Power supply device and air conditioner

Abstract

The invention discloses a power supply device and an air conditioner. The power supply device comprises a power supply circuit and a control module. The power supply circuit comprises a first input end, a second input end, an X capacitor, a power-on buffer module, a discharge branch and a rectifier module. The discharge branch comprises a first switching device and a discharge resistor which are connected in sequence, the power-on buffer module comprises a protection resistor and a second switching device which are connected in parallel, the X capacitor and the discharge branch are connected to a first input end and a second input end, one end of the protection resistor is connected with the X capacitor, the other end of the protection resistor is connected with the discharge branch, and the rectifier module is connected with the X capacitor; the control module is configured to control the first switching device to be switched on and control the second switching device to be switched off in response to the fact that the first input end and the second input end are in a power-down state, so that the discharge branch, the protection resistor and the X capacitor form a discharge loop. According to the invention, electric control loss can be avoided while rapid discharge is realized after the plug is unplugged.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply control, and in particular to a power supply device and an air conditioner. Background Art

[0002] At present, home appliances such as air conditioners need to meet the safety standard "GB4706.1-2005 Safety of Household and Similar Electrical Appliances", which requires that for products with plugs, the voltage between the live and neutral wires cannot exceed 34V within 1 second after the plug is unplugged. In order to meet the national magnetic compatibility standards and other EMC requirements, current home appliances generally have filter circuits, which contain X capacitors. X capacitors will discharge slowly after the plug is unplugged. Therefore, in order to meet safety requirements, current home appliances generally connect multiple discharge resistors in parallel between the live and neutral wires, but the increased resistance will cause an increase in electrical control losses, which is not conducive to improving the energy efficiency of the entire machine. Summary of the invention

[0003] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a power supply device and an air conditioner, which can achieve rapid discharge after the plug is unplugged and avoid electrical control loss.

[0004] In a first aspect, an embodiment of the present invention provides a power supply device, comprising: a power supply circuit and a control module; the power supply circuit comprises a first input terminal, a second input terminal, an X capacitor, a power-on buffer module, a discharge branch and a rectifier module; the discharge branch comprises a first switch device and a discharge resistor connected in sequence, the power-on buffer module comprises a protection resistor and a second switch device connected in parallel, the X capacitor is connected to the first input terminal and the second input terminal, the first switch device is connected to the first input terminal, the discharge resistor is connected to the second input terminal, one end of the protection resistor is connected to the X capacitor, and the other end is connected to the discharge branch, and the rectifier module is connected to the X capacitor; the control module is configured to: in response to the first input terminal and the second input terminal being in a power-off state, control the first switch device to close, and control the second switch device to open, so that the discharge branch, the protection resistor and the X capacitor form a discharge loop.

[0005] The power supply device provided by the embodiment of the present invention has at least the following beneficial effects: when the power supply circuit is in a power-off state, the discharge resistor and the protection resistor are introduced by closing the first switch device and disconnecting the second switch device, so that the discharge resistor, the protection resistor and the X capacitor form a discharge loop to discharge the X capacitor; wherein the protection resistor in the power-on buffer module can not only prevent the capacitor of the subsequent circuit from being impacted by the surge current during the power-on stage of the power supply circuit, but also participate in the construction of the discharge loop when the power supply circuit is in a power-off state, and can also short-circuit the protection resistor by closing the second switch device when the power supply circuit is normally powered, thereby reducing the electric control loss, realizing the reuse of the protection resistor, and reducing the circuit cost; in addition, since the discharge resistor and the protection resistor are only connected to the circuit in the discharge stage after the power supply circuit is powered off, and are bypassed during normal power supply, the protection resistor and the discharge resistor are effectively prevented from causing energy loss when the power supply circuit is normally powered, which helps to improve the energy efficiency of the system.

[0006] In the power supply device provided by the embodiment of the present invention, the power-on buffer module and the discharge branch are located between the X capacitor and the rectifier module, and the X capacitor is connected to the discharge branch through the protection resistor.

[0007] In the power supply device provided in the embodiment of the present invention, the power-on buffer module is located between the X capacitor and the rectifier module, the discharge branch is located at the output side of the rectifier module, and the X capacitor is connected to the discharge branch via the protection resistor and the rectifier module in sequence.

