Overvoltage protection circuit and method and energy storage system

Abstract

The embodiment of the invention provides an overvoltage protection circuit and method and an energy storage system, and belongs to the technical field of overvoltage protection circuits. The circuit comprises a sampling module which is electrically connected with a power supply end and a comparison module and is used for sampling an input voltage of the power supply end to obtain a sampling voltage; the reference power supply module is electrically connected with the power supply end, the sampling module, the comparison module and the control module and used for determining reference voltage according to the input voltage and preset protection voltage; the comparison module is also electrically connected with the control module and is used for comparing the sampling voltage with the reference voltage and generating a control signal according to a comparison result; and the control module is also electrically connected with the load end and is used for controlling a power supply loop between the power supply end and the load end to be connected or disconnected according to the control signal. Through the provided scheme, bidirectional overvoltage protection between the load end and the power supply end can be realized, and the stability of the energy storage system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of overvoltage protection circuits, and in particular to an overvoltage protection circuit, method and energy storage system. Background Art

[0002] At present, when building an energy storage system platform, the energy storage system platform needs to be connected to the load device. Due to failure to check the parameters of the load device or abnormal control during the operation of the energy storage system platform, overvoltage may occur, damaging the load device or affecting other devices. Most of the existing overvoltage protection solutions for energy storage system platforms only provide unidirectional overvoltage protection and cannot achieve bidirectional overvoltage protection. Summary of the invention

[0003] In order to solve the above technical problems, the embodiments of the present application provide an overvoltage protection circuit, method and energy storage system.

[0004] In a first aspect, an embodiment of the present application provides an overvoltage protection circuit, the circuit comprising: a sampling module, a reference power supply module, a comparison module and a control module;

[0005] The sampling module is electrically connected to the power supply end and the comparison module respectively, and is used to sample the input voltage of the power supply end to obtain a sampled voltage;

[0006] The reference power supply module is electrically connected to the power supply end, the sampling module, the comparison module and the control module respectively, and is used to determine the reference voltage according to the input voltage and the preset protection voltage;

[0007] The comparison module is also electrically connected to the control module, and is used to compare the sampled voltage with the reference voltage, and generate a control signal according to the comparison result;

[0008] The control module is also electrically connected to the load end, and is used to control the power supply circuit between the power supply end and the load end to be turned on or off according to the control signal.

[0009] In one implementation, the reference power supply module includes: a first voltage stabilizing unit, a voltage limiting unit and a first voltage dividing unit;

[0010] The voltage limiting unit is connected to the power supply end;

[0011] The voltage limiting unit is connected to the first voltage stabilizing unit and the first voltage dividing unit respectively;

[0012] The first voltage stabilizing unit is connected to the sampling module, the comparison module and the control module respectively, and is used to provide working voltage to the sampling module, the comparison module and the control module;

[0013] The first voltage dividing unit is also connected to the comparison module. The first voltage dividing unit is used to generate the reference voltage and input the reference voltage to the comparison module.

[0014] In one embodiment, the first voltage dividing unit includes: a first voltage dividing resistor and a second voltage dividing resistor;

[0015] The first end of the first voltage-dividing resistor is electrically connected to the first end of the second voltage-dividing resistor and the comparison module respectively;

[0016] The second end of the first voltage-dividing resistor is electrically connected to the voltage-limiting unit and the first voltage-stabilizing unit respectively, wherein the resistance ratio of the first voltage-dividing resistor and the second voltage-dividing resistor is determined according to the reference voltage;

[0017] The first end of the first voltage-dividing resistor is used to output the reference voltage to the comparison module.

[0018] In one embodiment, the voltage limiting unit includes: a first current limiting resistor, and the first voltage stabilizing unit includes: a voltage stabilizing diode and a filter capacitor;

[0019] The first end of the first current limiting resistor is electrically connected to the power supply end;

[0020] The second end of the first current limiting resistor is electrically connected to the first end of the filter capacitor, the cathode of the voltage stabilizing diode and the second end of the first voltage dividing resistor respectively;

[0021] The anode of the voltage stabilizing diode is electrically connected to the first end of the filter capacitor.

[0022] In one embodiment, the control module includes: a first switch unit and a first control unit;

[0023] The first control unit is electrically connected to the first switch unit and is used to receive the control signal and send the control signal to the first switch unit;

[0024] The first switch unit is used to control the power supply circuit between the power supply end and the load end to be turned on or off according to the control signal.

[0025] In one embodiment, the first switch unit includes: a first switch tube, a second switch tube, a protection diode and a second current limiting resistor, and the first control unit includes: a third switch tube, a pull-up resistor, a first diode and a third current limiting resistor;

[0026] The source of the first switch tube is electrically connected to the source of the second switch tube;

[0027] The drain of the first switch tube is electrically connected to the cathode of the protection diode;

[0028] The drain of the second switch tube is also electrically connected to the load end;

[0029] The first end of the second current limiting resistor is electrically connected to the positive electrode of the protection diode;

[0030] The second end of the second current limiting resistor is electrically connected to the cathode of the protection diode;

[0031] The cathode of the first diode is electrically connected to the base of the third switch tube;

[0032] The anode of the first diode is electrically connected to the second end of the third current limiting resistor and the comparison module respectively;

[0033] The emitter stage of the third switch tube is electrically connected to the power supply end;

[0034] The collector of the third switch tube is electrically connected to the first end of the pull-up resistor;

[0035] The second end of the pull-up resistor is electrically connected to the gate of the first switch tube, the gate of the second switch tube, the anode of the protection diode and the first end of the second current limiting resistor respectively;

[0036] The first end of the third current limiting resistor is electrically connected to the reference power supply module;

[0037] The second end of the third current limiting resistor is also electrically connected to the comparison module.

