Surge suppression circuit and electrical equipment

Abstract

The invention provides a surge suppression circuit and electrical equipment, and the surge suppression circuit comprises an optocoupler; the input end of the optocoupler control circuit is connected with the first direct-current bus and the second direct-current bus, the output end of the optocoupler control circuit is connected with the transmitting end of the optocoupler, and the optocoupler control circuit is used for controlling the conducting state of the optocoupler according to the surge; the first switch tube is arranged on the second direct current bus; the first input end of the voltage driving circuit is connected with the first direct current bus, the second input end of the voltage driving circuit is connected with the second direct current bus and the first receiving end of the optocoupler, and the output end of the voltage driving circuit is connected with the second receiving end of the optocoupler and the control end of the first switching tube; wherein under the condition that the first direct current bus and / or the second direct current bus have the surge, the first switch tube switches the working state according to the surge.

Description

Technical Field

[0001] The present invention relates to the technical field of circuits, and more particularly, to a surge suppression circuit and an electrical device. Background Art

[0002] A surge is a transient high voltage or large current. During the process of an electrical device being struck by lightning, turned on, or turned off an inductive load, a surge voltage and surge current several times or dozens of times the rated voltage and rated current will be formed on the DC bus. The above-mentioned surge can cause damage to the internal components of the electrical device.

[0003] Most of the surge suppression circuits proposed in the related technical solutions are passive circuits, and also include a part of active circuits.

[0004] Figure 1 The topological schematic diagram of the passive circuit in the related technical solution is shown, as Figure 1 shown, the passive circuit includes a thermistor 101', a varistor 102', a rectifier filter circuit 103', and an electrolytic capacitor 104'. Specifically, the thermistor 101' increases the input impedance of the subsequent circuit, thereby suppressing the current flowing into the subsequent circuit; the varistor 102' plays a role in limiting the subsequent voltage, and according to different varistor specifications, the voltage limiting value is from dozens to hundreds of volts; the electrolytic capacitor 104' stores surge energy to prevent the energy from flowing to the subsequent stage and damaging the subsequent components.

[0005] Figure 2 The topological schematic diagram of the active circuit in the related technical solution is shown, as Figure 2 shown, the active circuit includes: a varistor 102', a rectifier filter circuit 103', an active surge suppression circuit 105', and an electrolytic capacitor 104'.

[0006] Among them, an electrolytic capacitor is used to store surges in the above-mentioned passive circuit and active circuit. The fundamental reason is that the current control accuracy of the above-mentioned surge suppression circuit is poor, the range of surge current is relatively large, and only the electrolytic capacitor can be used to absorb it. However, the electrolytic capacitor has problems such as large volume and short service life, which makes the volume and mass of the existing surge suppression circuit relatively large, and there are also problems that the reliability cannot be guaranteed and the service life is relatively short. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art or related technologies.

[0008] To this end, the first aspect of the present invention is to provide a surge suppression circuit.

[0009] The second aspect of the present invention is to provide an electrical device.

[0010] In view of this, according to the first aspect of the present invention, the present invention provides a surge suppression circuit, including: an optocoupler; an optocoupler control circuit, the input end of the optocoupler control circuit is connected to the first DC bus and the second DC bus, and the output end of the optocoupler control circuit is connected to the emitter of the optocoupler, and is used to control the conduction state of the optocoupler according to the surge; a first switching tube, arranged on the second DC bus; a voltage driving circuit, the first input end of the voltage driving circuit is connected to the first DC bus, the second input end of the voltage driving circuit is connected to the second DC bus and the first receiving end of the optocoupler, and the output end of the voltage driving circuit is connected to the second receiving end of the optocoupler and the control end of the first switching tube; wherein, in the case that there is a surge on the first DC bus and / or the second DC bus, the first switching tube switches its working state according to the surge.

[0011] The technical solution of the present invention proposes a surge suppression circuit. By setting the above-mentioned surge suppression circuit, it is possible to control the optocoupler to conduct when there is a surge on the first DC bus and / or the second DC bus, thereby pulling down the voltage at the output end of the voltage driving circuit, so as to switch the working state of the first switching tube, and thus achieve the control of the surge. In this process, the control accuracy of the surge current can be improved, and the treatment of the surge can be realized without using electrolytic capacitors. Based on this, compared with the surge suppression circuit proposed by the related technical solution, the surge suppression circuit proposed by the present invention can overcome the problems of short service life and too large size caused by electrolytic capacitors, and thus enable the device applying the surge suppression circuit proposed by the present invention to be miniaturized while extending the service life of the device applying the surge suppression circuit proposed by the present invention.

[0012] The technical solution of this application is realized based on the following principle. Specifically, when there is no surge on the first DC bus and / or the second DC bus, the optocoupler does not work, and the first switching tube conducts in the saturation region. At this time, the surge suppression circuit proposed by the present invention presents a low-resistance state, and it can be regarded as a thermistor.

[0013] When a surge occurs on the first DC bus and / or the second DC bus, the optocoupler control circuit can output a voltage to the emitter of the optocoupler, causing the light-emitting diode in the optocoupler to emit light. The photosensitive transistor in the optocoupler receives the light emitted by the light-emitting diode and forms a loop with the second DC bus under the voltage output by the output end of the voltage driving circuit. Since the output end of the voltage driving circuit is also connected to the control end of the first switching tube, when the photosensitive transistor receives the light emitted by the light-emitting diode and forms a loop between the output end of the voltage driving circuit and the second DC bus, the voltage value at the output end of the voltage driving circuit is pulled down, that is, the input voltage at the control end of the first switching tube is pulled down, causing the working state of the first switching tube to switch from conduction in the saturation region to conduction in the amplification region.

