A controller

Abstract

The embodiment of the application provides a controller for controlling a fan, comprising a rectifier unit, a switching power supply conversion unit, a delay unit, a fan starting control unit and a fan interface; the output end of the rectifier unit is connected with the input end of the switching power supply conversion unit, the switching power supply conversion unit converts the bus voltage output by the rectifier unit to generate the first direct current voltage required by the delay unit; the switching power supply conversion unit has an overvoltage protection function; the delay unit is connected to the first output end of the switching power supply conversion unit and receives the first direct current voltage; the fan starting control unit comprises a controllable switch, the control end of the controllable switch is connected with the delay unit, when the delay time set by the delay unit is reached, the delay unit controls the controllable switch to be closed; the first end of the controllable switch is connected with the output of the rectifier unit, and the second end of the controllable switch is connected with the fan interface. The controller can realize overvoltage protection of the fan.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor control, in particular to a controller related to a fan. BACKGROUND

[0002] In the field of household appliances, a DC fan is often used to achieve air flow, thereby achieving the function of heat dissipation. Therefore, how to safely and reliably control the fan is a technical problem to be solved. SUMMARY

[0003] Therefore, the present application provides a controller for controlling a fan, which can achieve overvoltage protection.

[0004] To achieve the above-mentioned purpose, the embodiments of the present application provide the following technical solutions:

[0005] A controller for controlling a fan, comprising a rectifier unit, a switching power supply conversion unit, a delay unit, a fan start control unit and a fan interface.

[0006] The output end of the rectifier unit is connected to the input end of the switching power supply conversion unit, and the switching power supply conversion unit converts the bus voltage output by the rectifier unit to generate a first DC voltage required by the delay unit; the switching power supply conversion unit has an overvoltage protection function.

[0007] The delay unit is connected to the first output end of the switching power supply conversion unit and receives the first DC voltage; the fan start control unit comprises a controllable switch, the control end of the controllable switch is connected to the delay unit, and when the set delay time length of the delay unit is reached, the delay unit controls the controllable switch to close; the first end of the controllable switch is connected to the output of the rectifier unit, and the second end of the controllable switch is connected to the fan interface; the fan interface is used to connect with the fan. The controller realizes the delay start of the fan through the delay unit, and the switching power supply conversion unit can realize overvoltage detection before the fan starts, thereby realizing overvoltage protection, so that the fan will not work under overvoltage, thereby protecting the fan and related devices of the fan circuit.

[0008] Optionally, the delay time length of the delay unit is greater than the start-up time length of the switching power supply conversion unit.

[0009] Optionally, the switching power supply conversion unit comprises a flyback conversion circuit and a switching control chip 121; the delay unit comprises a 555 timing chip; and the controllable switch is a relay.

[0010] Optionally, the fan interface comprises a power input end and a communication power end; the power input end is connected to the second end of the controllable switch; the switching power supply unit further comprises a second output end for outputting a second direct current voltage; the communication power end of the fan interface is connected to the second output end, and the second direct current voltage is used as the communication power of the fan.

[0011] The application further provides a controller for controlling a fan, comprising a rectifying unit, a switching power supply unit, a first delay unit, a second delay unit, an overshoot suppression unit, a fan starting control unit and a fan interface.

[0012] The input end of the switching power supply unit is connected to the output end of the rectifying unit, and the switching power supply unit converts the bus voltage output by the rectifying unit to generate a third direct current voltage required by the second delay unit; the switching power supply unit has an overvoltage protection function.

[0013] The second delay unit is connected to the third output end of the switching power supply unit and receives the third direct current voltage; the overshoot suppression unit comprises a current-limiting resistor and a second controllable switch connected in series; the control end of the second controllable switch is connected to the second delay unit, and when the set delay time length of the second delay unit is reached, the second delay unit controls the second controllable switch to be closed.

[0014] The first delay unit is connected to the second delay unit, and when the set delay time length of the second delay unit is reached, the first delay unit is powered on and works.