[0038] In one embodiment, the comparison module is used to output a low impedance state when the sampled voltage is higher than the reference voltage, and send a low-level control signal to the first control unit to turn off the third switch tube; and, when the sampled voltage is lower than the reference voltage, output a high impedance state, and send a high-level control signal to the first control unit to turn on the third switch tube;

[0039] The first control unit is used to control the first switch tube and the second switch tube to be disconnected when the third switch tube is in the disconnected state, so that the power supply circuit between the power supply end and the load end is disconnected; and, when the third switch tube is in the on state, control the first switch tube and the second switch tube to be turned on, so that the power supply circuit between the power supply end and the load end is turned on.

[0040] In one embodiment, the control module further includes: a second control unit;

[0041] The second control unit is connected to the load end and the first control unit, and is used to receive a first driving signal sent by the load end, generate a second driving signal according to the first driving signal, and send the second driving signal to the first control unit;

[0042] The first control unit is used to control the power supply circuit between the power supply end and the load end to be turned on or off according to the second driving signal.

[0043] In one embodiment, the second control unit includes: a fourth current limiting resistor and a photocoupler;

[0044] The first end of the fourth current limiting resistor is communicatively connected to the load end;

[0045] The first end of the photoelectric coupler is electrically connected to the second end of the fourth current limiting resistor;

[0046] The second end of the photoelectric coupler is electrically connected to the comparison module and the first control unit respectively, and the photoelectric coupler is used to generate the second drive signal according to the received first drive signal, and send the second drive signal to the first control unit.

[0047] In one embodiment, the comparison module includes: a comparison unit, a protection unit and an anti-reverse connection unit;

[0048] The protection unit is electrically connected to the sampling module;

[0049] The anti-reverse connection unit is electrically connected to the control module;

[0050] The comparison unit is electrically connected to the reference power supply module and the protection unit respectively, and is used to compare the sampled voltage with the reference voltage, generate the control signal according to the comparison result, and send the control signal to the control module.

[0051] In one embodiment, the comparison unit includes: a comparator, the protection unit includes: a protection resistor, and the reverse connection prevention unit includes: a second diode;

[0052] The positive input terminal of the comparator is electrically connected to the first terminal of the protection resistor;

[0053] The negative input terminal of the comparator is electrically connected to the reference power supply module;

[0054] The second end of the protection resistor is electrically connected to the sampling module;

[0055] The output terminal of the comparator is electrically connected to the cathode of the second diode;

[0056] An anode of the second diode is electrically connected to the control module.

[0057] In one embodiment, the sampling module includes: a sampling unit and a computing unit;

[0058] The computing unit is electrically connected to the reference power supply module and the comparison module;

[0059] The sampling unit is electrically connected to the power supply end and the operation unit respectively, and is used to sample the input voltage of the power supply end to obtain a sampled voltage.

[0060] In one embodiment, the sampling module includes: a second voltage dividing unit and a second voltage stabilizing unit;

[0061] The second voltage dividing unit is electrically connected to the power supply end and the second voltage stabilizing unit, respectively, and is used to divide the input voltage of the power supply end to obtain a sampling voltage;

[0062] The second voltage stabilizing unit is electrically connected to the comparison module, and is used to send the sampled voltage to the comparison module.

[0063] In one embodiment, the circuit further comprises: a protection module;

[0064] The protection module is electrically connected to the power supply end and the load end respectively, and is used to limit the charging speed of the input voltage entering the load end.

[0065] In one embodiment, the protection module includes: a third diode, a thermistor, and a current limiting switch;

[0066] The cathode of the third diode is electrically connected to the first end of the current limiting switch;

[0067] The anode of the third diode is electrically connected to the first end of the thermistor;

[0068] The second end of the thermistor is electrically connected to the second end of the current limiting switch;

[0069] The first end of the current limiting switch is also electrically connected to the power supply end;

[0070] The second end of the current limiting switch is also electrically connected to the load end.

[0071] In a second aspect, an embodiment of the present application provides an energy storage system, which includes a power supply end, a load end, and the overvoltage protection circuit described in the first aspect, and the overvoltage protection circuit is electrically connected to the power supply end and the load end, respectively.

[0072] In a third aspect, an embodiment of the present application provides an overvoltage protection method, which is applied to the overvoltage protection circuit described in the first aspect, and the method includes: sampling the input voltage of the power supply end through a sampling module to obtain a sampled voltage; determining a reference voltage according to the input voltage and a preset protection voltage through a reference power supply module; comparing the sampled voltage and the reference voltage through the comparison module, and generating a control signal according to the comparison result; and controlling the power supply circuit between the power supply end and the load end to be turned on or off according to the control signal through the control module.

[0073] In one embodiment, the method further comprises:

[0074] Receiving the first driving signal sent by the load end through the second control unit, generating a second driving signal according to the first driving signal, and sending the second driving signal to the first control unit;

[0075] The first control unit controls the power supply circuit between the power supply end and the load end to be turned on or off according to the second driving signal.

[0076] The overvoltage protection circuit, method and energy storage system provided by the present application are as follows: the sampling module is electrically connected to the power supply end and the comparison module respectively, and is used to sample the input voltage of the power supply end to obtain the sampling voltage; the reference power supply module is electrically connected to the power supply end, the sampling module, the comparison module and the control module respectively, and is used to determine the reference voltage according to the input voltage and the preset protection voltage; the comparison module is also electrically connected to the control module, and is used to compare the sampling voltage and the reference voltage, and generate a control signal according to the comparison result; the control module is also electrically connected to the load end, and is used to control the power supply circuit between the power supply end and the load end to be turned on or off according to the control signal. Through the provided scheme, bidirectional overvoltage protection between the load end and the power supply end can be achieved, and the stability of the energy storage system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope of protection of the present application. In each of the drawings, similar components are numbered similarly.

