A small and medium power AC power supply line protection device for quick cutting

Abstract

The application provides a small and medium power AC power supply line protection device for quick disconnection, characterized in that the method comprises the following steps: a laser detector for converting an optical signal into an electrical signal, a monostable trigger circuit coupled to the laser detector, an IGBT tube coupled to the monostable trigger circuit and used for controlling the on-off of an AC loop, a driving circuit coupled to the IGBT tube and used for driving the IGBT tube, and an optical-electric conversion module for converting an optical pulse signal into a voltage pulse signal. After the voltage pulse signal passes through a pulse width extension module, the pulse width of the voltage pulse signal is extended, and the extended voltage pulse signal is provided to an AC switch device driving module. The driving module controls the switching state of the AC switch device according to the received voltage signal, thereby realizing the on-off control of the power supply link.

Description

Technical Field

[0001] This application relates to the field of power supply line protection technology, and in particular to a protection device for small and medium power AC power supply lines for rapid disconnection. Background Technology

[0002] When electromagnetic pulse (EMP) activity occurs, the electromagnetic waves, after striking the antenna of the microwave station, couple through the antenna system to other electronic devices within the station, threatening the safety of downstream equipment. Among these downstream devices, many are connected to AC links. Upon detecting EMP activity, the AC circuit must be quickly disconnected to ensure the safety of the downstream equipment. Summary of the Invention

[0003] This invention provides a protection device for small and medium power AC power supply lines for rapid disconnection, thereby at least solving the problem of AC links not being able to be disconnected in a timely manner in related technologies.

[0004] According to an embodiment of the present invention, a protection device for small and medium power AC power supply lines for rapid disconnection is characterized in that the method includes: a laser detector for converting optical signals into electrical signals, a monostable multivibrator circuit coupled to the laser detector, an IGBT transistor coupled to the monostable multivibrator circuit and used for controlling the on / off state of the AC circuit, and a drive circuit coupled to the IGBT transistor and used for driving the IGBT transistor.

[0005] Furthermore, there are two IGBT transistors connected in reverse series.

[0006] Furthermore, the IGBT is an IGBT of model SGTP30U60FD1PU.

[0007] Furthermore, the laser detector is a photodetector diode.

[0008] Furthermore, the photodetector diode is an indium gallium arsenide PIN photodetector diode.

[0009] Furthermore, the driving circuit includes a push-pull driving circuit consisting of a transistor and resistors and capacitors coupled to the transistor.

[0010] According to this invention, when the AC power supply link rapid disconnection device receives an optical pulse trigger signal, the photoelectric conversion module converts the optical pulse signal into a voltage pulse signal. The voltage pulse signal then passes through a pulse width extension module to extend its pulse width before being provided to the AC switching device drive module. The drive module then controls the switching state of the AC switching device based on the received voltage signal, thereby achieving on / off control of the power supply link. Attached Figure Description

[0011] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall circuit structure of an embodiment of this application; Figure 2 This is a schematic diagram of the photodetector bias circuit provided in an embodiment of this application; Figure 3 The schematic diagram of the IGBT provided in the embodiments of this application; Figure 4 The AC shutdown schematic diagram provided for the embodiments of this application; Figure 5 This is a schematic diagram of the IGBT drive principle provided in an embodiment of this application; Figure 6 This is a schematic diagram of the monostable trigger circuit structure provided in an embodiment of this application. Detailed Implementation The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0012] Example: Refer to Figure 1 As shown, a protective device for small to medium power AC power supply lines for rapid disconnection includes: Photoelectric conversion module: used to receive pulsed light signals and convert them into electrical signals; Pulse width extension module: used to convert electrical signals into drive signals; Driver module: Used to receive drive signals and perform drive operations; AC switching devices: controlled by the drive module, used for on / off control of AC circuits.

[0013] Specifically, the AC power supply link quick disconnection device is mainly used to disconnect the AC power supply circuit of electrical equipment. After receiving the trigger control signal (optical pulse signal), the AC power supply link quick disconnection device needs to convert the optical signal into an electrical signal that can trigger the drive module. Therefore, a photoelectric conversion module is needed to complete the conversion from optical signal to electrical signal. In this embodiment, a laser detector is selected as the photoelectric conversion module, which has the advantages of short response time and wide detection frequency band, and is used to convert the received optical signal into an electrical signal. The photoelectric conversion module mainly consists of a laser detector and a photoelectric conversion circuit. The laser detector is an indium gallium arsenide PIN photodetector diode, which can receive laser signals of 800-1700nm and convert the laser signal into current for external output. The photoelectric conversion circuit mainly uses a transistor and a resistor to form a voltage bias circuit, which amplifies the weak current of the laser detector and converts it into a voltage signal through the resistor, which is then sent to the control module. Using the selected photodetector, the optical signal can be converted into a current signal. Through the bias circuit of the photodetector, the current signal is further converted into a voltage signal that the control module can collect and recognize, wherein the bias circuit refers to... Figure 2 As shown in the diagram, the reverse bias circuit of the photodetector is used. A 5V voltage is applied in reverse to the negative terminal of photodetector D2 through resistor R1. When D2 does not detect a light signal, no photocurrent is generated inside D2, and it can be considered to be in a turned-off state. At this time, transistor Q1 is in a cutoff state, and the output voltage is low. When D2 detects a light signal, a photocurrent Ig is generated inside it, and D2 is reverse-biased. At this time, the 5V voltage generates a current Ir through R1, which, together with the photocurrent Ig inside D2, acts on the base of the transistor, causing transistor Q1 to conduct. Once Q1 conducts, a 5V voltage is applied in the series circuit of R1, the collector and emitter of the transistor, and R6. Through the voltage divider principle, a high-level state can be detected at the output terminal. This bias circuit converts the light signal received by the photodetector into a voltage level signal, which is then provided to the subsequent modules. In this embodiment, the laser detector selected for the photoelectric conversion module has a response time of 0.8ns. Combined with the bias circuit built with transistors and resistors, the conversion of optical signals to electrical signals is achieved in a relatively simple circuit form, with a short overall response time.

