Temperature detection circuit and energy storage system

Abstract

The utility model relates to a temperature detection circuit and an energy storage system, the temperature detection circuit comprises a temperature sampling circuit, a switch circuit, an optocoupler isolation circuit and a control circuit, the temperature sampling circuit samples the temperature of a resonance circuit and an inverter radiator end, and outputs a temperature detection signal to the switch circuit; the switching circuit changes the working state according to the received detection signal and generates a corresponding switching signal, so that the isolating circuit changes the working state according to the received switching signal and generates a corresponding voltage signal, and finally, the control circuit determines whether the temperature of the resonant circuit and the temperature of the inverter radiator end are abnormal or not according to the received voltage signal. Therefore, on the basis of realizing temperature detection, the temperature detection circuit also adopts the switch circuit and the optical coupler isolation circuit to completely isolate a high-voltage temperature detection signal from the control circuit, so that the safety distance meets the safety distance standard, and the safety is improved.

Description

Technical Field

[0001] The utility model relates to the field of temperature detection, in particular to a temperature detection circuit and an energy storage system. Background Art

[0002] Energy storage systems are widely used, including energy conversion and storage devices, such as resonant circuits and inverters. When the resonant circuit and inverter are working, their temperature needs to be detected to generate a high-voltage temperature detection signal, and a heat sink is used to dissipate the temperature of the resonant circuit and inverter to prevent overheating. In traditional temperature detection circuits, the temperature detection signal sampled by the temperature sampling circuit is directly transmitted to the control circuit part, resulting in the EMC safety distance not meeting the safety standard and low safety. Utility Model Content

[0003] The embodiments of the utility model aim to provide a temperature detection circuit and an energy storage system, which can isolate a high-voltage temperature detection signal from a control circuit, meet safety regulations and safety distance requirements, and improve safety.

[0004] In order to solve the above technical problems, the present utility model provides the following technical solutions:

[0005] In a first aspect, an embodiment of the utility model provides a temperature detection circuit, comprising: a temperature sampling circuit, a switch circuit, an optical coupling isolation circuit and a control circuit, wherein the switch circuit is connected to the input ends of the temperature sampling circuit and the optical coupling isolation circuit respectively, and the output end of the optical coupling isolation circuit is connected to the control circuit;

[0006] The temperature sampling circuit is used to sample the temperature of the resonant circuit and the inverter heat sink end, and output a temperature detection signal to the switch circuit;

[0007] The switch circuit is used to change its working state according to the received detection signal and generate a corresponding switch signal, and the optical coupling isolation circuit is used to change its working state according to the received switch signal and generate a corresponding voltage signal;

[0008] The control circuit is used to determine whether the temperature of the resonant circuit and the inverter heat sink end is abnormal according to the received voltage signal.

[0009] In some embodiments, the switching circuit includes a first resistor and a first transistor, one end of the first resistor is respectively connected to the temperature sampling circuit and the base of the first transistor, the other end of the first resistor and the emitter of the first transistor are grounded together, and the collector of the first transistor is connected to the input end of the optocoupler isolation circuit.

[0010] In some embodiments, the optocoupler isolation circuit includes a second resistor, an optocoupler, a third resistor, and a fourth resistor;

[0011] The second resistor is connected to the switch circuit and the anode of the diode of the optocoupler respectively, the collector of the transistor of the optocoupler is connected to the third resistor, and the emitter of the transistor of the optocoupler is connected to the fourth resistor and the control circuit respectively.

[0012] In some embodiments, the temperature sampling circuit includes a first sampling module and a second sampling module;

[0013] The first sampling module and the second sampling module are commonly connected to the switch circuit through a first node. The first sampling module is used to sample the temperature of the resonant circuit and output a first temperature detection signal. The second sampling module is used to sample the temperature of the inverter heat sink end and output a second temperature detection signal.