[0078] Figure 1 A schematic diagram of the structure of an overvoltage protection circuit provided in an embodiment of the present application is shown;

[0079] Figure 2 A schematic diagram of the structure of an energy storage system provided in an embodiment of the present application is shown;

[0080] Figure 3A circuit diagram of an overvoltage protection circuit provided by an embodiment of the present application is shown;

[0081] Figure 4 A circuit diagram of a reference power supply module of an overvoltage protection circuit provided in an embodiment of the present application is shown;

[0082] Figure 5 A control module circuit diagram of an overvoltage protection circuit provided in an embodiment of the present application is shown;

[0083] Figure 6 A schematic diagram of a comparison module circuit of an overvoltage protection circuit provided in an embodiment of the present application is shown;

[0084] Figure 7 A circuit diagram of a sampling module of an overvoltage protection circuit provided in an embodiment of the present application is shown;

[0085] Figure 8 Another circuit diagram of a sampling module of the overvoltage protection circuit provided in an embodiment of the present application is shown;

[0086] Fig. 9 A circuit diagram of a protection module of an overvoltage protection circuit provided in an embodiment of the present application is shown;

[0087] Fig.10 Another schematic diagram of the structure of the energy storage system provided in the embodiment of the present application is shown;

[0088] Fig.11 A flow chart of an overvoltage protection method provided in an embodiment of the present application is shown.

[0089] Icons: 10-energy storage system; 11-power supply end; 12-overvoltage protection circuit; 13-load end; 121-reference power supply module; 122-sampling module; 123-comparison module; 124-control module; 125-protection module; 1210-first voltage dividing unit; 1212-first voltage stabilizing unit; 1211-voltage limiting unit; 1240-first switching unit; 1241-first control unit; 1242-second control unit; 1231-comparison unit; 1230-protection unit; 1232-anti-reverse connection unit; 1220-sampling unit; 1221-operation unit; 1222-second voltage dividing unit; 1223-second voltage stabilizing unit. DETAILED DESCRIPTION

[0090] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0091] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0092] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present invention, are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or adding the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0093] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0094] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present invention belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present invention.

[0095] When building the energy storage system 10 platform, some problems may arise that lead to overvoltage conditions. On the one hand, if the product parameters are not carefully checked, it may cause anomalies during the operation of the energy storage system 10, thereby generating overvoltage. On the other hand, even during the operation of the energy storage system 10, overvoltage may occur due to control abnormalities. Overvoltage may cause damage to the product, shorten its life and affect its performance, and impair the overall stability and reliability of the system. Based on this, the present application proposes an overvoltage protection circuit 12, which can achieve bidirectional overvoltage protection between the load end 13 and the power supply end 11, thereby improving the stability of the energy storage system 10.

[0096] It is understandable that the overvoltage protection circuit 12 of the embodiment of the present application is applicable to all high voltage DC voltage systems. The overvoltage protection circuit 12 is described below in conjunction with some specific embodiments.

[0097] Example 1

[0098] like Figure 1 As shown, Figure 1A schematic diagram of the structure of the overvoltage protection circuit 12 is shown, including: a sampling module 122, a reference power supply module 121, a comparison module 123 and a control module 124; the sampling module 122 is electrically connected to the comparison module 123; the reference power supply module 121 is electrically connected to the sampling module 122, the comparison module 123 and the control module 124 respectively; the comparison module 123 is also electrically connected to the control module 124. Through the overvoltage protection circuit 12, the inverter and the electrical equipment can be effectively prevented from being damaged due to the excessively high supply voltage, the stability of the energy storage system 10 is improved, and the service life of the electrical equipment and the inverter is further extended.

[0099] This embodiment provides an energy storage system 10, see Figure 2 , Figure 2 and Figure 1 The difference is that Figure 2 It is a structural diagram of the energy storage system 10, and an electrical connection relationship between the overvoltage protection circuit 12 and the power supply terminal 11 and the load terminal 13 is added. Specifically, the sampling module 122 is electrically connected to the power supply terminal 11 of the energy storage system 10, and the input voltage of the power supply terminal 11 is sampled by the sampling module 122 to obtain a sampled voltage, the reference power supply module 121 is connected to the power supply terminal 11, and the reference voltage is determined according to the input voltage and the preset protection voltage, the comparison module 123 generates a control signal according to the comparison result of the sampled voltage and the reference voltage, the control module 124 is electrically connected to the load terminal 13, and the control module 124 controls the power supply circuit between the power supply terminal 11 and the load terminal 13 to be turned on or off according to the control signal.

[0100] It is understandable that the power supply end 11 can specifically be a battery pack, a battery module or other power supply equipment, and its existence form is not limited here. The load end 13 includes an inverter and an electrical device connected to the inverter. The power supply is obtained from the power supply end 11, and the overvoltage protection circuit 12 is used to prevent the input power supply voltage from being too high, and the power supply is converted through the inverter to supply power to the electrical device connected thereto. The overvoltage protection circuit 12 can effectively avoid damage to the inverter and electrical devices due to excessive power supply voltage, thereby improving the stability of the energy storage system 10 and further extending the service life of the electrical equipment and the inverter.

[0101] like Figure 3 As shown, Figure 3 It is a circuit diagram of the overvoltage protection circuit 12, wherein the reference power supply module 121 includes: a first voltage stabilizing unit 1212, a voltage limiting unit 1211 and a first voltage dividing unit 1210; the voltage limiting unit 1211 is connected to the power supply end 11; the voltage limiting unit 1211 is respectively connected to the first voltage stabilizing unit 1212 and the first voltage dividing unit 1210; the first voltage stabilizing unit 1212 is respectively connected to the sampling module 122, the comparison module 123 and the control module 124.