[0008] In the power supply device provided by the embodiment of the present invention, the power-on buffer module and the discharge branch are located at the output side of the rectifier module, and the X capacitor is connected to the discharge branch via the rectifier module and the protection resistor in sequence.

[0009] In the power supply device provided by the embodiment of the present invention, the power-on buffer module and the discharge branch are located at the input side of the X capacitor, and the discharge branch is connected to the X capacitor through the protection resistor.

[0010] In the power supply device provided in the embodiment of the present invention, the power supply circuit further includes an input voltage detection unit for detecting an input voltage between the first input terminal and the second input terminal; the control module is further configured as follows: The input voltage within a first preset time period is acquired, and in response to the input voltage showing a downward trend within the first preset time period, it is determined that the first input terminal and the second input terminal are in a power-off state.

[0011] In the power supply device provided in an embodiment of the present invention, within the first preset time period, the input voltage at each sampling moment is smaller than the input voltage at the previous sampling moment, and it is determined that the input voltage shows a downward trend within the first preset time period.

[0012] In the power supply device provided in the embodiment of the present invention, the control module is further configured as follows: Acquiring the input voltage, and determining a conduction duty cycle of the first switching device according to the input voltage and a safety voltage threshold; The first switching device is controlled according to the on-duty ratio.

[0013] In the power supply device provided in the embodiment of the present invention, the control module is further configured as follows: The input voltage is obtained, and when the input voltage is less than a first safety voltage threshold, the first switch device is controlled to be disconnected.

[0014] In the power supply device provided in the embodiment of the present invention, the power supply circuit further includes a boost module connected to the output side of the rectifier module, the output side of the boost module is provided with a bus voltage detection unit for detecting the bus voltage, and the control module is further configured as follows: The bus voltage is obtained, and when the bus voltage is less than a second safety voltage threshold, the first switching device is controlled to be disconnected.

[0015] In a second aspect, an embodiment of the present invention provides an air conditioner, comprising the power supply device as described in the embodiment of the first aspect above.

[0016] The air conditioner provided according to the embodiment of the present invention has at least the following beneficial effects: when the power supply circuit is in a power-off state, the discharge resistor and the protection resistor are introduced by closing the first switch device and opening the second switch device, so that the discharge resistor, the protection resistor and the X capacitor form a discharge loop to discharge the X capacitor; wherein the protection resistor in the power-on buffer module can not only prevent the capacitor of the subsequent circuit from being impacted by the surge current during the power-on stage of the power supply circuit, but also participate in the construction of the discharge loop when the power supply circuit is in a power-off state, but also can short-circuit the protection resistor by closing the second switch device when the power supply circuit is in normal power supply, thereby reducing the electric control loss, realizing the reuse of the protection resistor, and reducing the circuit cost; in addition, since the discharge resistor and the protection resistor are only connected to the circuit in the discharge stage after the power supply circuit is powered off, and are bypassed during normal power supply, the protection resistor and the discharge resistor can be effectively prevented from causing energy loss when the power supply circuit is in normal power supply, which is helpful to improve the energy efficiency of the system.

[0017] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0019] The present invention is further described below in conjunction with the accompanying drawings and embodiments; Figure 1 is a schematic diagram of the structure of a power supply device provided by an embodiment of the present invention; Figure 2 yes Figure 1 Equivalent schematic diagram of the discharge circuit constructed in ; Figure 3 is a schematic diagram of the structure of a power supply circuit provided by another embodiment of the present invention; Figure 4 yes Figure 3 Equivalent schematic diagram of the discharge circuit constructed in ; Figure 5 is a schematic diagram of the structure of a power supply circuit provided by another embodiment of the present invention; Figure 6 yes Figure 5 Equivalent schematic diagram of the discharge circuit constructed in ; Figure 7 is a schematic diagram of the structure of a power supply circuit provided by another embodiment of the present invention; Figure 8 yes Figure 7 Equivalent schematic diagram of the discharge circuit constructed in ; Fig. 9 It is a schematic diagram of the circuit effect of voltage sampling provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0020] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0021] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, "above", "below", "within", etc. are understood to include the number itself, "any one" means one or more, "at least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. If there is a description of the first and the second, it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0022] It should be noted that the terms such as setting, installing, and connecting in the embodiments of the present invention should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the embodiments of the present invention in combination with the specific content of the technical solution. For example, the term "connection" can be a mechanical connection, an electrical connection, or mutual communication; it can be directly connected or indirectly connected through an intermediate medium.