[0014] In some embodiments, the first sampling module includes a first sampling resistor unit and a first comparator;

[0015] The first sampling resistor unit is connected to the inverting input terminal of the first comparator, and the first sampling resistor unit is used to sample the temperature of the resonant circuit and generate a corresponding first voltage division signal;

[0016] The non-inverting input terminal of the first comparator is used to access a first reference voltage, the output terminal of the first comparator is connected to the first node, and the first comparator is used to generate the corresponding first temperature detection signal according to the first voltage division signal and the first reference voltage.

[0017] In some embodiments, the second sampling module includes a second sampling resistor unit and a second comparator;

[0018] The second sampling resistor unit is connected to the inverting input terminal of the second comparator, and the second sampling resistor unit is used to sample the temperature of the inverter heat sink end and generate a corresponding second voltage division signal;

[0019] The non-inverting input terminal of the second comparator is used to access the first reference voltage, the output terminal of the second comparator is connected to the first node, and the second comparator is used to generate the corresponding second temperature detection signal according to the second voltage division signal and the first reference voltage.

[0020] In some embodiments, the temperature sampling circuit further includes an over-temperature recovery module;

[0021] One end of the over-temperature recovery module is used to receive the first reference voltage, and the other end of the over-temperature recovery module is connected to the first node. When the temperature of the resonant circuit and / or the temperature of the inverter heat sink end recovers to a first preset threshold, the over-temperature recovery module is used to output a recovery voltage signal to the switching circuit.

[0022] In some embodiments, the over-temperature recovery module includes a seventh resistor, a first diode, and an eighth resistor;

[0023] One end of the seventh resistor is used to access the first reference voltage, the other end of the seventh resistor is connected to the anode of the first diode, and the cathode of the first diode is respectively connected to the eighth resistor and the first node.

[0024] In some embodiments, the temperature sampling circuit further includes a protection module, and the protection module is connected to the first sampling resistance unit, the second sampling resistance unit and the first node respectively;

[0025] When the first sampling resistor unit and / or the second sampling resistor unit are not inserted, or when the temperature of the resonant circuit and / or the temperature of the inverter heat sink end is lower than a second preset threshold, the protection module is used to generate a corresponding first low-level signal according to the received first voltage-divided signal, the second voltage-divided signal and the second reference voltage, and output it to the first node, so that the switch circuit generates a corresponding second low-level signal, and then the optical coupling isolation circuit generates a corresponding third low-level signal, and the control circuit is further used to turn off the corresponding drive signal according to the third low-level signal.

[0026] In a second aspect, an embodiment of the utility model provides an energy storage system, wherein the energy storage system includes the temperature detection circuit as described above.

[0027] In various embodiments of the utility model, the temperature detection circuit includes a temperature sampling circuit, a switch circuit, an optocoupler isolation circuit and a control circuit, wherein the switch circuit is respectively connected to the input ends of the temperature sampling circuit and the optocoupler isolation circuit, the output end of the optocoupler isolation circuit is connected to the control circuit, the temperature sampling circuit samples the temperature of the resonant circuit and the inverter heat sink end, and outputs a temperature detection signal to the switch circuit, the switch circuit changes its working state according to the received detection signal, and generates a corresponding switch signal, so that the isolation circuit changes its working state according to the received switch signal, and generates a corresponding voltage signal, and finally the control circuit determines whether the temperature of the resonant circuit and the inverter heat sink end is abnormal according to the received voltage signal. Therefore, compared with the technical solution of directly transmitting the temperature detection signal to the control circuit, the temperature detection circuit, on the basis of realizing temperature detection, also uses a switch circuit and an optocoupler isolation circuit to completely isolate the high-voltage temperature detection signal from the control circuit, so that the safety distance meets the safety distance standard, thereby improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0029] Figure 1 It is a structural schematic diagram of a temperature detection circuit provided by an embodiment of the utility model;

[0030] Figure 2 It is a structural schematic diagram of a temperature detection circuit provided by an embodiment of the utility model;

[0031] Figure 3 It is a circuit structure diagram of a temperature detection circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0033] Energy storage systems include the input and output of energy and materials, energy conversion and storage equipment, which often involve multiple energies, multiple devices, multiple materials, and multiple processes. They are complex energy systems that change over time. Energy storage systems generally include resonant circuits and inverters, such as LLC resonant circuits. When AC square wave voltage or current is applied to both ends of the resonant network, high-frequency resonance will be generated. This resonance will cause components such as inductors, capacitors, and transformers to interact with each other, thereby achieving DC-DC conversion. The inverter is a power electronic device that converts DC power into a constant voltage or frequency-modulated AC voltage. Its working principle is mainly based on the switching characteristics of semiconductor devices (such as field effect transistors or thyristors). It controls the power supply voltage and current through rapid switching, thereby achieving conversion from DC to AC.