[0014] As the surge energy continues to increase, the voltage at the output terminal of the voltage drive circuit is pulled down to 0 volts. At this time, the first switching transistor is turned off to inhibit the transfer of surge energy on the second DC bus, thereby playing a role in surge suppression.

[0015] In addition, the voltage across the first switching transistor increases with the increase of the surge energy, and it also bears a part of the surge voltage, limiting the voltage on the second DC bus to a certain value, thereby reducing the probability of damage to the subsequent devices connected to the second DC bus due to excessive voltage. During this process, the stable, reliable and continuous operation of the subsequent devices connected to the second DC bus is ensured.

[0016] In some technical solutions, the first switching transistor can be a switching device such as a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), an Insulate-Gate Bipolar Transistor (IGBT), a triode, or a thyristor.

[0017] In addition, the surge suppression circuit proposed in this application also has the following additional technical features.

[0018] In some technical solutions, optionally, the emitting end of the optocoupler includes a first emitting end and a second emitting end, and the optocoupler control circuit includes: a first power supply circuit, the input end of the first power supply circuit is connected to the first DC bus and the second DC bus, and the output end of the first power supply circuit is connected to the first emitting end; a second switching transistor, the first end of the second switching transistor is connected to the second emitting end, and the second end of the second switching transistor is connected to the second DC bus; a voltage detection circuit, the input end of the voltage detection circuit is connected to the first DC bus and the second DC bus, and the output end of the voltage detection circuit is connected to the control end of the second switching transistor, which is used to collect the voltage value of the surge and output a control voltage corresponding to the voltage value of the surge to the control end of the second switching transistor.

[0019] In this technical solution, the optocoupler control circuit includes a first power supply circuit, which takes power from the first DC bus and the second DC bus by using the first power supply circuit, and supplies power to the first emitting end of the optocoupler based on the connection relationship between the first power supply circuit and the optocoupler. Furthermore, when the second switching transistor is in the conducting state, the first emitting end and the second emitting end of the optocoupler are conducted, and then a loop is formed with the second DC bus.

[0020] In this case, the control of whether the light-emitting diode in the optocoupler emits light can be achieved according to the conducting state of the second switching transistor.

[0021] In the above technical solution, the input end of the voltage detection circuit is connected to the first DC bus and the second DC bus. Therefore, in the case of surges on the first DC bus and the second DC bus, the above surges will act on the voltage detection circuit. Since the voltage detection circuit is connected to the control end of the second switching tube, therefore, the above surges will also act on the second switching tube. Obviously, the presence of surges will control the conduction state of the second switching tube, and further realize the control of whether the light-emitting diode in the optocoupler emits light.

[0022] Obviously, the second switching tube and the optocoupler can be automatically turned on and off according to the surges. Therefore, in the case of surges, the second switching tube can be turned on in time to control the light-emitting diode of the optocoupler to emit light in time. After the photosensitive transistor in the optocoupler receives the light emitted by the light-emitting diode, the voltage at the control end of the first switching tube can be pulled down in time, so that the second switching tube is switched from conduction in the saturation region to conduction in the amplification region until it is turned off, so as to realize the control of surges.

[0023] In the above technical solution, since the first power supply circuit draws power from the first DC bus and the second DC bus, therefore, there is no need to set an additional power supply circuit on the basis of the surge suppression circuit, which reduces the complexity of the surge suppression circuit and further reduces the cost of the surge suppression circuit.

[0024] In the above technical solution, optionally, the second switching tube can be a triode or a MOSFET.

[0025] In some technical solutions, optionally, the first power supply circuit includes: a first resistor, the first end of the first resistor is connected to the first DC bus; a second resistor, the first end of the second resistor is connected to the second end and the first emitter of the first resistor, and the second end of the second resistor is connected to the second DC bus.

[0026] In this technical solution, the first resistor and the second resistor are connected in series between the first DC bus and the second DC bus. At this time, a voltage will be formed on the first resistor and the second resistor by the surge, and the first end of the second resistor is connected to the first emitter. Obviously, the voltage division of the surge on the second resistor will be applied to the first emitter. At this time, power can be supplied to the light-emitting diode of the optocoupler, and at the same time, a stable current can be provided to the light-emitting diode when the light-emitting diode meets the light-emitting conditions.

[0027] In addition, since the second end of the second resistor is connected to the second DC bus and the first end of the second resistor is connected to the first emitter, that is, the second switching tube and the light-emitting diode of the optocoupler are connected in series and respectively connected to the first end and the second end of the second resistor, so that the voltage between the first end and the second end of the second switching tube is limited by the voltage division of the surge on the second resistor, so as to ensure the stable operation of the second switching tube.

[0028] In some technical solutions, optionally, the first resistor is a resistor formed by connecting multiple resistors in series.

[0029] In some technical solutions, optionally, the voltage detection circuit includes: a third resistor, the first end of the third resistor is connected to the first DC bus; a fourth resistor, the first end of the fourth resistor is connected to the second end of the third resistor and the control end of the second switching tube, and the second end of the fourth resistor is connected to the second DC bus.

[0030] In this technical solution, the third resistor and the fourth resistor are connected in series and are respectively connected to the first DC bus and the second DC bus. Therefore, the voltage value at the first end of the fourth resistor will change dynamically according to the magnitude of the surge.

