Switch module, step-down circuit and power supply system for photovoltaic energy storage

Abstract

The utility model provides a switch module, a step-down circuit and a power supply system for photovoltaic energy storage, and the switch module comprises a first switch unit, a second switch unit and a clamping drive unit. Wherein the first end of the first switch unit is connected with a power supply, the first end of the second switch unit is connected with the second end of the first switch unit, the second end of the second switch unit is connected with a load, the clamping driving unit is connected with the second switch unit in parallel, and the charging end of the clamping driving unit is connected with the first end of the first switch unit; the controlled end of the first switch unit is connected with the discharging end of the clamping driving unit, the controlled end of the second switch unit is connected with the control end of the control module, and when the control module controls the second switch unit to be switched on, the clamping driving unit discharges and enables the first switch unit to be switched on. According to the switch module disclosed by the invention, the switch module can be suitable for relatively high input voltage by utilizing the series voltage division effect of the first switch unit and the second switch unit.

Description

Technical Field

[0001] The present disclosure relates to the field of switching technology, and in particular, to a switching module, a buck circuit, and a power supply system for photovoltaic energy storage. Background Art

[0002] With the rapid development of the photovoltaic energy storage industry, the voltage levels in the power supply system are getting higher and higher. Among them, there are many functional devices in the power supply system, such as switches in the buck circuit. However, due to the limited power of the switches, the buck circuit cannot be applied to relatively high input high voltages, resulting in limited functions of the power supply system and difficulty in meeting the usage requirements. Summary of the Invention

[0003] The present disclosure aims to solve at least one of the technical problems in the related art to some extent.

[0004] To this end, an object of the present disclosure is to provide a switching module, a buck circuit, and a power supply system for photovoltaic energy storage.

[0005] To achieve the above object, a first aspect of the present disclosure provides a switching module, including: a first switching unit, a second switching unit, and a clamping drive unit; wherein, a first end of the first switching unit is connected to a power supply, and a first end of the second switching unit is connected to a second end of the first switching unit, a second end of the second switching unit is connected to a load, the clamping drive unit is connected in parallel with the second switching unit, and a charging end of the clamping drive unit is connected to the first end of the first switching unit; a controlled end of the first switching unit is connected to a discharging end of the clamping drive unit, a controlled end of the second switching unit is connected to a control end of a control module, and when the control module controls the second switching unit to conduct, the clamping drive unit discharges and makes the first switching unit conduct.

[0006] Optionally, the clamping drive unit includes: a first capacitor, a first end of the first capacitor is respectively connected to the first end of the second switching unit and the controlled end of the first switching unit, and a second end of the first capacitor is connected to the second end of the second switching unit; wherein, when the control module controls the second switching unit to turn off, the first capacitor charges and makes the first switching unit turn off; when the control module controls the second switching unit to conduct, the first capacitor discharges and makes the first switching unit conduct.

[0007] Optionally, the clamping drive unit further includes: a transient suppression diode, an anode of the transient suppression diode is connected to the first end of the first capacitor, and a cathode of the transient suppression diode is connected to the second end of the first capacitor.

[0008] Optionally, the clamping drive unit further includes: a first resistor, which is connected in series between the first end of the first capacitor and the controlled end of the first switch unit, and the first end of the first resistor is connected to the first end of the first capacitor, and the second end of the first resistor is connected to the controlled end of the first switch unit.

[0009] Optionally, the clamping drive unit further includes: a zener diode, which is connected in series between the first end of the first capacitor and the first end of the second switch unit, and the anode of the zener diode is connected to the first end of the first capacitor, and the cathode of the zener diode is connected to the first end of the second switch unit.

[0010] Optionally, the first switch unit includes: a first MOS, the drain of the first MOS is connected to the power supply, the source of the first MOS is connected to the first end of the second switch unit, and the gate of the first MOS is connected to the discharge end of the clamping drive unit; a second resistor, the first end of the second resistor is connected to the drain of the first MOS, and the second end of the second resistor is connected to the gate of the first MOS.