[0034] When the resonant circuit and inverter are working, their temperature needs to be detected to generate a high-voltage temperature detection signal, and a heat sink is used to dissipate the temperature of the resonant circuit and inverter to prevent them from overheating. In traditional temperature detection circuits, the temperature detection signal sampled by the temperature sampling circuit is directly transmitted to the control circuit part, resulting in the EMC safety distance not meeting the safety standard.

[0035] Therefore, the utility model provides a temperature detection circuit, which completely isolates the temperature detection signal from the control circuit on the basis of realizing temperature detection, so that the safety distance meets the safety distance standard and improves safety.

[0036] See also Figure 1 , Figure 1 is a schematic diagram of a temperature detection circuit provided by an embodiment of the utility model, such as Figure 1 As shown, the temperature detection circuit 100 includes a temperature sampling circuit 10, a switch circuit 20, an optocoupler isolation circuit 30 and a control circuit 40. The switch circuit 20 is connected to the input ends of the temperature sampling circuit 10 and the optocoupler isolation circuit 30 respectively, and the output end of the optocoupler isolation circuit 30 is connected to the control circuit 40.

[0037] The temperature sampling circuit 10 samples the temperature of the resonant circuit and the inverter heat sink end, and outputs a temperature detection signal to the switch circuit 20. The switch circuit 20 changes its working state according to the received detection signal and generates a corresponding switch signal, so that the isolation circuit changes its working state according to the received switch signal and generates a corresponding voltage signal. Finally, the control circuit 40 determines whether the temperature of the resonant circuit and the inverter heat sink end is abnormal according to the received voltage signal.

[0038] For example: if the temperature of the resonant circuit or the temperature of the inverter heat sink end does not exceed the over-temperature point, the temperature sampling circuit 10 outputs a corresponding temperature detection signal to the switch circuit 20. The temperature detection signal at this time can be a high-level signal, which causes the switch circuit 20 to become a conductive working state. The switch circuit 20 outputs a corresponding switch signal. The switch signal at this time is a low-level signal, which causes the isolation circuit to become a conductive working state. The isolation circuit outputs a corresponding voltage signal. The voltage signal at this time is a high-level signal. The control circuit 40 receives the high-level signal and determines that the temperature of the resonant circuit or the inverter heat sink end is normal and no over-temperature phenomenon occurs.

[0039] For another example: if the temperature of the resonant circuit or the temperature of the inverter heat sink exceeds the over-temperature point, the temperature sampling circuit 10 outputs a corresponding temperature detection signal to the switch circuit 20. The temperature detection signal at this time can be a low-level signal, which causes the switch circuit 20 to change to a cut-off working state. The switch circuit 20 outputs a corresponding switch signal. At this time, the switch signal is a high-level signal, which causes the isolation circuit to change to a cut-off working state. The isolation circuit outputs a corresponding voltage signal. At this time, the voltage signal is a low-level signal. When the control circuit 40 receives the low-level signal, it determines that the temperature of the resonant circuit or the inverter heat sink is abnormal, and an over-temperature phenomenon occurs.

[0040] The control circuit 40 can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single chip microcomputer, an ARM (Acorn RISC Machine) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination of these components. In addition, the control circuit 40 can also be any conventional processor, controller, microcontroller or state machine. The control circuit 40 can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP and / or any other such configuration.

[0041] In summary, compared with the technical solution in which the temperature detection signal is directly transmitted to the control circuit, this temperature detection circuit, on the basis of realizing temperature detection, also uses a switching circuit and an optocoupler isolation circuit to completely isolate the high-voltage temperature detection signal from the control circuit, so that the safety distance meets the safety distance standard, thereby improving safety.