[0102] In the above embodiment, if Figure 4 As shown, Figure 4 It is a circuit diagram of a reference power supply module 121 of an overvoltage protection circuit 12, wherein a first voltage-dividing unit 1210 includes: a first voltage-dividing resistor R10 and a second voltage-dividing resistor R11; a first end of the first voltage-dividing resistor R10 is electrically connected to a first end of the second voltage-dividing resistor R11 and a comparison module 123, respectively; a second end of the first voltage-dividing resistor R10 is electrically connected to a voltage-limiting unit 1211 and a first voltage-stabilizing unit 1212, respectively; the voltage-limiting unit 1211 includes: a first current-limiting resistor R9, and the first voltage-stabilizing unit 1212 includes: a voltage-stabilizing diode Z1 and a filter capacitor C3; a first end of the first current-limiting resistor R9 is electrically connected to a power supply end 11; a second end of the first current-limiting resistor R9 is electrically connected to a first end of the filter capacitor C3, a cathode of the voltage-limiting diode Z1 and a second end of the first voltage-dividing resistor R10, respectively; an anode of the voltage-limiting diode Z1 is electrically connected to a first end of the filter capacitor C3.

[0103] It should be noted that the resistance ratio of the first voltage-dividing resistor R10 and the second voltage-dividing resistor R11 is determined according to the reference voltage, and the first end of the first voltage-dividing resistor R10 is used to output the reference voltage to the comparison module 123 .

[0104] For example, since the maximum voltage threshold that the inverter at the load end 13 can withstand is 600V, 600V is set as the preset protection voltage. When the input voltage may reach 900V, it is necessary to reduce 900V to within 3V through the sampling module 122, that is, reduce it by 300 times. At the same time, after reducing the preset protection voltage 600V by 300 times, a 2V reference voltage is obtained, which is 5V after the voltage regulator tube is stabilized. 2V is divided from 5V through the first voltage-dividing resistor R10 and the second voltage-dividing resistor R11, and the first end of the first voltage-dividing resistor R10 is used to output the reference voltage 2V to the comparison module 123, then the resistance ratio of the first voltage-dividing resistor R10 and the second voltage-dividing resistor R11 is determined to be 3 to 2.

[0105] It is further explained that the embodiment of the present application is provided with a 5V Zener diode Z1, and the Zener diode Z1 provides a stable operating voltage for the sampling module 122, the comparison module 123 and the control module 124.

[0106] By setting the reference power supply module 121 to ensure that the voltage output to these modules remains stable, the sampling module 122 can accurately sample the voltage of the power supply terminal 11, the comparison module 123 can perform accurate comparison under a stable reference voltage, and the control module 124 can also perform reliable control based on a stable signal. At the same time, when a peak voltage appears, it is buffered by a current limiting resistor to avoid damage to the overvoltage protection circuit 12.

[0107] In one embodiment, the control module 124 includes: a first switch unit 1240, a first control unit 1241 and a second control unit 1242; the first control unit 1241 is electrically connected to the first switch unit 1240. The control module 124 also includes: a second control unit 1242; the second control unit 1242 is connected to the load end 13 and the first control unit 1241.

[0108] In the above embodiment, if Figure 5 As shown, Figure 5 1 is a circuit diagram of a control module 124 of an overvoltage protection circuit 12, wherein a first switch unit 1240 includes: a first switch tube Q1, a second switch tube Q2, a protection diode Z2, and a second current limiting resistor R16, and a first control unit 1241 includes: a third switch tube Q3, a pull-up resistor R15, a first diode D1, and a third current limiting resistor R13; a source of the first switch tube Q1 is electrically connected to a source of the second switch tube Q2; a drain of the first switch tube Q1 is electrically connected to a negative electrode of the protection diode Z2; a drain of the second switch tube Q2 is also electrically connected to a load terminal 13; a first end of the second current limiting resistor R16 is electrically connected to a positive electrode of the protection diode Z2; a second end of the second current limiting resistor R16 is electrically connected to a positive electrode of the protection diode Z2; The cathode of the first diode D1 is electrically connected to the base of the third switch tube Q3; the anode of the first diode D1 is electrically connected to the second end of the third current limiting resistor R13 and the comparison module 123 respectively; the emitter of the third switch tube Q3 is electrically connected to the power supply terminal 11; the collector of the third switch tube Q3 is electrically connected to the first end of the pull-up resistor R15; the second end of the pull-up resistor R15 is electrically connected to the gate of the first switch tube Q1, the gate of the second switch tube Q2, the anode of the protection diode Z2 and the first end of the second current limiting resistor R16 respectively; the first end of the third current limiting resistor R13 is electrically connected to the reference power supply module 121; the second end of the third current limiting resistor R13 is also electrically connected to the comparison module 123.

[0109] In this embodiment, the working state of the first switch tube Q1 and the second switch tube Q2 is determined by the third switch tube Q3. If the third switch tube Q3 is in the off state, the gate voltage of the first switch tube Q1 and the second switch tube Q2 is equal to the source voltage, and the conduction condition cannot be met, so the first switch tube Q1 and the second switch tube Q2 are turned off. Among them, the first switch tube Q1 and the second switch tube Q2 are PMOS tubes, the third switch tube Q3 is an NPN transistor, and the protection diode Z2 is a TVS diode, which is used to protect the first switch tube Q1 and the second switch tube Q2.

[0110] It should be noted that when the voltage at the load end 13 increases abnormally, the second switch tube Q2 changes its switch state due to changes in parameters such as gate and source voltages, thereby preventing the abnormally high voltage from causing reverse impact on the input side or other parts of the circuit.