[0011] Optionally, the second switch unit includes: a second MOS, the drain of the second MOS is connected to the second end of the first switch unit, the source of the second MOS is connected to the load, and the gate of the second MOS is connected to the control end of the control module.

[0012] The second aspect of the present disclosure provides a buck circuit, including: a switch module provided in the first aspect of the present disclosure; a freewheeling module, the first end of the freewheeling module is respectively connected to the second end of the second switch unit in the switch module and the first end of the load, and the second end of the freewheeling module is connected to the second end of the load. When the second switch unit is turned off, the freewheeling module is used to supply power to the load.

[0013] Optionally, the freewheeling module includes: a freewheeling diode, the cathode of the freewheeling diode is connected to the second end of the second switch unit, the anode of the freewheeling diode is connected to the second end of the load; an inductor, the first end of the inductor is connected to the cathode of the freewheeling diode, and the second end of the inductor is connected to the first end of the load; a second capacitor, the first end of the second capacitor is connected to the second end of the inductor, and the second end of the second capacitor is connected to the anode of the freewheeling diode.

[0014] The third aspect of the present disclosure provides a power supply system for photovoltaic energy storage, including: a buck circuit provided in the second aspect of the present disclosure.

[0015] The technical solutions provided by the present disclosure may include the following beneficial effects:

[0016] Through the synchronous operation of the first switching unit and the second switching unit, the on / off control of the path between the power supply and the load is realized. Moreover, by utilizing the series voltage division effect of the first switching unit and the second switching unit, the switching module can be applied to a relatively high input voltage. Thus, when the switching module is applied to devices such as buck circuits, the function of the power supply system can be ensured, thereby meeting the usage requirements.

[0017] Additional aspects and advantages of the present disclosure will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present disclosure will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, where:

[0019] Figure 1 is a schematic structural diagram of a buck circuit proposed in an embodiment of the present disclosure;

[0020] As shown in the figure: 1. First switching unit, 11. First MOS;

[0021] 2. Second switching unit, 12. Second MOS;

[0022] 3. Clamping drive unit, 4. Freewheeling module;

[0023] C1. First capacitor, C2. Second capacitor;

[0024] R1. First resistor, R2. Second resistor;

[0025] V1. Transient suppression diode, V2. Zener diode, V3. Freewheeling diode;

[0026] L. Inductor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Embodiments of the present disclosure will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present disclosure and should not be construed as limiting the present disclosure. On the contrary, the embodiments of the present disclosure include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0028] As Figure 1As shown in the figure, an embodiment of the present disclosure provides a switching module, including: a first switching unit 1, a second switching unit 2, and a clamping drive unit 3. Among them, the first end of the first switching unit 1 is connected to a power supply, the first end of the second switching unit 2 is connected to the second end of the first switching unit 1, the second end of the second switching unit 2 is connected to a load, the clamping drive unit 3 is connected in parallel with the second switching unit 2, the charging end of the clamping drive unit 3 is connected to the first end of the first switching unit 1, the controlled end of the first switching unit 1 is connected to the discharging end of the clamping drive unit 3, the controlled end of the second switching unit 2 is connected to the control end of the control module, and when the control module controls the second switching unit 2 to conduct, the clamping drive unit 3 discharges and makes the first switching unit 1 conduct.

[0029] It can be understood that, since the first end of the first switching unit 1 is connected to the power supply, the first end of the second switching unit 2 is connected to the second end of the first switching unit 1, and the second end of the second switching unit 2 is connected to the load, when the first switching unit 1 and the second switching unit 2 are turned off, the disconnection of the path between the power supply and the load can be realized, and when the first switching unit 1 and the second switching unit 2 are turned on, the connection of the path between the power supply and the load can be realized. Thus, by sequentially connecting the first switching unit 1 and the second switching unit 2 in series between the power supply and the load, the on-off control of the path between the power supply and the load is realized.