[0015] The fan starting control unit comprises a third controllable switch, the control end of the third controllable switch is connected to the first delay unit, and when the set delay time length of the first delay unit is reached, the first delay unit controls the third controllable switch to be closed; the fan starting control unit and the overshoot suppression unit are connected in parallel between the positive output end of the rectifying unit and the positive power end of the fan interface; the fan interface is used to be connected to the fan, and the positive power end is connected to the fan capacitor. The controller realizes the delay starting of the fan through the second delay unit and the first delay unit, the switching power supply unit can realize the overvoltage detection before the starting of the fan, so as to realize the overvoltage protection, so that the fan will not work under overvoltage, and the related devices of the fan and the fan circuit are protected, and the second delay unit, the first delay unit and the overshoot suppression unit can prevent the overvoltage damage of the fan starting capacitor.

[0016] Optionally, the delay time length of the second delay unit is greater than the starting time length of the switching power supply unit, and the delay time length of the first delay unit is greater than the charging time length of the fan capacitor.

[0017] Optionally, the switching power conversion unit comprises a flyback conversion circuit and a switching control chip 221; the first delay unit comprises a 555 timing chip; the second delay unit comprises a 555 timing chip; the second controllable switch or the third controllable switch is a relay.

[0018] Optionally, the fan interface further comprises a communication power supply end; the switching power conversion unit further comprises a second output end, the second output end being used for outputting a second direct current voltage; the communication power supply end of the fan interface is connected to the second output end, and the second direct current voltage is used as a communication power supply of the fan.

[0019] Optionally, the current-limiting resistor is a PTC resistor.

[0020] The application provides a controller for controlling a fan, so that the fan does not work after overvoltage, thereby avoiding damage to the fan and related devices of the fan circuit. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute a part of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0022] Figure 1 The circuit block diagram of the controller provided by an embodiment of the present application is shown in the figure;

[0023] Figure 2 The circuit schematic diagram of the controller provided by another embodiment of the present application is shown in the figure;

[0024] Figure 3 The circuit block diagram of the controller provided by another embodiment of the present application is shown in the figure;

[0025] Figure 4 The circuit schematic diagram of the controller provided by another embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0027] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a 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. Without further limitation, 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 said element.

[0028] DC fans are frequently used in household appliances for heat dissipation and air exchange. They are simple to control, have a wide power range, and are generally powered by the DC bus voltage after rectification and filtering of AC power. However, if the power supply voltage is too high, or in the case of a three-phase type fan where the neutral wire is connected as a phase wire or the neutral wire is not connected, the voltage may exceed the tolerance range of the components, causing an overvoltage fault. This can range from minor issues like component burnout and control failure, preventing the fan from working properly, to major accidents such as fires. DC fans powered by the DC bus voltage after AC power filtering and rectification are widely used in household appliances. Because DC fans are high-voltage devices, overvoltage poses a risk of component burnout and fire, requiring extremely high reliability.

[0029] Therefore, to prevent overvoltage faults or overvoltage risks, overvoltage protection is implemented when overvoltage occurs. This application provides a controller, such as... Figure 1 As shown, the controller is used to control the fan and includes a rectifier unit 11, a switching power supply conversion unit 12, a delay unit 13, a fan start control unit 14, and a fan interface 15.

[0030] The output terminal of the rectifier unit 11 is connected to the input terminal of the switching power conversion unit 12. The switching power conversion unit 12 converts the bus voltage Vbus output by the rectifier unit 11 to generate the first DC voltage V1 required by the delay unit 13. The switching power conversion unit 12 has an overvoltage protection function. The switching power conversion unit 12 can be a flyback switching converter, which converts the bus voltage Vbus into the first DC voltage V1. V1 is output to the delay unit 13 to provide power to the delay unit for its operation.

[0031] The delay unit 13 is connected to the first output end of the switching power supply conversion unit 12, and the switching power supply conversion unit can also have only one output end, which is also referred to as the first output end herein, and receives the first direct current voltage V1; the fan starting control unit 14 includes a controllable switch, and the control end of the controllable switch is connected to the delay unit 13, that is, the controllable switch is controlled to be closed by the delay unit 13, and specifically, when the delay time set by the delay unit is reached, the delay unit controls the controllable switch to be closed; the delay time of the delay unit can be realized by an RC delay circuit, or can be realized by a timing chip such as a 555 timer; the first end of the controllable switch is connected to the output of the rectifier unit, and the second end of the controllable switch is connected to the fan interface; when the controllable switch is closed, the bus voltage Vbus output by the rectifier unit is connected to the fan interface through the controllable switch, and specifically, is connected to the power supply end of the fan interface to supply power to the fan; the fan interface is used to be connected to the fan.

