive PFC. The working principle of the power factor correction module 102 will be briefly explained below:

[0108] When circuit 100 is operating normally, the aforementioned operating voltage enters circuit 100 through the LN line. At this time, the first surge protection unit 101 does not activate. Then, the first rectifier bridge BD1 converts the operating voltage into DC power and outputs the converted DC power to the first reactor L1. At this time, because the voltage of the converted DC power is low, the voltage drop of the first reactor L1 is also low. The reverse electromotive force generated by the first reactor L1 is low. The first reactor L1 and the first electrolytic capacitor E1 cooperate to charge and discharge, thereby achieving the purpose of "voltage boosting" and "voltage and current waveform shaping".

[0109] When a surge occurs in circuit 100, the surge voltage enters circuit 100 through the LN line. At this time, the surge voltage is clamped to the preset voltage threshold by the first surge protection unit 101. Because the voltage level of the surge voltage and the clamped surge voltage is very high, it will rapidly charge the first electrolytic capacitor E1 in a short time, and the first reactor L1 will generate a large back electromotive force V. L At this time, the back pressure borne by the first rectifier bridge BD1 is V. LThe sum of the voltages of the first electrolytic capacitor E1 and the first rectifier bridge BD1 will exceed the withstand voltage of the first rectifier bridge BD1, which may cause the diodes in the first rectifier bridge BD1 to break down.

[0110] Among them, V L =L*di / dt, where L is the reactance value of the first reactor L1, and di / dt represents the rate of change of current with time. Generally, the higher the voltage level of the surge voltage and the clamped surge voltage, the larger di / dt will be.

[0111] It is understandable that, because the first terminal of the first reactor L1 is connected to the first terminal of the second surge protection unit 103, and the second terminal of the first reactor L1 is connected to the second terminal of the second surge protection unit 103, the reverse electromotive force V generated by the first reactor L1... L If the voltage exceeds the operating voltage of the second surge protection unit 103, the second surge protection unit 103 will conduct, transferring the reverse electromotive force V. L The energy is quickly released, thus dissipating the back electromotive force V. L By clamping the operating voltage, the reverse voltage borne by the first rectifier bridge BD1 is reduced, thus minimizing the risk of damage to the first rectifier bridge BD1 by the reverse electromotive force.

[0112] In this way, the risk of the first rectifier bridge BD1 being broken down by high reverse voltage can be reduced in the event of surge voltage.

[0113] In one possible implementation, see [link to previous section] Figure 2 The power factor correction module 102 also includes a filter capacitor C0.

[0114] The filter capacitor C0 is connected between the third and fourth terminals of the first rectifier bridge in the power factor correction module 102.

[0115] This reduces noise in the power factor correction module 102 output, thereby improving the stability of the circuit 100.

[0116] In one possible implementation, see [link to previous section] Figure 2 The second surge protection unit 103 includes: a first discharge tube GDT1.

[0117] The first end of the first discharge tube GDT1 is connected to the first end of the first reactor L1, and the second end of the first discharge tube GDT1 is connected to the second end of the first reactor L1.

[0118] The first discharge tube GDT1 is configured to turn on when the reverse electromotive force is greater than the operating voltage of the first discharge tube GDT1, so as to clamp the reverse electromotive force generated by the power factor correction module 102 to the operating voltage.

[0119] Optionally, the first discharge tube GDT1 can be the gas discharge tube described above.

[0120] It is worth noting that when the voltage across the first discharge tube GDT1 does not exceed the operating voltage, it maintains a high impedance state. When the voltage across the first discharge tube GDT1 exceeds the operating voltage, it quickly enters a low impedance state to form a low-impedance discharge path, rapidly dissipating the energy of the surge voltage and / or the reverse electromotive force. In this way, the reverse electromotive force generated by the first reactor L1 can be clamped at the operating voltage, thereby reducing the reverse voltage borne by the first rectifier bridge BD1 and minimizing the risk of damage to the first rectifier bridge BD1 by the reverse electromotive force.