[0030] Moreover, since the clamping drive unit 3 is connected in parallel with the second switching unit 2, the charging end of the clamping drive unit 3 is connected to the first end of the first switching unit 1, the controlled end of the first switching unit 1 is connected to the discharging end of the clamping drive unit 3, and the controlled end of the second switching unit 2 is connected to the control end of the control module, when the control module controls the second switching unit 2 to turn off, the clamping drive unit 3 can be charged by the power supply and make the first switching unit 1 turn off, and when the control module controls the second switching unit 2 to conduct, the clamping drive unit 3 can discharge to the first switching unit 1, thereby controlling the first switching unit 1 to conduct. Thus, by the charging and discharging of the clamping drive unit 3, the synchronous on-off of the first switching unit 1 and the second switching unit 2 is realized.

[0031] Among them, through the synchronous action of the first switching unit 1 and the second switching unit 2, the on-off control of the path between the power supply and the load is realized. And, by the series voltage division effect of the first switching unit 1 and the second switching unit 2, the switching module can be applied to a higher input voltage. Thus, when the switching module is applied to devices such as a buck circuit, the function of the power supply system can be guaranteed, and further the usage requirements can be met.

[0032] It should be noted that the voltage division function of the first switch unit 1 and the second switch unit 2 can achieve a relatively large input voltage. For example, the maximum voltage of each switch unit is 500V. In related embodiments, only one switch unit is used for on-off control, and the maximum input voltage that can be achieved is 500V. However, in this embodiment, by using the cooperation of the first switch unit 1 and the second switch unit 2, an input voltage of 1000V can be achieved. That is to say, the series structure of the first switch unit 1 and the second switch unit 2 in this embodiment effectively increases the range of the input voltage. Further, in the case of the same input voltage, the overall circuit topology is effectively simplified. Similarly, the switch module in this embodiment can also output a larger power.

[0033] The first switch unit 1 is used to turn on and off synchronously with the second switch unit 2 to jointly control the on and off of the path between the power supply and the load. The specific type of the first switch unit 1 can be set according to actual needs, and no limitation is imposed on this.

[0034] The second switch unit 2 is used to conduct or turn off under the control of the control module, and drives the first switch unit 1 to turn on and off synchronously by using the clamping drive unit 3. The specific type of the second switch unit 2 can be set according to actual needs, and no limitation is imposed on this.

[0035] The clamping drive unit 3 is used to drive the first switch unit 1 to turn on and off synchronously under the on and off action of the second switch unit 2. The specific type of the clamping drive unit 3 can be set according to actual needs, and no limitation is imposed on this.

[0036] Among them, when the second switch unit 2 is turned off, the second switch unit 2 has no influence on the voltage of the clamping drive unit 3. Therefore, the clamping drive unit 3 is charged by the power supply, and the controlled end of the first switch unit 1 has no electrical energy to drive and is in the off state. When the second switch unit 2 is turned on, since the second switch unit 2 and the clamping drive unit 3 are in parallel, the voltage of the clamping drive unit 3 tends to the voltage of the second switch unit 2, thereby realizing the discharge to the first switch unit 1. Thus, the first switch unit 1 is turned on under the action of the clamping drive unit 3 releasing electrical energy.

[0037] The power supply is used to supply power to the load. The specific types of the power supply and the load can be set according to actual needs, and no limitation is imposed on this.

[0038] The control module is used to control the on and off of the second switch unit 2. The specific type of the control module can be set according to actual needs, and no limitation is imposed on this. By way of example, the control module can be a control chip. Among them, the switch module is independent of the control module, so it can be set with a larger power without being limited by the size of the control module.