[0014] Reference Figure 6As shown, in this embodiment, the pulse width extension module uses a Class D flip-flop to form a monostable multivibrator circuit, which has the advantages of rising edge triggering and fast level switching speed. It is used to convert the trigger signal into a level signal that can be used to drive the switching device. The voltage pulse signal converted from the optical pulse signal has a very short pulse duration period (tens of ns). When the pulse width (i.e., pulse duration period) of the signal is relatively small, the subsequent driving circuit cannot respond to the pulse signal in time, and therefore cannot control the on and off states of the switching device. In this embodiment, in order to solve the problem of the small pulse width of the voltage pulse signal, a pulse width extension module is introduced into the circuit. The function of this module is to extend the duration period of the voltage pulse signal, that is, to extend the pulse width, which is beneficial to the response of the subsequent driving module to the pulse signal. Based on the above analysis, it can be concluded that the pulse width extension function requirement of the AC power supply link fast disconnection device is the same as that of the DC power supply link fast disconnection device. Therefore, the pulse extension module and the DC power supply link fast disconnection module adopt the same technical solution, which will not be elaborated here. The AC switching device uses a high-power IGBT, which has the advantages of fast switching speed and large current carrying capacity, and is used to realize the on and off control of the AC circuit.

[0015] Reference Figure 3-5 As shown, the AC switching device selected in this embodiment is an IGBT transistor. An IGBT transistor is a Darlington structure composite device with a GTR as the main element and a MOSFET as the driving element. It has three external electrodes: G (gate), C (collector), and E (emitter). IGBT transistors have fast switching speeds and large current handling capacity. In this embodiment, the preferred IGBT transistor is model SGTP30U60FD1PU, which has a withstand voltage of 600V, a collector current of up to 30A, a turn-off delay of 46ns, a turn-off fall time of 82ns, and a total turn-off time of 128ns.

[0016] During IGBT operation, the on / off / blocking states of the IGBT can be controlled by adjusting the magnitudes of its collector-emitter voltage UCE and gate-emitter voltage UGE.

[0017] 1) When a zero or negative voltage is applied to the gate-emitter of the IGBT, the IGBT is in the off state.

[0018] 2) When the collector-emitter voltage UCE < 0, the IGBT is in reverse blocking state.

[0019] 3) When the collector-emitter voltage UCE > 0, there are two cases: If the gate-emitter voltage UGE < Uth, the channel cannot be formed, and the IGBT is in a forward blocking state.

[0020] If the gate-emitter voltage UGE > Uth, a gate channel is formed, and the IGBT is in the conducting state (normal operation).

[0021] Where Uth is the gate turn-on voltage.

[0022] IGBTs are primarily used for DC power supply circuit control. To improve the turn-off response speed of the AC circuit, this scheme utilizes two IGBTs connected in reverse series to control the AC circuit's on / off state. Referring to the figure, after applying a 5V voltage to the gate of the IGBT: When the AC current is in the positive half-cycle, L-IN+ is a positive voltage and L-IN- is a negative voltage. At this time, there is a positive voltage of 5V between the gate and emitter of Q6, and Q6 is conducting. There is a negative voltage between the collector and emitter of Q7, which is in a reverse blocking state. Diode D2 is in a forward conducting state. At this time, the AC current flows through L-IN+, Q6, D2, and L-IN+ in sequence, and the power supply circuit is in a conducting state.

[0023] When the AC current is in the negative half-cycle, L-IN- is a positive voltage and L-IN+ is a negative voltage. At this time, there is a positive voltage of 5V between the gate and emitter of Q7, and Q7 is conducting. There is a negative voltage between the collector and emitter of Q6, which is in a reverse blocking state. Diode D1 is in a forward conducting state. At this time, the AC current flows through L-IN-, Q7, D1, and L-IN- in sequence, and the power supply circuit is in a conducting state.