[0121] In one possible implementation, see [link to relevant documentation]. Figure 3 and Figure 4 The power factor correction module 102 includes: a second rectifier bridge BD2, a second reactor L2, a switching transistor Q, a diode D, a second electrolytic capacitor E2, a sampling resistor R0, and a detection unit J.

[0122] The first and second ends of the second rectifier bridge BD2 are connected to the first surge protection unit 101, the third end of the second rectifier bridge BD2 is connected to the first end of the second reactor L2, and the fourth end of the second rectifier bridge BD2 is connected to the first end of the sampling resistor R0 and the first end of the detection unit J.

[0123] The second terminal of the second reactor L2 is connected to the first terminal of the switching transistor Q and the positive terminal of the diode D, respectively.

[0124] The negative terminal of diode D is connected to the first plate of the second electrolytic capacitor E2, and the negative terminal of diode D is also used to connect the electrical load F.

[0125] The second end of the sampling resistor R0 is connected to the second terminal of the switching transistor Q, the second plate of the second electrolytic capacitor E2, and the second end of the detection unit J, respectively. In addition, the second end of the sampling resistor R0 is also used to connect the electrical load F.

[0126] The third terminal of the switching transistor Q is used to input a control signal, and the switching transistor Q is configured to turn on or off under the action of the control signal.

[0127] The second surge protection unit 103 is connected in parallel with the second reactor L2, or the second surge protection unit 103 is connected in parallel with the second reactor L2 and the diode D.

[0128] Optionally, the second rectifier bridge BD2 is used to convert the clamped surge voltage from AC to DC to obtain the converted surge voltage. Generally, the second rectifier bridge BD2 can be composed of four diodes. This application does not limit this.

[0129] In this embodiment, the second reactor L2 can be a passive reactor, serving as a boost inductor. Generally, the second reactor L2 can be used as a high-frequency energy storage device, storing energy when the switch Q is on and releasing energy when the switch Q is off to boost the output voltage. Furthermore, it can reconstruct the input current or voltage waveform into a quasi-sine wave through the high-frequency switching of the switch Q. The second reactor L2 can generate the reverse electromotive force under the action of the converted surge voltage and output the reverse electromotive force to both ends of the second surge protection unit 103.

[0130] In this embodiment, the second electrolytic capacitor E2 can absorb the high-frequency pulse energy output by the reactor and filter out the ripple generated when the switching transistor Q is turned on and off, so as to output a stable high-voltage DC to the electrical load F.

[0131] In this embodiment, diode D has unidirectional conduction characteristics, which can prevent reverse current flow when the second reactor L2 and / or the second electrolytic capacitor E2 release electrical energy. Furthermore, diode D can also provide a discharge path for the second reactor when the switch Q is turned off.

[0132] In this embodiment, the switching transistor Q can be an NPN transistor, and this application does not limit this. Generally, the switching transistor Q can be used to control the second reactor L2 to store or release energy. See also... Figure 3 The control signal k can be input from the third terminal (base) of the switching transistor Q to control the switching transistor Q to turn on or off.

[0133] Optionally, the control signal may be generated by the controller or processor in the household appliance according to a preset power factor correction strategy or actual needs. This application does not limit this aspect.

[0134] In this embodiment, the detection unit J can collect the real-time current or real-time voltage in the power factor correction module 102 through the sampling resistor R0. The detection unit J can then directly determine whether there is a voltage or current anomaly, or send the collected data to the corresponding controller or processor for judgment, thereby implementing corresponding anomaly protection (such as short-circuit protection, overload protection, etc.). Furthermore, the detection unit J can also generate a corresponding feedback signal based on the collected real-time current, and then use this feedback signal to precisely adjust the power factor correction performance of the power factor correction module 102.