[0039] Such as Figure 1As shown, in some embodiments, the clamping drive unit 3 includes: a first capacitor C1, a first end of the first capacitor C1 is respectively connected to a first end of the second switch unit 2 and a controlled end of the first switch unit 1, and a second end of the first capacitor C1 is connected to a second end of the second switch unit 2. Wherein, when the control module controls the second switch unit 2 to turn off, the first capacitor C1 is charged and the first switch unit 1 is turned off; when the control module controls the second switch unit 2 to turn on, the first capacitor C1 discharges and the first switch unit 1 is turned on.

[0040] It can be understood that, since the first end of the first capacitor C1 is connected to the first end of the second switch unit 2, and the second end of the first capacitor C1 is connected to the second end of the second switch unit 2, when the control module controls the second switch unit 2 to turn off, the first capacitor C1 can be charged using the power supply and the first switch unit 1 is turned off. When the control module controls the second switch unit 2 to turn on, the first capacitor C1 can discharge to the first switch unit 1, thereby controlling the first switch unit 1 to turn on. Thus, by using the charging and discharging of the first capacitor C1, the synchronous on and off of the first switch unit 1 and the second switch unit 2 are realized.

[0041] It should be noted that the first capacitor C1 is used to drive the first switch unit 1 to turn on and off synchronously under the on and off action of the second switch unit 2. The specific type of the first capacitor C1 can be set according to actual needs, and no limitation is made thereto.

[0042] As Figure 1 shown, in some embodiments, the clamping drive unit 3 further includes: a transient voltage suppressor diode V1 (Transient Voltage Suppressor, TVS), an anode of the transient voltage suppressor diode V1 is connected to the first end of the first capacitor C1, and a cathode of the transient voltage suppressor diode V1 is connected to the second end of the first capacitor C1.

[0043] It can be understood that, since the anode of the transient voltage suppressor diode V1 is connected to the first end of the first capacitor C1, and the cathode of the transient voltage suppressor diode V1 is connected to the second end of the first capacitor C1, the first capacitor C1 and the second switch unit 2 can achieve voltage clamping by using the transient voltage suppressor diode V1, thereby ensuring the voltage division cooperation between the first switch unit 1 and the second switch unit 2, and further realizing the applicability of the switching module to high-voltage input.

[0044] It should be noted that the transient suppression diode V1 is a semiconductor device for circuit protection, mainly used to suppress transient voltage spikes. The transient suppression diode V1 utilizes the avalanche breakdown characteristic of the PN junction. When the applied voltage exceeds its breakdown voltage, the device quickly changes from a high impedance to a low impedance, rapidly discharging the overvoltage energy, and at the same time clamping the abnormal overvoltage at a lower level to protect the subsequent circuit from damage. The specific type of the transient suppression diode V1 can be set according to actual needs, and no limitation is imposed on this.

[0045] Among them, by using the transient suppression diode V1 to achieve voltage clamping, the device selection of the first switching unit 1, the second switching unit 2, etc. can be carried out with a large margin according to the range of the input voltage.

[0046] As Figure 1 shown, in some embodiments, the clamping drive unit 3 further includes: a first resistor R1, the first resistor R1 is connected in series between the first end of the first capacitor C1 and the controlled end of the first switching unit 1, and the first end of the first resistor R1 is connected to the first end of the first capacitor C1, and the second end of the first resistor R1 is connected to the controlled end of the first switching unit 1.

[0047] It can be understood that since the first end of the first resistor R1 is connected to the first end of the first capacitor C1, and the second end of the first resistor R1 is connected to the controlled end of the first switching unit 1, the first resistor R1 can control the discharge speed of the first capacitor C1 by using the current limiting effect, and at the same time ensure the safe drive of the first capacitor C1 for the first switching unit 1.

[0048] It should be noted that the first resistor R1 is used for current limiting, and the specific type of the first resistor R1 can be set according to actual needs, and no limitation is imposed on this.

[0049] As Figure 1 shown, in some embodiments, the clamping drive unit 3 further includes: a zener diode V2, the zener diode V2 is connected in series between the first end of the first capacitor C1 and the first end of the second switching unit 2, and the anode of the zener diode V2 is connected to the first end of the first capacitor C1, and the cathode of the zener diode V2 is connected to the first end of the second switching unit 2.