[0023] It should be noted that the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] At present, home appliances such as air conditioners need to meet the safety standard "GB4706.1-2005 Safety of Household and Similar Electrical Appliances", which requires that for products with plugs, the voltage between the live and neutral wires cannot exceed 34V within 1 second after the plug is unplugged. In order to meet the national magnetic compatibility standards and other EMC requirements, current home appliances generally have filter circuits, which contain X capacitors. X capacitors will discharge slowly after the plug is unplugged. Therefore, in order to meet safety requirements, current home appliances generally connect multiple discharge resistors in parallel between the live and neutral wires, but the increased resistance will cause an increase in electrical control losses, which is not conducive to improving the energy efficiency of the entire machine.

[0025] Based on this, an embodiment of the present invention proposes a power supply device and an air conditioner. When the power supply circuit is in a power-off state, a discharge resistor and a protection resistor are introduced by closing a first switch device and disconnecting a second switch device, so that the discharge resistor, the protection resistor and the X capacitor form a discharge loop to discharge the X capacitor; wherein the protection resistor in the power-on buffer module can not only prevent the capacitor of the subsequent circuit from being impacted by surge current during the power-on stage of the power supply circuit, but also participate in the construction of the discharge loop when the power supply circuit is in a power-off state, and can also short-circuit the protection resistor by closing the second switch device when the power supply circuit is normally powered, thereby reducing the electric control loss, realizing the reuse of the protection resistor, and reducing the circuit cost; in addition, since the discharge resistor and the protection resistor are only connected to the circuit in the discharge stage after the power supply circuit is powered off, and are bypassed during normal power supply, the protection resistor and the discharge resistor are effectively prevented from causing energy loss when the power supply circuit is normally powered, which helps to improve the energy efficiency of the system.

[0026] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0027] It is understandable that the power supply circuit of household appliances generally includes an AC filter module, a rectifier module, a buck-boost module and an inverter module, and also includes a control module for controlling the power supply circuit, wherein the AC filter module filters the power supply connected to the power grid, and the AC filter module includes an X capacitor, which is a capacitor connected across two power lines (i.e., the first input terminal and the second input terminal) to suppress differential mode interference. After the power supply circuit (for example, unplugging the plug) loses power, due to the accumulation of charges at both ends of the X capacitor, it cannot be quickly released in a short time, and there will be a large residual voltage at both ends of the X capacitor, so that the safety standard of residual voltage less than 34V within 1s cannot be met between the neutral and live wires of the plug. When the power cord plug is unplugged, it is easy to cause electric shock to the human body, so it is necessary to quickly release the residual charge in the X capacitor. After the input capacitor is filtered by the AC filter module, it is input to the rectifier module for rectification and converted into a DC power supply. The buck-boost module adjusts the input DC voltage to an appropriate voltage level so that the subsequent inverter module can convert the DC power into constant-frequency and constant-voltage or frequency-modulated and voltage-regulated AC power to provide the required power to the load (such as a motor, etc.).

[0028] Take the power supply circuit of the air conditioner as an example, refer to Figure 1 , Figure 1: is a schematic diagram of the structure of the power supply device provided by an embodiment of the present invention. The power supply circuit of the air conditioner is connected to an external AC power supply through a first input terminal and a second input terminal. The external AC power supply is input to the AC filter module and passes through the X capacitor C1 to charge the X capacitor C1. The filtered power supply is input to the rectifier module for rectification, and the rectified DC power supply is transmitted to the BOOST type boost module for voltage boosting. The boosted power supply is then transmitted to the inverter module, and the inverter module supplies power to the motor, forming a power supply circuit for supplying power to the load. Among them, Figure 1 As shown, a discharge resistor R1, a protection resistor R2, a first switch device RY1 and a second switch device RY2 are additionally arranged between the AC filter module (i.e., the X capacitor C1) and the rectifier module, the first end A of the X capacitor C1 is connected to one end of the protection resistor R2, the other end of the protection resistor R2 is simultaneously connected to one end of the first switch device RY1 and the first input end C of the rectifier module, the other end of the first switch device RY1 is connected to one end of the discharge resistor R1, the other end of the discharge resistor R1 is connected to the connection point between the second end B of the X capacitor C1 and the second input end D of the rectifier module, and the second switch device RY2 is connected to both ends of the protection resistor R2. It should be noted that at this time, the discharge branch and the protection resistor R2 are both located on the output side of the X capacitor C1, i.e., the same side.