[0135] It is worth noting that the power factor correction module 102 provided in this embodiment is an active PFC. The working principle of the power factor correction module 102 will be briefly explained below:

[0136] When circuit 100 is operating normally, the aforementioned operating voltage enters circuit 100 through the LN line. At this time, the first surge protection unit 101 does not activate. Then, the second rectifier bridge BD2 converts the operating voltage into DC power and outputs the converted DC power to the second reactor L2. Simultaneously, the switching transistor Q is turned on or off under the action of the control signal, causing the second reactor L2 to store or release electrical energy. At this time, because the voltage of the converted DC power is low, the voltage drop of the second reactor L2 is also low. The reverse electromotive force generated by the second reactor L2 is low. The second reactor L2 and the second electrolytic capacitor E2 cooperate to charge and discharge, thereby achieving the purpose of "voltage boosting" and "voltage and current waveform shaping".

[0137] When a surge occurs in circuit 100, the surge voltage enters circuit 100 through the LN line. At this time, the surge voltage is clamped to the preset voltage threshold by the first surge protection unit 101. Because the voltage level of the surge voltage and the clamped surge voltage is very high, it will rapidly charge the second electrolytic capacitor E2 in a short period of time, and the second reactor L2 will generate a large reverse electromotive force. At this time, the reverse voltage that the second rectifier bridge BD2 withstands is the sum of the voltages of the second electrolytic capacitor E2. This reverse voltage will exceed the withstand voltage of the second rectifier bridge BD2, which may cause the diodes in the second rectifier bridge BD2 to break down.

[0138] Furthermore, when the switching transistor Q is turned on, the surge voltage or the clamped surge voltage will generate a very high voltage spike in the sampling resistor R0, which may cause the detection unit J to misjudge or malfunction, leading to the power factor correction module 102 shutting down or other abnormal states. Moreover, a reactor with a relatively low operating voltage can be selected as the second reactor L2 to minimize the impact of the surge voltage on the detection unit J.

[0139] Understandably, because the second surge protection unit 103 is connected in parallel with the second reactor L2, or the second surge protection unit 103 is connected in parallel with the second reactor L2 and the diode D, the second surge protection unit 103 will conduct when the reverse electromotive force generated by the second reactor L2 is greater than the operating voltage of the second surge protection unit 103. This will quickly dissipate the energy of the reverse electromotive force, thus clamping the reverse electromotive force to the operating voltage, thereby reducing the reverse voltage on the second rectifier bridge BD2 and minimizing the risk of damage to the second rectifier bridge BD2 by the reverse electromotive force.

[0140] Since the second surge protection unit 103 can quickly dissipate the energy of the surge voltage and / or the reverse electromotive force, the voltage spike generated by the sampling resistor R0 when the switch Q is turned on can be reduced as much as possible.

[0141] In this way, the risk of the second rectifier bridge BD2 being damaged by high reverse voltage can be reduced in the event of surge voltage. At the same time, it can also minimize the possibility of malfunctions in the detection unit J.

[0142] In one possible implementation, see [link to previous section] Figure 3 The power factor correction module 102 also includes a filter capacitor C0.

[0143] The filter capacitor C0 is connected between the third and fourth terminals of the second rectifier bridge in the power factor correction module 102.

[0144] This reduces noise in the power factor correction module 102 output, thereby improving the stability of the circuit 100.

[0145] In one possible implementation, see [link to previous section] Figure 3 The second surge protection unit 103 includes: a second discharge tube GDT2.

[0146] The first end of the second discharge tube GDT2 is connected to the first end of the second reactor L2, and the second discharge tube GDT2 is connected to the second end of the second reactor L2.

[0147] The second discharge tube GDT2 is configured to turn on when the reverse electromotive force is greater than the operating voltage of the second discharge tube GDT2, so as to clamp the reverse electromotive force generated by the power factor correction module 102 to the operating voltage.

[0148] Optionally, the second discharge tube GDT2 can be the gas discharge tube described above.

