Feedback type strong electromagnetic pulse power supply protection circuit and method

Abstract

This invention relates to a feedback-type high-power electromagnetic pulse (HMP) power supply protection circuit and method, belonging to the field of electromagnetic compatibility (EMC) technology. The circuit includes a feedback sampling unit, a delay unit, and a graded protection unit. The feedback sampling unit samples and compares the pulse voltage amplitude and pulse duration; the delay isolation unit isolates fast pulse signals, maintaining the integrity of the pulse in the sampling circuit and protecting the protection circuit and downstream equipment when the pulse is too long; the graded protection unit provides separate protection for fast-edge narrow pulses and long-duration pulses. The feedback sampling unit includes a voltage amplitude sampling circuit and a pulse duration sampling circuit. The graded protection unit includes a first-stage fast-response branch and a second-stage discharge branch. This invention is applied to high-power electromagnetic pulse protection for DC and AC power ports. From the perspective of graded protection, different protection schemes are selected according to the pulse characteristics to maximize the safety of the power supply system and downstream equipment.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic compatibility technology, and in particular to a power port strong electromagnetic pulse protection circuit. Specifically, it is a feedback protection circuit that samples the energy of a strong electromagnetic pulse at the power port, connects it to different levels of protection absorption circuits according to the energy level to discharge different types of electromagnetic pulse energy, and quickly restores the insulation state after the pulse energy is absorbed. Background Technology

[0002] Strong electromagnetic pulses, including fast-edge narrow pulses and long-duration pulses, can cause damage to downstream equipment due to overvoltage or overcurrent when injected into the power supply port. A protection circuit is added to the power supply port to absorb and clamp the pulse energy, protecting downstream equipment. This protection circuit consists of a series-parallel structure of a varistor, a gas discharge tube, and a transient voltage suppressor. When the injected pulse is a fast-edge narrow pulse, the protection circuit needs to respond quickly to activate the protection function; however, its energy absorption is limited. The large energy of a long-duration pulse can damage the protection circuit and cause a power supply system failure. When the injected pulse is a long-duration pulse, the protection circuit needs to have a large energy discharge capability; however, its response time is limited. Under fast-edge narrow pulse conditions, the protection circuit may not respond, damaging downstream equipment. Therefore, without knowing the waveform characteristics of the injected pulse, a feedback-free protection circuit cannot effectively meet the protection requirements of different pulses. Summary of the Invention

[0003] Technical problems to be solved

[0004] To avoid the shortcomings of the prior art, the present invention provides a feedback-type strong electromagnetic pulse power supply protection circuit.

[0005] Technical solution

[0006] A feedback-type high electromagnetic pulse power supply protection circuit is characterized by comprising a feedback sampling unit, a delay isolation unit, and a graded protection unit; the feedback sampling unit is connected to the positive and negative terminals of the power supply to sample and compare the pulse voltage amplitude and pulse duration; the delay isolation unit is connected between the feedback sampling unit and the graded protection unit to isolate fast pulse signals, maintain the integrity of the pulse in the sampling circuit, and protect the protection circuit and downstream equipment when the pulse is too long; the graded protection unit is connected to the positive and negative terminals of the power supply to protect against fast-edge narrow pulses and long-duration continuous pulses respectively.

[0007] A further technical solution of the present invention: The feedback sampling unit includes a voltage amplitude sampling circuit and a pulse duration sampling circuit; the voltage amplitude sampling circuit includes resistors R1 and R2, one end of resistor R1 is connected to the positive terminal of the power supply, the other end is connected to one end of resistor R2, the other end of resistor R2 is connected to the negative terminal of the power supply, and the connection point of R1 and R2 is connected to the comparator circuit via a matching resistor R3; the pulse duration sampling circuit includes resistor R4 and capacitor C1, one end of resistor R4 is connected to the positive terminal of the power supply, the other end is connected to one end of capacitor C1, the other end of capacitor C1 is connected to the negative terminal of the power supply, and the connection point of R4 and C1 is connected to the comparator circuit via a matching resistor R5; the comparator circuit includes comparator A, comparator B and comparator C, the negative input terminal of comparator A is connected to resistor R5, and the output terminal is connected to the delay isolation unit to control MOSFET switch Q1, the positive input terminal of comparator B is connected to resistor R3, and the output terminal is connected to the gate of the first-stage control MOSFET switch Q2 of the graded protection unit, and the negative input terminal of comparator C is connected to resistor R5, and the output terminal is connected to the gate of the second-stage control MOSFET switch Q3 of the graded protection unit.