[0029] like Figure 1 As shown, the embodiment of the present invention takes an air conditioner as an example. If the air conditioner (i.e., the power supply circuit) is in working state and the plug is suddenly unplugged, the power stored in the X capacitor C1 will be quickly consumed because the high-power loads such as the compressor and the fan are still in working state for a short time. However, if the air conditioner (i.e., the power supply circuit) is in standby state and the load is in shutdown state, at this time, the electric energy stored in the X capacitor C1 is difficult to be released quickly. Therefore, when the first input terminal and the second input terminal of the power supply circuit are in a power-off state, such as after the plug is unplugged, the control module in the power supply device can close the first switch device RY1 and disconnect the second switch device RY2 at the same time, and connect the discharge branch and the protection resistor R2 to the power supply circuit at the same time. At this time, the X capacitor C1, the protection resistor R2 and the discharge branch form a discharge loop, which can realize the rapid discharge of the X capacitor C1. Specifically, refer to Figure 2 , Figure 2 The embodiment of the present invention provides Figure 1 From the equivalent schematic diagram of the discharge loop constructed in FIG. 1 , it can be seen that the charge stored on the X capacitor C1 passes through the protection resistor R2 and the first switch device RY1 to form a loop with the discharge resistor R1 for consumption, thereby being able to quickly release the residual charge in the X capacitor C1 .

[0030] When the first switch device RY1 is in the disconnected state, the discharge branch is in the open circuit state, and the discharge resistor R1 is not connected to the power supply circuit of the power supply circuit. When the second switch device RY2 is in the closed state, the protection resistor R2 is short-circuited, and the protection resistor R2 is not connected to the power supply circuit of the power supply circuit. Therefore, when the power supply circuit is normally powered (non-power-on stage), the first switch device RY1 can be disconnected and the second switch device RY2 can be closed, so that the discharge resistor R1 and the protection resistor R2 are separated from the power supply circuit of the power supply circuit, so that the discharge resistor R1 and the protection resistor R2 introduced when the power supply circuit is normally powered will not cause additional electric control loss and will not affect the electric control efficiency of the circuit. Since the discharge resistor R1, the protection resistor R2, the first switch device RY1 and the second switch device RY2 introduced in the construction of the discharge circuit of the power supply circuit are all conventional electronic devices, there is no need to introduce or switch additional AC loads for discharge, and the discharge circuit is easy to construct and control, and the cost is low, and it has good versatility.

[0031] It is worth noting that the protection resistor R2 is used to prevent the capacitor of the subsequent circuit (such as the output capacitor C2 in the BOOST boost module) from being impacted by surge current during the power-on stage of the power supply circuit. A positive temperature coefficient thermistor (PTC) can be used. Therefore, during the discharge process, the characteristic that the resistance of the PTC resistor increases with increasing temperature can be utilized, which can reduce the material selection requirements for the discharge resistor R1 and use a resistor with a smaller resistance and power as the discharge resistor R1, thereby optimizing the circuit cost.

[0032] It is understandable that the first switch device RY1 and the second switch device RY2 can be a single element capable of realizing a switch function, such as a relay, an optocoupler device, a transistor switch (such as a MOS tube, an IGBT, etc.), or a combination of multiple elements that realize a switch function, such as a logic gate circuit formed by a combination of transistors. It is worth noting that the switching states of the first switch device RY1 and the second switch device RY2 can be independently controlled without interfering with each other, or can be jointly controlled. For example, the first switch device RY1 and the second switch device RY2 can form a single-pole double-throw mutually exclusive relay, that is, when the first switch device RY1 is in a closed state, the second switch device RY2 is in an open state, and when the first switch device RY1 is in an open state, the second switch device RY2 is in a closed state.