[0149] It is worth noting that when the voltage across the second discharge tube GDT2 does not exceed the operating voltage, it maintains a high impedance state. When the voltage across the second discharge tube GDT2 exceeds the operating voltage, it quickly enters a low impedance state to form a low-impedance discharge path, rapidly dissipating the energy of the surge voltage and / or the reverse electromotive force. In this way, the reverse electromotive force generated by the second reactor L2 can be clamped to the operating voltage, thereby reducing the reverse voltage across the second rectifier bridge BD2 and minimizing the risk of damage to BD2 from the reverse electromotive force. Simultaneously, it also minimizes the voltage spike generated by the sampling resistor R0 when the switching transistor Q is turned on.

[0150] In one possible implementation, see [link to previous section] Figure 4The second surge protection unit 103 includes: a second discharge tube GDT2 and a voltage-resistant diode D0.

[0151] The first end of the second discharge tube GDT2 is connected to the first end of the second reactor L2. The second discharge tube GDT2 is connected to the positive terminal of the voltage-resistant diode D0, and the negative terminal of the voltage-resistant diode D0 is connected to the negative terminal of the diode D.

[0152] The second discharge tube GDT2 is configured to turn on when the reverse electromotive force is greater than the operating voltage of the second discharge tube GDT2, so as to clamp the reverse electromotive force generated by the power factor correction module 102 to the operating voltage.

[0153] Optionally, the withstand voltage range of the withstand diode D0 is greater than that of the diode D mentioned above.

[0154] It is worth noting that, since the second reactor L2 often generates a reverse electromotive force during surges, thus forming a high-voltage spike, and the diode D has a low reverse breakdown voltage, it is easily broken down by this reverse electromotive force. However, after the second discharge tube GDT2 and the voltage-degrading diode D0 are connected in series, the effective breakdown voltage of the second surge protection unit 103 can be made to be the sum of the reverse breakdown threshold of the voltage-degrading diode D0 and the forward voltage drop of the second discharge tube GDT2.

[0155] Specifically, when the aforementioned surge voltage occurs, the second discharge tube GDT2 quickly enters a low-impedance state, thus forming a low-impedance path. At this time, the impedance of the second reactor L2 is relatively high. Due to the current shunting relationship between the second surge protection unit 103, the second reactor L2, and the diode D in parallel, most of the surge current will preferentially pass through the second discharge tube GDT2 and the voltage-depositing diode D0, rather than through the second reactor L2 and the diode D. In addition, after the second discharge tube GDT2 and the voltage-depositing diode D0 are turned on, the voltage of the second reactor L2 and the diode D will be clamped to a lower level (e.g., the sum of the operating voltage of the second discharge tube GDT2 and the forward voltage drop of the voltage-depositing diode D0), making the actual voltage applied to the diode D much lower than the breakdown voltage of the diode D. In this way, the second rectifier bridge BD2 can be protected from damage while the diode D is protected, which can further improve the safety of the circuit 100.

[0156] Taking the power factor correction module 102 as a passive PFC as an example, the operation of the power factor correction module 102 during surges will be roughly explained. Figure 1 Based on this, continue to see Figure 5 The first rectifier bridge BD1 in the power factor correction module 102 includes diodes Da, Db, Dc, and Dd.

[0157] During the positive half-cycle of the power factor correction module 102, diodes Da and Dd are conducting, and the peak reverse voltage across diodes Db and Dc is Vac*1.414, where Vac is the clamped surge voltage input to the first rectifier bridge BD1. At this time, the first reactor L1 generates a reverse electromotive force VL, and the voltage across the first electrolytic capacitor E1 is VE1. The reverse voltage across diodes Db and Dc is VL+VE1, which exceeds the withstand voltage of each diode in the first rectifier bridge BD1, causing each diode in the first rectifier bridge BD1 to break down.

[0158] It should be noted that the power factor correction module 102 may also include any other possible devices.