[0031] In addition, since the control end of the second switching tube is connected to the first end of the fourth resistor, the on or off of the second switching tube is controlled by the surge. As can be seen from the above, the on state of the second switching tube affects the working state of the first switching tube. Based on this, the on and off of the second switching tube can be dynamically controlled according to the magnitude of the surge. In the case of a surge, automatic control of the optocoupler can be achieved to reduce the impact of the surge on the device where the surge suppression circuit is located, thereby improving the reliability of the device where the surge suppression circuit is located.

[0032] Specifically, in the case of a surge in the first DC bus circuit and / or the second DC bus circuit, the voltage at the first end of the second resistor increases. At this time, the second switching tube conducts, and a loop is formed between the second emitting end of the optocoupler and the second DC bus. Furthermore, the light-emitting diode in the optocoupler emits light, and then the voltage at the control end of the first switching tube is adjusted to control the working state of the first switching tube.

[0033] In some technical solutions, optionally, the voltage driving circuit includes: a fifth resistor, the first end of the fifth resistor is connected to the first DC bus; a voltage stabilizing diode, the first end of the voltage stabilizing diode is connected to the second end of the fifth resistor and the second receiving end of the optocoupler; a sixth resistor, the first end of the sixth resistor is connected to the second end of the voltage stabilizing diode, and the second end of the sixth resistor is connected to the second DC bus and the first receiving end of the optocoupler.

[0034] In this technical solution, the fifth resistor, the voltage regulator diode, and the sixth resistor are connected in series between the first DC bus and the second DC bus. So that in the case where there is a surge on the first DC bus and / or the second DC bus, a voltage division can be formed at the first end of the voltage regulator diode, and then power is supplied to the second receiving end of the optocoupler. The first receiving end of the optocoupler is connected to the second DC bus. Therefore, when the photosensitive transistor of the optocoupler receives the light emitted by the light-emitting diode of the optocoupler, the first receiving end of the optocoupler is connected to the first receiving end of the optocoupler, short-circuiting the voltage regulator diode and the sixth resistor. At this time, the voltage division formed at the first end of the voltage regulator diode will decrease. In this case, the voltage acting on the control end of the first switching tube will decrease. Correspondingly, the operating state of the first switching tube will change, such as switching from conduction in the self-saturation region to conduction in the amplification region. As the surge energy increases, until the first switching tube is cut off, so as to achieve the control of the surge.

[0035] In the above technical solution, optionally, the fifth resistor is a resistor formed by connecting multiple resistors in series.

[0036] In some technical solutions, optionally, the voltage drive circuit further includes: a first capacitor. The first end of the first capacitor is connected to the first end of the voltage regulator diode, and the second end of the first capacitor is connected to the second end of the sixth resistor.

[0037] In this technical solution, by setting the first capacitor, the first capacitor is used to filter out the clutter on the first DC bus and / or the second DC bus, thereby improving the reliability of the operation of the surge suppression circuit.

[0038] In some technical solutions, optionally, the voltage drive circuit further includes: a third switching tube, which is arranged between the second end of the sixth resistor and the first receiving end of the optocoupler. The first end of the third switching tube is connected to the first end of the voltage regulator diode, the second end of the third switching tube is connected to the second end of the sixth resistor, and the control end of the third switching tube is connected to the first receiving end of the optocoupler.

[0039] In this technical solution, by setting the third switching tube, the optocoupler can adjust the voltage at the control end of the first switching tube by controlling the conduction state of the third switching tube. In this process, the third switching tube has an amplification factor. Based on this amplification factor, the switching speed of the first switching tube from conduction in the self-saturation region to conduction in the amplification region until cut-off can be accelerated, so that when a surge occurs, the first switching tube can be quickly cut off, and the control of the surge can be realized in time, reducing the damage of the surge to the equipment where the surge suppression circuit is located.

[0040] In some technical solutions, optionally, the third switching tube is a triode.

[0041] In some technical solutions, optionally, the voltage driving circuit further includes: a seventh resistor connected in series between the first end of the voltage stabilizing diode and the second end of the fifth resistor. The first end of the seventh resistor is connected to the second end of the fifth resistor and the second receiving end of the optocoupler, and the second end of the seventh resistor is connected to the first end of the voltage stabilizing diode.

[0042] In this technical solution, by setting the seventh resistor, in the case of a surge, the seventh resistor is used to raise the voltage of the second receiving end of the optocoupler, avoiding that as the surge energy increases, the voltage of the second receiving end of the optocoupler is excessively reduced, ultimately causing the first receiving end and the second receiving end of the optocoupler to be unable to stably form a conduction condition, affecting the operation of the photosensitive transistor, and ultimately due to the inability of the optocoupler to operate, the voltage at the control end of the first switching tube stops being pulled down, resulting in the first switching tube remaining continuously in the conducting state and being unable to cut off the second DC bus, and ultimately being unable to control the surge.

[0043] In the above technical solution, the value of the seventh resistor can be selected according to actual usage needs, and its specific value will not be elaborated here.

[0044] In some technical solutions, optionally, the surge suppression circuit further includes: a second capacitor, the first end of the second capacitor is connected to the input end of the optocoupler control circuit.

[0045] In this technical solution, by setting the second capacitor, in the case of a surge existing on the first DC bus and / or the second DC bus, the second capacitor is used to store the surge energy to ensure the safety of the devices connected to the output side of the second capacitor.

[0046] In some technical solutions, optionally, the second capacitor is a thin film capacitor.

[0047] According to the second aspect of the present invention, the present invention provides an electrical device, including: a surge suppression circuit as described in any one of the above.