[0033] It is understandable that the positions of the power-on buffer module and the discharge branch can be adjusted according to the actual application of the power supply circuit. For details, please refer to Figure 3 , Figure 3: is a schematic diagram of the structure of the power supply circuit provided by another embodiment of the present invention. It can be seen that a power-on buffer module is provided between the X capacitor C1 and the rectifier module, and the discharge branch is located at the output side of the rectifier module, that is, the discharge branch is located between the rectifier module and the boost module; one end of the protection resistor R2 is connected to the first end A of the X capacitor C1, and the other end is connected to the first input end C of the rectifier module. Similarly, the second switch device RY2 is connected to both ends of the protection resistor R2, forming a parallel connection relationship with the protection resistor R2; one end of the first switch device RY1 is connected to the first output end E of the rectifier module, and the other end is connected to one end of the discharge resistor R1, and the other end of the discharge resistor R1 is connected to the second output end F of the rectifier module. It should be noted that the discharge branch and the protection resistor R2 are both located at the output side of the X capacitor C1, that is, the same side.

[0034] At this time, when the first input terminal and the second input terminal of the power supply circuit are in a power-off state, the control module can close the first switch device RY1 and disconnect the second switch device RY2, and connect the discharge branch and the protection resistor R2 to the power supply circuit at the same time. The X capacitor C1, the protection resistor R2, the rectifier module and the discharge branch form a discharge loop, which can realize the rapid discharge of the X capacitor C1. For details, refer to Figure 4 , Figure 4 The embodiment of the present invention provides Figure 3 From the equivalent schematic diagram of the discharge circuit constructed in FIG. 1 , it can be seen that the charge stored on the X capacitor C1 passes through the protection resistor R2 and the rectifier bridge of the rectifier module, and then is consumed by the first switch device RY1 and the discharge resistor R1 to form a loop, thereby being able to quickly release the residual charge in the X capacitor C1.

[0035] Similarly, in Figure 3 In the power supply circuit shown, when the first switch device RY1 is in the disconnected state, the discharge branch is also in the open state, and the discharge resistor R1 is not connected to the power supply circuit of the power supply circuit; when the second switch device RY2 is in the closed state, the protection resistor R2 is short-circuited, and the protection resistor R2 is also not connected to the power supply circuit of the power supply circuit.

[0036] It is worth noting that the BOOST-type boost module is also equipped with a fast recovery diode (FRD), which effectively prevents current backflow and protects the circuit from the influence of reverse current. In order to avoid the influence on the circuit, the discharge branch is set between the rectifier module and the FRD diode.

[0037] It is understandable that the discharge branch and the power-on buffer module can also be arranged at the output side of the rectifier module, that is, also at the output side of the X capacitor C1. For details, please refer to Figure 5 , Figure 5is a structural schematic diagram of a power supply circuit provided by another embodiment of the present invention. It can be seen that no power-on buffer module or discharge branch is provided between the X capacitor C1 and the rectifier module, and the power-on buffer module and the discharge branch are both located between the rectifier module and the boost module, wherein one end of the protection resistor R2 is connected to the first output terminal E of the rectifier module, and the other end is simultaneously connected to one end of the first switch device RY1 and the input terminal of the boost module, the other end of the first switch device RY1 is connected to the second output terminal F of the rectifier module through the discharge resistor R1, and the second switch device RY2 is connected to both ends of the protection resistor R2.

[0038] At this time, when the first input terminal and the second input terminal of the power supply circuit are in a power-off state, the control module can close the first switch device RY1 and disconnect the second switch device RY2, and connect the discharge branch and the protection resistor R2 to the power supply circuit at the same time. The X capacitor C1, the protection resistor R2, the rectifier module and the discharge branch form a discharge loop, which can realize the rapid discharge of the X capacitor C1. For details, refer to Figure 6 , Figure 6 The embodiment of the present invention provides Figure 5 From the equivalent schematic diagram of the discharge circuit constructed in FIG. 1 , it can be seen that the charge stored on the X capacitor C1 passes through the rectifier bridge of the rectifier module, passes through the protection resistor R2, and then passes through the first switch device RY1 and the discharge resistor R1 to form a loop for consumption, thereby being able to quickly release the residual charge in the X capacitor C1.