[0042] See also Figure 2 , Figure 2 A temperature detection circuit is provided in an embodiment of the present utility model. Figure 2 As shown, the temperature sampling circuit 10 includes a first sampling module 101 and a second sampling module 102 , wherein the first sampling module 101 and the second sampling module 102 are commonly connected to the switch circuit 20 via a first node.

[0043] The first sampling module 101 samples the temperature of the resonant circuit and outputs a first temperature detection signal to the switch circuit 20. Similarly, the second sampling module 102 samples the temperature of the inverter heat sink and outputs a second temperature detection signal to the switch circuit 20. Both the first temperature detection signal and the second temperature detection signal can change the voltage at the first node of the switch circuit 20 to change the working state of the switch circuit 20.

[0044] For example, if the temperature of the resonant circuit is over-temperature, the first sampling module 101 samples the temperature of the resonant circuit and generates a corresponding first temperature detection signal, which may be a low-level signal. The first temperature detection signal acts on the first node, so that the switch circuit 20 is in a cut-off working state.

[0045] Similarly, if the temperature of the inverter heat sink end is overheated, the second sampling module 102 samples the temperature of the inverter heat sink end and generates a corresponding second temperature detection signal, which can be a low-level signal. The second temperature detection signal acts on the first node, so that the switch circuit 20 is in the cut-off working state.

[0046] In some embodiments, please refer to Figure 2 The first sampling module 101 includes a first sampling resistor unit 1011 and a first comparator U1, wherein the first sampling resistor unit 1011 is connected to the inverting input terminal of the first comparator U1, the non-inverting input terminal of the first comparator U1 is used to access the first reference voltage, and the output terminal of the first comparator U1 is connected to the first node.

[0047] The first sampling resistor unit 1011 samples the temperature of the resonant circuit, and different temperatures generate different resistance values, thereby generating a corresponding first voltage division signal NTC_LLC. The first comparator U1 compares the first voltage division signal NTC_LLC with the first reference voltage to generate a corresponding first temperature detection signal.

[0048] For example, if the temperature of the resonant circuit is not overheated, the voltage of the first voltage-divided signal NTC_LLC generated by the first sampling resistor unit 1011 is small, the voltage of the first voltage-divided signal NTC_LLC is less than the first reference voltage, the first comparator U1 does not flip, and the output first temperature detection signal is a high-level signal, which acts on the first node;

[0049] If the temperature of the resonant circuit is overheated, the voltage of the first voltage-divided signal NTC_LLC generated by the first sampling resistor unit 1011 is larger, and the voltage of the first voltage-divided signal NTC_LLC is greater than the first reference voltage. The first comparator U1 flips, and the output first temperature detection signal is a low-level signal, which acts on the first node.

[0050] In some embodiments, the second sampling module 102 includes a second sampling resistor unit 1021 and a second comparator U2, wherein the second sampling resistor unit 1021 is connected to the inverting input terminal of the second comparator U2, the non-inverting input terminal of the second comparator U2 is used to access the first reference voltage, and the output terminal of the second comparator U2 is connected to the first node.

[0051] The second sampling resistor unit 1021 samples the temperature of the inverter heat sink end, and different temperatures generate different resistance values, thereby generating a corresponding second voltage division signal NTC_I NV. The second comparator U2 compares the second voltage division signal NTC_I NV with the first reference voltage to generate a corresponding second temperature detection signal.

[0052] The working principles of the second sampling resistor unit 1021 and the second comparator U2 are the same as those of the first sampling resistor unit 1011 and the first comparator U1 , and are not described in detail herein.

[0053] The first reference voltage can be set as needed. In the present embodiment, the first reference voltage is +2.5V, which can be directly provided by a power supply or generated by a high-voltage power supply through a power conversion circuit.

[0054] When the temperature of the resonant circuit or the inverter heat sink is over-temperature, that is, when the temperature exceeds the over-temperature point, the temperature detection circuit can continue to work only after the temperature of the resonant circuit or the inverter heat sink slowly recovers to the first preset threshold.