[0048] In some technical solutions, optionally, the electrical device further includes: a rectifier circuit, the input end of the rectifier circuit is used to connect to an alternating current, the output end of the rectifier circuit is connected to the first DC bus and the second DC bus of the surge suppression circuit; a load, the first power supply end of the load is connected to the first DC bus, and the second power supply end of the load is connected to the second DC bus.

[0049] In this technical solution, by setting the rectifier circuit, the rectifier circuit is used to rectify the connected alternating current, thereby outputting rectified direct current, and the surge suppression circuit is used to control the surge on one side of the rectifier circuit, reducing the impact of the surge on the load, so as to protect the load and reduce the probability of the load malfunctioning.

[0050] In some technical solutions, optionally, the electrical device includes one of the following: a switching power supply, an energy storage inverter, and a charging pile.

[0051] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0053] Figure 1 shows a topological schematic diagram of a passive circuit in a related technical solution;

[0054] Figure 2 shows a topological schematic diagram of an active circuit in a related technical solution;

[0055] Figure 3 shows one of the topological schematic diagrams of a surge suppression circuit in an embodiment of the present application;

[0056] Figure 4 shows another topological schematic diagram of a surge suppression circuit in an embodiment of the present application;

[0057] Figure 5 shows a topological schematic diagram of an electrical device in an embodiment of the present application.

[0058] Wherein, Figure 1 and Figure 2 the corresponding relationship between the reference numerals and the component names in is:

[0059] 101' thermistor, 102' varistor, 103' rectifier filter circuit, 104' electrolytic capacitor, 105' active surge suppression circuit.

[0060] Wherein, Figures 3 to 5 the corresponding relationship between the reference numerals and the component names in is:

[0061] 102 optocoupler, 104 optocoupler control circuit, Q1 first switching transistor, 106 voltage drive circuit, 1042 first power supply circuit, Q2 second switching transistor, 1044 voltage detection circuit, R1 first resistor, R2 second resistor, R3 third resistor, R4 fourth resistor, R5 fifth resistor, TVS voltage regulator diode, R6 sixth resistor, C1 first capacitor, C2 second capacitor, Q3 third switching transistor, R7 seventh resistor, 200 rectifier circuit, 300 load, PBUS first DC bus, NBUS second DC bus. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0062] To better understand the above aspects, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0063] In the following description, numerous specific details are set forth to facilitate a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0064] Figure 3 FIG. 1 shows one of the topological schematic diagrams of the surge suppression circuit in an embodiment of the present application. Figure 4 FIG. 2 shows another topological schematic diagram of the surge suppression circuit in an embodiment of the present application.

[0065] In one embodiment of the present application, as Figure 3 , Figure 4 and Figure 5 shown, a surge suppression circuit is provided, including: an optocoupler 102; an optocoupler control circuit 104, the input end of the optocoupler control circuit 104 is connected to the first DC bus PBUS and the second DC bus NBUS, and the output end of the optocoupler control circuit 104 is connected to the emitter of the optocoupler 102 for controlling the conduction state of the optocoupler 102 according to the surge; a first switching transistor Q1 disposed on the second DC bus NBUS; a voltage driving circuit 106, the first input end of the voltage driving circuit 106 is connected to the first DC bus PBUS, the second input end of the voltage driving circuit 106 is connected to the second DC bus NBUS and the first receiving end of the optocoupler 102, and the output end of the voltage driving circuit 106 is connected to the second receiving end of the optocoupler 102 and the control end of the first switching transistor Q1; wherein, in the case of a surge on the first DC bus PBUS and / or the second DC bus NBUS, the first switching transistor Q1 switches its working state according to the surge.

[0066] Embodiments of the present invention propose a surge suppression circuit. By setting the above-mentioned surge suppression circuit, when there is a surge on the first DC bus PBUS and / or the second DC bus NBUS, the optocoupler 102 can be controlled to conduct, thereby pulling down the voltage at the output end of the voltage drive circuit 106, so as to switch the operating state of the first switching transistor Q1, thereby achieving the control of the surge. During this process, the control accuracy of the surge current can be improved, and the treatment of the surge can be achieved without using electrolytic capacitors. Based on this, compared with the surge suppression circuits proposed in related embodiments, the surge suppression circuit proposed by the present invention can overcome the problems of short service life and too large size of electrolytic capacitors. Therefore, the device applying the surge suppression circuit proposed by the present invention can be miniaturized while extending the service life of the device applying the surge suppression circuit proposed by the present invention.

[0067] Embodiments of the present application are implemented based on the following principle. Specifically, when there is no surge on the first DC bus PBUS and / or the second DC bus NBUS, the optocoupler 102 does not work, and the first switching transistor Q1 conducts in the saturation region. At this time, the surge suppression circuit proposed by the present invention presents a low-resistance state and can be regarded as a thermistor.

[0068] When a surge occurs on the first DC bus PBUS and / or the second DC bus NBUS, the optocoupler control circuit 104 can output a voltage to the emitter of the optocoupler 102, causing the light-emitting diode in the optocoupler 102 to emit light. The photosensitive transistor in the optocoupler 102 receives the light emitted by the light-emitting diode and forms a loop with the second DC bus NBUS under the voltage output at the output end of the voltage drive circuit 106. Since the output end of the voltage drive circuit 106 is connected to the control end of the first switching transistor Q1 at the same time, when the photosensitive transistor receives the light emitted by the light-emitting diode and a loop is formed between the output end of the voltage drive circuit 106 and the second DC bus NBUS, the voltage value at the output end of the voltage drive circuit 106 is pulled down, that is, the input voltage at the control end of the first switching transistor Q1 is pulled down, causing the operating state of the first switching transistor Q1 to switch from conduction in the saturation region to conduction in the amplification region.