[0039] Similarly, in Figure 6 In the power supply circuit shown, when the first switch device RY1 is in the disconnected state, the discharge branch is also in the open state, and the discharge resistor R1 is not connected to the power supply circuit of the power supply circuit; when the second switch device RY2 is in the closed state, the protection resistor R2 is short-circuited, and the protection resistor R2 is also not connected to the power supply circuit of the power supply circuit.

[0040] It is understandable that the discharge branch and the power-on buffer module can also be arranged on the input side of the X capacitor C1, referring to Figure 7 , Figure 7 is a structural schematic diagram of a power supply circuit provided by another embodiment of the present invention. It can be seen that the discharge branch and the power-on buffer module are located between the X capacitor C1 and two input terminals (the first input terminal and the second input terminal). Specifically, one end of the first switch device RY1 is connected to the first input terminal and one end of the protection resistor R2 at the same time, the first end A of the X capacitor C1 is connected to the first input terminal through the other end of the protection resistor R2, the other end of the first switch device RY1 is connected to the connection point between the second input terminal and the second end B of the X capacitor C1 through the discharge resistor R1, and the second switch device RY2 is connected to both ends of the protection resistor R2, forming a parallel connection relationship with the protection resistor R2.

[0041] At this time, when the first input terminal and the second input terminal of the power supply circuit are in a power-off state, the control module can close the first switch device RY1 and disconnect the second switch device RY2, and connect the discharge branch and the protection resistor R2 to the power supply circuit at the same time. The X capacitor C1, the protection resistor R2, and the discharge branch form a discharge loop, which can realize the rapid discharge of the X capacitor C1. For details, refer to Figure 8 , Figure 8 The embodiment of the present invention provides Figure 7 From the equivalent schematic diagram of the discharge circuit constructed in FIG. 1 , it can be seen that the charge stored on the X capacitor C1 is consumed through the protection resistor R2 , the first switch device RY1 , and then the discharge resistor R1 to form a circuit to quickly release the residual charge in the X capacitor C1 .

[0042] Similarly, in Figure 7 In the power supply circuit shown, when the first switch device RY1 is in the disconnected state, the discharge branch is also in the open state, and the discharge resistor R1 is not connected to the power supply circuit of the power supply circuit; when the second switch device RY2 is in the closed state, the protection resistor R2 is short-circuited, and the protection resistor R2 is also not connected to the power supply circuit of the power supply circuit.

[0043] It is understandable that a voltage and current sampling function module may be provided in the power supply circuit, for example, a sampling circuit that can sample and detect electrical parameters such as the input voltage, output voltage, and output current of the power supply circuit. Figure 1 Taking the power supply circuit shown in FIG. 1 as an example, the voltage sampling end of the input voltage detection unit can be connected to the output end of the rectifier module to collect the voltage output by the rectifier module. Since the main function of the rectifier module is to convert the AC power supply connected to the input end into a DC power supply, and the subsequent modules of the power supply circuit all rely on the rectifier module for power supply, the voltage output by the rectifier module can be regarded as the input voltage of the power supply circuit. Specifically, Figure 1 As shown, the voltage sampling end of the input voltage detection unit is connected to the first output end C of the rectifier module. At this time, if it is detected that the input voltage continues to decrease for a period of time, it can be considered that the first input end and the second input end are in a power-off state, that is, the power supply circuit is unplugged, and the first switch device RY1 can be immediately closed and the second switch device RY2 can be disconnected, so that the discharge branch, the protection resistor R2 and the X capacitor C1 form a discharge loop to discharge the X capacitor C1.

[0044] The voltage sampling terminal of the input voltage detection unit can also be set at the output terminal of the AC filter module, such as Fig. 9 As shown, Fig. 9: is a schematic diagram of the circuit effect of voltage sampling provided by an embodiment of the present invention. It can be seen that the input voltage detection unit can be connected to the first end A and the second end B of the X capacitor C1 respectively, and directly samples the AC voltage of the filtered AC power supply connected to the power supply circuit, and uses it as the input voltage of the power supply circuit. Similarly, if it is detected that the input voltage continues to decrease over a period of time, it can be confirmed that the first input terminal and the second input terminal are in a power-off state.