[0055] Specifically, Figure 2 As shown, the temperature sampling circuit 10 further includes an over-temperature recovery module 103, one end of the over-temperature recovery module 103 is used to receive the first reference voltage, and the other end of the over-temperature recovery module 103 is connected to the first node. When the temperature of the resonant circuit and / or the temperature of the inverter heat sink end is restored to the first preset threshold, the over-temperature recovery module 103 outputs a recovery voltage signal to the switch circuit 20, and the current direction of the recovery process is the first reference voltage, the over-temperature recovery module 103 and the first node.

[0056] The first preset threshold is an over-temperature recovery point, and its specific value can be inferred from the specific value of the first preset threshold based on the recovery process current and the first reference voltage.

[0057] In some embodiments, when the first sampling resistor unit 1011 and / or the second sampling resistor unit 1021 is not inserted, or when the temperature of the resonant circuit and / or the temperature of the inverter heat sink end is lower than the second preset threshold, the temperature detection circuit can also automatically identify the non-insertion situation and perform abnormal protection.

[0058] Specifically, Figure 2As shown, the temperature sampling circuit 10 further includes a protection module 104, which is connected to the first sampling resistor unit 1011, the second sampling resistor unit 1021 and the first node respectively. When the first sampling resistor unit 1011 and / or the second sampling resistor unit 1021 are not inserted, or when the temperature of the resonant circuit and / or the temperature of the inverter heat sink end is lower than the second preset threshold, the protection module 104 generates a corresponding first low-level signal according to the received first voltage-divided signal NTC_LLC, the second voltage-divided signal NTC_I NV and the second reference voltage, and outputs it to the first node, so that the switch circuit 20 generates a corresponding second low-level signal, and then the optical coupling isolation circuit 30 generates a corresponding third low-level signal, so that the control circuit 40 turns off the corresponding drive signal according to the third low-level signal to protect the system from abnormality.

[0059] The second preset threshold and the second reference voltage can be set as needed.

[0060] See also Figure 3 , Figure 3 Schematic diagram of a circuit structure of a temperature detection circuit provided by an embodiment of the utility model, such as Figure 3 As shown, the switch circuit 20 includes a first resistor R1 and a first transistor Q1, one end of the first resistor R1 is connected to the temperature sampling circuit 10 and the base of the first transistor Q1 respectively, the other end of the first resistor R1 and the emitter of the first transistor Q1 are grounded together, and the collector of the first transistor Q1 is connected to the input end of the optocoupler isolation circuit 30.

[0061] The optocoupler isolation circuit 30 includes a second resistor R2, an optocoupler U5, a third resistor R3, and a fourth resistor R4. The second resistor R2 is connected to the switch circuit 20 and the anode of the diode of the optocoupler U5, respectively. Specifically, the second resistor R2 is connected to the collector of the first transistor Q1 and the anode of the diode of the optocoupler U5, respectively, the collector of the transistor of the optocoupler U5 is connected to the third resistor R3, and the emitter of the transistor of the optocoupler U5 is connected to the fourth resistor R4 and the control circuit 40 (not shown in the figure).

[0062] The first sampling resistor unit 1011 includes a first thermistor RT1, a fifth resistor R5 and a first capacitor C1. One end of the first thermistor RT1 is connected to the first power supply, and the other end of the first thermistor RT1 is respectively connected to the fifth resistor R5, one end of the first capacitor C1 and the inverting input end of the first comparator U1. The other end of the fifth resistor R5 and the other end of the first capacitor C1 are grounded together.

[0063] The second sampling resistor unit 1021 includes a second thermistor RT2, a sixth resistor R6 and a second capacitor C2, one end of the second thermistor RT2 is connected to the first power supply, the other end of the second thermistor RT2 is respectively connected to the sixth resistor R6, one end of the second capacitor C2 and the inverting input end of the second comparator U2, and the other end of the sixth resistor R6 and the other end of the second capacitor C2 are grounded together.