[0111] It is further explained that when the input voltage is too high, the input voltage of the power supply terminal 11 is sampled by the sampling module 122 to obtain the sampled voltage, the reference power supply module 121 determines the reference voltage according to the input voltage and the preset protection voltage, and the comparison module 123 compares the sampled voltage with the reference voltage. When the input voltage is too high, causing the sampled voltage to be greater than the reference voltage, the comparison module 123 generates a corresponding control signal, and the control module 124 disconnects the power supply circuit between the power supply terminal 11 and the load terminal 13 according to the control signal, thereby achieving forward overvoltage protection. When the voltage at the load terminal 13 is too high, the power supply circuit between the power supply terminal 11 and the load terminal 13 is disconnected by the second switch tube Q2, thereby achieving reverse overvoltage protection.

[0112] In one embodiment, the second control unit 1242 includes: a fourth current limiting resistor R14 and a photocoupler U3; the first end of the fourth current limiting resistor R14 is communicatively connected to the load end 13; the first end of the photocoupler U3 is electrically connected to the second end of the fourth current limiting resistor R14; the second end of the photocoupler U3 is electrically connected to the comparison module 123 and the first control unit 1241 respectively.

[0113] It should be noted that the optocoupler U3 generates a second drive signal based on the first drive signal by receiving the first drive signal sent by the MCU of the inverter at the load end 13, and sends the second drive signal to the first control unit 1241. If the second drive signal is a high-level drive signal, the third switch tube Q3 is controlled to be disconnected, thereby disconnecting the first switch tube Q1 and the second switch tube Q2, and further disconnecting the power supply circuit between the power supply end 11 and the load end 13.

[0114] It can be understood that when the MCU of the inverter itself is in a faulty or abnormal state and needs to disconnect from the outside, it can actively send a CRTL signal to disconnect. By increasing the active control of the MCU, the fault state of the MCU can be prevented from affecting the power-consuming equipment, thereby improving the safety of the entire system.

[0115] In one embodiment, the comparison module 123 includes: a comparison unit 1231, a protection unit 1230 and an anti-reverse connection unit 1232; the protection unit 1230 is electrically connected to the sampling module 122; the anti-reverse connection unit 1232 is electrically connected to the control module 124; the comparison unit 1231 is electrically connected to the reference power supply module 121 and the protection unit 1230, respectively, for comparing the sampling voltage and the reference voltage, generating a control signal according to the comparison result, and sending the control signal to the control module 124.

[0116] In the above embodiment, if Figure 6 As shown, Figure 6It is a circuit diagram of a comparison module 123 of an overvoltage protection circuit 12, wherein the comparison unit 1231 includes: a comparator U2, the protection unit 1230 includes: a protection resistor R12, and the anti-reverse connection unit 1232 includes: a second diode D2; the positive input terminal of the comparator U2 is electrically connected to the first end of the protection resistor R12; the negative input terminal of the comparator U2 is electrically connected to the reference power supply module 121; the second end of the protection resistor R12 is electrically connected to the sampling module 122; the output terminal of the comparator U2 is electrically connected to the cathode of the second diode D2; and the anode of the second diode D2 is electrically connected to the control module 124.

[0117] It should be understood that the comparison module 123 is used to output a low impedance state when the sampling voltage is higher than the reference voltage, and send a low-level control signal to the first control unit 1241 to disconnect the third switch tube Q3; and, when the sampling voltage is lower than the reference voltage, output a high impedance state, and send a high-level control signal to the first control unit 1241 to turn on the third switch tube Q3; the first control unit 1241 is used to control the first switch tube Q1 and the second switch tube Q2 to disconnect when the third switch tube Q3 is in the disconnected state, so that the power supply circuit between the power supply end 11 and the load end 13 is disconnected; and, when the third switch tube Q3 is in the on state, control the first switch tube Q1 and the second switch tube Q2 to turn on, so that the power supply circuit between the power supply end 11 and the load end 13 is turned on. In one embodiment, the sampling module 122 includes: a sampling unit 1220 and an operation unit 1221; the operation unit 1221 is electrically connected to the reference power supply module 121 and the comparison module 123; the sampling unit 1220 is electrically connected to the power supply end 11 and the operation unit 1221, respectively, and is used to sample the input voltage of the power supply end 11 to obtain a sampled voltage.

[0118] In the above embodiment, if Figure 7 As shown, Figure 7Schematic diagram of a sampling module 122 of an overvoltage protection circuit 12, wherein the sampling unit 1220 includes: a first sampling resistor R1, a second sampling resistor R2, a third sampling resistor R3, a fourth sampling resistor R4, a fifth sampling resistor R5, a sixth sampling resistor R6, a seventh sampling resistor R7, an eighth sampling resistor R8, a first sampling capacitor C1, and a second sampling capacitor C2, and the operation unit 1221 includes: an operation amplifier U1; a first end of the first sampling resistor R1 is electrically connected to the power supply terminal 11; a second end of the first sampling resistor R1 is electrically connected to a first end of the second sampling resistor R2; a second end of the second sampling resistor R2 is electrically connected to a first end of the third sampling resistor R3; a second end of the third sampling resistor R3 is electrically connected to a non-inverting input terminal of the operation amplifier U1; a first end of the sixth sampling resistor R6 is electrically connected to the power supply terminal 11 The second end of the sixth sampling resistor R6 is electrically connected to the first end of the fifth sampling resistor R5; the second end of the fifth sampling resistor R5 is electrically connected to the first end of the seventh sampling resistor R7; the second end of the seventh sampling resistor R7 is electrically connected to the inverting input terminal of the operational amplifier U1; the first end of the fourth sampling resistor R4 is electrically connected to the first end of the first sampling capacitor C1; the second end of the fourth sampling resistor R4 is electrically connected to the second end of the first sampling capacitor C1 and the non-inverting input terminal of the operational amplifier U1; the first end of the eighth sampling resistor R8 is electrically connected to the first end of the second sampling capacitor C2 and the inverting input terminal of the operational amplifier U1; the second end of the eighth sampling resistor R8 is electrically connected to the second end of the second sampling capacitor C2 and the output terminal of the operational amplifier U1; the output terminal of the operational amplifier U1 is also electrically connected to the comparison module 123.

