Overvoltage protection circuit and energy storage power supply

Abstract

The utility model discloses an overvoltage protection circuit and an energy storage power supply, and the overvoltage protection circuit comprises a power supply circuit which is connected between a first line and a second line, and is used for converting a first voltage of a photovoltaic input interface into a second voltage, and outputting a reference voltage according to the second voltage; the first input end of the comparison circuit is connected with the power supply circuit, and the second input end of the comparison circuit is connected with the sampling circuit to receive sampling voltage; the driving circuit is connected with the output end of the comparison circuit; the main switch tube is arranged between the photovoltaic input interface and the MPPT circuit, the control end of the main switch tube is connected with the driving circuit, and the comparison circuit is used for controlling the main switch tube to be disconnected through the driving circuit when the sampling voltage is greater than the reference voltage; and the conduction speed of the driving circuit for controlling the conduction of the main switch tube is greater than the disconnection speed of the driving circuit for controlling the disconnection of the main switch tube. The overvoltage protection can be realized, the overvoltage of the photovoltaic input interface is avoided, and the interference caused by the current change when the main switching tube is switched off is reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of power supply, in particular to an overvoltage protection circuit and an energy storage power supply. BACKGROUND

[0002] The energy storage power supply comprises a plurality of photovoltaic input interfaces, each of which is independently arranged. In order to ensure the power generation amount of the energy storage power supply under weak light conditions, at least two photovoltaic components are connected in parallel to the photovoltaic input interface, and the photovoltaic input interface is usually designed according to the voltage of a single photovoltaic component.

[0003] In the case that at least two photovoltaic components are misconnected in series to the photovoltaic input interface, the voltage of the at least two photovoltaic components connected in series is much larger than the voltage of a single photovoltaic component, thereby causing the problem of overvoltage of the photovoltaic input interface. CONTENT OF THE UTILITY MODEL

[0004] The application mainly solves the technical problem of providing an overvoltage protection circuit and an energy storage power supply, which can solve the problem of overvoltage of the photovoltaic input interface.

[0005] The application provides an overvoltage protection circuit applied to an energy storage power supply, the energy storage power supply comprising at least one photovoltaic input interface, the photovoltaic input interface being used for being connected with an MPPT circuit in the energy storage power supply, the photovoltaic input interface comprising a high-voltage end and a low-voltage end, the high-voltage end being connected with the MPPT circuit through a first line, the low-voltage end being connected with the MPPT circuit through a second line, and the overvoltage protection circuit comprising:

[0006] a power supply circuit connected between the first line and the second line, used for converting a first voltage of the photovoltaic input interface into a second voltage and outputting a reference voltage according to the second voltage;

[0007] a sampling circuit connected between the first line and the second line;

[0008] a comparison circuit, a first input end of the comparison circuit being connected with the power supply circuit and receiving the second voltage and the reference voltage from the power supply circuit, and a second input end of the comparison circuit being connected with the sampling circuit and receiving a sampling voltage;

[0009] a driving circuit connected with an output end of the comparison circuit;

[0010] a main switch tube arranged between the photovoltaic input interface and the MPPT circuit, a control end of the main switch tube being connected with the driving circuit, and the comparison circuit being used for controlling the main switch tube to be turned off through the driving circuit when the sampling voltage is greater than the reference voltage; wherein the turn-on speed of the driving circuit controlling the main switch tube to be turned on is greater than the turn-off speed of the driving circuit controlling the main switch tube to be turned off.

[0011] The comparison circuit is configured to control the main switch to be turned on by the driving circuit when the sampling voltage is less than or equal to the reference voltage.

[0012] The first end of the main switch is connected to the low-voltage end through the second circuit, and the second end of the main switch is connected to the MPPT circuit through the second circuit.

[0013] The overvoltage protection circuit further comprises a delay circuit connected to the power supply circuit and the comparison circuit, and the delay circuit is configured to control the comparison circuit to control the main switch to be turned on or turned off by the driving circuit according to the sampling voltage and the reference voltage when the second voltage is greater than or equal to the first preset voltage.

[0014] The delay circuit is configured to output a first level to the comparison circuit when the second voltage is less than the first preset voltage, and the comparison circuit is configured to control the main switch to be kept off when the first level is received.

[0015] The delay circuit is configured to output a second level to the comparison circuit when the second voltage is greater than or equal to the first preset voltage, and the comparison circuit is configured to control the main switch to be turned on when the second level is received and the sampling voltage is less than or equal to the reference voltage, or to control the main switch to be turned off when the second level is received and the sampling voltage is greater than the reference voltage.

[0016] The delay circuit comprises a current limiting unit, a first voltage stabilizing unit, a first switching unit, and a voltage dividing unit, the first end of the first voltage stabilizing unit and the first end of the first switching unit are connected to the power supply circuit through the current limiting unit, the first end of the first voltage stabilizing unit and the first end of the first switching unit are connected to the enable end of the comparison circuit, the control end of the first switching unit is connected to the voltage dividing unit, the first end of the voltage dividing unit is connected to the power supply circuit, and the second end of the first voltage stabilizing unit, the second end of the first switching unit, and the second end of the voltage dividing unit are all connected to the second circuit.

[0017] The delay circuit further comprises a second voltage stabilizing unit and a filter unit, and the voltage dividing unit is connected to the power supply circuit through the second voltage stabilizing unit, and the control end of the first switching unit is connected to the voltage dividing unit through the filter unit.

[0018] The power supply circuit comprises a voltage stabilizing circuit and a reference voltage circuit, the voltage stabilizing circuit is connected between the first circuit and the second circuit, and is configured to convert the first voltage into the second voltage, and the reference voltage circuit is connected to the voltage stabilizing circuit and the comparison circuit, and is configured to output the reference voltage according to the second voltage.