[0008] A further technical solution of the present invention: the time delay isolation unit is implemented by a semiconductor switch and a common mode inductor. The semiconductor switch is connected in series in the power supply circuit. The input terminal of the common mode inductor is connected to the semiconductor switch and one pole of the power supply, respectively, and the output terminal is connected to the input pole of the graded protection unit.

[0009] A further technical solution of the present invention: The graded protection unit includes a first-level protection branch and a second-level protection branch. The first-level protection branch is composed of a MOSFET switch Q2, a transient voltage suppressor D1 and a current-limiting resistor R6 connected in series. The second-level protection branch is composed of a MOSFET switch Q3 and a varistor VDR1 connected in series. The two branches are connected in parallel with a fuse F1 and then connected in parallel across the two ends of the power supply circuit.

[0010] A feedback-type strong electromagnetic pulse power supply protection method, characterized in that:

[0011] When a fast-edge narrow pulse is injected, the feedback sampling unit samples the voltage amplitude and pulse duration. The voltage sampling circuit activates the first-level protection branch to provide first-level fast-response protection against the injected pulse, limit the voltage amplitude of the injected pulse, and provide voltage clamping protection for downstream equipment.

[0012] When a long-duration pulse is injected, the feedback sampling unit samples the voltage amplitude and pulse duration. The voltage sampling circuit activates the first-level protection branch, which first provides fast-response protection against the injected pulse and limits its voltage amplitude. After the pulse lasts for a certain period of time, the pulse duration sampling circuit activates the second-level protection branch to discharge the energy of the injected pulse. The first-level protection branch is then shut down after the two sampling circuits are compared, thus protecting the first-level protection branch and preventing short-circuit faults in the power supply system. When the pulse duration exceeds the discharge limit of the protection circuit, the time-delay isolation unit is shut down by the comparison value of the two sampling circuits, disconnecting the multi-level protection branch from the downstream equipment. The connection is restored after the pulse has passed.

[0013] Beneficial effects

[0014] The present invention provides a feedback-type high electromagnetic pulse power supply protection circuit, which has the following advantages:

[0015] 1. The voltage and duration of strong electromagnetic pulses are sampled and fed back to the graded protection unit. Graded protection methods are adopted for different types of electromagnetic pulses. Comprehensive protection can be provided for fast-edge narrow pulses and long-duration continuous pulses, and damage to the protection circuit and downstream equipment can be prevented, thus maximizing the safety of the power supply system and downstream equipment.

[0016] 2. The feedback sampling unit includes strong electromagnetic pulse voltage sampling and duration sampling, which fully reflects the response requirements and energy level of the strong electromagnetic pulse, providing a complete basis for graded protection for the protection unit.

[0017] 3. The graded protection unit adopts two-level protection branches. The first level can respond quickly and is mainly used to discharge high overvoltages and short-time fast-edge narrow pulses. The second level protection branch can discharge large currents and is mainly used to discharge long-time, low-overvoltage long-time continuous pulses.

[0018] 4. The time-delay isolation unit can isolate excessively long extreme pulses, disconnect the protection circuit from the downstream load equipment, and reconnect the protection circuit and downstream equipment after the extreme pulse is absorbed by the feedback sampling circuit, thus preventing short circuit faults in the power supply circuit and load damage faults. Attached Figure Description

[0019] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0020] Figure 1 Schematic diagram of a feedback-type high electromagnetic pulse power supply protection circuit;

[0021] Figure 2 Circuit diagram for feedback-type strong electromagnetic pulse power supply protection. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0023] This invention monitors the voltage amplitude and duration parameters of strong electromagnetic pulses and employs a feedback-type multi-level protection method. The first level provides fast-response protection for short-duration fast-edge narrow pulses, while the second level provides discharge protection for long-duration continuous pulses. When the pulse is too long, the protection circuit and protection equipment are disconnected and reconnected after the strong pulse has completely passed, thus maintaining the voltage of the downstream load equipment within a safe range.