[0069] As the surge energy continues to increase, the voltage at the output end of the voltage drive circuit 106 is pulled down to 0 volts. At this time, the first switching transistor Q1 is cut off to suppress the transfer of the surge energy on the second DC bus NBUS, thereby playing a role in surge suppression.

[0070] In addition, the voltage across the first switching transistor Q1 increases as the surge energy increases. It also bears a part of the surge voltage, limiting the voltage on the second DC bus NBUS to a certain value, thereby reducing the probability of damage to the subsequent devices connected to the second DC bus NBUS due to excessive voltage. During this process, the stable, reliable, and continuous operation of the subsequent devices connected to the second DC bus NBUS is ensured.

[0071] It is worth noting that after the surge disappears, the optocoupler 102 and the first switching transistor Q1 can return to the state before the surge occurs, that is, return to the initial low-resistance state, and the surge suppression circuit is completely unaffected.

[0072] In some embodiments, the first switching transistor Q1 can be a switching device such as a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), an Insulate-Gate Bipolar Transistor (IGBT), a bipolar transistor, or a thyristor.

[0073] In some embodiments, optionally, the emitting end of the optocoupler 102 includes a first emitting end and a second emitting end. The optocoupler control circuit 104 includes: a first power supply circuit 1042, the input end of the first power supply circuit 1042 is connected to the first DC bus PBUS and the second DC bus NBUS, and the output end of the first power supply circuit 1042 is connected to the first emitting end; a second switching transistor Q2, the first end of the second switching transistor Q2 is connected to the second emitting end, and the second end of the second switching transistor Q2 is connected to the second DC bus NBUS; a voltage detection circuit 1044, the input end of the voltage detection circuit 1044 is connected to the first DC bus PBUS and the second DC bus NBUS, and the output end of the voltage detection circuit 1044 is connected to the control end of the second switching transistor Q2, which is used to collect the voltage value of the surge and output a control voltage corresponding to the voltage value of the surge to the control end of the second switching transistor Q2.

[0074] In this embodiment, the optocoupler control circuit 104 includes a first power supply circuit 1042, which takes power from the first DC bus PBUS and the second DC bus NBUS by using the first power supply circuit 1042, and supplies power to the first emitting end of the optocoupler 102 based on the connection relationship between the first power supply circuit 1042 and the optocoupler 102. Then, when the second switching transistor Q2 is in the conducting state, the first emitting end and the second emitting end of the optocoupler 102 are conducted, and a loop is formed with the second DC bus NBUS.

[0075] In this case, the control of whether the light-emitting diode in the optocoupler 102 emits light can be realized according to the conducting state of the second switching transistor Q2.

[0076] In the above embodiment, the input end of the voltage detection circuit 1044 is connected to the first DC bus PBUS and the second DC bus NBUS. Therefore, in the case where there are surges on the first DC bus PBUS and the second DC bus NBUS, the above surges will act on the voltage detection circuit 1044. Since the voltage detection circuit 1044 is connected to the control end of the second switching transistor Q2, therefore, the above surges will also act on the second switching transistor Q2. Obviously, the presence of the surges will control the conduction state of the second switching transistor Q2, and further realize the control of whether the light-emitting diode in the optocoupler 102 emits light.

[0077] Obviously, the second switching transistor Q2 and the optocoupler 102 can be automatically turned on and off according to the surges. Further, in the case where there are surges, the second switching transistor Q2 can be turned on in time to control the light-emitting diode of the optocoupler 102 to emit light in time. After the photosensitive transistor in the optocoupler 102 receives the light emitted by the light-emitting diode, the voltage at the control end of the first switching transistor Q1 is pulled down in time, so that the second switching transistor Q2 is switched from conduction in the saturation region to conduction in the amplification region until it is turned off, so as to realize the control of the surges.

[0078] In the above embodiment, since the first power supply circuit 1042 draws power from the first DC bus PBUS and the second DC bus NBUS, therefore, there is no need to provide an additional power supply circuit on the basis of the surge suppression circuit, thereby reducing the complexity of the surge suppression circuit and further reducing the cost of the surge suppression circuit.

[0079] In the above embodiment, optionally, the second switching transistor Q2 can be a triode or a MOSFET.

[0080] In some embodiments, optionally, the first power supply circuit 1042 includes: a first resistor R1, the first end of the first resistor R1 is connected to the first DC bus PBUS; a second resistor R2, the first end of the second resistor R2 is connected to the second end and the first emitter of the first resistor R1, and the second end of the second resistor R2 is connected to the second DC bus NBUS.

[0081] In this embodiment, the first resistor R1 and the second resistor R2 are connected in series between the first DC bus PBUS and the second DC bus NBUS. At this time, the surges will form voltages on the first resistor R1 and the second resistor R2, and the first end of the second resistor R2 is connected to the first emitter. Obviously, the voltage divided by the second resistor R2 by the surges will be applied to the first emitter. At this time, while the power supply can be provided for the light-emitting diode of the optocoupler 102, a stable current can also be provided for the light-emitting diode when the light-emitting diode meets the light-emitting conditions.

[0082] In addition, since the second end of the second resistor R2 is connected to the second DC bus NBUS, and the first end of the second resistor R2 is connected to the first emitting end, that is, the second switching transistor Q2 and the light-emitting diode of the optocoupler 102 are connected in series and then respectively connected to the first end and the second end of the second resistor R2, so that the voltage between the first end and the second end of the second switching transistor Q2 is limited by the voltage division of the surge on the second resistor R2, thereby ensuring the stable operation of the second switching transistor Q2.