[0032] In this embodiment, when the alternating current power is connected to the input end of the rectifier unit, the bus voltage Vbus is output by the rectifier unit; the bus voltage is simultaneously transmitted to the switching power supply conversion unit and the fan starting control unit, but the switching power supply conversion unit outputs the first direct current voltage V1 only after the switching power supply conversion unit works, and the delay unit works only after receiving V1, and the delay unit controls the controllable switch of the fan starting control unit to be closed only after a specific delay time; when the controllable switch is closed, the bus voltage Vbus is output to the fan interface through the controllable switch, and when the fan is connected to the fan interface, the bus voltage provides power supply for the fan. Before the delay time is reached, the controllable switch is opened, and the fan is disconnected from the bus voltage, so that the fan will not fail due to overvoltage even if the bus voltage is overvoltage. The switching power supply conversion unit generally has an overvoltage protection function, and the starting time of the switching power supply conversion unit is very short, generally tens of milliseconds, and the delay time of the delay unit can be freely set, and specifically, the delay time of the delay unit is set to be greater than the starting time of the switching power supply conversion unit, and the delay time is set to be 1 second, 2 seconds, etc. When the input alternating current is overvoltage, the switching power supply conversion unit normally enters the starting state, and the starting time is generally tens of milliseconds. During the starting process, the switching power supply conversion unit works to output the first direct current voltage V1, the first direct current voltage V1 is controlled to close the controllable switch of the fan starting control unit only after a delay, so that the switching power supply conversion unit has sufficient time (delay time) to complete the starting and detect the input overvoltage state to stop working in the input overvoltage state. After stopping working, the first direct current voltage V1 is not output any more, so that the controllable switch cannot be closed, the overvoltage bus voltage cannot be connected to the fan interface, and the fan cannot work, so that the fan or other electrical devices are protected; until the input overvoltage state is removed.

[0033] In one embodiment, as shown in FIG. 1, the switching power supply conversion unit 12 is connected to the first output end of the rectifier unit 11, and receives the bus voltage Vbus output by the rectifier unit 11; the delay unit 13 is connected to the first output end of the switching power supply conversion unit 12, and receives the first direct current voltage V1 output by the switching power supply conversion unit 12; the fan starting control unit 14 includes a controllable switch, and the control end of the controllable switch is connected to the delay unit 13, that is, the controllable switch is controlled to be closed by the delay unit 13, and specifically, when the delay time set by the delay unit is reached, the delay unit controls the controllable switch to be closed; the delay time of the delay unit can be realized by an RC delay circuit, or can be realized by a timing chip such as a 555 timer; the first end of the controllable switch is connected to the output of the rectifier unit, and the second end of the controllable switch is connected to the fan interface; when the controllable switch is closed, the bus voltage Vbus output by the rectifier unit is connected to the fan interface through the controllable switch, and specifically, is connected to the power supply end of the fan interface to supply power to the fan; the fan interface is used to be connected to the fan. Figure 2As shown, the switching power conversion unit includes a flyback conversion circuit and a switching control chip 121; the design of the flyback conversion circuit and the selection of the switching control chip are designed as required, as long as it has an overvoltage protection function and can output a first DC voltage matching the power supply voltage of the delay unit. Further, the 555 timing chip is a commonly used timing chip, which can be set in the delay unit in this embodiment, that is, the delay time is set by the 555 timing chip. When the 555 timing chip receives the power supply voltage, which is the first DC voltage V1 in this case, after the set delay time, the 555 timer outputs a control signal to control the controllable switch, which is turned on. Specifically, the control signal can also be a control voltage equal to the value of the first DC voltage V1; further, the controllable switch can be set as a relay, IGBT or other controllable switch.