[0064] The over-temperature recovery module 103 includes a seventh resistor R7, a first diode D1, and an eighth resistor R8. One end of the seventh resistor R7 is used to access the first reference voltage, the other end of the seventh resistor R7 is connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected to the eighth resistor R8 and the first node respectively. In this embodiment, one end of the seventh resistor R7 is connected to the non-inverting input terminal of the first comparator U1 and the non-inverting input terminal of the second comparator U2.

[0065] The protection module 104 includes a third comparator U3 and a fourth comparator U4, wherein the inverting input terminal of the third comparator U3 and the inverting input terminal of the fourth comparator U4 are both used to access the second reference voltage, the non-inverting input terminal of the third comparator U3 is used to receive the first voltage-divided signal NTC_LLC, the non-inverting input terminal of the fourth comparator U4 is used to receive the second voltage-divided signal NTC_I NV, and the output terminal of the third comparator U3 and the output terminal of the fourth comparator U4 are commonly connected to the first node.

[0066] In this embodiment, a current limiting resistor R9 can also be set at the first node, one end of the current limiting resistor R9 is connected to the output end of the first comparator U1 and the output end of the second comparator U2, and the other end of the current limiting resistor R9 is connected to the output end of the third comparator U3 and the output end of the fourth comparator U4.

[0067] In some embodiments, the voltage of the first power supply is greater than the first reference voltage, the first reference voltage is greater than the second reference voltage, the first preset threshold is a positive temperature, and the second preset threshold is a negative temperature. For ease of understanding, specific detailed embodiments are listed for further explanation. For example, the first thermistor RT1 and the second thermistor RT2 are both negative temperature coefficient thermistors, the voltage of the first power supply is +5V, the first reference voltage is +2.5V, the second reference voltage is +0.13V, the first preset threshold is 64 degrees, the second preset threshold is -10 degrees, and the over-temperature point is 94 degrees. It should be noted that the above parameters can be set according to demand and are not used to limit the present utility model.

[0068] Combination Figure 3 , the working principle of the temperature detection circuit can be described as follows:

[0069] When the temperature of the resonant circuit and the inverter heat sink end is lower than 94 degrees and greater than -10 degrees, the resistance of the first thermistor RT1 is larger, greater than the resistance of the fifth resistor R5, the first thermistor RT1 and the fifth resistor R5 are connected in series to divide the voltage, the voltage of the first voltage-divided signal NTC_LLC is less than the voltage of the first reference voltage +2.5V, the voltage of pin 6 of the first comparator U1 is less than the voltage of its pin 7, the first comparator U1 does not flip, and pin 1 of the first comparator U1 is pulled high by +5V_2 and the eighth resistor R8, that is, the first temperature detection signal output by the first comparator U1 is a high-level signal, and the high-level signal acts on the base of the first transistor Q1, so that the first transistor Q1 is turned on, and the first transistor Q1 is turned on. The collector of a transistor Q1 is pulled low, and +15V, the second resistor R2, pin 1 of the optocoupler U5, the first transistor Q1 and the ground form a power supply loop, the diode of the optocoupler U5 is pulled low and turned on, and then the transistor of the optocoupler U5 is turned on, and +5V, the third resistor R3, the transistor of the optocoupler U5, the fourth resistor R4 and the ground form a loop. The voltage signal T_OTP output by the optocoupler U5 is obtained by series voltage division of the +5V voltage by the third resistor R3 and the fourth resistor R4, which is a high-level signal. The voltage signal T_OTP is transmitted to the control circuit 40, and the control circuit 40 determines that the temperature of the resonant circuit and the inverter heat sink end is normal according to the voltage signal T_OTP.