[0083] In some embodiments, optionally, the first resistor R1 is a resistor formed by connecting a plurality of resistors in series.

[0084] In some embodiments, optionally, the voltage detection circuit 1044 includes: a third resistor R3, the first end of the third resistor R3 is connected to the first DC bus PBUS; a fourth resistor R4, the first end of the fourth resistor R4 is connected to the second end of the third resistor R3 and the control end of the second switching transistor Q2, and the second end of the fourth resistor R4 is connected to the second DC bus NBUS.

[0085] In this embodiment, the third resistor R3 and the fourth resistor R4 are connected in series and are respectively connected to the first DC bus PBUS and the second DC bus NBUS. Therefore, the voltage value at the first end of the fourth resistor R4 will change dynamically according to the magnitude of the surge.

[0086] In addition, since the control end of the second switching transistor Q2 is connected to the first end of the fourth resistor R4, the conduction or cutoff of the second switching transistor Q2 is controlled by the surge. As can be seen from the above, the conduction state of the second switching transistor Q2 affects the working state of the first switching transistor Q1. Based on this, the conduction and cutoff of the second switching transistor Q2 can be dynamically controlled according to the magnitude of the surge. In the case of a surge, automatic control of the optocoupler 102 can be achieved to reduce the impact of the surge on the device where the surge suppression circuit is located, thereby improving the reliability of the device where the surge suppression circuit is located.

[0087] Specifically, in the case where there is a surge in the first DC bus PBUS circuit and / or the second DC bus NBUS circuit, the voltage at the first end of the second resistor R2 increases. At this time, the second switching transistor Q2 conducts, and a loop is formed between the second emitting end of the optocoupler 102 and the second DC bus NBUS. Furthermore, the light-emitting diode in the optocoupler 102 emits light, and then the voltage at the control end of the first switching transistor Q1 is adjusted to control the working state of the first switching transistor Q1.

[0088] In some embodiments, optionally, the voltage driving circuit 106 includes: a fifth resistor R5, a first end of the fifth resistor R5 is connected to the first DC bus PBUS; a voltage stabilizing diode TVS, a first end of the voltage stabilizing diode TVS is connected to a second end of the fifth resistor R5 and a second receiving end of the optocoupler 102; a sixth resistor R6, a first end of the sixth resistor R6 is connected to a second end of the voltage stabilizing diode TVS, and a second end of the sixth resistor R6 is connected to the second DC bus NBUS and a first receiving end of the optocoupler 102.

[0089] In this embodiment, the fifth resistor R5, the voltage stabilizing diode TVS, and the sixth resistor R6 are connected in series between the first DC bus PBUS and the second DC bus NBUS, so that in the case where there is a surge on the first DC bus PBUS and / or the second DC bus NBUS, a voltage division can be formed at the first end of the voltage stabilizing diode TVS, and then power is supplied to the second receiving end of the optocoupler 102. The first receiving end of the optocoupler 102 is connected to the second DC bus NBUS. Therefore, when the photosensitive transistor of the optocoupler 102 receives the light emitted by the light emitting diode of the optocoupler 102, the first receiving end of the optocoupler 102 is connected to the first receiving end of the optocoupler 102, short-circuiting the voltage stabilizing diode TVS and the sixth resistor R6. At this time, the voltage division formed at the first end of the voltage stabilizing diode TVS will decrease. In this case, the voltage acting on the control end of the first switching transistor Q1 will decrease. Correspondingly, the operating state of the first switching transistor Q1 will change, such as switching from conduction in the self-saturation region to conduction in the amplification region. As the surge energy increases, until the first switching transistor Q1 is cut off, so as to achieve the control of the surge.

[0090] In the above embodiment, optionally, the fifth resistor R5 is a resistor formed by connecting multiple resistors in series.

[0091] Exemplarily, if the voltage at the control end of the first switching transistor Q1 is represented by VD, then:

[0092] VD = Vin × R6 / (R5 + R6) + Vz × R5 / (R5 + R6);

[0093] Wherein, Vz is the voltage stabilizing value of the voltage stabilizing diode TVS, and Vin is the input voltage of the first DC bus PBUS and the second DC bus NBUS.

[0094] Based on this, the voltage at the control end of the second switching transistor Q2, that is, the voltage at the base of the second switching transistor Q2, is represented by VB:

[0095] Then VB = Vbus × R4 / (R3 + R4), where Vbus is the output voltage of the first DC bus PBUS and the second DC bus NBUS.

[0096] During normal operation, VB < Vbe (Vbe is the saturation conduction voltage of the second switching transistor Q2, approximately 0.7V). Q2 is cut off, there is no current on the diode side of the optocoupler 102, the triode side of the optocoupler 102 is not conducting, that is, the photosensitive transistor is not conducting, VD is around 5V to 15V, and the first switching transistor Q1 is in saturation conduction.

[0097] When a surge occurs, Vbus increases, VB increases. When VB > Vbe, the second switching transistor Q2 conducts, there is current on the diode side of the optocoupler 102, then the triode of the optocoupler 102 conducts, that is, VD decreases, and the first switching transistor Q1 gradually enters the amplification region from the saturation region; when the surge energy further increases and Vbus reaches a certain value, causing VD to approach 0V, the first switching transistor Q1 is cut off, playing a role in surge suppression; at the same time, because the voltage across the first switching transistor Q1 also increases with the increase of the surge energy, it bears a part of the surge voltage, limiting the voltage of Vbus to a certain value, avoiding excessive voltage stress on the subsequent devices, and ensuring the stable, reliable and continuous operation of the subsequent stage.