[0050] It can be understood that since the anode of the zener diode V2 is connected to the first end of the first capacitor C1, and the cathode of the zener diode V2 is connected to the first end of the second switching unit 2, when the first capacitor C1 discharges, the voltage at the controlled end of the first switching unit 1 can be stabilized at a preset voltage, thereby ensuring the stable conduction of the first switching unit 1.

[0051] It should be noted that the voltage - regulating diode V2 is used for voltage regulation. The voltage - regulating diode V2 is also known as a Zener diode, which is a special type of semiconductor diode designed to maintain a stable voltage level. When current passes through the voltage - regulating diode V2, even if the current changes, its voltage will remain at a constant value close to its designed voltage. The specific type of the voltage - regulating diode V2 can be set according to actual needs, and no restrictions are imposed on this.

[0052] As Figure 1 shown, in some embodiments, the first switching unit 1 includes: a first MOS11 and a second resistor R2. The drain of the first MOS11 is connected to the power supply, the source of the first MOS11 is connected to the first end of the second switching unit 2, the gate of the first MOS11 is connected to the discharge end of the clamping drive unit 3, the first end of the second resistor R2 is connected to the drain of the first MOS11, and the second end of the second resistor R2 is connected to the gate of the first MOS11.

[0053] It can be understood that since the drain of the first MOS11 is connected to the power supply, the source of the first MOS11 is connected to the first end of the second switching unit 2, and the gate of the first MOS11 is connected to the discharge end of the clamping drive unit 3, when the control module controls the second switching unit 2 to turn off, the power supply charges the clamping drive unit 3 through the second resistor R2 and cannot drive the gate of the first MOS11. And when the control module controls the second switching unit 2 to turn on, the clamping drive unit 3 discharges and drives the gate of the first MOS11, making the drain and source of the first MOS11 conduct. Thus, the synchronous on - off of the first MOS11 and the second switching unit 2 is achieved.

[0054] It should be noted that MOS is MOSFET (Metal - Oxide - Semiconductor Field - Effect Transistor). MOS is a voltage - controlled semiconductor device that controls the current flow between the source (Source) and the drain (Drain) by changing the gate (Gate) voltage. The specific type of the first MOS11 can be set according to actual needs, and no restrictions are imposed on this.

[0055] The second resistor R2 is used to provide a starting voltage. The specific type of the second resistor R2 can be set according to actual needs, and no restrictions are imposed on this.

[0056] As Figure 1 shown, in some embodiments, the second switching unit 2 includes: a second MOS12. The drain of the second MOS12 is connected to the second end of the first switching unit 1, the source of the second MOS12 is connected to the load, and the gate of the second MOS12 is connected to the control end of the control module.

[0057] It can be understood that since the drain of the second MOS 12 is connected to the second end of the first switching unit 1, the source of the second MOS 12 is connected to the load, and the gate of the second MOS 12 is connected to the control end of the control module, the control module can utilize the drive of the gate of the second MOS 12 to realize the on / off control of the path between the drain and the source of the second MOS 12, and further utilize the cooperation of the second MOS 12 and the first switching unit 1 to realize the on / off control of the path between the power supply and the load.

[0058] It should be noted that the specific type of the second MOS 12 can be set according to actual needs, and there is no limitation in this regard.

[0059] The switching module of this embodiment utilizes the series connection of the first MOS 11 and the second MOS 12 and the drive cooperation of the first capacitor C1, transient suppression diode V1, etc. to realize the on / off control of high-voltage input. Moreover, the topological structure of this embodiment is simple, the range of device selection is wide, and the cost can be effectively saved.