[0024] A feedback-type high-voltage electromagnetic pulse (HEP) power supply protection circuit is applied to the protection of DC and AC power supply ports from high-voltage electromagnetic pulses. From a graded protection perspective, different protection schemes are selected based on the pulse characteristics to maximize the safety of the power supply system and downstream equipment. The circuit composition includes a feedback sampling unit, a delay unit, and a graded protection unit. The feedback sampling unit samples and compares the pulse voltage amplitude and pulse duration; the delay isolation unit isolates fast pulse signals, maintaining the integrity of the pulse in the sampling circuit and protecting the protection circuit and downstream equipment when the pulse is too long; the graded protection unit provides separate protection for fast-edge narrow pulses and long-duration continuous pulses. The feedback sampling unit includes a voltage amplitude sampling circuit and a pulse duration sampling circuit. The graded protection unit includes a first-stage fast-response branch and a second-stage discharge branch.

[0025] The feedback sampling unit is connected to both the positive and negative terminals of the power supply; the delay unit is connected between the feedback sampling unit and the graded protection unit; there are two sets of graded protection units, connected to the positive and negative terminals of the power supply respectively. The voltage sampling circuit includes a high-voltage arm resistor, a low-voltage arm resistor, and a matching resistor; the pulse duration sampling circuit includes a charging resistor, a charging capacitor, and a matching resistor. The above sampling signal outputs need to pass through a comparator to control the opening and closing of the protection loop and protection branch.

[0026] The time-delay isolation circuit is implemented using a semiconductor switch and a common-mode inductor. The semiconductor switch is connected in series in the power supply circuit, and the input terminal of the common-mode inductor is connected to the switch and one pole of the power supply, respectively. The output terminal is connected to the input pole of the graded protection unit.

[0027] The first-level protection branch adopts a fast-response, low-energy discharge method, which includes a normally open switch, a transient voltage suppressor, a current-limiting resistor, and a resettable fuse connected in series. The second-level protection branch adopts a slow-response, high-energy discharge method, which includes a normally open switch, a varistor, and a resettable fuse connected in series.

[0028] When a fast-edge narrow pulse is injected, the feedback sampling unit samples the voltage amplitude and pulse duration. The voltage sampling circuit activates the first-level protection branch to provide first-level fast-response protection against the injected pulse, limit the voltage amplitude of the injected pulse, and provide voltage clamping protection for downstream equipment.

[0029] When a long-duration pulse is injected, the feedback sampling unit samples the voltage amplitude and pulse duration. The voltage sampling circuit activates the first-level protection branch, providing fast-response protection against the injected pulse and limiting its voltage amplitude. After the pulse has lasted for a certain period, the pulse duration sampling circuit activates the second-level protection branch to discharge the energy of the injected pulse. The first-level protection branch is then shut down after comparison by the two sampling circuits, thus protecting it and preventing short-circuit faults in the power supply system. When the pulse duration exceeds the discharge limit of the protection circuit, the time-delay isolation unit is shut down by the comparison value of the two sampling circuits, disconnecting the multi-level protection branch from downstream equipment. Connection is restored only after the pulse has passed.

[0030] like Figure 1 As shown, this invention is installed between the AC / DC power interface and the load device to prevent damage to the protected equipment from different types of strong electromagnetic pulses. This invention includes a feedback sampling unit, a time-delay isolation unit, and a graded protection unit. The feedback sampling unit monitors the amplitude and duration of the electromagnetic pulse voltage; the time-delay isolation unit is used to delay and isolate the pulse to ensure the reliable operation of the subsequent graded protection unit; the graded protection unit includes two levels of protection branches, which protect the protective components by switching between the protection branches.

[0031] The specific work process is described as follows:

[0032] When a strong electromagnetic pulse enters the power supply line, the feedback sampling unit samples the voltage amplitude and duration of the pulse. The voltage amplitude sampling signal controls the first-stage fast-response protection branch to be turned on for voltage clamping; the duration sampling signal controls the second-stage energy absorption protection branch to be turned on for energy discharge and disconnects the first-stage protection branch for protection. When the pulse duration is too long, the time-delay isolation circuit disconnects the protection branch from the load circuit for protection. After the energy discharge is completed, the load circuit is turned on.