[0119] It should be noted that the sampling resistance value is adjusted according to the required protection voltage level of the electrical equipment. The specific input sampling resistance determines the maximum value based on the minimum input current of the operational amplifier U1, and the sampling resistance determines the minimum value based on the maximum output current of the operational amplifier U1. The final matching resistance value is determined based on the reduction ratio that the sampling module 122 needs to reduce to less than 3V.

[0120] For example, assume the input voltage is V1. By sampling and reducing V1 to within 3V, the minimum reduction ratio of the sampling module 122 is V1 / 3 times. Denote the reduction ratio of the sampling module 122 as β, and set R1 = R6, R2 = R5, R3 = R7, R4 = R8, (R1 + R2 + R3) / R4 = β; the operational amplifier U1 is powered by 5V. According to its input bias current Iib, the maximum resistance value of the sampling resistor does not exceed V1 / Iib, that is, R1 + R2 + R3 < V1 / Iin. The resistance value of the sampling resistor should not be too small. If the resistance value of the sampling resistor is too small, it will cause excessive current consumption and at the same time there will be noise interference. Take the resistance value of the sampling resistor according to the reduction ratio β. The power of the sampling resistor is 1 / 4W, and the withstand voltage value is 200V. The number of sampling resistors is taken as an integer greater than V1 / 200. The specific number of sampling resistors is not limited here.

[0121] As an alternative solution, as Figure 8 shown, the sampling module 122 includes: a second voltage dividing unit 1222 and a second voltage stabilizing unit 1223; the second voltage dividing unit 1222 is electrically connected to the power supply terminal 11 and the second voltage stabilizing unit 1223 respectively, and is used to divide the input voltage of the power supply terminal 11 to obtain a sampling voltage; the second voltage stabilizing unit 1223 is electrically connected to the comparison module 123.

[0122] Through Figure 8 the third voltage dividing resistor R18, the fourth voltage dividing resistor R19, the fifth voltage dividing resistor R20 and the sixth voltage dividing resistor R21 in it to divide the obtained power supply, and the number of voltage dividing resistors needs to meet the basic requirements of withstand voltage and power.

[0123] Among them, the first end of the third voltage dividing resistor R18 is electrically connected to the power supply terminal, the second end of the third voltage dividing resistor R18 is electrically connected to the first end of the fourth voltage dividing resistor R19, the second end of the fourth voltage dividing resistor R19 is electrically connected to the first end of the fifth voltage dividing resistor R20 and the negative electrode of the voltage stabilizing diode Z3 respectively, the second end of the fifth voltage dividing resistor R20 is electrically connected to the first end of the sixth voltage dividing resistor R21, the second end of the sixth voltage dividing resistor R21 is electrically connected to the power supply terminal, the negative electrode of the voltage stabilizing diode Z3 is also electrically connected to the comparison module, and the positive electrode of the voltage stabilizing diode Z3 is electrically connected to the power supply terminal.

[0124] At the same time, replace Figure 7 the operational amplifier U1 in it with the voltage stabilizing diode Z3. After dividing the input voltage through the sampling resistor, directly input it to the voltage stabilizing diode Z1. The voltage stabilizing diode Z1 uses the divided input voltage as the sampling voltage and inputs it to the comparison module 123. Through this solution, the hardware cost can be saved.

[0125] In one embodiment, the circuit further includes: a protection module 125 ; the protection module 125 is electrically connected to the power supply terminal 11 and the load terminal 13 , respectively, and is used to limit the charging speed of the input voltage entering the load terminal 13 .

[0126] In the above embodiment, if Fig. 9 As shown, Fig. 9 1 is a circuit diagram of a protection module 125 of an overvoltage protection circuit 12, wherein the protection module 125 includes: a third diode D3, a thermistor R17 and a current limiting switch K1; a cathode of the third diode D3 is electrically connected to a first end of the current limiting switch K1; an anode of the third diode D3 is electrically connected to a first end of the thermistor R17; a second end of the thermistor R17 is electrically connected to a second end of the current limiting switch K1; the first end of the current limiting switch K1 is also electrically connected to a power supply end 11; and a second end of the current limiting switch K1 is also electrically connected to a load end 13.

[0127] It should be noted that the first diode D1 , the second diode D2 and the third diode D3 are all anti-reverse connection diodes, wherein the conduction directions of the first diode D1 and the second diode D2 are opposite, and the conduction directions of the second diode D2 and the third diode D3 are the same.

[0128] It is further explained that the current limiting switch K1 is a relay, and the protection module 125 is respectively connected to the power supply terminal 11 and the load terminal 13. When the input voltage rise rate of the power supply terminal 11 is too large when it is powered on, the input voltage rise rate is reduced by the protection module 125. It can be understood that if the power supply terminal 11 is a battery, the battery can be regarded as a large capacitor, and the electrical equipment connected to the load terminal 13 also has a large capacitor. At this time, the electrical equipment connected to the load terminal 13 enters the startup stage.

[0129] When the power supply end 11 charges the capacitor of the load end 13, the voltage rising slope is approximately 1 in milliseconds, which will generate a huge capacitor charging current, and the overvoltage protection circuit 12 may not be able to act in time. The MCU of the inverter controls the current limiting switch K1 to disconnect, and the load end 13 and the power supply end 11 are connected through the third anti-reverse diode D3 and the thermistor R17. The capacitor charging current is limited by the thermistor R17, so that the rising slope of the output voltage of the load end 13 is determined by the thermistor R17, thereby extending the time for the electrical equipment at the load end 13 to reach overvoltage, protecting the electrical equipment at the load end 13, and reserving sufficient time for the reaction time of each module in the overvoltage protection circuit 12.