[0034] In addition, in some applications, the fan not only has a power input end, but also has a communication power end. The fan power is generally several hundred volts, and the DC bus voltage Vbus belongs to the range of the working power supply voltage of the fan. The communication power end can only receive a DC voltage of tens of volts, so the communication power end voltage needs to be converted from the bus voltage by the switching power conversion unit. In an embodiment of a fan controller containing a communication function, the fan interface includes a power input end and a communication power end; the power input end is connected to the second end of the controllable switch; the switching power conversion unit further includes a second output end for outputting a second DC voltage V2; the communication power end of the fan interface is connected to the second output end, and the second DC voltage V2 is used as the communication power of the fan. It should be noted that if the communication power voltage (second DC voltage V2) of the fan is the same as the first DC voltage V1, the second DC voltage can be obtained from the first output end of the switching power conversion unit, that is, the second output end and the first output end are the same output end; but if the communication power voltage (second DC voltage V2) of the fan is different from the first DC voltage V1, the switching power conversion unit needs to set the second output end, which can be realized by adding a secondary side output winding in the flyback conversion unit.

[0035] In a fan control, the DC bus voltage is connected to the input end of the switching power conversion unit and the fan interface, the output end of the switching power conversion unit is used to provide the communication power of the fan, and the delay unit and the fan start control unit are not set; with this design, when the power is overvoltage, the switching conversion unit needs to enter the start state first to detect the overvoltage and enter the overvoltage protection, which generally takes tens of milliseconds. At this time, the DC bus voltage Vbus directly supplies power to the fan circuit, and the input voltage is too high to damage the fan circuit or other components. The controller provided by the present application increases the delay unit and the fan start control unit, which can effectively prevent the problem of overvoltage damage.

[0036] The embodiment of the present application also provides a controller, which is especially suitable for controlling the fan circuit with a fan starting capacitor, that is, a large electrolytic capacitor is connected between the power input end (positive power end) of the fan and the ground. Figure 3 As shown in the figure, in the embodiment, the controller comprises a rectifying unit 21, a switching power supply conversion unit 22, a first delay unit 23, a second delay unit 26, an overshoot suppression unit 27, a fan starting control unit 24 and a fan interface 25.

[0037] The input end of the switching power supply conversion unit 22 is connected with the output end of the rectifying unit 21, and the switching power supply conversion unit 22 converts the bus voltage Vbus output by the rectifying unit 21 to generate the third direct current voltage V3 required by the second delay unit 26; the switching power supply conversion unit 22 has an overvoltage protection function; similarly, the switching power supply conversion unit 22 can be a flyback switching converter, which converts the bus voltage Vbus into the third direct current voltage V3, and V3 is output to the second delay unit 26 to provide power for the operation of the second delay unit 26.

[0038] The second delay unit 26 is connected to the third output end of the switching power supply conversion unit and receives the third direct current voltage V3; the overshoot suppression unit 27 comprises a current-limiting resistor and a second controllable switch connected in series; the control end of the second controllable switch is connected with the second delay unit, and when the set delay time length of the second delay unit is reached, the second delay unit controls the second controllable switch to be closed.

[0039] The first delay unit 23 is connected with the second delay unit, and when the set delay time length of the second delay unit 26 is reached, the first delay unit is powered to work; the delay time length of the first and second delay units can be realized by an RC delay circuit, or a timing chip such as a 555 timer.

[0040] The fan starting control unit 24 comprises a third controllable switch, and the control end of the third controllable switch is connected with the first delay unit 23; when the set delay time length of the first delay unit 23 is reached, the first delay unit 23 controls the third controllable switch to be closed; the fan starting control unit and the overshoot suppression unit are connected in parallel between the positive output end of the rectifying unit and the positive power end of the fan interface, specifically, the current-limiting resistor and the second controllable switch of the overshoot suppression unit are connected in series and are connected in parallel with the third controllable switch of the fan starting control unit; in a specific embodiment, the current-limiting resistor can be a PTC (positive temperature efficient) resistor.

[0041] The fan interface is used to connect with the fan, and the positive power supply end is connected with the fan capacitor.

