CN112332395B - Discharge circuit, surge protection circuit, ignition circuit, and electronic device - Google Patents
Discharge circuit, surge protection circuit, ignition circuit, and electronic device Download PDFInfo
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- CN112332395B CN112332395B CN202011140519.1A CN202011140519A CN112332395B CN 112332395 B CN112332395 B CN 112332395B CN 202011140519 A CN202011140519 A CN 202011140519A CN 112332395 B CN112332395 B CN 112332395B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
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Abstract
The embodiment of the invention discloses a discharge circuit, a surge protection circuit, an ignition circuit and electronic equipment. The discharge circuit comprises at least two switching devices and at least two impedance branches, wherein two ends of the at least two switching devices which are connected in series are respectively and electrically connected with a first end and a second end of the discharge circuit; the impedance branches are in one-to-one correspondence with the switching devices and are connected in parallel with the corresponding switching devices; wherein, for the same high frequency, the high frequency impedance modes of the impedance branch are unequal, and the high frequency is greater than the power frequency. The technical scheme provided by the embodiment of the invention can reduce the impact breakdown voltage of the whole circuit, reduce the protection blind area and even remove the blind area.
Description
Technical Field
The invention relates to the technical field of discharge circuits, in particular to a discharge circuit, a surge protection circuit, an ignition circuit and electronic equipment.
Background
The protection of electromagnetic pulse (EMP) and Lightning electromagnetic pulse (LEMP) mainly utilizes the high-voltage characteristic of EMP and LEMP to protect pertinently at present, and a Gas Discharge Tube (GDT) is designed aiming at high voltage or overvoltage characteristic, utilizes penning effect to fill Gas with certain air pressure in a packaging space, and coats a cathode material on a metal electrode, so that the device presents certain direct current withstand voltage characteristic and pulse breakdown voltage characteristic. Glass gas discharge tubes and ceramic gas discharge tubes are currently available.
Taking a GDT with a dc breakdown voltage of 3000V as an example, the impact breakdown voltage of the GDT is about 3600V, the environment in which the GDT is used is mostly in an environment with a withstand voltage of 1500VAC, the peak voltage of the ac environment is 2121VDC, even if the environment design improves the withstand voltage by 20%, the withstand voltage of the equipment is 1500 × 1.2 × 1.414=2545vdc, from the data point of view, EMP or LEMP between 2545V and 3600V cannot be protected, which is a dead zone of 3000VGDT, and at present, no good solution is provided in practical application; in practical application and test, the probability that equipment is damaged by EMP and LEMP is very high, GDT of other voltage classes has the same problem, and the impact breakdown voltage is too high, so that a protection blind area exists.
Disclosure of Invention
The embodiment of the invention provides a discharge circuit, a surge protection circuit, an ignition circuit and electronic equipment.
In a first aspect, an embodiment of the present invention provides a discharge circuit, including:
the two ends of the at least two switching-type devices after being connected in series are respectively and electrically connected with the first end and the second end of the discharge circuit;
the impedance branches are in one-to-one correspondence with the switching devices and are connected in parallel with the corresponding switching devices;
for the same high frequency, the high frequency impedance modes of the impedance branches are unequal, and the high frequency is larger than the power frequency.
Further, sorting is performed according to the sizes of the high-frequency impedance modes of the impedance branches, and in two impedance branches adjacent to the serial number, the direct-current breakdown voltage of the switching device corresponding to the impedance branch with the large high-frequency impedance mode is less than or equal to the direct-current breakdown voltage of the switching device corresponding to the impedance branch with the small high-frequency impedance mode.
Further, when the voltage between the first end and the second end of the discharge circuit generates high-frequency surge impact interference, the switching device is turned on earlier as the high-frequency impedance mode of the impedance branch corresponding to the switching device is larger.
Further, the power frequency impedance modes of all the impedance branches are equal; the dc breakdown voltages of all switching devices are equal.
Further, sorting is carried out according to the size of the high-frequency impedance mode of the impedance branches, and in two impedance branches with adjacent serial numbers, | Z H1 |>5|Z H2 L, wherein l Z H1 I is the high-frequency impedance mode of the impedance branch with large high-frequency impedance mode, | Z H2 L is the high-frequency impedance mode of the impedance branch with small high-frequency impedance mode; v BRX ：V BRY ＝|Z L1 |：|Z L2 L, wherein V BRX DC breakdown voltage, V, of switching devices corresponding to impedance branches of large impedance mode of high frequency BRY The DC breakdown voltage of the switching device corresponding to the impedance branch with small high-frequency impedance mode, | Z L1 I is the power frequency impedance mode of the impedance branch with large high frequency impedance mode, Z L2 And | is the power frequency impedance mode of the impedance branch with the small high-frequency impedance mode.
Furthermore, except the impedance branch with the minimum high-frequency impedance mode, any impedance branch in the other impedance branches comprises a first sub-branch and a first capacitive element which are connected in series, and two ends after being connected in series are respectively and electrically connected with two ends of the corresponding switching device; the first sub-branch comprises at least one of a first resistive element and a first inductive element; the power frequency impedance mode of the first capacitive element is 5 times larger than that of the first sub-branch; the high-frequency impedance mode of the first sub-branch is 5 times larger than that of the first capacitive element;
the impedance branch circuit with the minimum high-frequency impedance mode comprises a second capacitive element, wherein two ends of the second capacitive element are respectively and electrically connected with two ends of the corresponding switch-type devices; the capacitance value of the first capacitive element is equal to the capacitance value of the second capacitive element.
Furthermore, the impedance branch with the minimum high-frequency impedance mode further comprises a second sub-branch, the second sub-branch is connected with the second capacitive element in series, and two ends of the second sub-branch after being connected in series are respectively and electrically connected with two ends of the corresponding switch-type devices;
the second sub-branch comprises at least one of a second resistive element and a second inductive element, and a high frequency impedance mode of the first sub-branch is larger than a high frequency impedance mode of the second sub-branch.
Further, the first sub-branch comprises a first resistive element, the second sub-branch comprises a second resistive element,
sequencing according to the sizes of the high-frequency impedance modes of the impedance branches, wherein in the two impedance branches with adjacent sequence numbers, the resistance value of the resistor in the impedance branch with the large high-frequency impedance mode is 5 times larger than that of the resistor in the impedance branch with the small high-frequency impedance mode;
Further, the first sub-branch comprises a first inductive element, the second sub-branch comprises a second inductive element,
sequencing according to the sizes of the high-frequency impedance modes of the impedance branches, wherein in the two impedance branches adjacent to the sequence number, the inductance value of the inductor in the impedance branch with the large high-frequency impedance mode is 5 times larger than the inductance value of the inductor in the impedance branch with the small high-frequency impedance mode;
Further, the switching device comprises: gas discharge tubes, semiconductor discharge tubes, air gaps, graphite gaps, or spark gaps.
Further, the number of the switching devices is three, and the high-frequency impedance mode of the impedance branch corresponding to the switching devices which are sequentially connected in series in the middle is the smallest.