[0060] As Figure 1 shown, the present disclosure embodiment also proposes a buck circuit, including: the switching module and a freewheeling module 4 as in the present disclosure embodiment. The first end of the freewheeling module 4 is respectively connected to the second end of the second switching unit 2 in the switching module and the first end of the load, and the second end of the freewheeling module 4 is connected to the second end of the load. When the second switching unit 2 is turned off, the freewheeling module 4 is used to supply power to the load.

[0061] It can be understood that since the first end of the freewheeling module 4 is respectively connected to the second end of the second switching unit 2 in the switching module and the first end of the load, and the second end of the freewheeling module 4 is connected to the second end of the load, when the second switching unit 2 is turned off, the freewheeling module 4 can supply power to the load, thereby ensuring the continuous power supply from the power supply to the load. At the same time, through the synchronous action of the first switching unit 1 and the second switching unit 2, the on / off control of the path between the power supply and the load is realized. Moreover, by utilizing the series voltage division effect of the first switching unit 1 and the second switching unit 2, the switching module can be applied to a relatively high input voltage. Thus, the realization of the buck function is ensured, and further when the buck circuit is applied to a power supply system, the usage requirements can be met.

[0062] It should be noted that when the second switching unit 2 is turned on, the power supply supplies power to both the freewheeling module 4 and the load at the same time. When the second switching unit 2 is turned off, the freewheeling module 4 supplies power to the load. The freewheeling module 4 is used for freewheeling. The specific type of the freewheeling module 4 can be set according to actual needs, and there is no limitation in this regard.

[0063] As Figure 1As shown, in some embodiments, the freewheeling module 4 includes a freewheeling diode V3, an inductor L, and a second capacitor C2. The cathode of the freewheeling diode V3 is connected to the second terminal of the second switching unit 2, the anode of the freewheeling diode V3 is connected to the second terminal of the load, the first terminal of the inductor L is connected to the cathode of the freewheeling diode V3, and the second terminal of the inductor L is connected to the first terminal of the load. The first terminal of the second capacitor C2 is connected to the second terminal of the inductor L, and the second terminal of the second capacitor C2 is connected to the anode of the freewheeling diode V3.

[0064] It can be understood that when the second switching unit 2 is turned on, the first switching unit 1 is synchronously turned on, and the freewheeling diode V3 is turned off, so that the power supply supplies power to the inductor L, the second capacitor C2, and the load. When the second switching unit 2 is turned off, the first switching unit 1 is synchronously turned off, and the freewheeling diode V3 is turned on, so that the inductor L and the second capacitor C2 supply power to the load. Thus, continuous power supply from the power supply to the load is achieved, ensuring stable step-down power supply of the step-down circuit.

[0065] It should be noted that the freewheeling diode V3 is used for unidirectional conduction to cooperate with the inductor L and the second capacitor C2 to achieve freewheeling. The specific type of the freewheeling diode V3 can be set according to actual needs and is not limited thereto.

[0066] The inductor L has functions such as current limiting and energy storage. The specific type of the inductor L can be set according to actual needs and is not limited thereto.

[0067] The capacitor has functions such as smoothing voltage and controlling output voltage. The specific type of the capacitor can be set according to actual needs and is not limited thereto.

[0068] The embodiments of the present disclosure also propose a power supply system for photovoltaic energy storage, including a step-down circuit as in the embodiments of the present disclosure.

[0069] It can be understood that when the second switching unit 2 is turned off, the freewheeling module 4 can supply power to the load, thus ensuring continuous power supply from the power supply to the load. At the same time, through the synchronous action of the first switching unit 1 and the second switching unit 2, on-off control of the path between the power supply and the load is achieved. Moreover, by using the series voltage division effect of the first switching unit 1 and the second switching unit 2, the switching module can be applied to a relatively high input voltage. Thus, the realization of the step-down function is ensured, and further the power supply requirements of the power supply system are met.