[0019] The comparison circuit comprises a comparator and a voltage stabilizing unit, the first input end of the comparator is connected with the reference voltage circuit, the first power supply end of the comparator is connected with the voltage stabilizing circuit, the enable end of the comparator is connected with the delay circuit of the overvoltage protection circuit, the second input end of the comparator is connected with the sampling circuit, the output end of the comparator is connected with the first input end of the comparator through the voltage stabilizing unit and is connected with the driving circuit.

[0020] The application further provides an energy storage power supply comprising at least one photovoltaic input interface, an MPPT circuit and the above-mentioned overvoltage protection circuit, the photovoltaic input interface is used for being connected with the MPPT circuit, the photovoltaic input interface comprises a high-voltage end and a low-voltage end, the high-voltage end is connected with the MPPT circuit through a first line, the low-voltage end is connected with the MPPT circuit through a second line, and the overvoltage protection circuit is connected between the first line and the second line.

[0021] The application has the beneficial effects that the overvoltage protection circuit of the application is applied to the energy storage power supply, the energy storage power supply comprises at least one photovoltaic input interface, the photovoltaic input interface is used for being connected with the MPPT circuit in the energy storage power supply, the overvoltage protection circuit comprises a power supply circuit, a sampling circuit, a comparison circuit, a driving circuit and a main switch tube, the first input end of the comparison circuit is connected with the power supply circuit to receive a reference voltage from the power supply circuit, the second input end of the comparison circuit is connected with the sampling circuit to receive a sampling voltage, the driving circuit is connected with the output end of the comparison circuit, the main switch tube is arranged between the photovoltaic input interface and the MPPT circuit, the control end of the main switch tube is connected with the driving circuit, and the comparison circuit is used for controlling the main switch tube to be turned off through the driving circuit when the sampling voltage is greater than the reference voltage. The sampling voltage and the reference voltage are compared through the comparison circuit, the comparison circuit is used for controlling the main switch tube to be turned off through the driving circuit when the sampling voltage is greater than the reference voltage, the main switch tube is controlled to be turned off in the case that the photovoltaic input interface is overvoltage, overvoltage protection can be realized, the photovoltaic input interface is prevented from being overvoltage, the circuit is simple, and the cost is reduced. In addition, the turn-on speed of the main switch tube controlled by the driving circuit is greater than the turn-off speed of the main switch tube controlled by the driving circuit, the MPPT circuit has not worked when the energy storage power supply is just started, the current of the first line and the second line is very small, that is, the current of the driving circuit is very small, the comparison circuit controls the main switch tube to be turned on through the driving circuit when the sampling voltage is less than or equal to the reference voltage, and fast turn-on is realized; when the sampling voltage is greater than the reference voltage, that is, the photovoltaic input interface is overvoltage, the current of the first line and the second line is very large, the current of the driving circuit is large, the turn-off resistance of the main switch tube is large, and the main switch tube realizes slow turn-off to reduce the interference caused by current change when the main switch tube is turned off. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings. Among them:

[0023] Figure 1 is a frame schematic diagram of an embodiment of the overvoltage protection circuit provided by the present application;

[0024] Figure 2 is a frame schematic diagram of another embodiment of the overvoltage protection circuit provided by the present application;

[0025] Figure 3 is a circuit schematic diagram of an embodiment of the delay circuit in Figure 2

[0026] Figure 4 is a circuit schematic diagram of another embodiment of the delay circuit in Figure 2

[0027] Figure 5 is a circuit schematic diagram of an embodiment of the overvoltage protection circuit in Figure 2 DETAILED DESCRIPTION

[0028] The embodiments of the technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments of the present application, and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0030] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0031] ​​​Reference to“an embodiment” herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase“in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all referring to a common embodiment, or an embodiment that is identical to other embodiments. One of ordinary skill in the art is familiar with the express and implied disclosures herein.

[0032] In the description of the embodiments of the application, the term“a plurality of” refers to two or more (including two), and similarly,“a plurality of groups” refers to two or more groups (including two groups), and“a plurality of pieces” refers to two or more pieces (including two pieces).

[0033] In the description of the embodiments of the application, the technical terms“center”,“longitudinal”,“transverse”,“length”,“width”,“thickness”,“upper”,“lower”,“front”,“rear”,“left”,“right”,“vertical”,“horizontal”,“top”,“bottom”,“inner”,“outer”,“clockwise”,“counterclockwise”,“axial”,“radial”,“circumferential” and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the application.

[0034] In the description of the embodiments of the application, unless otherwise explicitly specified and limited, the technical terms“mounting”,“connection”,“connection”,“fixing” and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be connected between, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the application can be understood according to the specific circumstances.

[0035] The energy storage power supply is applied to balcony photovoltaic. In order to improve the efficiency, the energy storage power supply includes a plurality of photovoltaic input interfaces, and each photovoltaic input interface is independently arranged. In order to ensure the power generation of the energy storage power supply under weak light conditions, at least two photovoltaic modules are usually connected in parallel to the photovoltaic input interface, and the photovoltaic input interface is usually designed according to the voltage of a single photovoltaic module. In the case that at least two photovoltaic modules are mistakenly connected in series to the photovoltaic input interface, the voltage of the at least two photovoltaic modules connected in series is much larger than the voltage of a single photovoltaic module, resulting in an overvoltage problem of the photovoltaic input interface. For example, the photovoltaic input interface is designed according to a voltage of 60V, the maximum voltage of a single photovoltaic module is 60V, and the voltage of two photovoltaic modules connected in series is 120V. When the two photovoltaic modules connected in series are connected to the photovoltaic input interface, the photovoltaic input interface has an overvoltage problem.