Further, the switching device comprises a gas discharge tube,
the discharge circuit further comprises K second gas discharge tubes and K third capacitors, wherein K is an integer greater than or equal to 2, and the K second gas discharge tubes are connected in series to form a first series branch;
k second gas discharge tubes are connected in series to form K +1 first nodes, the other K first nodes except the first node connected with the first end of the first series branch are in one-to-one correspondence with K third capacitors, and any first node is electrically connected with the first end of the first series branch through the corresponding third capacitor;
two ends of the at least two switching devices which are connected with the first series branch in series are respectively and electrically connected with the first end and the second end of the discharge circuit;
the DC breakdown voltage of the second gas discharge tube is smaller than that of the switching device.
Furthermore, the high frequency is larger than or equal to 25000Hz, and the power frequency is smaller than or equal to 68Hz.
In a second aspect, an embodiment of the present invention further provides a surge protection circuit, including the discharge circuit provided in any embodiment of the present invention.
In a third aspect, the embodiment of the present invention further provides an ignition circuit, including the discharge circuit provided in any embodiment of the present invention.
In a fourth aspect, an embodiment of the present invention further provides an electronic device, including the discharge circuit provided in any embodiment of the present invention.
The discharge circuit in the technical scheme of the embodiment of the invention comprises at least two switching devices and at least two impedance branches, wherein two ends of the at least two switching devices after being connected in series are respectively and electrically connected with a first end and a second end of the discharge circuit; the impedance branches are in one-to-one correspondence with the switching devices and are connected in parallel with the corresponding switching devices; for the same high frequency, the high frequency impedance modes of the impedance branch circuits are unequal, the high frequency is larger than the power frequency, so that when surge impact such as lightning strike occurs, all the switch-type devices do not reach respective impact breakdown voltage at the same time, the voltage between the switch-type devices which are firstly broken down is rapidly reduced, the surge voltage is almost completely applied to the rest switch-type devices which are not broken down, breakdown occurs when the voltage of the rest switch-type devices which are not broken down gradually reaches the direct-current breakdown voltage of the rest switch-type devices along with the rise of the voltage of the rest switch-type devices which are not broken down, and the actual impact breakdown voltage V of the discharge circuit is larger than the power frequency BR0 Of breakdown voltages less than the sum of all switching devices, i.e. V BR0 ＇<V BR1 ＇+V BR2 ＇+…+V BRn ' solves the problem that when surge impact such as lightning strike occurs, the surge impact voltage is increased to the direct current breakdown voltage which is equal to V BR1 +V BR2 +…+V BRn Of a single switching device (equal to V) BR1 ＇+V BR2 ＇+…+V BRn ' would be breakdown switched on, resulting in too high a shoot through voltage, a problem with dead zones of protection.
Drawings
Fig. 1 is a schematic structural diagram of a discharge circuit according to an embodiment of the present invention;
fig. 2 is an application scenario of a discharge circuit according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention;
FIG. 10 is a schematic diagram of a discharge circuit according to another embodiment of the present invention;
FIG. 11 is a schematic diagram of a discharge circuit according to another embodiment of the present invention;
FIG. 12 is a schematic diagram of a discharge circuit according to another embodiment of the present invention;
fig. 13 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention;
fig. 14 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention;
FIG. 15 is a schematic diagram of a discharge circuit according to another embodiment of the present invention
FIG. 16 is a schematic diagram of a discharge circuit according to another embodiment of the present invention;
fig. 17 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
The embodiment of the invention provides a discharge circuit. Fig. 1 is a schematic structural diagram of a discharge circuit according to an embodiment of the present invention. Fig. 2 is an application scenario of a discharge circuit according to an embodiment of the present invention. The discharge circuit includes: at least two switching devices 10 and at least two impedance branches 20.
Wherein, two ends of the at least two switching devices 10 after being connected in series are respectively electrically connected with a first end V1 and a second end V2 of the discharge circuit; the impedance branches 20 correspond to the switching devices 10 one by one, and the impedance branches 20 are connected in parallel with the corresponding switching devices 10; wherein, for the same high frequency, the high frequency impedance modes of the impedance branch 20 are not equal, and the high frequency is greater than the power frequency.
Fig. 1 exemplarily shows a case where two switching devices 10 are a first switching device 10-1 and a second switching device 10-2, respectively, and two impedance branches 20 are a first impedance branch 20-1 and a second impedance branch 20-2, respectively, the first switching device 10-1 corresponds to the first impedance branch 20-1, and the second switching device 10-2 corresponds to the second impedance branch 20-2. Wherein, any impedance branch 20 may comprise at least one of the following components: the resistive element, the inductive element, and the capacitive element may be connected in series and/or in parallel, which is not limited in this embodiment of the present invention. The resistive element may include a resistor. The inductive element may comprise an inductance. The inductor can be a magnetic bead inductor, and compared with a common inductor, the inductor is small in size and low in cost. The capacitive element may comprise at least one of: capacitance and elements with inter-pole capacitance. The element with inter-pole capacitance may comprise a varistor or a transient suppression diode. The impedance mode of the impedance branch 20 in which the high frequency impedance mode is the largest may increase with increasing frequency. The impedance mode of the impedance branch 20 with the smallest high frequency impedance mode may decrease with increasing frequency. At least one of the impedance branches 20 comprises a capacitive element to avoid a drop in insulation caused by the use of only inductance and resistance. Fig. 2 exemplarily shows a case where the discharge circuit is applied to a surge protection circuit. The first end V1 of the discharge circuit 1 may be electrically connected to a first ac supply line, which may illustratively be live L, and the second end V2 of the discharge circuit 1 may be electrically connected to a second ac supply line, which may illustratively be neutral N. The discharge circuit 1 can be turned on when overvoltage such as surge interference occurs on the first alternating current supply line and the second alternating current supply line to discharge surge current, so that overvoltage protection of the circuit 2 to be protected is realized. Optionally, the switching device comprises: gas discharge tubes, semiconductor discharge tubes, air gaps, graphite gaps, or spark gaps. Optionally, high frequency f H Greater than or equal to 25000Hz. The magnitude of the high frequency can be equal to the frequency of surge impact such as lightning stroke. Optionally, power frequency f L Is less than or equal to 68Hz. The power frequency can be the frequency of the power supply voltage when the power supply works normally. Optionally, power frequency f L May be 50Hz, 60Hz or 0Hz. In normal operation, the supply voltage may be ac or dc.
Wherein, | Z 11 |：|Z 12 |：…：|Z 1n |≠V BR1 ：V BR2 ：…：V BRn ，|Z 1i I is the high frequency impedance mode, V, of the i-th impedance branch 20 BRi The direct current breakdown voltage of the ith switching device 10 is represented, n is the number of the impedance branches 20, n is an integer greater than or equal to 2, i is equal to 1, 2 \8230n, and n is set so that when high-frequency surge impact interference occurs to the voltage between the first end V1 and the second end V2 of the discharge circuit, all the switching devices 10 do not reach respective impact breakdown voltages at the same time.