[0070] When the temperature of the resonant circuit is higher than 94 degrees, at this time, the resistance of the first thermistor RT1 is less than 1.2K ohms, then the voltage of the first voltage-dividing signal NTC_LLC is greater than 2.5V, the first comparator U1 flips, and the first temperature detection signal outputted from its pin 1 is a low-level signal, which acts on the base of the first transistor Q1 through the ninth resistor, so that the first transistor Q1 is in a cut-off working state, and the output switch signal is a high-level signal, which acts on the anode of the diode of the optocoupler U5, so that the optocoupler U5 is also in a cut-off working state, and the emitter of the transistor of the optocoupler U5 is pulled down, and the output voltage signal T_OTP is a low-level signal, and the control circuit 40 determines that the temperature of the resonant circuit is abnormal according to the voltage signal T_OTP. Similarly, when the temperature of the inverter heat sink end is higher than 94 degrees, the voltage signal T_OTP received by the control circuit 40 is also a low-level signal, and it is determined that the temperature of the inverter heat sink end is abnormal.

[0071] After overheating, the system can work normally only when the temperature of the resonant circuit and the inverter heat sink end are both lower than 64 degrees. The overtemperature recovery process is as follows: when the system reports an abnormality because the temperature of the resonant circuit and the inverter heat sink end is higher than 94 degrees, the 2nd pin of the second comparator U2 is pulled low, that is, the 2nd pin of the first diode D1 is 0V, and the 1st pin of the first diode D1 is 0.7V. The current flow in the recovery process is as follows, +2.5V1 / the tenth resistor R10 / the 7th pin of the first comparator U1 / the seventh resistor R7 / the first diode D1 / the 2nd pin of the second comparator U2. At this time, the voltage of the 7th pin of the first comparator U1 is calculated to be 1.47V through Ohm's law, and the resistance of the first thermistor RT1 is inferred to be 2.88k ohms. By looking up the table, the NTC temperature is 64 degrees at this time, that is, the overtemperature recovery point is 64 degrees.

[0072] If any one of the first thermistor RT1 and the second thermistor RT2 is not inserted, for example, if the first thermistor RT1 is not inserted, the voltage of the first voltage-divided signal NTC_LLC is 0V, and the voltage of the 9th pin of the third comparator U3 is less than the second reference voltage (0.13V). At this time, the third comparator U3 flips, and its 14th pin outputs a first low-level signal. The first low-level signal turns off the first transistor Q1, and the first transistor Q1 outputs a second low-level signal. The optocoupler U5 is turned off to generate a third low-level signal. At this time, the third low-level signal is the voltage signal T_OTP, and the control circuit 40 determines that the temperature is abnormal to perform protection.

[0073] If the temperature of either the resonant circuit or the inverter heat sink is lower than -10 degrees, for example, the temperature of the resonant circuit is lower than -10 degrees, the resistance of the first thermistor RT1 is greater than 46K ohms. At this time, the voltage of the first voltage-divided signal NTC_LLC is less than the voltage of pin 8 of the third comparator U3, 0.13V. The third comparator U3 flips and outputs a first low-level signal. The first transistor Q1 is turned off. The first transistor Q1 outputs a second low-level signal. The optocoupler U5 is turned off to generate a third low-level signal. At this time, the third low-level signal is the voltage signal T_OTP. The control circuit 40 determines that the temperature is abnormal and turns off the corresponding drive signal for protection.

[0074] The working principle of the inverter heat sink end temperature being lower than -10 degrees is the same as the resonant circuit temperature being lower than -10 degrees, which will not be repeated here.

[0075] Therefore, the temperature detection circuit can realize temperature detection and also has an over-temperature recovery function, a function of identifying whether the thermistor is inserted, and a low-temperature protection function.

[0076] In summary, the temperature detection circuit not only realizes temperature detection, but also uses a switch circuit and an optocoupler isolation circuit to completely isolate the high-voltage temperature detection signal from the control circuit, so that the safety distance meets the safety distance standard and improves safety.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Under the idea of ​​the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A temperature detection circuit, characterized in that: include: A temperature sampling circuit, a switch circuit, an optocoupler isolation circuit and a control circuit, wherein the switch circuit is connected to the input ends of the temperature sampling circuit and the optocoupler isolation circuit respectively, and the output end of the optocoupler isolation circuit is connected to the control circuit; The temperature sampling circuit is used to sample the temperature of the resonant circuit and the inverter heat sink end, and output a temperature detection signal to the switch circuit; The switch circuit is used to change its working state according to the received detection signal and generate a corresponding switch signal, and the optical coupling isolation circuit is used to change its working state according to the received switch signal and generate a corresponding voltage signal; The control circuit is used to determine whether the temperature of the resonant circuit and the inverter heat sink end is abnormal according to the received voltage signal.