[0036] In existing technologies, differential signals can be sampled and fed to a DSP (Digital Signal Processor). However, since the gate of the switching transistor and the ground of the subsequent DSP are not common, an isolated drive circuit is required to drive the switching transistor, meaning an isolated power supply is needed for the drive circuit. Assuming there are four photovoltaic input interfaces, four isolated power supplies are required, resulting in complex and costly circuitry. Furthermore, since the photovoltaic modules power the DSP, and two photovoltaic modules connected in series power the DSP, the isolated power supply needs to be designed for 120V, further increasing costs.

[0037] Current energy storage power supplies are low-power supplies, and the overvoltage protection circuit uses a PMOS transistor located at the positive terminal of the energy storage power supply. However, for high-power energy storage power supplies, the current is larger, requiring PMOS transistors with lower internal resistance. These low-resistance PMOS transistors are difficult to find and are expensive.

[0038] Please see Figure 1 As shown, Figure 1 This is a schematic diagram of a framework of an embodiment of the overvoltage protection circuit provided in this application. The overvoltage protection circuit 10 of this embodiment is applied to an energy storage power supply 1, which has at least one photovoltaic input interface 20. The photovoltaic input interface 20 is used to connect to the MPPT (Maximum Power Point Tracking) circuit 30 in the energy storage power supply 1. For example, the energy storage power supply 1 is applied to a balcony photovoltaic system.

[0039] The photovoltaic input interface 20 includes a high-voltage terminal PV+ and a low-voltage terminal PV-. The high-voltage terminal PV+ is connected to the MPPT circuit 30 via a first line 21, and the low-voltage terminal PV- is connected to the MPPT circuit 30 via a second line 22. The MPPT circuit 30 is a prior art MPPT circuit and will not be described in detail here.

[0040] In some embodiments, the photovoltaic input interface 20 can connect to at least two photovoltaic modules, which are connected in parallel to ensure the power generation of the energy storage power supply 1 under low light conditions; for example, the photovoltaic input interface 20 connects two photovoltaic modules connected in parallel.

[0041] The overvoltage protection circuit 10 in this embodiment includes a power supply circuit 11, a sampling circuit 12, a comparison circuit 13, a delay circuit 14, a drive circuit 151, and a main switch Q2.

[0042] The power supply circuit 11 is connected between the first line 21 and the second line 22, and receives the first voltage from the photovoltaic input interface 20 through the first line 21 and the second line 22, which can be the power supply voltage of the energy storage power supply 1. The power supply circuit 11 is configured to convert the first voltage into a second voltage and output a reference voltage according to the second voltage; and the power supply circuit 11 can provide the second voltage and the reference voltage for the comparison circuit 13.

[0043] The sampling circuit 12 is connected between the first line 21 and the second line 22, and receives the first voltage from the photovoltaic input interface 20 through the first line 21 and the second line 22, which can be used for sampling the first voltage to obtain a sampling voltage.

[0044] The first input end of the comparison circuit 13 is connected with the power supply circuit 11 and receives the reference voltage from the power supply circuit 11; and the second input end of the comparison circuit 13 is connected with the sampling circuit 12 and receives the sampling voltage from the sampling circuit 12.

[0045] The driving circuit 151 is connected with the output end of the comparison circuit 13; and the main switch Q2 is arranged between the photovoltaic input interface 20 and the MPPT circuit 30, the control end of the main switch Q2 is connected with the driving circuit 151, and the comparison circuit 13 is configured to control the main switch Q2 to be turned off through the driving circuit 151 when the sampling voltage is greater than the reference voltage.

[0046] In some embodiments, the first end of the main switch Q2 is connected with the photovoltaic input interface 20, and the second end of the main switch Q2 is connected with the MPPT circuit 30. In this embodiment, the main switch Q2 is an N-type MOS tube, the first end of the main switch Q2 is the source of the N-type MOS tube, the second end of the main switch Q2 is the drain of the N-type MOS tube, and the control end of the main switch Q2 is the gate of the N-type MOS tube. In other embodiments, the main switch Q2 can also be other types of switch tubes, such as a P-type MOS tube.

[0047] The driving circuit 151 controls the turn-on speed of the main switch Q2 to be greater than the turn-off speed of the main switch Q2 controlled by the driving circuit 151.

[0048] In some embodiments, when the energy storage power supply 1 is just started, the MPPT circuit 30 has not yet worked, at this time, the current of the first circuit 21 and the second circuit 22 is small, that is, the current of the driving circuit 151 is small, the comparison circuit 13 controls the main switch tube Q2 to be turned on through the driving circuit 151 when the sampling voltage is less than or equal to the reference voltage, and fast turn-on is realized. When the sampling voltage is greater than the reference voltage, that is, the photovoltaic input interface 20 is overvoltage, the current of the first circuit 21 and the second circuit 22 is large, the current of the driving circuit 151 is large, the turn-off resistance of the main switch tube Q2 is large, and the main switch tube Q2 realizes slow turn-off to reduce the interference generated by the current change when the main switch tube Q2 is turned off.