[0042] In this embodiment, as Figure 3When the AC power is connected to the input end of the rectifier unit 21, the bus voltage Vbus is outputted through the rectifier unit 21; the bus voltage is simultaneously transmitted to the switching power supply conversion unit 22, the fan starting control unit 24 and the overshoot suppression unit 27, but the switching power supply conversion unit 22 will output the third DC voltage V3 only after the switching power supply conversion unit 22 is in operation, and the second delay unit 26 will work only after receiving V3; after a specific delay time, the second delay unit 26 will control the second controllable switch in the overshoot suppression unit 27 to be closed, and the first delay unit 23 will work at the same time; after the second delay unit 26 reaches the delay time and controls the second controllable switch in the overshoot suppression unit 27 to be closed, and before the first delay unit 23 controls the third controllable switch in the fan starting control unit 24 to be closed, the overshoot suppression unit 27 is connected between the output end of the rectifier unit 21 and the positive power end of the fan interface, and the bus voltage charges the fan starting capacitor through the overshoot suppression unit 27; because of the existence of the current-limiting resistor in the overshoot suppression unit 27, the charging current is small, and the fan starting capacitor will not be damaged due to the excessive current. Therefore, the delay time of the first delay unit 23 is set to be greater than the charging time of the fan capacitor, so that the fan starting capacitor can be effectively protected. When the delay time of the first delay unit 23 reaches, the third controllable switch in the fan starting control unit is closed; when the controllable switch is closed, the overshoot suppression unit 27 is short-circuited, and the bus voltage Vbus is outputted to the fan interface through the third controllable switch in the fan starting control unit; when the fan is connected to the fan interface, the bus voltage provides power supply for the fan to work, so as to reduce the loss of the current-limiting resistor and improve the efficiency. Before the delay time of the second delay unit reaches, the controllable switches in the overshoot suppression unit 27 and the fan starting control unit 24 are both disconnected, and the fan is also disconnected with the bus voltage, so that even if the bus voltage is overvoltage, the fan will not have overvoltage failure.And the switching power supply conversion unit generally has overvoltage protection function, and its starting length is very short, generally for tens of ms, and the delay time of the third delay unit can be freely set. Specifically, the delay time of the delay unit is set to be greater than the starting time of the switching power supply conversion unit, such as 1s, 2s, etc. When the input AC voltage is overvoltage, the switching power supply conversion unit 22 normally enters the starting state, and the starting time generally needs tens of milliseconds. During the starting process, the switching power supply conversion unit works, outputs the third DC voltage V3, and the third DC voltage V3 controls the second controllable switch K2 of the overvoltage suppression unit 27 to close after a delay, so that the switching power supply conversion unit 22 has sufficient time (delay time) to complete the starting and detect the input overvoltage state under the input overvoltage state, and then stop working. After stopping working, the third DC voltage V3 is no longer output, so that the second controllable switch K2 cannot be closed, and the first delay unit 23 cannot obtain the working voltage, that is, the first delay unit 23 cannot work, and the third controllable switch K3 of the fan starting control unit 24 also cannot be closed. The overvoltage bus voltage cannot be connected to the fan interface, and the fan cannot work, thereby protecting the fan or other electrical devices. Until the input overvoltage state is removed. Based on this, in an embodiment, the delay time of the second delay unit is set to be greater than the starting time of the switching power supply conversion unit; and the delay time of the first delay unit is greater than the charging time of the fan capacitor.

[0043] In an embodiment, as shown in Figure 4 The switching power supply conversion unit 22 includes a flyback conversion circuit and a switching control chip 221. The design of the flyback conversion circuit and the selection of the switching control chip are designed as needed. As long as it has overvoltage protection function and can output third DC voltage V3 matching the power supply voltage of the second delay unit 26, it is available. Further, the 555 timing chip is a commonly used timing chip. In this embodiment, the first or second delay unit can include a 555 timing chip, that is, the delay time of the first or second delay unit is set by the 555 timing chip. When the 555 timing chip receives the power supply voltage, which is the third DC voltage V3 here, after the set delay time, the 555 timer outputs the control signal of the second controllable switch K2 and the power supply voltage of the first delay unit 23, controls K2 to close and controls the first delay unit 23 to work. Specifically, the control signal and the power supply voltage of the first delay unit 23 can also be a voltage signal equal to the value of the third DC voltage V3. Further, the second controllable switch or the third controllable switch is a controllable switch such as a relay and an IGBT.