The dc breakdown voltage may be an average voltage value at which breakdown of the switching device starts at a voltage with a rising steepness below 100V/s. The surge breakdown voltage (or pulse voltage) may be the voltage at which the switching device starts to breakdown under the action of a transient voltage pulse with a specified rise steepness, which may be 100V/us or 1KV/us. The response time or the action time delay of a switching device is related to the rise steepness of the voltage pulse, and the impulse breakdown voltage of the switching device is different for different rise steepnesses. The smaller the dc breakdown voltage of the switching device, the smaller its impulse breakdown voltage.
When high-frequency surge impact interference occurs in the voltage between the first end V1 and the second end V2 of the discharge circuit, the frequency of the surge voltage is very high, breakdown occurs when the voltage of part of the switching devices 10 reaches the dc breakdown voltage thereof first, and the voltage of the rest of the switching devices 10 does not reach the dc breakdown voltage thereof at this time. Since the voltage across the switching device 10 that is first broken down decreases rapidly, the surge voltage is almost completely applied to the remaining non-broken down switching devices 10, and as the voltage of the remaining non-broken down switching devices 10 increases, breakdown occurs when the dc breakdown voltage is gradually reached, the entire discharge circuit is turned on, and current is discharged. At this time, the actual surge breakdown voltage V of the discharge circuit BR0 ' greater than the direct-current breakdown voltage of the switching device which was first broken down, the actual shoot-through voltage V of the discharge circuit BR0 Of less than the sum of the breakdown voltages of all switching devices, i.e. V BR0 ＇<V BR1 ＇+V BR2 ＇+…+V BRn Of which V BRi ' is the shoot-through voltage of the ith switching device 10.
Illustratively, as shown in figure 1, the first switching device 10-1 has a dc breakdown voltage of V BR1 The DC breakdown voltage of the second switching device 10-2 is V BR2 The high-frequency impedance mode of the first impedance branch 20-1 is | Z 11 The high-frequency impedance mode of the second impedance branch 20-2 is | Z 12 L. the method is used for the preparation of the medicament. If Z 11 |：|Z 12 |>V BR1 ：V BR2 When surge shock such as lightning strike occurs, the first switching device 10-1 is broken down first. If Z 11 |：|Z 12 |<V BR1 ：V BR2 When surge shock such as lightning strike occurs, the second switching device 10-2 is broken down first.
By connecting the impedance branch 20 to each switching device 10, when surge impact such as lightning strike occurs, all switching devices 10 do not reach respective impact breakdown voltage at the same time, and breakdown occurs when the voltage of part of switching devices 10 reaches the dc breakdown voltage thereof first, and at this time, the voltage of the rest of switching devices 10 does not reach the dc breakdown voltage thereof. Since the voltage between the switching devices 10 that are first broken down decreases rapidly, the surge voltage is almost completely applied to the remaining non-broken down switching devices 10, and as the voltage of the remaining non-broken down switching devices 10 increases, breakdown occurs when the dc breakdown voltage thereof is gradually reached, the entire discharge circuit is turned on, and current is discharged. Actual surge breakdown voltage V of the discharge circuit BR0 ' greater than the direct-current breakdown voltage of the switching device which was first broken down, the actual shoot-through voltage V of the discharge circuit BR0 ' greater than the direct-current breakdown voltage of the switching device which is subsequently subjected to breakdown, the actual surge breakdown voltage V of the discharge circuit BR0 Of breakdown voltages less than the sum of all switching devices, i.e. V BR0 ＇<V BR1 ＇+V BR2 ＇+…+V BRn ' therefore the discharge circuit has a lower breakdown voltage, the discharge circuit is substituted for a direct current breakdown voltage equal to V BR1 +V BR2 +…+V BRn The single switch device solves the problem that when surge impact such as lightning stroke occurs, the surge impact voltage is increased to the DC breakdown voltage equal to V BR1 +V BR2 +…+V BRn Of a single switching device (equal to V) BR1 ＇+V BR2 ＇+…+V BRn ' time) the single switching device will be breakdown conducting, resulting in too high a shoot through voltage, with the problem of a blanket region.
The discharge circuit in the technical solution of this embodiment includes at least two switching devices and at least two impedance branches, wherein two ends of the at least two switching devices after being connected in series are electrically connected to a first end and a second end of the discharge circuit, respectively; the impedance branches are in one-to-one correspondence with the switching devices and are connected in parallel with the corresponding switching devices; for the same high frequency, the high frequency impedance modes of the impedance branch circuits are unequal, and the high frequency is larger than the power frequency, so that when surge impact such as lightning strike occurs, all the switch-type devices do not reach respective impact breakdown voltage at the same time, the voltage between the switch-type devices which are firstly subjected to breakdown is rapidly reduced, the surge voltage is almost completely applied to the rest switch-type devices which are not subjected to breakdown, and along with the rise of the voltage of the rest switch-type devices which are not subjected to breakdownHigh, breakdown occurs when the DC breakdown voltage is gradually reached, and the actual impact breakdown voltage V of the discharge circuit BR0 Of breakdown voltages less than the sum of all switching devices, i.e. V BR0 ＇<V BR1 ＇+V BR2 ＇+…+V BRn ' solves the problem that when surge impact such as lightning strike occurs, the surge impact voltage is increased to the direct current breakdown voltage which is equal to V BR1 +V BR2 +…+V BRn When the impact breakdown voltage of a single switch-type device is high, the single switch-type device is broken down and conducted, so that the problem of too high impact breakdown voltage and protection blind area exists.
Optionally, sorting is performed according to the sizes of the high-frequency impedance modes of the impedance branches 20, and in two impedance branches 20 adjacent to each other in sequence number, | Z H1 |：|Z H2 |>V BRX ：V BRY Wherein, | Z H1 I is the high-frequency impedance mode of the impedance branch with large high-frequency impedance mode, | Z H2 I is the high-frequency impedance mode of the impedance branch with the small high-frequency impedance mode, V BRX DC breakdown voltage, V, of switching devices corresponding to impedance branches of large high-frequency impedance mode BRY The direct current breakdown voltage of the switching device corresponding to the impedance branch with small high-frequency impedance mode.
When high-frequency surge impact interference occurs to the voltage between the first end V1 and the second end V2 of the discharge circuit, the switching device 10 with low direct-current breakdown voltage is firstly subjected to breakdown, and the switching device 10 with high direct-current breakdown voltage is subjected to breakdown later, so that the situation that the switching device 10 with high direct-current breakdown voltage is subjected to breakdown earlier, and the situation that the switching device 10 with low direct-current breakdown voltage is subjected to failure due to overlarge voltage of the switching device 10 with high direct-current breakdown voltage is caused after the switching device 10 with high direct-current breakdown voltage is subjected to breakdown is avoided.