[0049] The overvoltage protection circuit 10 of the embodiment includes a power supply circuit 11, a sampling circuit 12, a comparison circuit 13, a driving circuit 151, and a main switch tube Q2. The first input end of the comparison circuit 13 is connected with the power supply circuit 11 to receive the reference voltage from the power supply circuit 11. The second input end of the comparison circuit 13 is connected with the sampling circuit 12 to receive the sampling voltage. The driving circuit 151 is connected with the output end of the comparison circuit 13. The main switch tube Q2 is arranged between the photovoltaic input interface 20 and the MPPT circuit 30. The control end of the main switch tube Q2 is connected with the driving circuit 151. The comparison circuit 13 is used to control the main switch tube Q2 to be turned off through the driving circuit 151 when the sampling voltage is greater than the reference voltage. The sampling voltage and the reference voltage are compared through the comparison circuit 13. The comparison circuit 13 is used to control the main switch tube Q2 to be turned off through the driving circuit 151 when the sampling voltage is greater than the reference voltage, and the main switch tube Q2 is controlled to be turned off in the case that the photovoltaic input interface 20 is overvoltage, so that overvoltage protection can be realized, the photovoltaic input interface 20 is prevented from being overvoltage, the circuit is simple, and the cost is reduced. In addition, the turn-on speed of the main switch tube Q2 controlled by the driving circuit 151 is greater than the turn-off speed of the main switch tube Q2 controlled by the driving circuit 151, and the interference generated by the current change when the main switch tube Q2 is turned off is reduced.

[0050] According to some embodiments of the present application, the comparison circuit 13 of the embodiment is used to control the main switch tube Q2 to be turned on through the driving circuit 151 when the sampling voltage is less than or equal to the reference voltage.

[0051] In some embodiments, the comparison circuit 13 is used to output a first level to the driving circuit 151 when the sampling voltage is less than or equal to the reference voltage, and the driving circuit 151 controls the main switch tube Q2 to be turned on. The comparison circuit 13 is used to output a second level to the driving circuit 151 when the sampling voltage is greater than the reference voltage, and the driving circuit 151 controls the main switch tube Q2 to be turned off. The first level is a high level, and the second level is a low level.

[0052] For example, when two photovoltaic components are connected in parallel, the first voltage is 62V, at this time the sampling voltage is equal to the reference voltage, the comparison circuit 13 outputs high level to the driving circuit 151, the driving circuit 151 controls the main switch tube Q2 to be turned on, and the photovoltaic input interface 20 is connected with the MPPT circuit 30 through the second line 22 and the main switch tube Q2. When two photovoltaic components are connected in series, the first voltage is 120V, at this time the sampling voltage is greater than the reference voltage, the comparison circuit 13 outputs low level to the driving circuit 151, the driving circuit 151 controls the main switch tube Q2 to be turned off, and the photovoltaic input interface 20 is disconnected from the MPPT circuit 30.

[0053] According to some embodiments of the present application, the main switch tube Q2 of the embodiment is arranged on the second line 22, and the output end of the comparison circuit 13 is connected with the control end of the main switch tube Q2 through the driving circuit 151. The first end of the main switch tube Q2 is connected with the low voltage end PV- through the second line 22, and the second end of the main switch tube Q2 is connected with the MPPT circuit 30 through the second line 22.

[0054] In some embodiments, when the sampling voltage is greater than the reference voltage, the comparison circuit 13 is used to output the second level to the driving circuit 151 to control the main switch tube Q2 to be turned off through the driving circuit 151. For example, when two photovoltaic components are connected in series, the first voltage is 120V, at this time the sampling voltage is greater than the reference voltage, the comparison circuit 13 controls the main switch tube Q2 to be turned off through the driving circuit 151, and the low voltage end PV- is disconnected from the MPPT circuit 30.

[0055] The first end of the main switch tube Q2 of the embodiment is connected with the low voltage end PV- through the second line 22, the second end of the main switch tube Q2 is connected with the MPPT circuit 30 through the second line 22, and the comparison circuit 13 is used to control the main switch tube Q2 to be turned off through the driving circuit 151 when the sampling voltage is greater than the reference voltage, so that the low voltage end PV- is disconnected from the MPPT circuit 30, overvoltage protection is realized, and overvoltage of the photovoltaic input interface 20 is avoided. In addition, by arranging the main switch tube Q2 on the second line 22, the embodiment is suitable for high-power energy storage power supply 1, and it is not necessary to find a switch tube with small internal resistance, so that the cost is reduced.

[0056] According to some embodiments of the present application, please refer to Figure 2 As shown in the figure, the overvoltage protection circuit 10 of the embodiment further includes a delay circuit 14, which is connected with the power supply circuit 11 and the comparison circuit 13 respectively, and is used to control the comparison circuit 13 to control the main switch tube Q2 to be turned on or turned off through the driving circuit 151 according to the sampling voltage and the reference voltage when the second voltage is greater than or equal to the first preset voltage.

[0057] When the second voltage is less than the first preset voltage, the main switch Q2 is in the amplification region, and the main switch Q2 is prone to be damaged by being overheated. The delay circuit 14 of the embodiment is configured to control the comparison circuit 13 to control the main switch Q2 to be turned on or turned off by the driving circuit 151 according to the sampling voltage and the reference voltage when the second voltage is greater than or equal to the first preset voltage, that is, the comparison circuit 13 is configured to realize the delay start when the second voltage is less than the first preset voltage, so as to avoid the main switch Q2 being damaged by being in the amplification region.

[0058] According to some embodiments of the present application, the delay circuit 14 of the embodiment is configured to output a first level to the comparison circuit 13 when the second voltage is less than the first preset voltage, and the comparison circuit 13 is configured to control the main switch Q2 to be kept off when the first level is received, so as to avoid the main switch Q2 being damaged by being in the amplification region for a long time after being turned on when the second voltage is less than the first preset voltage.

[0059] For example, the first preset voltage is 10.5V, the delay circuit 14 is configured to output the first level to the comparison circuit 13 when the second voltage is less than 10.5V, and the comparison circuit 13 is configured to output the second level, so as to control the main switch Q2 to be kept off, which is equivalent to that the comparison circuit 13 realizes the delay start, the first level is a high level, and the second level is a low level.

[0060] The delay circuit 14 is configured to output the second level to the comparison circuit 13 when the second voltage is greater than or equal to the first preset voltage, and the comparison circuit 13 is configured to control the main switch Q2 to be turned on when the second level is received and the sampling voltage is less than or equal to the reference voltage, or to be turned off when the second level is received and the sampling voltage is greater than the reference voltage.