[0045] When the first input terminal and the second input terminal are in a power-off state, the electric energy stored in the X capacitor C1 will be released in an attempt to maintain the voltage of the circuit. At this time, the input voltage of the power supply circuit is provided by the X capacitor C1. Therefore, by constructing a discharge circuit to release the electric energy of the X capacitor C1, the input voltage of the power supply circuit is quickly reduced, that is, the voltage between the neutral and live wires of the plug is reduced. Therefore, when it is detected that the input voltage between the first input terminal and the second input terminal is lower than the first safety voltage threshold, it can be considered that the safety requirements have been met, so that the control module disconnects the first switch device RY1 to avoid the control module being unable to control the first switch device RY1 to disconnect after the power is completely off, so that when the power supply circuit is powered on again, the first switch device RY1 is still connected to the power supply circuit of the power supply circuit, affecting the power supply efficiency of the power supply circuit. It should be noted that when the input voltage is lower than the first safety voltage threshold and the first switch device RY1 is disconnected, the second switch device RY2 can be maintained in a disconnected state, so that the protection resistor R2 is connected to the power supply circuit when the power supply circuit is powered on again, so as to avoid the electrolytic capacitor of the subsequent circuit from being impacted by the surge current and protect the circuit.

[0046] It is worth noting that the control module is respectively connected to the first switch device RY1, the second switch device RY2 and the input voltage detection unit, and the control module can obtain the input voltage of the power supply circuit through the input voltage detection unit to determine whether the power supply circuit is unplugged. Specifically, the control module can monitor the input voltage in real time. If the input voltage shows a continuous downward trend within the first preset time, it can be determined that the power supply circuit is in a power-off state, that is, the power supply circuit is unplugged. The input voltage can be continuously sampled, and the input voltage sampled each time within the first preset time can be arranged in time order to form time series data. Then, the time series data of the input voltage within the first preset time can be fitted by a linear regression method to obtain the slope of the input voltage changing with time within the first preset time. If the slope obtained by fitting is less than zero, and the absolute value of the slope is greater than a certain threshold, it can be indicated that the downward trend of the input voltage is significant, and it is confirmed that the input voltage shows a continuous downward trend within the first preset time.

[0047] In addition, the input voltage sampled each time within the first preset time period can be traversed, and the input voltages of adjacent sampling points (sampling moments) can be compared. If the input voltage of each sampling point is less than the input voltage of the previous sampling point in a preset proportion (such as more than 90%) of adjacent sampling points, then it can be determined that the input voltage presents a continuous downward trend within the first preset time period. According to actual needs and application scenarios, a voltage change threshold can be introduced in the comparison process of the input voltages at adjacent sampling moments. For each pair of adjacent sampling points in the time series data, the voltage change amount between them is calculated, that is, the voltage difference between the input voltages at two adjacent sampling moments. If the voltage change amount is less than the preset voltage difference threshold and is negative in a preset proportion (such as more than 90%) of adjacent sampling points, then it can be determined that the input voltage presents a continuous downward trend within the first preset time period.

[0048] In addition, a bus voltage detection unit connected to the control module may be provided in the power supply circuit, and a voltage sampling end of the bus voltage detection unit is connected to the output side of the boost module, such as Fig. 9 As shown, the voltage sampling end of the bus voltage detection unit is connected to the connection point between the output capacitor C2 in the BOOST boost module and the inverter module, and the bus voltage is collected through the bus voltage detection unit. The bus voltage is the voltage transmitted to the inverter module after rectification and boosting. The bus voltage is affected by the voltage level transmitted by the front-end circuit. Therefore, the bus voltage can reflect the input voltage of the power supply circuit, that is, the voltage between the zero and live wires of the plug. Therefore, the bus voltage can be obtained and compared. If the bus voltage is lower than the second safety voltage threshold, it can be considered that the safety requirements are met and the first switch device RY1 is disconnected. Similarly, when the first switch device RY1 is disconnected, the second switch device RY2 can be maintained in the disconnected state.