[0159] Moreover, the working principle of the power factor correction module 102 provided in this application embodiment is similar to that of any other possible related technologies. Therefore, this application embodiment will not elaborate on the specific structure and working principle of the power factor correction module 102, nor will it impose any additional limitations.

[0160] In one possible implementation, see [link to relevant documentation]. Figure 6 The first surge protection unit 101 includes: a varistor VR.

[0161] The first terminal of the varistor VR is connected to the first terminal of the power factor correction module 102, and the second terminal of the varistor VR is connected to the second terminal of the power factor correction module 102.

[0162] Furthermore, the first and second terminals of the varistor VR are used to input the surge voltage, respectively.

[0163] Optionally, the first end of the varistor VR can be used as the L line in the LN line mentioned above, and the second end of the varistor VR can be used as the N line in the LN line mentioned above. This application does not limit this.

[0164] It is worth noting that when the voltage across the varistor VR is lower than its varistor voltage, the varistor VR is in a high-resistance state, with a leakage current in the microamplitude range. In this state, it is equivalent to an open circuit and has no impact on the circuit. When the voltage across the varistor VR is higher than its varistor voltage, the varistor VR is in a low-resistance state, guiding the surge current generated by the surge voltage through itself to the ground path, thereby clamping the surge voltage within a preset voltage threshold.

[0165] In one possible implementation, see [link to relevant documentation]. Figure 7 The first surge protection unit 101 also includes: a common-mode filter device G and a thermistor NTC.

[0166] The first terminal of the common-mode filter device G is connected to the first terminal of the varistor VR, the second terminal of the common-mode filter device G is connected to the second terminal of the varistor VR, the third terminal of the common-mode filter device G is connected to the first terminal of the thermistor NTC, and the fourth terminal of the common-mode filter device G is connected to the second terminal of the power factor correction module 102.

[0167] The second terminal of the thermistor NTC is connected to the first terminal of the power factor correction module 102.

[0168] Optionally, the common-mode filtering device G can be a common-mode filtering inductor, used to suppress common-mode electromagnetic interference in the circuit and improve the stability of the circuit 100.

[0169] Optionally, the thermistor NTC can be a negative temperature coefficient thermistor, which can play a dual role in circuit 100 in terms of surge current suppression and temperature compensation based on the characteristic that the resistance value decreases as the temperature increases.

[0170] In one possible implementation, see [link to previous section] Figure 7 The first surge protection unit 101 also includes: a fuse F0, a first protection capacitor C1 and / or a second protection capacitor C2.

[0171] The first terminal of fuse F0 is used to input the surge voltage, and the second terminal of fuse F0 is connected to the first terminal of varistor VR.

[0172] The first protection capacitor C1 is connected between the first and second terminals of the common-mode filter device G.

[0173] The second protection capacitor C2 is connected between the third and fourth terminals of the common-mode filter device G.

[0174] Optionally, the fuse F0 can cut off the current path when an abnormally large current or short circuit fault occurs in the circuit 100, so as to avoid damage to the various components in the circuit 100.

[0175] Optionally, the first protection capacitor C1 and the second protection capacitor C2 can suppress voltage spikes caused by parasitic parameters of the common-mode filter device G, prevent magnetic saturation, and enhance high-frequency noise suppression capabilities.

[0176] It is understood that, by incorporating various devices in the first surge protection unit 101, the surge voltage can be clamped and processed before it is input to the power factor correction module 102, thereby preventing damage to the power factor correction module 102 and subsequent circuits. This improves the safety and stability of the circuit 100.

[0177] As can be seen from the above embodiments, the circuit 100 provided in this application does not require an additional varistor between the two input terminals of the rectifier bridge in the power factor correction module 102. Therefore, this application can improve the safety of the circuit 100 while taking cost into consideration as much as possible.

[0178] Based on the foregoing embodiments, this application also provides a household appliance, which can be any possible appliance such as an air conditioner, refrigerator, washing machine, or microwave oven.