[0061] For example, the delay circuit 14 is configured to output a low level to the comparison circuit 13 when the second voltage is greater than or equal to 10.5V, and the comparison circuit 13 is configured to output a high level when the low level is received and the sampling voltage is less than or equal to the reference voltage, so as to control the main switch Q2 to be turned on, or to output a low level when the low level is received and the sampling voltage is greater than the reference voltage, so as to control the main switch Q2 to be turned off.

[0062] The delay circuit 14 of the embodiment is configured to output the first level to the comparison circuit 13 when the second voltage is less than the first preset voltage, and the comparison circuit 13 is configured to control the main switch Q2 to be kept off when the first level is received, so as to realize the delay start of the comparison circuit 13 and avoid the main switch Q2 being damaged by being in the amplification region for a long time after being turned on when the second voltage is less than the first preset voltage. The comparison circuit 13 is configured to output a high level when the second level is received and the sampling voltage is less than or equal to the reference voltage, and to output a low level when the second level is received and the sampling voltage is greater than the reference voltage, so as to realize the level inversion. The main switch Q2 is turned off to realize the overvoltage protection and avoid the overvoltage of the photovoltaic input interface 20.

[0063] According to some embodiments of the present application, please refer to Figure 2 and Figure 3 The delay circuit 14 of the present embodiment includes a current limiting unit 141, a first voltage stabilizing unit 142, a first switching unit 143, and a voltage dividing unit 144.

[0064] The first end of the first voltage stabilizing unit 142 and the first end of the first switching unit 143 are connected with the power supply circuit 11 through the current limiting unit 141, the first end of the first voltage stabilizing unit 142 and the first end of the first switching unit 143 are connected with the enable end SHDN of the comparison circuit 13, the control end of the first switching unit 143 is connected with the voltage dividing unit 144, the first end of the voltage dividing unit 144 is connected with the power supply circuit 11, the second end of the first voltage stabilizing unit 142, the second end of the first switching unit 143, and the second end of the voltage dividing unit 144 are all connected with the second line 22, i.e. the second end of the first voltage stabilizing unit 142, the second end of the first switching unit 143, and the second end of the voltage dividing unit 144 are grounded.

[0065] When the second voltage is less than the first preset voltage, the voltage dividing unit 144 is used to divide the second voltage, and the voltage after the division is lower than the on voltage of the first switching unit 143; the first switching unit 143 is off, the power supply circuit 11 supplies power to the first voltage stabilizing unit 142 through the current limiting unit 141, and the voltage received by the enable end SHDN of the comparison circuit 13 is the voltage of the first voltage stabilizing unit 142, i.e. the enable end SHDN of the comparison circuit 13 receives the first level.

[0066] When the second voltage is greater than or equal to the first preset voltage, the voltage dividing unit 144 is used to divide the second voltage, and the voltage after the division is equal to or greater than the on voltage of the first switching unit 143; the first switching unit 143 is on, the power supply circuit 11 is connected with the second line 22 through the current limiting unit 141 and the first switching unit 143, and the voltage received by the enable end SHDN of the comparison circuit 13 is the voltage of the second line 22, i.e. the enable end SHDN of the comparison circuit 13 receives the second level.

[0067] The delay circuit 14 of the present embodiment includes a current limiting unit 141, a first voltage stabilizing unit 142, a first switching unit 143, and a voltage dividing unit 144; when the second voltage is less than the first preset voltage, the first switching unit 143 is off, the power supply circuit 11 supplies power to the first voltage stabilizing unit 142 through the current limiting unit 141, and the enable end SHDN of the comparison circuit 13 receives the first level, so that the comparison circuit 13 realizes delay start, and avoids that the main switch tube Q2 is damaged due to long time in the amplification zone and serious heating after being turned on when the second voltage is less than the first preset voltage.

[0068] According to some embodiments of the present application, please refer toFigure 2 and Figure 4 As shown in FIG. 14, the delay circuit 14 of the embodiment further comprises a second voltage stabilizing unit 145 and a filter unit 146. The voltage dividing unit 144 is connected to the power supply circuit 11 through the second voltage stabilizing unit 145, and the control end of the first switching unit 143 is connected to the voltage dividing unit 144 through the filter unit 146. The second voltage stabilizing unit 145 is used to stabilize the voltage of the voltage dividing unit 144, and the filter unit 146 is used to filter the voltage after voltage division of the voltage dividing unit 144.

[0069] In some embodiments, the first switching unit 143 comprises a first switch Q1, the current limiting unit 141 comprises a first resistor R1, the first voltage stabilizing unit 142 comprises a first voltage stabilizing tube D1, the voltage dividing unit 144 comprises a third resistor R3 and a fourth resistor R4, the second voltage stabilizing unit 145 comprises a second voltage stabilizing tube D2, and the filter unit 146 comprises a first capacitor C1 and a second resistor R2.

[0070] In some embodiments, the first end of the first switch Q1 is connected to the power supply circuit 11 through the first resistor R1, the negative pole of the first voltage stabilizing tube D1 and the enable end SHDN of the comparison circuit 13 are connected to the first end of the first switch Q1, the control end of the first switch Q1 is connected to the power supply circuit 11 through the second resistor R2, the third resistor R3 and the second voltage stabilizing tube D2, one end of the first capacitor C1 and one end of the fourth resistor R4 are connected between the second resistor R2 and the third resistor R3, the positive pole of the first voltage stabilizing tube D1, the other end of the first capacitor C1, the other end of the fourth resistor R4 and the second end of the first switch Q1 are grounded.