[0044] In addition, in some applications, the fan not only has a power input end, but also has a communication power end. The fan power is generally several hundred volts, and the DC bus voltage Vbus belongs to the range of the fan working power voltage. The communication power end can only receive a DC voltage of tens of volts, and thus the communication power end voltage needs to be converted from the bus voltage by a switching power conversion unit. In an embodiment of a fan controller including a communication function, the fan interface includes a power input end (including a positive power end) and a communication power end; the positive power end is connected to the second end of the controllable switch; the switching power conversion unit further includes a second output end, the second output end is used to output a second DC voltage V2; the communication power end of the fan interface is connected to the second output end, and the second DC voltage V2 is used as the communication power of the fan. It should be noted that if the communication power voltage (the second DC voltage V2) of the fan is the same as the third DC voltage V3, the second DC voltage can be obtained from the third output end of the switching power conversion unit, that is, the second output end and the third output end are the same output end; but if the communication power voltage (the second DC voltage V2) of the fan is different from the third DC voltage V3, the switching power conversion unit needs to be provided with a second output end, which can be realized by adding a secondary winding in the flyback conversion unit. The controller provided in the embodiment not only can realize overvoltage protection, but also can realize protection of the fan starting capacitor, preventing the fan starting capacitor from being damaged due to excessive charging current during starting.

[0045] Each of the embodiments in the specification is described in a progressive manner, and the same and similar parts of each of the embodiments can be referred to each other. Each of the embodiments focuses on the difference from other embodiments. In particular, for the system or system embodiments, since it is basically similar to the method embodiments, it is described more simply, and the related parts can be referred to the part of the method embodiments. The above-described system and system embodiments are only illustrative, and the units described as separate components can be or can not be physically separated, and the components displayed as units can be or can not be physical units, that is, they can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiment according to actual needs. Those skilled in the art can understand and implement it without creative labor.

[0046] Those skilled in the art will further realize that the mechanisms of the various examples described herein are capable of being implemented using any number of combinations of the described features. Accordingly, these examples are not limited to the mechanisms described herein, but rather, the intent is to cover all modifications and alternatives equivalent thereto. The preceding description of the examples is illustrative, and not restrictive. Many other examples will be apparent to those of skill in the art upon reviewing the above description. The scope of the examples should, therefore, be determined not with reference to the above description, but instead should be given to the appended claims, along with their full scope of equivalents.

[0047] The above description of disclosed examples is intended to be illustrative, and not restrictive. Many other examples will be apparent to those of skill in the art upon reviewing the above description. The scope of the examples should, therefore, be determined not with reference to the above description, but instead should be given to the appended claims, along with their full scope of equivalents.

Claims

1. A controller for controlling a fan, characterized by, The rectifier unit, the switching power conversion unit, the first delay unit, the second delay unit, the overshoot suppression unit, the fan starting control unit and the fan interface are included. The input end of the switching power conversion unit is connected with the output end of the rectifier unit, and the switching power conversion unit converts the bus voltage output by the rectifier unit to generate the third DC voltage required by the second delay unit; the switching power conversion unit has an overvoltage protection function. The second delay unit is connected to the third output end of the switching power conversion unit and receives the third DC voltage; the overshoot suppression unit includes a current-limiting resistor and a second controllable switch connected in series; the control end of the second controllable switch is connected with the second delay unit, and when the set delay time length of the second delay unit is reached, the second delay unit controls the second controllable switch to be closed. The first delay unit is connected with the second delay unit, and when the set delay time length of the second delay unit is reached, the first delay unit is powered on to work. The fan starting control unit includes a third controllable switch, and the control end of the third controllable switch is connected with the first delay unit; when the set delay time length of the first delay unit is reached, the first delay unit controls the third controllable switch to be closed; the fan starting control unit and the overshoot suppression unit are connected in parallel between the positive output end of the rectifier unit and the positive power end of the fan interface; the fan interface is used to be connected with a fan, and the positive power end is connected with a fan capacitor.

2. The controller of claim 1, wherein, The delay time length of the second delay unit is greater than the starting time length of the switching power conversion unit; and the delay time length of the first delay unit is greater than the charging time length of the fan capacitor.

3. The controller of claim 2, wherein, The switching power conversion unit includes a flyback conversion circuit and a switching control chip; the first delay unit includes a 555 timing chip; the second delay unit includes a 555 timing chip; and the second controllable switch or the third controllable switch is a relay.

4. The controller of claim 2, wherein, The fan interface further includes a communication power end; the switching power conversion unit further includes a second output end for outputting a second DC voltage; and the communication power end of the fan interface is connected to the second output end, and the second DC voltage is used as the communication power of the fan.

5. The controller of claim 2, wherein, The current-limiting resistor is a PTC resistor.

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