Optionally, the impedance branches 20 are sorted according to the size of the high-frequency impedance mode, and in two impedance branches 20 adjacent to each other in the serial number, the dc breakdown voltage of the switching device 10 corresponding to the impedance branch 20 with the large high-frequency impedance mode is less than or equal to the dc breakdown voltage of the switching device 10 corresponding to the impedance branch 20 with the small high-frequency impedance mode, that is, | Z H1 |>|Z H2 |，V BRX ≤V BRY 。
The larger the high-frequency impedance mode of the impedance branch 20 is, the smaller the dc breakdown voltage of the switching device 10 corresponding to the impedance branch 20 is. Optionally, when a high frequency surge interference occurs in the voltage between the first terminal V1 and the second terminal V2 of the discharge circuit, the higher the high frequency impedance mode of the impedance branch 20 corresponding to the switching device 10 is, the earlier the switching device 10 is turned on. When the voltage between the first end V1 and the second end V2 of the discharge circuit generates high-frequency surge impact interference, the voltage on the switching device 10 with small dc breakdown voltage is higher and is firstly punctured, and the voltage on the switching device 10 with large dc breakdown voltage is punctured after being lower, so as to avoid the situation that the switching device 10 with large dc breakdown voltage is firstly punctured, and the voltage of the switching device 10 with small dc breakdown voltage is too high to cause failure after the switching device 10 with large dc breakdown voltage is punctured.
Optionally, sorting is performed according to the sizes of the high-frequency impedance modes of the impedance branches 20, and in two impedance branches 20 adjacent to each other in sequence number, | Z H1 |>5|Z H2 L, wherein l Z H1 I is the high-frequency impedance mode of the impedance branch 20 with a large high-frequency impedance mode, | Z H2 I is the high-frequency impedance mode of the impedance branch 20 whose high-frequency impedance mode is small.
Wherein, | Z H1 The greater the | Z |, the H2 The smaller |, the actual breakdown voltage V of the discharge circuit BR0 The closer to the shoot-through voltage of the switching device with the largest dc breakdown voltage is. When surge impact such as lightning strike occurs, the voltage of the switching device 10 corresponding to the impedance branch 20 with the largest high-frequency impedance mode is much larger than the voltages of the other switching devices 10, so that the surge voltage is almost completely applied to the switching device 10 corresponding to the impedance branch 20 with the largest high-frequency impedance mode, so that the switching device 10 corresponding to the impedance branch 20 with the largest high-frequency impedance mode is firstly broken down, the turn-on voltage of the switching device 10 corresponding to the impedance branch 20 with the largest high-frequency impedance mode is rapidly reduced, the surge voltage is almost completely applied to the switching device 10 corresponding to the impedance branch 20 with the second largest high-frequency impedance mode, so that the switching device 10 corresponding to the impedance branch 20 with the second largest high-frequency impedance mode is broken down, and so onThe switching devices are enabled to be punctured one by one according to the sequence of the sizes of the high-frequency impedance modes of the corresponding impedance branches.
Optionally, the dc breakdown voltages of all the switching devices 10 are equal, and the impulse breakdown voltages of all the switching devices 10 are equal, so as to minimize the impulse breakdown voltage of the discharge circuit.
Illustratively, as shown in fig. 1, the first switching device 10-1 has a dc breakdown voltage of V BR1 The second switching device 10-2 has a DC breakdown voltage of V BR2 . If V BR1 <V BR2 ，V BR1 <V BR0 /2，V BR2 >V BR0 /2，V BR1 +V BR2 ＝V BR0 The dc breakdown voltages of the two switching devices 10 are not equal, the surge breakdown voltages of the two switching devices 10 are not equal, and the actual surge breakdown voltage V of the discharge circuit BR0 Near a DC breakdown voltage of more than V BR0 The breakdown voltage of the switching device of/2. If V BR1 ＝V BR2 ，V BR1 ＝V BR0 /2，V BR2 ＝V BR0 /2，V BR1 +V BR2 ＝V BR0 The dc breakdown voltages of the two switching devices 10 are equal, the surge breakdown voltages of the two switching devices 10 are equal, and the actual surge breakdown voltage V of the discharge circuit is equal BR0 Near the DC breakdown voltage equal to V BR0 The breakdown voltage of the switching device of/2.
Optionally, V BRX ：V BRY ＝|Z L1 |：|Z L2 L, wherein V BRX DC breakdown voltage, V, of switching devices corresponding to impedance branches of large impedance mode of high frequency BRY The DC breakdown voltage of the switching device corresponding to the impedance branch with small high-frequency impedance mode, | Z L1 I is the power frequency impedance mode of the impedance branch with large high frequency impedance mode, | Z L2 I is the power frequency impedance mode of the impedance branch circuit with small high-frequency impedance mode, so that when the power frequency voltage state is realized, the partial pressure of the switching device with large direct-current breakdown voltage is larger, the partial pressure of the switching device with small direct-current breakdown voltage is smaller, the whole circuit is ensured not to be broken down, and the alternating-current resistance is ensuredAnd (4) leveling.
Wherein, during normal power supply, when power frequency voltage state, the partial pressure of switching device 10 that direct current breakdown voltage is big is great, and the partial pressure of switching device 10 that direct current breakdown voltage is little to guarantee that whole circuit does not take place to puncture, guarantee the withstand voltage level of interchange. During normal power supply, all switching devices 10 are non-conductive, the discharge circuit is non-conductive, and the voltage of any switching device 10 is less than its turn-on voltage. Under the power frequency state, the equivalent impedance of all impedance branches after being connected in series is greater than the 4 megaohm requirements of the standards of IEC60950, IEC61347 and the like.
Optionally, the power frequency impedance modes of all the impedance branches 20 are equal, so that the dc breakdown voltages of all the switching devices 10 are equal, the voltage division of the switching devices is equal, and the ac withstand voltage level is ensured. Optionally, the impedance mode of the first impedance branch 20-1 may increase with the increase of the frequency; the impedance mode of the second impedance branch 20-2 may decrease with increasing frequency to satisfy the magnitude relationship of the impedance modes at high and power frequencies.
Optionally, on the basis of the foregoing embodiment, fig. 3 is a schematic structural diagram of a discharge circuit according to an embodiment of the present invention, except for the impedance branch 20 with the smallest high-frequency impedance mode, in the remaining impedance branches, any impedance branch 20 includes a first sub-branch 21 and a first capacitive element C1 which are connected in series, and two ends of the impedance branch after being connected in series are respectively electrically connected to two ends of the corresponding switching device 10; the first sub-branch 21 comprises at least one of a first resistive element R1 and a first inductive element L1; the power frequency impedance mode of the first capacitive element C1 is 5 times larger than that of the first sub-branch 21; the high frequency impedance mode of the first sub-branch 21 is greater than 5 times the high frequency impedance mode of the first capacitive element C1.