[0071] In some embodiments, the first switch Q1 is an N-type MOS tube, the first end of the first switch Q1 is the drain of the N-type MOS tube, the second end of the first switch Q1 is the source of the N-type MOS tube, and the control end of the first switch Q1 is the gate of the N-type MOS tube. In other embodiments, the first switch Q1 can also be other types of switch tubes, such as a P-type MOS tube.

[0072] In some embodiments, the power supply circuit 11 is used to provide a second voltage to the first resistor R1 and the second voltage stabilizing tube D2; when the second voltage is less than a first preset voltage, the second voltage is divided by the voltage drop of the second voltage stabilizing tube D2, the third resistor R3 and the fourth resistor R4, the voltage at the control end of the first switch Q1 is lower than the conduction voltage of the first switch Q1, the first switch Q1 is turned off, the power supply circuit 11 supplies power to the first voltage stabilizing tube D1 through the resistor R1, and the voltage received by the enable end SHDN of the comparison circuit 13 is the voltage of the first voltage stabilizing tube D1, i.e. the enable end SHDN of the comparison circuit 13 receives the first level. For example, the second voltage is less than 10.5V, and the voltage of the first voltage stabilizing tube D1 is 3.3V. At this time, the voltage of the enable end SHDN of the comparison circuit 13 is 3.3V, i.e. it receives a high level.

[0073] When the second voltage is greater than or equal to the first preset voltage, the second voltage passes through the voltage drop of the second voltage stabilizing tube D2, the voltage division of the third resistor R3 and the fourth resistor R4, the voltage at the control end of the first switch tube Q1 is equal to the on voltage of the first switch tube Q1, the first switch tube Q1 is turned on, the power supply circuit 11 is grounded through the resistor R1 and the first switch tube Q1, and the enable end SHDN of the comparison circuit 13 receives the second level. For example, when the second voltage is greater than or equal to 10.5V, the voltage between the third resistor R3 and the fourth resistor R4 is 2.7V, the first switch tube Q1 is turned on, the power supply circuit 11 is grounded through the resistor R1 and the first switch tube Q1, and the voltage of the enable end SHDN of the comparison circuit 13 is 0V, that is, a low level is received.

[0074] The delay circuit 14 of the embodiment includes a current limiting unit 141, a first voltage stabilizing unit 142, a first switch unit 143, a voltage dividing unit 144, a second voltage stabilizing unit 145 and a filter unit 146. When the second voltage is less than the first preset voltage, the first switch unit 143 is turned off, the power supply circuit 11 supplies power to the first voltage stabilizing unit 142 through the current limiting unit 141, and the enable end SHDN of the comparison circuit 13 receives the first level, so that the comparison circuit 13 realizes the delay start and avoids damage to the main switch tube Q2 in the amplification zone.

[0075] According to some embodiments of the present application, as shown in Figure 2 and Figure 5 The power supply circuit 11 of the embodiment includes a voltage stabilizing circuit 111 and a reference voltage circuit 112. The voltage stabilizing circuit 111 is connected between the first line 21 and the second line 22 and is used to convert the first voltage into the second voltage. The reference voltage circuit 112 is connected with the voltage stabilizing circuit 111 and the comparison circuit 13 respectively and is used to output the reference voltage according to the second voltage.

[0076] The voltage stabilizing circuit 111 includes but is not limited to a low dropout regulator (LDO). The voltage stabilizing circuit 111 is used to supply power to the comparison circuit 13, provide the second voltage, realize the provision of stable voltage and improve the comparison accuracy of the comparison circuit 13. The reference voltage circuit 112 is used to output the reference voltage according to the second voltage, provide the reference voltage for the comparison circuit 13 and improve the accuracy of the reference voltage.

[0077] According to some embodiments of the present application, as shown in Figure 2 and Figure 5 The comparison circuit 13 of the embodiment includes a comparator 131 and a voltage stabilizing unit 132. The comparator 131 can be a comparator with push-pull function. The comparator 131 and the voltage stabilizing unit 132 can realize the function of a hysteresis comparator.

[0078] The first input end of the comparator 131 is connected with the reference voltage circuit 112 to receive the reference voltage. The first power supply end of the comparator 131 is connected with the voltage stabilizing circuit 111 to receive the second voltage, so that the voltage stabilizing circuit 111 supplies power to the comparator 131. The enable end SHDN of the comparator 131 is connected with the delay circuit 14, the second input end of the comparator 131 is connected with the sampling circuit 12 to receive the sampling voltage, and the output end of the comparator 131 is connected with the first input end of the comparator 131 through the voltage stabilizing unit 132 and is connected with the driving circuit 151. The enable end SHDN of the comparator 131 is the enable end SHDN of the comparison circuit 13, the first input end of the comparator 131 is the first input end of the comparison circuit 13, the second input end of the comparator 131 is the second input end of the comparison circuit 13, and the output end of the comparator 131 is the output end of the comparison circuit 13.

[0079] The driving circuit 151 includes the fifth resistor R5, the sixth resistor R6, the seventh resistor R7 and the diode D. The positive electrode of the diode D and one end of the sixth resistor R6 are connected with the output end of the comparator 131 through the fifth resistor R5, the negative electrode of the diode D and the other end of the sixth resistor R6 are connected with the control end of the main switch tube Q2, one end of the seventh resistor R7 is connected with the second line 22, and the other end of the seventh resistor R7 is connected with the control end of the main switch tube Q2.

[0080] The voltage stabilizing unit 132 includes the second capacitor C2, the eighth resistor R8 and the ninth resistor R9. The output end of the comparator 131 is connected with the first input end of the comparator 131 through the eighth resistor R8, one end of the ninth resistor R9 and one end of the second capacitor C2 are connected with the first input end of the comparator 131, and the other end of the ninth resistor R9 and the other end of the second capacitor C2 are connected with the second line 22.