[0098] In some embodiments, optionally, the voltage drive circuit 106 further includes: a first capacitor C1, the first end of the first capacitor C1 is connected to the first end of the voltage stabilizing diode TVS, and the second end of the first capacitor C1 is connected to the second end of the sixth resistor R6.

[0099] In this embodiment, by setting the first capacitor C1, the first capacitor C1 is used to filter out the clutter on the first DC bus PBUS and / or the second DC bus NBUS, thereby improving the reliability of the operation of the surge suppression circuit.

[0100] In some embodiments, optionally, the voltage drive circuit 106 further includes: a third switching transistor Q3, disposed between the second end of the sixth resistor R6 and the first receiving end of the optocoupler 102, the first end of the third switching transistor Q3 is connected to the first end of the voltage stabilizing diode TVS, the second end of the third switching transistor Q3 is connected to the second end of the sixth resistor R6, and the control end of the third switching transistor Q3 is connected to the first receiving end of the optocoupler 102.

[0101] In this embodiment, by setting the third switching transistor Q3, the optocoupler 102 can adjust the voltage at the control end of the first switching transistor Q1 by controlling the conduction state of the third switching transistor Q3. During this process, the third switching transistor Q3 has an amplification factor β. Based on this amplification factor β, it can accelerate the switching speed of the first switching transistor Q1 from saturation conduction to amplification conduction and then to cut-off, so that when a surge occurs, the first switching transistor Q1 can quickly cut off, timely realizing the control of the surge and reducing the damage of the surge to the device where the surge suppression circuit is located.

[0102] In some embodiments, optionally, the third switching transistor Q3 is a triode.

[0103] In some embodiments, optionally, the voltage driving circuit 106 further includes: a seventh resistor R7, connected in series between the first end of the voltage stabilizing diode TVS and the second end of the fifth resistor R5. The first end of the seventh resistor R7 is connected to the second end of the fifth resistor R5 and the second receiving end of the optocoupler 102, and the second end of the seventh resistor R7 is connected to the first end of the voltage stabilizing diode TVS.

[0104] In this embodiment, by setting the seventh resistor R7, in the case of a surge, the seventh resistor R7 is used to raise the voltage of the second receiving end of the optocoupler 102, avoiding that as the surge energy increases, the voltage of the second receiving end of the optocoupler 102 is excessively reduced, ultimately causing the first receiving end and the second receiving end of the optocoupler 102 to be unable to stably form a conduction condition, affecting the operation of the photosensitive transistor, and ultimately because the optocoupler 102 cannot operate, the voltage of the control end of the first switching transistor Q1 stops being pulled down, causing the first switching transistor Q1 to continuously remain in the conducting state and unable to cut off the second DC bus NBUS, ultimately unable to control the surge.

[0105] In the above embodiment, the value of the seventh resistor R7 can be selected according to actual usage needs, and its specific value will not be elaborated here.

[0106] In some embodiments, optionally, the surge suppression circuit further includes: a second capacitor C2, the first end of the second capacitor C2 is connected to the input end of the optocoupler control circuit 104.

[0107] In this embodiment, by setting the second capacitor C2, in the case of a surge existing on the first DC bus PBUS and / or the second DC bus NBUS, the second capacitor C2 is used to store the surge energy to ensure the safety of the devices connected to the output side of the second capacitor C2.

[0108] In some embodiments, optionally, the second capacitor C2 is a thin film capacitor.

[0109] In some embodiments, the present invention provides an electrical device, including: a surge suppression circuit as described in any one of the above.

[0110] An embodiment of the present invention provides an electrical device, including the surge suppression circuit as described above. By setting the surge suppression circuit, when there is a surge on the first DC bus PBUS and / or the second DC bus NBUS, the optocoupler 102 can be controlled to conduct, thereby pulling down the voltage at the output terminal of the voltage drive circuit 106, so as to switch the operating state of the first switching transistor Q1, and thus achieve the control of the surge. In this process, the control accuracy of the surge current can be improved, and the treatment of the surge can be realized without using electrolytic capacitors. Based on this, compared with the surge suppression circuit proposed in the related embodiments, the surge suppression circuit proposed by the present invention can overcome the problems of short service life and too large size caused by electrolytic capacitors. Furthermore, the device applying the surge suppression circuit proposed by the present invention can be miniaturized while extending the service life of the device applying the surge suppression circuit proposed by the present invention.

[0111] It should be noted that after the surge disappears, the optocoupler 102 and the first switching transistor Q1 can return to the state before the surge occurs, that is, return to the initial low-resistance state, and the surge suppression circuit is completely unaffected.

[0112] In some embodiments, optionally, the electrical device further includes: a rectifier circuit 200, the input end of the rectifier circuit 200 is used to connect to alternating current, and the output end of the rectifier circuit 200 is connected to the first DC bus PBUS and the second DC bus NBUS of the surge suppression circuit; a load 300, the first power supply end of the load 300 is connected to the first DC bus PBUS, and the second power supply end of the load 300 is connected to the second DC bus NBUS.

[0113] In this embodiment, by setting the rectifier circuit 200, the rectifier circuit 200 is used to rectify the input alternating current, so as to output rectified direct current, and the surge suppression circuit is used to control the surge on one side of the rectifier circuit 200, reducing the impact of the surge on the load 300, so as to protect the load 300 and reduce the probability of the load 300 malfunctioning.