Fig. 3 exemplarily shows a case where the first switching device 10-1 includes a gas discharge tube, the second switching device 10-2 includes a gas discharge tube, the impedance branch with the smallest high-frequency impedance mode is the second impedance branch 20-2, and the first sub-branch 21 in the first impedance branch 20-1 includes the first resistive element R1. High frequency impedance mode of the first impedance branch 20-1
w H ＝2πf H ，f H Is a high frequency; power frequency impedance mode of the first impedance branch 20-1
w L ＝2πf L ，f L Is the power frequency. Wherein, R is 1 Is the resistance value, C, of the first resistive element R1 1 Is the capacitance value of the first capacitive element C1. R 1 The larger, | Z 11 The larger the | is. C 1 The larger, | Z 21 The smaller the | is.
Fig. 4 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention, and fig. 4 exemplarily shows that in a case where the first sub-branch 21 of the first impedance branch 20-1 includes the first inductive element L1, a high-frequency impedance mode of the first impedance branch 20-1
Power frequency impedance mode of the first impedance branch 20-1
Wherein L is 1 The inductance value of the first inductive element L1. L is 1 The larger, f H The larger, | Z 11 The larger the | is.
Optionally, on the basis of the above implementation, with continued reference to fig. 3 and fig. 4, the impedance branch 20 with the smallest high-frequency impedance mode includes a second capacitive element C2, and two ends of the second capacitive element C2 are electrically connected to two ends of the corresponding switching device 10, respectively; the capacitance of the first capacitive element C1 is equal to the capacitance of the second capacitive element C2.
When the power supply is normal, the first capacitive element C1 and the second capacitive element C2 perform a main voltage division function in a power frequency voltage state, and the power frequency capacitive reactance mode of the first capacitive element C1 and the second capacitive element C2 can be far larger than the power frequency impedance mode of the first sub-branch 21. In the event of surge impact such as lightning strike, the first sub-branch 21 plays a major role, and the high-frequency impedance mode of the first sub-branch 21 may be much larger than the high-frequency capacitive reactance modes of the second capacitive element C2 and the first capacitive element C1.
Wherein the high frequency impedance mode of the second impedance branch 20-2
Power frequency impedance mode of second impedance branch 20-2
Wherein, C 2 Is the capacitance value of the second capacitive element C2. C 2 The smaller, | Z 22 The larger the | is.
Optionally, on the basis of the above embodiment, fig. 5 is a schematic structural diagram of another discharge circuit provided in the embodiment of the present invention, where the impedance branch 20 with the smallest high-frequency impedance mode further includes a second sub-branch 22, the second sub-branch 22 is connected in series with the second capacitive element C2, and two ends of the series connection are respectively electrically connected to two ends of the corresponding switching device 10. Optionally, the second sub-branch 22 includes at least one of a second resistive element R2 and a second inductive element L2, and a high-frequency impedance mode of the first sub-branch 21 is larger than a high-frequency impedance mode of the second sub-branch 22.
When the power supply is normal, in a power frequency voltage state, the first capacitive element C1 and the second capacitive element C2 play a main voltage division role, and the power frequency capacitive reactance mode of the first capacitive element C1 and the second capacitive element C2 can be far larger than the power frequency impedance mode of the first sub-branch 21 and the second sub-branch 22. In the event of surge impact such as lightning strike, the first sub-branch 21 and the second sub-branch 22 perform a main voltage division function, and the high-frequency impedance mode of the first sub-branch 21 and the second sub-branch 22 may be much larger than the high-frequency capacitive impedance mode of the second capacitive element C2 and the first capacitive element C1.
Wherein fig. 5 exemplarily shows that the first switching device 10-1 comprises a semiconductor discharge tube, the second switching device 10-2 comprises a semiconductor discharge tube, the impedance branch with the smallest high frequency impedance mode is the second impedance branch 20-2, the first sub-branch 21 of the first impedance branch 20-1 comprises the first resistive element R1, the second sub-branch 22 of the second impedance branch 20-2 comprises the second resistive element R2, and the high frequency impedance mode of the second impedance branch 20-2
Power frequency impedance mode of second impedance branch 20-2
Wherein R is 2 Is the resistance value of the second resistive element R2. C 2 The smaller, | Z 22 The larger the | is. R is 2 The smaller, | Z 12 The smaller the | is.
Optionally, on the basis of the foregoing embodiment, fig. 6 is a schematic structural diagram of a discharge circuit according to another embodiment of the present invention, where the first sub-branch 21 includes a first resistive element R1, and the second sub-branch 22 includes a second resistive element R2. When the power supply is normal, the first capacitive element C1 and the second capacitive element C2 play a main voltage division role in a power frequency voltage state. When surge shock such as lightning strike occurs, the first resistive element R1 and the second resistive element R2 mainly divide voltage. Alternatively to this, the first and second parts may,
optionally, on the basis of the above embodiment, with reference to fig. 6, sorting is performed according to the sizes of the high-frequency impedance modes of the impedance branches 20, and in two impedance branches 20 adjacent to each other in sequence number, the resistance value of the resistor in the impedance branch 20 with the large high-frequency impedance mode is greater than 5 times the resistance value of the resistor in the impedance branch 20 with the small high-frequency impedance mode.
Alternatively, on the basis of the above-described embodiment, with continued reference to figure 6,
wherein R is 1max The resistance value, C, of the first resistive element R1 in the impedance branch 20 having the largest high-frequency impedance mode 1 Is the capacitance value of the first capacitive element C1, f H At a high frequency, f L Is the power frequency.
Fig. 6 exemplarily shows three switching devices 10, which are a first switching device 10-1, a second switching device 10-2 and a third switching device 10-3, and three impedance branches 20, which are a first impedance branch 20-1, a second impedance branch 20-2 and a third impedance branch 20-3, respectively, where the first switching device 10-1 corresponds to the first impedance branch 20-1, the second switching device 10-2 corresponds to the second impedance branch 20-2, the third switching device 10-3 corresponds to the third impedance branch 20-3, the impedance branch with the smallest high-frequency impedance mode is the second impedance branch 20-2, and the impedance branch with the largest high-frequency impedance mode is the first impedance branch 20-1. The first resistive element R1 of the first sub-branch 21 of the first impedance branch 20-1 has a resistance value R 1max The first resistive element R1 of the first sub-branch 21 of the third impedance branch 20-3 has a resistance value R 1mid The second resistive element R2 of the second sub-branch 21 of the second impedance branch 20-2 has a resistance value R 2 Wherein R is 1max ＞5R 1mid ，R 1mid ＞5R 2 . When the resistance difference between the two impedance branches 20 adjacent to each other in the sequence number is larger, the higher the voltage of the switching device 10 corresponding to the impedance branch 20 having the larger high-frequency impedance mode is, and the lower the voltage of the switching device 10 corresponding to the impedance branch 20 having the larger high-frequency impedance mode is, the lower the surge breakdown voltage of the discharge circuit is, the closer to the surge breakdown voltage of the switching device having the largest dc breakdown voltage is, when surge shock such as lightning strike occurs.