[0130] In this embodiment, the protection module 125 can avoid damage to electrical equipment caused by too rapid voltage rise, effectively reduce the risk of overvoltage and overcurrent of electrical equipment during startup, improve the protection effect of electrical equipment from multiple aspects, and ensure the safe and stable operation of electrical equipment.

[0131] The overvoltage protection circuit 12 provided in the present application can realize bidirectional overvoltage protection between the load end 13 and the power supply end 11 , thereby improving the stability of the energy storage system 10 .

[0132] This embodiment provides an energy storage system 10, such as Fig.10 As shown, Fig.10 It is a structural schematic diagram of an energy storage system 10, including a power supply end 11, a load end 13 and an overvoltage protection circuit 12 provided in the aforementioned embodiment, and the overvoltage protection circuit 12 is electrically connected to the power supply end 11 and the load end 13 respectively.

[0133] The energy storage system 10 provided in this embodiment can realize the bidirectional overvoltage protection function that can be realized by the overvoltage protection circuit provided in the above embodiments, and will not be described again here to avoid repetition.

[0134] This embodiment provides an overvoltage protection method, such as Fig.11 As shown, Fig.11 1 is a flow chart of an overvoltage protection method, which is applied to the overvoltage protection circuit of the above embodiment. The method includes:

[0135] S101, sampling the input voltage of the power supply end through a sampling module to obtain a sampled voltage;

[0136] S102, determining a reference voltage according to an input voltage and a preset protection voltage by a reference power supply module;

[0137] S103, comparing the sampled voltage with the reference voltage through a comparison module, and generating a control signal according to the comparison result;

[0138] S104, controlling the power supply circuit between the power supply end and the load end to be turned on or off according to the control signal through the control module.

[0139] In one embodiment, the method also includes: receiving a first drive signal emitted by the load end through a second control unit, generating a second drive signal based on the first drive signal, and sending the second drive signal to the first control unit; controlling the power supply circuit between the power supply end and the load end to be turned on or off through the first control unit according to the second drive signal.

[0140] The overvoltage protection method provided in the present application is applied to the overvoltage protection circuit of the above embodiment, which can realize bidirectional overvoltage protection between the load end and the power supply end, thereby improving the stability of the energy storage system.

[0141] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or the flow diagram, and the combination of boxes in the structure diagram and / or the flow diagram, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0142] In addition, the functional modules or units in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0143] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application.

[0144] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. An overvoltage protection circuit, characterized in that: The circuit comprises: a sampling module, a reference power supply module, a comparison module and a control module; The sampling module is electrically connected to the power supply end and the comparison module respectively, and is used to sample the input voltage of the power supply end to obtain a sampled voltage; The reference power supply module is electrically connected to the power supply end, the sampling module, the comparison module and the control module respectively, and is used to determine the reference voltage according to the input voltage and the preset protection voltage; The comparison module is also electrically connected to the control module, and is used to compare the sampled voltage with the reference voltage, and generate a control signal according to the comparison result; The control module is also electrically connected to the load end, and is used to control the power supply circuit between the power supply end and the load end to be turned on or off according to the control signal.

2. The overvoltage protection circuit according to claim 1, characterized in that: The reference power supply module comprises: a first voltage stabilizing unit, a voltage limiting unit and a first voltage dividing unit; The voltage limiting unit is connected to the power supply end; The voltage limiting unit is connected to the first voltage stabilizing unit and the first voltage dividing unit respectively; The first voltage stabilizing unit is connected to the sampling module, the comparison module and the control module respectively, and is used to provide working voltage to the sampling module, the comparison module and the control module; The first voltage dividing unit is also connected to the comparison module. The first voltage dividing unit is used to generate the reference voltage and input the reference voltage to the comparison module.

3. The overvoltage protection circuit according to claim 2, characterized in that: The first voltage dividing unit includes: a first voltage dividing resistor and a second voltage dividing resistor; The first end of the first voltage-dividing resistor is electrically connected to the first end of the second voltage-dividing resistor and the comparison module respectively; The second end of the first voltage-dividing resistor is electrically connected to the voltage-limiting unit and the first voltage-stabilizing unit respectively, wherein the resistance ratio of the first voltage-dividing resistor and the second voltage-dividing resistor is determined according to the reference voltage; The first end of the first voltage-dividing resistor is used to output the reference voltage to the comparison module.

4. The overvoltage protection circuit according to claim 3, characterized in that: The voltage limiting unit includes: a first current limiting resistor, and the first voltage stabilizing unit includes: a voltage stabilizing diode and a filter capacitor; The first end of the first current limiting resistor is electrically connected to the power supply end; The second end of the first current limiting resistor is electrically connected to the first end of the filter capacitor, the cathode of the voltage stabilizing diode and the second end of the first voltage dividing resistor respectively; The anode of the voltage stabilizing diode is electrically connected to the first end of the filter capacitor.

5. The overvoltage protection circuit according to claim 1, characterized in that: The control module comprises: a first switch unit and a first control unit; The first control unit is electrically connected to the first switch unit and is used to receive the control signal and send the control signal to the first switch unit; The first switch unit is used to control the power supply circuit between the power supply end and the load end to be turned on or off according to the control signal.