[0179] In one possible manner, the household appliance may include at least the power factor correction circuit 100 provided in any of the above embodiments.

[0180] In one possible embodiment, if the household appliance is an air conditioner, the air conditioner may also include a refrigerant circulation loop, comprising a compressor, a condenser, and an evaporator connected in sequence, the refrigerant circulation loop being used to circulate the refrigerant within the refrigerant circulation loop.

[0181] An indoor fan is used to rotate and drive the airflow in the room.

[0182] Return air temperature sensor is used to detect the return air temperature of the air conditioner.

[0183] Any power factor correction circuit 100 provided in any of the above embodiments.

[0184] And a controller connected to the power factor correction circuit.

[0185] Those skilled in the art will understand that the structures of the household appliances listed in the embodiments of this application are only part of the structure of the household appliances and do not constitute a limitation on the household appliances to which the solution of this application is applied. Specific household appliances may include more or fewer components than those mentioned in the embodiments of this application, or combine certain components, or have different component arrangements.

[0186] The descriptions of the above household appliance embodiments are similar to those of the above circuit embodiments, and have similar beneficial effects to the method embodiments. For technical details not disclosed in the household appliance embodiments of this application, please refer to the descriptions of the circuit embodiments of this application for understanding.

[0187] It should be understood that the phrases "one embodiment," "an embodiment," or "some embodiments" mentioned throughout the specification mean that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment," "in one embodiment," or "in some embodiments" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above-described embodiments are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. The descriptions of the various embodiments above tend to emphasize the differences between the various embodiments; their similarities or commonalities can be referred to mutually, and for the sake of brevity, they will not be repeated here.

[0188] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three kinds of relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0189] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0190] The methods disclosed in the several circuit embodiments provided in this application can be arbitrarily combined without conflict to obtain new circuit embodiments.

[0191] The features disclosed in the several circuit or household appliance embodiments provided in this application can be arbitrarily combined without conflict to obtain new circuit or household appliance embodiments.

[0192] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0193] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A power factor correction circuit, characterized by, Applied to household appliances; the circuit includes: a first surge protection unit, a power factor correction module, and a second surge protection unit; The first surge protection unit is connected to the power factor correction module, and the first surge protection unit is used to input surge voltage; the first surge protection unit is configured to: clamp the surge voltage at a preset voltage threshold when the surge voltage is received, and output the clamped surge voltage to the power factor correction module. The power factor correction module is also connected to the second surge protection unit, and the power factor correction module is also used to connect to the electrical load; the power factor correction module is configured to: when receiving the clamped surge voltage input from the first surge protection unit, convert the clamped surge voltage, and output a reverse electromotive force to the second surge protection unit based on the converted surge voltage; The second surge protection unit is configured to turn on when the back electromotive force is greater than the operating voltage of the second surge protection unit, so as to clamp the back electromotive force generated by the power factor correction module to the operating voltage.

2. The power factor correction circuit of claim 1, wherein, The power factor correction module includes: a first rectifier bridge, a first reactor, and a first electrolytic capacitor; The first end and the second end of the first rectifier bridge are respectively connected to the first surge protection unit, the third end of the first rectifier bridge is respectively connected to the first end of the first reactor and the first end of the second surge protection unit, the fourth end of the first rectifier bridge is connected to the first plate of the first electrolytic capacitor, and the fourth end of the first rectifier bridge is also used to connect the electrical load. The second end of the first reactor is connected to the second plate of the first electrolytic capacitor and the second end of the second surge protection unit, respectively, and the second end of the first reactor is also used to connect the electrical load.

3. The power factor correction circuit of claim 2, wherein, The second surge protection unit includes: a first discharge tube; The first end of the first discharge tube is connected to the first end of the first reactor, and the second end of the first discharge tube is connected to the second end of the first reactor; The first discharge tube is configured to conduct when the reverse electromotive force is greater than the operating voltage of the first discharge tube, so as to clamp the reverse electromotive force generated by the power factor correction module to the operating voltage.