Optionally, on the basis of the above embodiment, fig. 7 is a schematic structural diagram of another discharging circuit according to an embodiment of the present invention, in which the first sub-branch 21 includes a first inductive element L1, and the second sub-branch 22 includes a second inductive element L2. When the power supply is normal, the first capacitive element C1 and the second capacitive element C2 play a main voltage division role in a power frequency voltage state. When surge shock such as lightning strike occurs, the first inductive element L1 and the second inductive element L2 mainly perform voltage division.
The impedance branches 20 are sorted according to the magnitude of the high-frequency impedance mode, and in two impedance branches 20 adjacent to each other in the serial number, the inductance value of the inductance in the impedance branch 20 with the large high-frequency impedance mode is greater than 5 times the inductance value of the inductance in the impedance branch 20 with the small high-frequency impedance mode.
Fig. 7 exemplarily shows three switching devices 10, which are a first switching device 10-1, a second switching device 10-2 and a third switching device 10-3, and three impedance branches 20, which are a first impedance branch 20-1, a second impedance branch 20-2 and a third impedance branch 20-3, respectively, where the first switching device 10-1 corresponds to the first impedance branch 20-1, the second switching device 10-2 corresponds to the second impedance branch 20-2, the third switching device 10-3 corresponds to the third impedance branch 20-3, the impedance branch with the smallest high-frequency impedance mode is the second impedance branch 20-2, and the impedance branch with the largest high-frequency impedance mode is the first impedance branch 20-1. The first inductive element L1 of the first sub-branch 21 of the first impedance branch 20-1 has a resistance value L 1max The resistance value of the first inductive element L1 of the first sub-branch 21 of the third impedance branch 20-3 is L 1mid The resistance value of the second inductive element L2 of the second sub-branch 21 of the second impedance branch 20-2 is L 2 Wherein, L 1max ＞5L 1mid ，L 1mid ＞5L 2 . The larger the difference in inductance between the two impedance branches 20 adjacent to each other in the serial number is, the higher the voltage of the switching device 10 corresponding to the impedance branch 20 having the higher impedance mode is, and the lower the voltage of the switching device 10 corresponding to the impedance branch 20 having the higher impedance mode is, the lower the breakdown voltage of the discharge circuit is, and the closer the breakdown voltage of the switching device having the highest dc breakdown voltage is, when surge shock such as lightning strike occurs.
Fig. 8 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention. FIG. 8 illustrates an exemplary impedance branch with the smallest high-frequency impedance mode as the second impedance branch 20-2, where the first sub-branch 11 of the first impedance branch 20-1 includes the first resistive element R1, and the second impedance branch 20-2In case the second sub-branch 22 comprises the second inductive element L2, the high frequency impedance mode of the second impedance branch 20-2
Power frequency impedance mode of the second impedance branch 20-2
Wherein L is 2 The inductance value of the second inductive element L2. C 2 The smaller, | Z 22 The larger the | is. L is 2 The smaller, | Z 12 The smaller the | is. When the power supply is normal, the first capacitive element C1 and the second capacitive element C2 play a main voltage division role in a power frequency voltage state. When surge shock such as lightning strike occurs, the first resistive element R1 and the second inductive element L2 mainly perform a voltage dividing function.
Optionally, on the basis of the above embodiment, with reference to fig. 8, sorting is performed according to the sizes of the high-frequency impedance modes of the impedance branches 20, in two impedance branches 20 adjacent to each other in sequence number, a sub-branch in the impedance branch 20 with a large high-frequency impedance mode includes a resistor, a sub-branch in the impedance branch 20 with a small high-frequency impedance mode includes an inductor, and the resistance value of the resistor in the impedance branch 20 with a large high-frequency impedance mode is greater than 5 times the high-frequency inductive reactance of the inductor in the impedance branch 20 with a small high-frequency impedance mode. Illustratively, as shown in FIG. 8, R 1 ＞5|jw H L 2 |。
Fig. 9 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention. Fig. 9 exemplarily shows a case where the impedance branch with the smallest high-frequency impedance mode is the second impedance branch 20-2, the first sub-branch 11 in the first impedance branch 20-1 includes the first inductive element L1, and the second sub-branch 21 in the second impedance branch 20-2 includes the second resistive element R2. When the power supply is normal, the first capacitive element C1 and the second capacitive element C2 play a main voltage division role in a power frequency voltage state. When surge shock such as lightning strike occurs, the first inductive element L1 and the second resistive element R2 mainly perform voltage division.
Alternatively, on the basis of the above-described embodiment, with continued reference to fig. 9, the impedance branch 20 is high in terms of heightThe sizes of the frequency impedance modes are sequenced, in two impedance branches 20 adjacent to each other in sequence number, a sub-branch in the impedance branch 20 with a large frequency impedance mode includes an inductor, a sub-branch in the impedance branch 20 with a small frequency impedance mode includes a resistor, and the high-frequency inductive reactance of the inductor in the impedance branch 20 with a large frequency impedance mode is greater than 5 times the resistance of the resistor in the impedance branch 20 with a small frequency impedance mode. Illustratively, as shown in FIG. 9, | jw H L 1 |＞5R 2 。
Optionally, on the basis of the foregoing embodiment, fig. 10 is a schematic structural diagram of another discharge circuit provided in the embodiment of the present invention, where the number of the switching devices 10 is three, and the high-frequency impedance mode of the impedance branch 20 corresponding to the switching devices 10 sequentially located in the middle of the series connection is the smallest.
When surge impact such as lightning strike occurs, the switching device corresponding to the impedance branch with the minimum high-frequency impedance mode is started at last, the switching devices on the two sides are started firstly, and enough electric charge can be generated when the middle switching device is started. Set up like this, can let the electric capacity in the impedance branch road of high frequency impedance mould minimum a little bit, let the power frequency impedance of whole return circuit some high, also can make the discharge tube of circuit some more reliable.
Optionally, on the basis of the foregoing embodiment, fig. 12 is a schematic structural diagram of a discharge circuit according to another embodiment of the present invention, where the switching device 10 includes a gas discharge tube, and the discharge circuit further includes K second gas discharge tubes GDT2 and K third capacitors C3, where K is an integer greater than or equal to 2, and the K second gas discharge tubes GDT2 are connected in series to form a first series branch 40.
The K second gas discharge tubes GDT2 are connected in series to form K +1 first nodes N1, except for the first node N1 connected to the first end X1 of the first series branch 40, the remaining K first nodes N1 are in one-to-one correspondence with the K third capacitors C3, and any first node N11 is electrically connected to the first end X1 of the first series branch 40 through the corresponding third capacitor C3. Both ends of the at least two switching devices 10 connected in series with the first series branch 40 are electrically connected to the first end V1 and the second end V2 of the discharge circuit, respectively. The dc breakdown voltage of the second gas discharge tube GDT2 is smaller than the dc breakdown voltage of the switching device 10.