2. The temperature detection circuit according to claim 1, characterized in that: The switching circuit includes a first resistor and a first transistor, one end of the first resistor is connected to the temperature sampling circuit and the base of the first transistor respectively, the other end of the first resistor and the emitter of the first transistor are grounded together, and the collector of the first transistor is connected to the input end of the optocoupler isolation circuit.

3. The temperature detection circuit according to claim 1, characterized in that: The optocoupler isolation circuit includes a second resistor, an optocoupler, a third resistor and a fourth resistor; The second resistor is connected to the switch circuit and the anode of the diode of the optocoupler respectively, the collector of the transistor of the optocoupler is connected to the third resistor, and the emitter of the transistor of the optocoupler is connected to the fourth resistor and the control circuit respectively.

4. The temperature detection circuit according to claim 1, characterized in that: The temperature sampling circuit includes a first sampling module and a second sampling module; The first sampling module and the second sampling module are commonly connected to the switch circuit through a first node. The first sampling module is used to sample the temperature of the resonant circuit and output a first temperature detection signal. The second sampling module is used to sample the temperature of the inverter heat sink end and output a second temperature detection signal.

5. The temperature detection circuit according to claim 4, characterized in that: The first sampling module includes a first sampling resistor unit and a first comparator; The first sampling resistor unit is connected to the inverting input terminal of the first comparator, and the first sampling resistor unit is used to sample the temperature of the resonant circuit and generate a corresponding first voltage division signal; The non-inverting input terminal of the first comparator is used to access a first reference voltage, the output terminal of the first comparator is connected to the first node, and the first comparator is used to generate the corresponding first temperature detection signal according to the first voltage division signal and the first reference voltage.

6. The temperature detection circuit according to claim 5, characterized in that: The second sampling module includes a second sampling resistor unit and a second comparator; The second sampling resistor unit is connected to the inverting input terminal of the second comparator, and the second sampling resistor unit is used to sample the temperature of the inverter heat sink end and generate a corresponding second voltage division signal; The non-inverting input terminal of the second comparator is used to access the first reference voltage, the output terminal of the second comparator is connected to the first node, and the second comparator is used to generate the corresponding second temperature detection signal according to the second voltage division signal and the first reference voltage.

7. The temperature detection circuit according to claim 5, characterized in that: The temperature sampling circuit also includes an over-temperature recovery module; One end of the over-temperature recovery module is used to receive the first reference voltage, and the other end of the over-temperature recovery module is connected to the first node. When the temperature of the resonant circuit and / or the temperature of the inverter heat sink end recovers to a first preset threshold, the over-temperature recovery module is used to output a recovery voltage signal to the switching circuit.

8. The temperature detection circuit according to claim 7, characterized in that: The over-temperature recovery module includes a seventh resistor, a first diode and an eighth resistor; One end of the seventh resistor is used to access the first reference voltage, the other end of the seventh resistor is connected to the anode of the first diode, and the cathode of the first diode is respectively connected to the eighth resistor and the first node.

9. The temperature detection circuit according to claim 6, characterized in that: The temperature sampling circuit further includes a protection module, and the protection module is respectively connected to the first sampling resistance unit, the second sampling resistance unit and the first node; When the first sampling resistor unit and / or the second sampling resistor unit are not inserted, or when the temperature of the resonant circuit and / or the temperature of the inverter heat sink end is lower than a second preset threshold, the protection module is used to generate a corresponding first low-level signal according to the received first voltage-divided signal, the second voltage-divided signal and the second reference voltage, and output it to the first node, so that the switch circuit generates a corresponding second low-level signal, and then the optical coupling isolation circuit generates a corresponding third low-level signal, and the control circuit is further used to turn off the corresponding drive signal according to the third low-level signal.

10. An energy storage system, characterized in that: The energy storage system comprises the temperature detection circuit as described in any one of claims 1-9.

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