[0033] like Figure 2As shown, the feedback sampling unit includes a resistor sampling circuit and a capacitor sampling circuit. The resistor sampling circuit acquires the pulse voltage amplitude, and the capacitor sampling circuit acquires the pulse duration. Resistors R1 and R2 form the resistor sampling circuit; one end of resistor R1 is connected to the positive terminal of the power supply, and the other end is connected to one end of resistor R2. The other end of resistor R2 is connected to the negative terminal of the power supply. The connection point of R1 and R2 is connected to the comparator circuit via a matching resistor R3. Resistor R4 and capacitor C1 form the capacitor sampling circuit; one end of resistor R4 is connected to the positive terminal of the power supply, and the other end is connected to one end of capacitor C1. The other end of capacitor C1 is connected to the negative terminal of the power supply. The connection point of R4 and C1 is connected to the comparator circuit via a matching resistor R5. The comparator circuit includes comparators A, B, and C. The positive input of comparator A is connected to its output, and the negative input is connected to resistor R5. Its output is connected to the gate of the delay isolation unit controlling MOSFET switch Q1. The positive input of comparator B is connected to resistor R3, and the negative input is connected to resistor R5. Its output is connected to the gate of the first stage of the hierarchical protection unit controlling MOSFET switch Q2. The positive input of comparator C is connected to its output, and the negative input is connected to resistor R5. Its output is connected to the gate of the second stage of the hierarchical protection unit controlling MOSFET switch Q3. The delay isolation circuit includes MOSFET switch Q1 and a common-film inductor LC. MOSFET switch Q1 is connected in series at the positive terminal of the power supply input branch. The drain of MOSFET switch Q1 is connected to the positive input side of the power supply, and the source is connected to the positive output side of the power supply. The common-film inductor LC is connected in series in both branches of the power supply circuit. The graded protection unit consists of a first-level protection branch and a second-level protection branch. The first-level protection branch consists of a MOSFET switch Q2, a transient voltage suppressor D1, and a current-limiting resistor R6 connected in series. The drain of the MOSFET switch Q2 is connected to the positive output side of the power supply, and the source is connected to the negative terminal of the transient voltage suppressor D1. The positive terminal of D1 is connected to one end of the current-limiting resistor R6, and the other end of the current-limiting resistor R6 is connected to the fuse F1. The second-level protection branch consists of a MOSFET switch Q3 and a varistor VDR1 connected in series. The drain of the MOSFET switch Q3 is connected to the positive output side of the power supply, and the source is connected to one end of the varistor VDR1. The other end of the varistor VDR1 is connected to the fuse F1. The two branches are connected in parallel with the fuse F1 and then connected in parallel across the power supply circuit.

[0034] During normal power supply, the loop voltage generates a steady-state voltage across the resistor sampling circuit and the capacitor sampling circuit. Comparator A outputs a high level, comparator B outputs a low level, and comparator C outputs a low level. In this state, MOSFET switch Q1 is turned on, MOSFET switch Q2 is turned off, and MOSFET switch Q3 is turned off. The power supply loop connected to MOSFET switch Q1 and common-mode inductor LC operates normally, and the common-mode inductor LC acts as a filter.

[0035] When fast pulses and short-duration slow pulses are injected into the power supply circuit, the voltage on the low-voltage arm of the resistor divider rises. Due to the delay effect of the common-mode inductor LC, the voltage at the terminal of the graded protection unit remains stable. After the low-voltage arm voltage reaches a certain value, comparator B outputs a high level, while the output levels of other comparators remain unchanged. In this state, MOSFET switch Q2 is turned on, and the pulse voltage is discharged through the first-stage protection branch MOSFET Q2, transient voltage suppressor D1, current-limiting resistor R6, and resettable fuse F1. After the pulse energy is discharged, the low-voltage arm voltage of the resistor divider drops to its steady-state value, comparator B outputs a low level, and MOSFET Q2 is turned off, thus disconnecting the first-stage protection branch. In this mode, by clamping and absorbing fast pulses and short-duration slow pulses, the downstream load equipment is protected.

[0036] When a long-duration slow pulse is injected into the power supply circuit, the first-stage protection branch operates in the same manner as a short pulse, i.e., it is in the on state. As the pulse duration increases, the charging voltage on capacitor C1 gradually rises. When it rises to a certain value, comparator C outputs a high level, and comparator B outputs a low level. At this point, the delay unit no longer serves its pulse delay function, and MOSFET Q3 in the second-stage protection branch closes. The pulse energy is discharged through the branch of MOSFET Q3, varistor VDR1, and resettable fuse F1. MOSFET Q2 is then disconnected, turning off the first-stage protection branch. After the pulse energy is discharged, the voltage on capacitor C1 decreases, comparator C outputs a low level, and MOSFET Q3 turns off, thus disconnecting the second-stage protection branch. In this mode, by absorbing the energy of long-duration pulses, the downstream load equipment is protected.