[0070] It should be noted that in the description of the present disclosure, terms such as "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present disclosure, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0071] Any process or method description depicted in the flowchart or otherwise described herein may be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present disclosure includes additional implementations, where functions may be performed in a substantially simultaneous manner or in a reverse order according to the relevant functions, rather than in the order shown or discussed. This should be understood by those skilled in the art to which the embodiments of the present disclosure pertain.

[0072] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0073] Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A switch module, characterized in that: include: A first switch unit, a second switch unit and a clamp driving unit; Wherein, the first end of the first switch unit is connected to a power source, the first end of the second switch unit is connected to the second end of the first switch unit, the second end of the second switch unit is connected to a load, the clamp drive unit is connected to the second switch unit in parallel, and the charging end of the clamp drive unit is connected to the first end of the first switch unit; The controlled end of the first switch unit is connected to the discharge end of the clamp drive unit, the controlled end of the second switch unit is connected to the control end of the control module, and when the control module controls the second switch unit to be turned on, the clamp drive unit discharges and turns on the first switch unit.

2. The switch module according to claim 1, characterized in that: The clamp driving unit comprises: a first capacitor, wherein a first end of the first capacitor is connected to a first end of the second switch unit and a controlled end of the first switch unit respectively, and a second end of the first capacitor is connected to a second end of the second switch unit; Wherein, when the control module controls the second switch unit to turn off, the first capacitor is charged and the first switch unit is turned off; When the control module controls the second switch unit to be turned on, the first capacitor is discharged and the first switch unit is turned on.

3. The switch module according to claim 2, characterized in that: The clamp driving unit further includes: A transient suppression diode, wherein an anode of the transient suppression diode is connected to the first end of the first capacitor, and a cathode of the transient suppression diode is connected to the second end of the first capacitor.

4. The switch module according to claim 2, characterized in that: The clamp driving unit further includes: A first resistor is connected in series between a first end of the first capacitor and a controlled end of the first switch unit, and the first end of the first resistor is connected to the first end of the first capacitor, and the second end of the first resistor is connected to the controlled end of the first switch unit.

5. The switch module according to claim 2, characterized in that: The clamp driving unit further includes: A voltage regulator diode is connected in series between the first end of the first capacitor and the first end of the second switch unit, and the anode of the voltage regulator diode is connected to the first end of the first capacitor, and the cathode of the voltage regulator diode is connected to the first end of the second switch unit.

6. The switch module according to claim 1, characterized in that: The first switch unit comprises: a first MOS, wherein a drain of the first MOS is connected to the power supply, a source of the first MOS is connected to a first end of the second switch unit, and a gate of the first MOS is connected to a discharge end of the clamp driving unit; A second resistor, wherein a first end of the second resistor is connected to the drain of the first MOS, and a second end of the second resistor is connected to the gate of the first MOS.

7. The switch module according to claim 1, characterized in that: The second switch unit comprises: A second MOS, wherein a drain of the second MOS is connected to the second end of the first switch unit, a source of the second MOS is connected to the load, and a gate of the second MOS is connected to the control end of the control module.

8. A step-down circuit, characterized in that: include: The switch module according to any one of claims 1 to 7; A freewheeling module, wherein the first end of the freewheeling module is respectively connected to the second end of the second switch unit in the switch module and the first end of the load, and the second end of the freewheeling module is connected to the second end of the load. When the second switch unit is turned off, the freewheeling module is used to supply power to the load.

9. The step-down circuit according to claim 8, characterized in that: The freewheeling module comprises: a freewheeling diode, wherein a cathode of the freewheeling diode is connected to the second end of the second switch unit, and an anode of the freewheeling diode is connected to the second end of the load; an inductor, wherein a first end of the inductor is connected to a cathode of the freewheeling diode, and a second end of the inductor is connected to a first end of the load; A second capacitor, wherein a first end of the second capacitor is connected to the second end of the inductor, and a second end of the second capacitor is connected to the anode of the freewheeling diode.

10. A power supply system for photovoltaic energy storage, characterized in that: include: The step-down circuit according to claim 8 or 9.

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