4. The power factor correction circuit of claim 1, wherein, The power factor correction module includes: a second rectifier bridge, a second reactor, a switching transistor, a diode, a second electrolytic capacitor, a sampling resistor, and a detection unit; The first and second ends of the second rectifier bridge are respectively connected to the first surge protection unit, the third end of the second rectifier bridge is respectively connected to the first end of the second reactor, and the fourth end of the second rectifier bridge is respectively connected to the first end of the sampling resistor and the first end of the detection unit. The second terminal of the second reactor is connected to the first terminal of the switching transistor and the positive terminal of the diode, respectively; The negative terminal of the diode is connected to the first plate of the second electrolytic capacitor, and the negative terminal of the diode is also used to connect to the electrical load. The second end of the sampling resistor is connected to the second terminal of the switching transistor, the second plate of the second electrolytic capacitor, and the second end of the detection unit J, respectively. The second end of the sampling resistor is also used to connect to the electrical load. The third terminal of the switching transistor is used to input a control signal, and the switching transistor is configured to turn on or off under the action of the control signal. The second surge protection unit is connected in parallel with the second reactor, or the second surge protection unit is connected in parallel with the second reactor and the diode.

5. The power factor correction circuit as described in claim 4, characterized in that, The second surge protection unit includes: a second discharge tube; The first end of the second discharge tube is connected to the first end of the second reactor, and the second discharge tube is connected to the second end of the second reactor; The second discharge tube is configured to turn on when the reverse electromotive force is greater than the operating voltage of the second discharge tube, so as to clamp the reverse electromotive force generated by the power factor correction module to the operating voltage.

6. The power factor correction circuit as described in claim 4, characterized in that, The second surge protection unit includes: a second discharge tube and a voltage-resistant diode; The first end of the second discharge tube is connected to the first end of the second reactor, the second discharge tube is connected to the positive terminal of the voltage-resistant diode, and the negative terminal of the voltage-resistant diode is connected to the negative terminal of the diode. The second discharge tube is configured to turn on when the reverse electromotive force is greater than the operating voltage of the second discharge tube, so as to clamp the reverse electromotive force generated by the power factor correction module to the operating voltage.

7. The power factor correction circuit as described in claim 2 or 4, characterized in that, The power factor correction module also includes: a filter capacitor; The filter capacitor is connected between the third and fourth terminals of the first rectifier bridge in the power factor correction module; or, The filter capacitor is connected between the third and fourth terminals of the second rectifier bridge in the power factor correction module.

8. The power factor correction circuit as described in any one of claims 1-6, characterized in that, The first surge protection unit includes: a varistor; The first end of the varistor is connected to the first end of the power factor correction module, and the second end of the varistor is connected to the second end of the power factor correction module. Furthermore, the first and second ends of the varistor are respectively used to input the surge voltage.

9. The power factor correction circuit as described in claim 8, characterized in that, The first surge protection unit also includes: a common-mode filter and a thermistor; The first terminal of the common-mode filter is connected to the first terminal of the varistor, the second terminal of the common-mode filter is connected to the second terminal of the varistor, the third terminal of the common-mode filter is connected to the first terminal of the thermistor, and the fourth terminal of the common-mode filter is connected to the second terminal of the power factor correction module. The second terminal of the thermistor is connected to the first terminal of the power factor correction module; The first surge protection unit also includes: a fuse, a first protection capacitor and / or a second protection capacitor; The first end of the fuse is used to input the surge voltage, and the second end of the fuse is connected to the first end of the varistor; The first protection capacitor is connected between the first and second terminals of the common-mode filter device. The second protection capacitor is connected between the third and fourth terminals of the common-mode filter device.

10. A household appliance, characterized in that, The household appliance includes at least the power factor correction circuit described in any one of claims 1-9.

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