[0037] When the pulse duration is too long, comparator A outputs a low level, MOSFET Q1 turns off, thus disconnecting the graded protection unit. Energy is then absorbed by the feedback sampling unit. After the pulse disappears, comparator A outputs a high level, and MOSFET Q1 closes to connect the load device. In this mode, by isolating pulses with excessive duration, the graded protection unit and the downstream load device are protected.

[0038] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A feedback type high power electromagnetic pulse power supply protection circuit, characterized in that The circuit comprises a feedback sampling unit, a delay isolation unit and a hierarchical protection unit. The feedback sampling unit is connected between the positive and negative terminals of a power supply, samples and compares the pulse voltage amplitude and pulse duration. The delay isolation unit is connected between the feedback sampling unit and the hierarchical protection unit, isolates the fast pulse signal, maintains the integrity of the pulse in the sampling circuit, and protects the protection circuit and the subsequent equipment when the pulse is too long. The hierarchical protection unit is connected between the positive and negative terminals of the power supply, protects the fast edge narrow pulse and the long duration pulse respectively. The feedback sampling unit comprises a voltage amplitude sampling circuit and a pulse duration sampling circuit. The voltage amplitude sampling circuit comprises resistors R1 and R2. One end of the resistor R1 is connected to the positive terminal of the power supply, the other end is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the negative terminal of the power supply, and the connection point of R1 and R2 is connected to a comparison circuit through a matching resistor R3. The pulse duration sampling circuit comprises a resistor R4 and a capacitor C1. One end of the resistor R4 is connected to the positive terminal of the power supply, the other end is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to the negative terminal of the power supply, and the connection point of R4 and C1 is connected to the comparison circuit through a matching resistor R5. The comparison circuit comprises comparators A, B and C. The negative input end of the comparator A is connected to the resistor R5, and the output end is connected to the delay isolation unit to control the MOSFET switch Q1. The positive input end of the comparator B is connected to the resistor R3, and the output end is connected to the gate of the first-stage control MOSFET switch Q2 of the hierarchical protection unit. The negative input end of the comparator C is connected to the resistor R5, and the output end is connected to the gate of the second-stage control MOSFET switch Q3 of the hierarchical protection unit.

2. The feedback type strong electromagnetic pulse power supply protection circuit according to claim 1, characterized in that: The delay isolation unit is realized by a semiconductor switch and a common-mode inductor. The semiconductor switch is connected in series in the power supply circuit, and the input end of the common-mode inductor is connected to the semiconductor switch and the positive terminal of the power supply respectively, and the output end is connected to the input terminal of the hierarchical protection unit.

3. A feedback type strong electromagnetic pulse power supply protection circuit according to claim 2, characterized in that: The hierarchical protection unit comprises a first-stage protection branch and a second-stage protection branch. The first-stage protection branch is composed of a MOSFET switch Q2, a transient voltage suppressor D1 and a current-limiting resistor R6 connected in series. The second-stage protection branch is composed of a MOSFET switch Q3 and a pressure-sensitive resistor VDR1 connected in series. The two branches are connected in parallel and connected to the power supply circuit through a fuse F1.

4. A feedback-type strong electromagnetic pulse power protection method based on the circuit of claim 3, characterized in that: when a fast edge narrow pulse is injected, the feedback sampling unit samples the voltage amplitude and pulse duration, the first-stage protection branch is started by the voltage sampling circuit, the first-stage fast response protection is performed on the injected pulse, the voltage amplitude of the injected pulse is limited, and the voltage clamping protection is performed on the subsequent equipment. When the long time duration pulse is injected, the feedback sampling unit samples the voltage amplitude and the pulse duration, the first level protection branch is started by the voltage sampling circuit, the injected pulse is first protected by fast response, and the voltage amplitude of the injected pulse is limited; after the pulse lasts for a certain time, the second level protection branch is started by the pulse duration sampling circuit, the energy of the injected pulse is discharged, and after comparison by the two sampling circuits, the first level protection branch is turned off to protect the first level protection branch and avoid short circuit failure of the power supply system; when the pulse duration exceeds the discharge limit of the protection circuit, the delay isolation unit is turned off by the comparison value of the two sampling circuits, and the multi-level protection branch is disconnected from the subsequent equipment, and then connected after the pulse is over.

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