[0049] It should be noted that when the control module determines that the power supply circuit is in a power-off state and needs to control the first switch device RY1 to be closed, the first switch device RY1 can be controlled to be continuously closed. At this time, in the discharge circuit, the discharge current formed by the electric energy stored in the X capacitor C1 will continue to pass through the discharge resistor R1 and the protection resistor R2, so that the electric energy can be quickly converted into heat energy for release; or, the control module can also control the first switch device RY1 by duty cycle control, that is, adjust the closing time and disconnection time of the first switch device RY1 within a fixed period. When the duty cycle control is adopted, the discharge current will be divided into multiple short pulses passing through the discharge resistor R1, and the average current during each pulse, therefore, the power that the discharge resistor R1 needs to withstand will also be reduced accordingly, which means that a discharge resistor R1 with a lower power level can be selected, thereby reducing the circuit cost and volume. Specifically, the control module can generate a conduction duty cycle according to the current input voltage of the power supply circuit (i.e., the residual voltage of the X capacitor C1) and the first safety voltage threshold, and then use the conduction duty cycle to control the first switch device RY1, so that the input voltage during the discharge process can be used for real-time feedback, and the duty cycle can be adjusted more accurately to optimize the discharge process, thereby preventing the discharge resistor R1 from being subjected to excessive current shock, which is helpful to improve discharge efficiency and safety, and reduce the difficulty of thermal management.

[0050] It can be understood by those skilled in the art that Figures 1 to 9 The structure of the power supply device shown in the figure does not constitute a limitation on the embodiments of the present invention, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0051] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A power supply device, characterized in that: include: Power supply circuit and control module; The power supply circuit includes a first input terminal, a second input terminal, an X capacitor, a power-on buffer module, a discharge branch and a rectifier module; the discharge branch includes a first switch device and a discharge resistor connected in sequence, the power-on buffer module includes a protection resistor and a second switch device connected in parallel, the X capacitor is connected to the first input terminal and the second input terminal, the first switch device is connected to the first input terminal, the discharge resistor is connected to the second input terminal, one end of the protection resistor is connected to the X capacitor, and the other end is connected to the discharge branch, and the rectifier module is connected to the X capacitor; The control module is configured to: In response to the first input terminal and the second input terminal being in a power-off state, the first switch device is controlled to be closed, and the second switch device is controlled to be opened, so that the discharge branch, the protection resistor and the X capacitor form a discharge loop.

2. The power supply device according to claim 1, characterized in that: The power-on buffer module and the discharge branch are located between the X capacitor and the rectifier module, and the X capacitor is connected to the discharge branch through the protection resistor.

3. The power supply device according to claim 1, characterized in that: The power-on buffer module is located between the X capacitor and the rectifier module, the discharge branch is located at the output side of the rectifier module, and the X capacitor is connected to the discharge branch via the protection resistor and the rectifier module in sequence.

4. The power supply device according to claim 1, characterized in that: The power-on buffer module and the discharge branch are located at the output side of the rectifier module, and the X capacitor is connected to the discharge branch through the rectifier module and the protection resistor in sequence.

5. The power supply device according to claim 1, characterized in that: The power-on buffer module and the discharge branch are located at the input side of the X capacitor, and the discharge branch is connected to the X capacitor through the protection resistor.

6. The power supply device according to claim 1, characterized in that: The power supply circuit further includes an input voltage detection unit for detecting an input voltage between the first input terminal and the second input terminal; the control module is further configured to: The input voltage within a first preset time period is acquired, and in response to the input voltage showing a downward trend within the first preset time period, it is determined that the first input terminal and the second input terminal are in a power-off state.

7. The power supply device according to claim 6, characterized in that: During the first preset time period, the input voltage at each sampling moment is smaller than the input voltage at the previous sampling moment, and it is determined that the input voltage shows a downward trend during the first preset time period.

8. The power supply device according to claim 6, characterized in that: The control module is further configured to: Acquiring the input voltage, and determining a conduction duty cycle of the first switching device according to the input voltage and a safety voltage threshold; The first switching device is controlled according to the on-duty ratio.

9. The power supply device according to claim 6, characterized in that: The control module is further configured to: The input voltage is obtained, and when the input voltage is less than a first safety voltage threshold, the first switch device is controlled to be disconnected.

10. The power supply device according to claim 1, characterized in that: The power supply circuit further includes a boost module connected to the output side of the rectifier module, the output side of the boost module is provided with a bus voltage detection unit for detecting the bus voltage, and the control module is further configured as follows: The bus voltage is obtained, and when the bus voltage is less than a second safety voltage threshold, the first switching device is controlled to be disconnected.

11. An air conditioner, characterized in that: Comprising the power supply device according to any one of claims 1 to 10.

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