6. The overvoltage protection circuit according to claim 5, characterized in that: The first switch unit includes: a first switch tube, a second switch tube, a protection diode and a second current limiting resistor, and the first control unit includes: a third switch tube, a pull-up resistor, a first diode and a third current limiting resistor; The source of the first switch tube is electrically connected to the source of the second switch tube; The drain of the first switch tube is electrically connected to the cathode of the protection diode; The drain of the second switch tube is also electrically connected to the load end; The first end of the second current limiting resistor is electrically connected to the positive electrode of the protection diode; The second end of the second current limiting resistor is electrically connected to the cathode of the protection diode; The cathode of the first diode is electrically connected to the base of the third switch tube; The anode of the first diode is electrically connected to the second end of the third current limiting resistor and the comparison module respectively; The emitter stage of the third switch tube is electrically connected to the power supply end; The collector of the third switch tube is electrically connected to the first end of the pull-up resistor; The second end of the pull-up resistor is electrically connected to the gate of the first switch tube, the gate of the second switch tube, the anode of the protection diode and the first end of the second current limiting resistor respectively; The first end of the third current limiting resistor is electrically connected to the reference power supply module; The second end of the third current limiting resistor is also electrically connected to the comparison module.

7. The overvoltage protection circuit according to claim 6, characterized in that: The comparison module is used to output a low impedance state when the sampled voltage is higher than the reference voltage, and send a low-level control signal to the first control unit to turn off the third switch tube; and, when the sampled voltage is lower than the reference voltage, output a high impedance state and send a high-level control signal to the first control unit to turn on the third switch tube; The first control unit is used to control the first switch tube and the second switch tube to be disconnected when the third switch tube is in the disconnected state, so that the power supply circuit between the power supply end and the load end is disconnected; and, when the third switch tube is in the on state, control the first switch tube and the second switch tube to be turned on, so that the power supply circuit between the power supply end and the load end is turned on.

8. The overvoltage protection circuit according to claim 5, characterized in that: The control module further includes: a second control unit; The second control unit is connected to the load end and the first control unit, and is used to receive a first driving signal sent by the load end, generate a second driving signal according to the first driving signal, and send the second driving signal to the first control unit; The first control unit is used to control the power supply circuit between the power supply end and the load end to be turned on or off according to the second driving signal.

9. The overvoltage protection circuit according to claim 8, characterized in that: The second control unit comprises: a fourth current limiting resistor and a photoelectric coupler; The first end of the fourth current limiting resistor is communicatively connected to the load end; The first end of the photoelectric coupler is electrically connected to the second end of the fourth current limiting resistor; The second end of the photoelectric coupler is electrically connected to the comparison module and the first control unit respectively, and the photoelectric coupler is used to generate the second drive signal according to the received first drive signal, and send the second drive signal to the first control unit.

10. The overvoltage protection circuit according to claim 1, characterized in that: The comparison module includes: a comparison unit, a protection unit and an anti-reverse connection unit; The protection unit is electrically connected to the sampling module; The anti-reverse connection unit is electrically connected to the control module; The comparison unit is electrically connected to the reference power supply module and the protection unit respectively, and is used to compare the sampled voltage with the reference voltage, generate the control signal according to the comparison result, and send the control signal to the control module.

11. The overvoltage protection circuit according to claim 10, characterized in that: The comparison unit includes: a comparator, the protection unit includes: a protection resistor, and the anti-reverse connection unit includes: a second diode; The positive input terminal of the comparator is electrically connected to the first terminal of the protection resistor; The negative input terminal of the comparator is electrically connected to the reference power supply module; The second end of the protection resistor is electrically connected to the sampling module; The output terminal of the comparator is electrically connected to the cathode of the second diode; An anode of the second diode is electrically connected to the control module.

12. The overvoltage protection circuit according to claim 1, characterized in that: The sampling module includes: a sampling unit and a computing unit; The operation unit is electrically connected to the reference power supply module and the comparison module respectively; The sampling unit is electrically connected to the power supply end and the operation unit respectively, and is used to sample the input voltage of the power supply end to obtain a sampled voltage.

13. The overvoltage protection circuit according to claim 1, characterized in that: The sampling module includes: a second voltage dividing unit and a second voltage stabilizing unit; The second voltage dividing unit is electrically connected to the power supply end and the second voltage stabilizing unit, respectively, and is used to divide the input voltage of the power supply end to obtain a sampling voltage; The second voltage stabilizing unit is electrically connected to the comparison module, and is used to send the sampled voltage to the comparison module.

14. The overvoltage protection circuit according to any one of claims 1 to 13, characterized in that: The circuit further comprises: a protection module; The protection module is electrically connected to the power supply end and the load end respectively, and is used to limit the charging speed of the input voltage entering the load end.

15. The overvoltage protection circuit according to claim 14, characterized in that: The protection module includes: a third diode, a thermistor and a current limiting switch; The cathode of the third diode is electrically connected to the first end of the current limiting switch; The anode of the third diode is electrically connected to the first end of the thermistor; The second end of the thermistor is electrically connected to the second end of the current limiting switch; The first end of the current limiting switch is also electrically connected to the power supply end; The second end of the current limiting switch is also electrically connected to the load end.

16. An energy storage system, characterized in that: It comprises a power supply end, a load end and the overvoltage protection circuit according to any one of claims 1 to 15, wherein the overvoltage protection circuit is electrically connected to the power supply end and the load end respectively.

17. An overvoltage protection method, characterized in that: Applied to the overvoltage protection circuit according to any one of claims 1 to 15, the method comprising: The input voltage of the power supply end is sampled by the sampling module to obtain a sampled voltage; Determine a reference voltage according to the input voltage and a preset protection voltage by a reference power supply module; Comparing the sampled voltage with the reference voltage through the comparison module, and generating a control signal according to the comparison result; The control module controls the power supply circuit between the power supply end and the load end to be turned on or off according to the control signal.

18. The overvoltage protection method according to claim 17, characterized in that: The method further comprises: Receiving the first driving signal sent by the load end through the second control unit, generating a second driving signal according to the first driving signal, and sending the second driving signal to the first control unit; The first control unit controls the power supply circuit between the power supply end and the load end to be turned on or off according to the second driving signal.

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