Wherein, for the same high frequency, the high frequency impedance mode of the impedance branch 20 with the minimum high frequency impedance mode is larger than that of the third capacitor C3
Wherein, C 3 The capacitance value of the third capacitor C3 is set so that the switching device 10 is turned on first when the surge impact such as lightning strike occurs and the voltage division is large; the gas discharge tubes GDT2 connected in series have small partial pressure and then are conducted. Optionally, the capacitance of the second capacitive element C2 is smaller than the capacitance of the third capacitor C3. K gas discharge tubes GDT2 can be integrated as a multi-gap gas discharge tube. Arc light pressure can be raised to gas discharge tube GDT2 of a plurality of series connections for after overvoltage such as thunderbolt disappears, when power frequency current (frequency can be 50Hz or 60 Hz) continues to flow gas discharge tube GDT2 of series connection, at power frequency continuous current zero point in-process, gas discharge tube GDT2 can turn off by oneself, and the continuous current of rupture power frequency. The high follow current interruption capability of the plurality of gas discharge tubes GDT2 connected in series enables follow current under the working voltage of abnormal voltage to be automatically cut off to achieve the purpose of follow current breaking.
Optionally, as shown in fig. 12, the first end of the at least two switching devices 10 after being connected in series is electrically connected to the first end V1 of the discharge circuit through the first series branch 40; the second end of the at least two switching devices 10 after being connected in series is electrically connected to the second end V2 of the discharge circuit. Fig. 12 exemplarily shows that the first terminal of the at least two switching devices 10 after being connected in series is electrically connected to the second terminal X2 of the first series branch 40; the first end X1 of the first series branch 40 is electrically connected with the first end V1 of the discharge circuit; the second end of the at least two switching devices 10 connected in series is electrically connected to the second end V2 of the discharge circuit.
Fig. 13 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention. Fig. 12 exemplarily shows that the first terminals of the at least two switching devices 10 after being connected in series are electrically connected to the first terminal X1 of the first series branch 40; the second end X2 of the first series branch 40 is electrically connected with the second end V2 of the first series branch 40 and the discharge circuit; the second terminals of the at least two switching devices 10 connected in series are electrically connected to the first terminal V1 of the discharge circuit.
Optionally, on the basis of the foregoing embodiment, fig. 14 is a schematic structural diagram of another discharge circuit provided in the embodiment of the present invention, where the discharge circuit further includes a first varistor MOV1, and two ends of at least two switching devices 10 connected in series with the first varistor MOV1 are respectively electrically connected to a first end V1 and a second end V2 of the discharge circuit.
Wherein, for the same high frequency, the high frequency impedance mode of the impedance branch 20 with the minimum high frequency impedance mode is larger than the high frequency impedance mode of the interelectrode capacitance of the first voltage dependent resistor MOV1
Wherein, C 4 The capacitance value of the interelectrode capacitance of the first voltage dependent resistor MOV1 is used, so that when surge impact such as lightning strike occurs, the partial voltage of the switching device is large, and the switching device is firstly conducted; the first voltage dependent resistor MOV1 is switched on after a small voltage division. Optionally, the high-frequency impedance mode of the impedance branch 20 with the smallest high-frequency impedance mode is larger than that of the impedance branch
Optionally, the capacitance of the second capacitive element C2 is smaller than the capacitance of the inter-electrode capacitance of the first varistor MOV 1. The inter-electrode capacitance of the first varistor MOV1 may be the parasitic capacitance of the first varistor MOV 1. The gas discharge tube is matched with the piezoresistor for use, and the problem that the single piezoresistor is easy to ignite due to overlarge leakage current when the piezoresistor is used is solved by utilizing the low leakage current characteristic of the gas discharge tube when the piezoresistor is not switched on. The clamping high voltage characteristic of the piezoresistor and the high voltage of the gas discharge tube combination are far greater than the working voltage of the power supply, so that the current of the power supply cannot be poured into the circuit, and the method is equivalent to a barrage.
Optionally, on the basis of the foregoing embodiment, fig. 15 is a schematic structural diagram of another discharge circuit provided in the embodiment of the present invention, where the discharge circuit further includes a second varistor MOV2, and a first end of the at least two switching devices 10 after being connected in series is electrically connected to a second end V2 of the discharge circuit; the second end of the at least two switching devices 10 after being connected in series is electrically connected with the third end V3 of the discharge circuit through a second piezoresistor MOV 2; the second end of the at least two switching devices 10 connected in series is electrically connected to the first end V1 of the discharge circuit via a first varistor MOV 1.
Wherein, for the same high frequency, the high frequency impedance mode of the impedance branch 20 with the minimum high frequency impedance mode is larger than the high frequency impedance mode of the interelectrode capacitance of the second voltage dependent resistor MOV2
Wherein, C 5 The capacitance value of the interelectrode capacitance of the second voltage dependent resistor MOV2 is set so that when surge impact such as lightning strike occurs at the second end V2 and the third end V3 of the discharge circuit, the partial voltage of the switching device 10 is large and the switching device is firstly conducted; the second voltage dependent resistor MOV2 is low in voltage and then is turned on. Optionally, the capacitance of the second capacitive element C2 is smaller than the capacitance of the inter-electrode capacitance of the second varistor MOV 2. The inter-electrode capacitance of the second varistor MOV2 may be the parasitic capacitance of the second varistor MOV 2. Optionally, the first end V1 of the discharge circuit may be electrically connected to the live wire, the third end V3 of the discharge circuit may be electrically connected to the neutral wire, and the second end V2 of the discharge circuit may be grounded.
Fig. 16 is a schematic structural diagram of another discharge circuit according to an embodiment of the present invention. Fig. 16 exemplarily shows a case where the impedance branch with the smallest high-frequency impedance mode is the second impedance branch 20-2, the first sub-branch 11 in the first impedance branch 20-1 includes the first resistive element R1, and the second sub-branch 21 in the second impedance branch 20-2 includes the second resistive element R2. Under the power frequency state, the capacitive reactance of the first capacitive element C1 and the second capacitive element C2 is far larger than the impedance of the first resistive element R1, C 1 ＝C 2 The voltage is approximately halved for the first switching device 10-1 and the second switching device 10-2. Under the surge state, the frequency is larger than or equal to 25000Hz, the capacitive reactance of the first capacitive element C1 and the second capacitive element C2 is far smaller than the impedance of the first resistive element R1 of the R1, the voltage is similar to the surge voltage, the first resistive element R1 and the second resistive element R2 are divided according to the resistance values, and R is 1 ：R 2 Greater than 5:1, the surge voltage is mainly distributed over the first resistive element R1, i.e. equal to the voltage main componentThe first switching device 10-1 is arranged on the first switching device 10-1, when the voltage is larger than the pulse voltage of the first switching device 10-1, the first switching device 10-1 breaks down (if the first switching device 10-1 is a gas discharge tube, the gas discharge tube enters a glow state), after the first switching device 10-1 breaks down, the voltage across the first switching device 10-1 drops rapidly, at this time, the surge voltage is mainly distributed across the second switching device 10-2, and the second switching device 10-2 is broken down. The first switching device 10-1 and the second switching device 10-2 are both gas discharge tubes, the dc breakdown voltage of each gas discharge tube is 1500V, and the pulse voltage is 2000V, so the pulse voltage of the entire discharge circuit is less than 2000+ (1500 × 0.25) =2375V. If the first parallel impedance branch 20-1 is not connected in parallel to the first switching device 10-1, and the second parallel impedance branch 20-2 is not connected in parallel to the second switching device 10-2, the pulse voltage after the first switching device 10-1 and the second switching device 10-2 are connected in series is 3500V, the first parallel impedance branch 20-1 is connected in parallel to the first switching device 10-1, the second parallel impedance branch 20-2 is connected in parallel to the second switching device 10-2, the pulse voltage of the whole discharge circuit is less than 2375V, and the pulse voltage is reduced by 3500-2375=1125v.