[0024] As can be seen from the above, when a 5V voltage is applied to the gate of the IGBT, the AC circuit becomes conductive.

[0025] After applying 0V to the gate of the IGBT: When the AC current is in the positive half-cycle, L-IN+ is a positive voltage and L-IN- is a negative voltage. At this time, the voltage between the gate and emitter of Q6 is 0V, and Q6 is turned off; the voltage between the gate and emitter of Q7 is 0V, and it is in the off state; D1 is in the reverse blocking state. At this time, the AC power supply circuit is in the off state.

[0026] When the AC current is in the negative half-cycle, L-IN+ is a negative voltage, and L-IN- is a positive and negative voltage, respectively. At this time, the voltage between the gate and emitter of Q7 is 0V, and Q7 is turned off; the voltage between the gate and emitter of Q6 is 0V, and it is in the off state; D2 is in the reverse blocking state. At this time, the AC power supply circuit is in the off state.

[0027] As can be seen from the above, when a 0V voltage is applied to the gate of the IGBT, the AC circuit is in a turned-off state.

[0028] Theoretically, by connecting two IGBTs in reverse series, the on / off state of the AC power supply circuit can be controlled. The collector-emitter voltage is 600V, the collector current is 30A, the drive voltage is 3.5–6.5V, the turn-off delay time is 46ns, and the turn-off fall time is 82ns. IGBTs offer advantages such as fast switching speed, high input impedance, and low conduction loss, and their drive circuits are mature. In this embodiment, the drive module is used to control the on / off state of the AC switching device. The drive module mainly uses a push-pull drive circuit composed of transistors, resistors, and capacitors. This type of circuit has strong current driving capability and can achieve rapid driving of the IGBT. The IGBT needs a gate voltage greater than its emitter voltage to turn on. Typically, the turn-on voltage of an IGBT is 3.5-6.5V. Therefore, a voltage of 5V is generally applied to the gate.

[0029] Based on the above two points, design the IGBT drive module circuit, as shown in the figure: When no voltage signal is input to transistor Q2, the transistor is off. At this time, a 5V voltage is applied to the bases of Q1 and Q4 in the push-pull circuit through resistors R1 and R2, turning Q1 on and Q4 off. The 5V voltage is then applied to the gate of the IGBT through Q1 and R7, putting the IGBT on. When a pulse voltage signal (5V amplitude) is input to the base of transistor Q2, Q2 turns on. At this time, a 0V voltage is applied to the bases of Q1 and Q4 in the push-pull circuit through Q2 and R2, turning Q1 off and Q4 on. The 0V voltage is then applied to the gate of the IGBT through Q4 and R7, putting the IGBT off. This drive circuit is a push-pull circuit, which has the advantage of improving current supply capability and quickly completing the charging process of the gate input capacitor, allowing the switching transistor to turn on quickly and avoiding high-frequency oscillations on the rising edge. The operating voltage is DC 5V, and the response time is <10ns.

[0030] When the AC power supply link fast disconnection device receives a light pulse trigger signal, it converts the light pulse signal into a voltage pulse signal through a photoelectric conversion module. The voltage pulse signal then passes through a pulse width extension module to extend its pulse width before being provided to the AC switching device drive module. The drive module then controls the switching state of the AC switching device based on the received voltage signal, thereby achieving on / off control of the power supply link.

[0031] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0032] The terminology used in the embodiments of this application is for the purpose of describing specific embodiments only and is not intended to limit the invention. The singular forms "a," "the," and "the" used in the embodiments of this application are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that in the description of this application, unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship; for example, A / B can mean A or B. "And / or" in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone, where A and B can be singular or plural.

[0033] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrase “if determination” or “if detection (of the condition or event of the statement)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the condition or event of the statement)” or “in response to detection (of the condition or event of the statement).”

[0034] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A protective device for small and medium power AC power supply lines for rapid disconnection, characterized in that, include: A laser detector for converting optical signals into electrical signals, a monostable multivibrator circuit coupled to the laser detector, an IGBT coupled to the monostable multivibrator circuit for controlling the switching on and off of the AC circuit, and a drive circuit coupled to the IGBT for driving the IGBT.

2. The protection device for small and medium power AC power supply lines for rapid disconnection according to claim 1, characterized in that, There are two IGBT transistors, which are connected in reverse series.

3. A protection device for small and medium power AC power supply lines for rapid disconnection according to claim 2, characterized in that, The IGBT is an IGBT of model SGTP30U60FD1PU.

4. A protection device for small and medium power AC power supply lines for rapid disconnection according to claim 1, characterized in that, The laser detector is a photodetector diode.

5. A protection device for small and medium power AC power supply lines for rapid disconnection according to claim 4, characterized in that, The photodetector diode is an indium gallium arsenide PIN photodetector diode.

6. A protection device for small and medium power AC power supply lines for rapid disconnection according to claim 1, characterized in that, The drive circuit includes a push-pull drive circuit consisting of a transistor and resistors and capacitors coupled to the transistor.

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