[0081] The sampling circuit 12 includes the tenth resistor R10 and the eleventh resistor R11. The tenth resistor R10 and the eleventh resistor R11 are connected between the first line 21 and the second line 22, the second input end of the comparator 131 is connected between the tenth resistor R10 and the eleventh resistor R11 to receive the sampling voltage.

[0082] According to some embodiments of the present application, as shown in Figure 2 and Figure 5 The reference voltage circuit 112 of the present embodiment includes the third voltage stabilizing tube D3 and the twelfth resistor R12, the comparison circuit 13 further includes the thirteenth resistor R13, the first end of the third voltage stabilizing tube D3 is connected with the voltage stabilizing circuit 111 through the twelfth resistor R12, the second end of the third voltage stabilizing tube D3 is connected with the second line 22, the third end of the third voltage stabilizing tube D3 is connected with the first end, and the first end of the third voltage stabilizing tube D3 is connected with the second input end of the comparator 131 through the thirteenth resistor R13.

[0083] The third Zener diode D3 can be used as a controllable precision voltage regulator. The output of the voltage regulator circuit 111 supplies power to the third Zener diode D3 and the twelfth resistor R12, so that the reference voltage circuit 112 outputs a stable reference voltage. For example, the reference voltage output by the reference voltage circuit 112 is 2.5V.

[0084] The reference voltage circuit 112 in this embodiment includes a third Zener diode D3 and a twelfth resistor R12. The first terminal of the third Zener diode D3 is connected to the voltage regulator circuit 111 through the twelfth resistor R12. The third Zener diode D3 can obtain a precise reference voltage, thereby improving the accuracy of the reference voltage.

[0085] According to some embodiments of this application, please refer to Figure 2 and Figure 5 As shown, the voltage regulator circuit 111 in this embodiment includes a third switch Q3, a fourth switch Q4, a fourteenth resistor R14, a fifteenth resistor R15, a third capacitor C3, a fourth Zener diode D4, a fourth capacitor C4, and a fifth capacitor C5.

[0086] The first terminals of the third switch Q3 and the fourth switch Q4 are connected to the first line 21 via the fourteenth resistor R14. The second terminal of the third switch Q3 is connected to the first power supply terminal of the comparator 131 via the twelfth resistor R12 and the thirteenth resistor R13. The third terminal of the third switch Q3 is connected to the second terminal of the fourth switch Q4. The third terminal of the fourth switch Q4 is connected to the second line 22 via the fourth Zener diode D4. One end of the fifteenth resistor R15 is connected to the first terminal of the third switch Q3. The other end of the fifteenth resistor R15 and one end of the third capacitor C3 are connected to the second terminal of the third switch Q3. The other end of the third capacitor C3 is connected to the second line 22. One end of the fourth capacitor C4 and one end of the fifth capacitor C5 are connected to the second terminal of the third switch Q3. The other ends of the fourth capacitor C4 and the fifth capacitor C5 are connected to the second line 22. The fifteenth resistor R15 can be implemented using multiple resistors connected in parallel. The fourth capacitor C4 and the fifth capacitor C5 are used to filter the second voltage output by the voltage regulator circuit 111.

[0087] In some embodiments, both the third switch Q3 and the fourth switch Q4 are NPN transistors. The first terminals of both the third switch Q3 and the fourth switch Q4 are the collectors of the NPN transistors, the second terminals of both the third switch Q3 and the fourth switch Q4 are the emitters of the NPN transistors, and the third terminals of both the third switch Q3 and the fourth switch Q4 are the bases of the NPN transistors. In other embodiments, the third switch Q3 and the fourth switch Q4 can be other types of switches, such as PNP transistors.

[0088] The voltage stabilizing circuit 111 of the embodiment can improve the input and output characteristics of the third switch tube Q3 and the fourth switch tube Q4 by superimposing the third switch tube Q3 and the fourth switch tube Q4, and can improve the amplification of the current. When the photovoltaic input interface 20 is connected to at least two photovoltaic components, the third switch tube Q3 and the fourth switch tube Q4 can improve the output of the voltage stabilizing circuit 11 in the case of weak light.

[0089] The application also provides a storage power supply 1, as shown in Figure 1 The storage power supply 1 includes at least one photovoltaic input interface 20, an MPPT circuit 30, and an overvoltage protection circuit 10. The overvoltage protection circuit 10 can be the overvoltage protection circuit 10 disclosed in the above embodiments, which will not be described here.

[0090] The photovoltaic input interface 20 is used to be connected with the MPPT circuit 30. For example, the storage power supply 1 is applied to balcony photovoltaic. The photovoltaic input interface 20 includes a high-voltage end PV+ and a low-voltage end PV-. The high-voltage end PV+ is connected with the MPPT circuit 30 through a first line 21, and the low-voltage end PV- is connected with the MPPT circuit 30 through a second line 22. The overvoltage protection circuit 10 is connected between the first line 21 and the second line 22, and can realize overvoltage disconnection of the photovoltaic input interface 20.

[0091] In summary, the overvoltage protection circuit 10 of the application includes a power supply circuit 11, a sampling circuit 12, a comparison circuit 13, a driving circuit 151, and a main switch tube Q2. The first input end of the comparison circuit 13 is connected with the power supply circuit 11 to receive a reference voltage from the power supply circuit 11. The second input end of the comparison circuit 13 is connected with the sampling circuit 12 to receive a sampling voltage. The driving circuit 151 is connected with the output end of the comparison circuit 13. The main switch tube Q2 is arranged between the photovoltaic input interface 20 and the MPPT circuit 30. The control end of the main switch tube Q2 is connected with the driving circuit 151. The comparison circuit 13 is used to control the main switch tube Q2 to be disconnected through the driving circuit 151 when the sampling voltage is greater than the reference voltage. The comparison circuit 13 is used to control the main switch tube Q2 to be disconnected through the driving circuit 151 when the sampling voltage is greater than the reference voltage. The main switch tube Q2 is controlled to be disconnected in the case of overvoltage of the photovoltaic input interface 20, which can realize overvoltage protection, avoid overvoltage of the photovoltaic input interface 20, and reduce the cost.