[0114] In some embodiments, optionally, the electrical device includes one of the following: a switching power supply, an energy storage inverter, a charging pile.

[0115] The terms "first" and "second" in the description and claims of the present application may explicitly or implicitly include one or more of such features. In the written description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally means an "or" relationship between the associated objects before and after.

[0116] In the claims, the specification and the drawings of the present invention, the term "a plurality of" means two or more, unless otherwise clearly defined. The orientation or positional relationship indicated by terms such as "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings. This is only for more convenient description of the present invention and to simplify the description process, rather than to indicate or imply that the device or element referred to must have the specific orientation, be constructed and operated in the specific orientation. Therefore, these descriptions should not be construed as limitations on the present invention; terms such as "connection", "installation", "fixation", etc. should all be understood in a broad sense. For example, "connection" can be a fixed connection between multiple objects, a detachable connection between multiple objects, or an integral connection; it can be a direct connection between multiple objects, or an indirect connection between multiple objects through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances of the above data.

[0117] In the claims, the specification and the drawings of the present invention, the description of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In the claims, the specification and the drawings of the present invention, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0118] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A surge suppression circuit, characterized in that, Comprising: Optocoupler; Optocoupler control circuit, the input end of the optocoupler control circuit is connected to the first DC bus and the second DC bus, and the output end of the optocoupler control circuit is connected to the emitter of the optocoupler, and is used to control the conduction state of the optocoupler according to the surge; First switching tube, arranged on the second DC bus; Voltage driving circuit, the first input end of the voltage driving circuit is connected to the first DC bus, the second input end of the voltage driving circuit is connected to the second DC bus and the first receiving end of the optocoupler, and the output end of the voltage driving circuit is connected to the second receiving end of the optocoupler and the control end of the first switching tube; Wherein, in the case that there is a surge in the first DC bus and / or the second DC bus, the first switching tube switches its working state according to the surge.

2. The surge suppression circuit according to claim 1, wherein The emitter of the optocoupler includes a first emitter and a second emitter, and the optocoupler control circuit includes: First power supply circuit, the input end of the first power supply circuit is connected to the first DC bus and the second DC bus, and the output end of the first power supply circuit is connected to the first emitter; Second switching tube, the first end of the second switching tube is connected to the second emitter, and the second end of the second switching tube is connected to the second DC bus; Voltage detection circuit, the input end of the voltage detection circuit is connected to the first DC bus and the second DC bus, and the output end of the voltage detection circuit is connected to the control end of the second switching tube, and is used to collect the voltage value of the surge and output a control voltage corresponding to the voltage value of the surge to the control end of the second switching tube.

3. The surge suppression circuit according to claim 2, wherein The first power supply circuit includes: First resistor, the first end of the first resistor is connected to the first DC bus; Second resistor, the first end of the second resistor is connected to the second end of the first resistor and the first emitter, and the second end of the second resistor is connected to the second DC bus.

4. The surge suppression circuit according to claim 2, wherein The voltage detection circuit includes: Third resistor, the first end of the third resistor is connected to the first DC bus; Fourth resistor, the first end of the fourth resistor is connected to the second end of the third resistor and the control end of the second switching tube, and the second end of the fourth resistor is connected to the second DC bus.

5. The surge suppression circuit according to any one of claims 1 to 4, characterized in that, The voltage driving circuit includes: Fifth resistor, the first end of the fifth resistor is connected to the first DC bus; Zener diode, the first end of the zener diode is connected to the second end of the fifth resistor and the second receiving end of the optocoupler; Sixth resistor, the first end of the sixth resistor is connected to the second end of the zener diode, and the second end of the sixth resistor is connected to the second DC bus and the first receiving end of the optocoupler.

6. The surge suppression circuit according to claim 5, characterized in that, The voltage driving circuit further includes: First capacitor, the first end of the first capacitor is connected to the first end of the zener diode, and the second end of the first capacitor is connected to the second end of the sixth resistor.

7. The surge suppression circuit according to claim 5, wherein The voltage driving circuit further includes: A third switching transistor is disposed between the second end of the sixth resistor and the first receiving end of the optocoupler. The first end of the third switching transistor is connected to the first end of the voltage stabilizing diode. The second end of the third switching transistor is connected to the second end of the sixth resistor. The control end of the third switching transistor is connected to the first receiving end of the optocoupler.

8. The surge suppression circuit according to claim 5, wherein The voltage driving circuit further includes: A seventh resistor is connected in series between the first end of the voltage stabilizing diode and the second end of the fifth resistor. The first end of the seventh resistor is connected to the second end of the fifth resistor and the second receiving end of the optocoupler. The second end of the seventh resistor is connected to the first end of the voltage stabilizing diode.

9. The surge suppression circuit according to any one of claims 1 to 4, characterized in that, The surge suppression circuit further includes: A second capacitor, the first end of which is connected to the input end of the optocoupler control circuit.

10. An electrical device, characterized in that, including: The surge suppression circuit according to any one of claims 1 to 9.

11. The electrical device according to claim 10, characterized in that, The electrical equipment further includes: A rectifying circuit, the input end of which is used to connect to an alternating current. The output end of the rectifying circuit is connected to the first DC bus and the second DC bus of the surge suppression circuit; A load, the first power supply end of which is connected to the first DC bus, and the second power supply end of which is connected to the second DC bus.

12. The electrical device according to claim 10 or 11, characterized in that, The electrical equipment includes one of the following: A switching power supply, an energy storage inverter, a charging pile.

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