[0092] The above description is only an embodiment of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the application.

Claims

1. An overvoltage protection circuit applied to an energy storage power supply, characterized in that, The energy storage power supply includes at least one photovoltaic input interface, the photovoltaic input interface is used for being connected with an MPPT circuit in the energy storage power supply, the photovoltaic input interface includes a high-voltage end and a low-voltage end, the high-voltage end is connected with the MPPT circuit through a first line, the low-voltage end is connected with the MPPT circuit through a second line, and the overvoltage protection circuit includes: A power supply circuit connected between the first line and the second line, used to convert a first voltage of the photovoltaic input interface into a second voltage, and output a reference voltage according to the second voltage; A sampling circuit connected between the first line and the second line; A comparison circuit, a first input end of the comparison circuit is connected with the power supply circuit, and the second voltage and the reference voltage are received from the power supply circuit, and a second input end of the comparison circuit is connected with the sampling circuit, and a sampling voltage is received; A drive circuit connected with an output end of the comparison circuit; A main switch tube arranged between the photovoltaic input interface and the MPPT circuit, a control end of the main switch tube is connected with the drive circuit, and the comparison circuit is used for controlling the main switch tube to be turned off through the drive circuit when the sampling voltage is greater than the reference voltage; wherein the turn-on speed of the drive circuit controlling the main switch tube to be turned on is greater than the turn-off speed of the drive circuit controlling the main switch tube to be turned off.

2. The overvoltage protection circuit of claim 1, wherein, The comparison circuit is used for controlling the main switch tube to be turned on through the drive circuit when the sampling voltage is less than or equal to the reference voltage.

3. The overvoltage protection circuit according to claim 1 or 2, characterized in that A first end of the main switch tube is connected with the low-voltage end through the second line, and a second end of the main switch tube is connected with the MPPT circuit through the second line.

4. The overvoltage protection circuit of claim 1, wherein, The overvoltage protection circuit further includes a delay circuit connected with the power supply circuit and the comparison circuit respectively, and the delay circuit is used for controlling the comparison circuit to control the main switch tube to be turned on or turned off through the drive circuit according to the sampling voltage and the reference voltage when the second voltage is greater than or equal to a first preset voltage.

5. The overvoltage protection circuit of claim 4, wherein, The delay circuit is used for outputting a first level to the comparison circuit when the second voltage is less than the first preset voltage, and the comparison circuit is used for controlling the main switch tube to be kept turned off when the first level is received; The delay circuit is used for outputting a second level to the comparison circuit when the second voltage is greater than or equal to the first preset voltage, and the comparison circuit is used for controlling the main switch tube to be turned on when the second level is received and the sampling voltage is less than or equal to the reference voltage, or controlling the main switch tube to be turned off when the second level is received and the sampling voltage is greater than the reference voltage.

6. The overvoltage protection circuit of claim 4, wherein, The delay circuit comprises a current limiting unit, a first voltage stabilizing unit, a first switch unit and a voltage dividing unit, a first end of the first voltage stabilizing unit and a first end of the first switch unit are connected with the power supply circuit through the current limiting unit, the first end of the first voltage stabilizing unit and the first end of the first switch unit are connected with the enable end of the comparison circuit, a control end of the first switch unit is connected with the voltage dividing unit, a first end of the voltage dividing unit is connected with the power supply circuit, a second end of the first voltage stabilizing unit, a second end of the first switch unit and a second end of the voltage dividing unit are all connected with the second line.

7. The overvoltage protection circuit of claim 6, wherein, The delay circuit further comprises a second voltage stabilizing unit and a filter unit, the voltage dividing unit is connected with the power supply circuit through the second voltage stabilizing unit, the control end of the first switch unit is connected with the voltage dividing unit through the filter unit.

8. The overvoltage protection circuit of claim 1, wherein, The power supply circuit comprises a voltage stabilizing circuit and a reference voltage circuit, the voltage stabilizing circuit is connected between the first line and the second line, for converting the first voltage into the second voltage, the reference voltage circuit is connected with the voltage stabilizing circuit and the comparison circuit respectively, for outputting the reference voltage according to the second voltage.

9. The overvoltage protection circuit of claim 8, wherein, The comparison circuit comprises a comparator and a voltage stabilizing unit, a first input end of the comparator is connected with the reference voltage circuit, a first power supply end of the comparator is connected with the voltage stabilizing circuit, an enable end of the comparator is connected with the delay circuit of the overvoltage protection circuit, a second input end of the comparator is connected with the sampling circuit, an output end of the comparator is connected with the first input end of the comparator through the voltage stabilizing unit, and is connected with the driving circuit.

10. An energy storage power supply, characterized by, The overvoltage protection circuit comprises at least one photovoltaic input interface, an MPPT circuit, a voltage stabilizing circuit, a comparison circuit, a delay circuit, a filter circuit and a driving circuit, the photovoltaic input interface is connected with the MPPT circuit, the photovoltaic input interface comprises a high voltage end and a low voltage end, the high voltage end is connected with the MPPT circuit through a first line, the low voltage end is connected with the MPPT circuit through a second line, the voltage stabilizing circuit is connected between the first line and the second line, the comparison circuit is connected with the voltage stabilizing circuit and the delay circuit, the delay circuit is connected with the filter circuit and the driving circuit.

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