Illustratively, with continued reference to fig. 5, both the first switching device 10-1 and the second switching device 10-2 are semiconductor discharge tubes. The direct current breakdown voltage of each semiconductor discharge tube is 800V, the pulse voltage is 900V, the alternating current environment, the withstand voltage of the discharge circuit is 800 x 2/1.414=1131V, the direct current breakdown voltage is 800 x 2=1600V, the pulse voltage is calculated to be less than 900+ (800 x (1 + 1)/[ (1 + 1) + (5 + 1) ] =1100V, the discharge circuit replaces the semiconductor discharge tube with the direct current breakdown voltage of 1600V, and the pulse voltage of the semiconductor discharge tube with the direct current breakdown voltage of 1600V is 1700V, so that the pulse voltage can be reduced by 1700-1100= V600or so.
Illustratively, with continued reference to FIG. 8, the first switching device 10-1 is a semiconductor discharge tube and the second switching device 10-2 is a gas discharge tube. The dc breakdown voltage of the semiconductor discharge tube is 800V, and the dc breakdown voltage of the gas discharge tube is 800V. Under the power frequency state, the power frequency voltage is mainly distributed on the first capacitive element and the second capacitive element C2, and the semiconductor discharge tube and the gas discharge tube are approximately divided into half parts. Under the AC environment, the withstand voltage of the discharge circuit is about (800 + 800)/1.414 =1131V. Under surge impact, the voltage distribution is determined by the first sub-branch 21 and the second sub-branch 22, the high-frequency impedance mode of the first sub-branch 21 is far greater than that of the second sub-branch 22, the voltage is mainly distributed on the first switching device 10-1, the semiconductor discharge tube breaks down first, then the gas discharge tube breaks down, the whole discharge circuit breaks down, the pulse voltage of the discharge circuit is +4V of the gas discharge tube, 4V of the discharge circuit is the voltage after the semiconductor discharge tube breaks down, the semiconductor discharge tube has no glow area, the pulse voltage of the gas discharge tube with the direct-current breakdown voltage of 800V is 1200V, and then the breakdown voltage of the whole discharge circuit is 1204V. The discharge circuit replaces a semiconductor discharge tube with 1600V direct-current breakdown voltage, and the pulse voltage of the semiconductor discharge tube with 1600V direct-current breakdown voltage is 1700V, so that the pulse voltage can be reduced by 1700-1204= 496V.
The embodiment of the invention provides a surge protection circuit. With continued reference to fig. 2 on the basis of the above-described embodiments, the surge protection circuit includes the discharge circuit provided by any of the embodiments of the present invention.
The surge protection circuit provided by the embodiment of the present invention includes the discharge circuit in the above embodiment, and therefore, the surge protection circuit provided by the embodiment of the present invention also has the beneficial effects described in the above embodiment, and details are not described here.
The embodiment of the invention provides an ignition circuit. On the basis of the above embodiments, the ignition circuit includes the discharge circuit provided in any of the embodiments of the present invention.
Optionally, the ignition circuit may further include a step-up transformer, a rectifier circuit, an energy storage capacitor, and a choke. When ignition is needed, the alternating current power supply is boosted and rectified by the booster transformer and the rectifying circuit, and then charges the energy storage capacitor. When the charging voltage of the energy storage capacitor reaches the impact breakdown voltage of the discharge circuit, the energy storage capacitor is conducted, and the energy storage capacitor releases voltage to the electric nozzle, so that the electric nozzle breaks down to generate electric sparks, and gas mixtures in a combustion chamber of an engine, gas equipment and the like are ignited. The discharge circuit can be substituted for the gas discharge tube in the existing ignition circuit.
The ignition circuit provided by the embodiment of the present invention includes the discharge circuit in the above embodiment, and therefore, the ignition circuit provided by the embodiment of the present invention also has the beneficial effects described in the above embodiment, and details are not described herein again.
The embodiment of the invention provides electronic equipment. Fig. 17 is a schematic structural diagram of an electronic device according to an embodiment of the present invention. The electronic device 100 includes a discharge circuit provided by any embodiment of the invention.
The electronic device 100 may include a surge protection circuit or an ignition circuit provided by any of the embodiments of the present invention. The electronic device 100 may be a television, a notebook computer, an air conditioner, a communication power supply, a camera, a network switch, or the like. The electronic device provided in the embodiment of the present invention includes the discharge circuit in the above embodiment, and thus the electronic device provided in the embodiment of the present invention also has the beneficial effects described in the above embodiment, and details are not described herein again.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (12)
1. A discharge circuit, comprising:
two ends of the at least two switching-type devices after being connected in series are respectively and electrically connected with the first end and the second end of the discharge circuit;
the impedance branches correspond to the switching-type devices one by one, and the impedance branches are connected with the corresponding switching-type devices in parallel;
for the same high frequency, the high frequency impedance modes of the impedance branches are unequal, and the high frequency is greater than the power frequency;
when high-frequency surge impact interference occurs to the voltage between the first end and the second end of the discharge circuit, the higher the high-frequency impedance mode of the impedance branch corresponding to the switching device is, the earlier the switching device is switched on;
sorting according to the high-frequency impedance mode of the impedance branch circuits, wherein in two impedance branch circuits with adjacent serial numbers, | Z H1 |＞5|Z H2 L, wherein l Z H1 I is the high-frequency impedance mode of the impedance branch with large high-frequency impedance mode, | Z H2 I is the high-frequency impedance mode of the impedance branch with small high-frequency impedance mode; v BRX ：V BRY ＝|Z L1 |：|Z L2 L, wherein V BRX DC breakdown voltage, V, of switching devices corresponding to impedance branches of large impedance mode of high frequency BRY The DC breakdown voltage of the switching device corresponding to the impedance branch with small high-frequency impedance mode, | Z L1 I is the power frequency impedance mode of the impedance branch with large high frequency impedance mode, | Z L2 And | is the power frequency impedance mode of the impedance branch with the small high-frequency impedance mode.
2. The discharge circuit according to claim 1, wherein, except the impedance branch with the smallest high-frequency impedance mode, any impedance branch comprises a first sub-branch and a first capacitive element connected in series, and the two ends of the impedance branch are electrically connected to the two ends of the corresponding switching device respectively; the first sub-branch comprises at least one of a first resistive element and a first inductive element; the power frequency impedance mode of the first capacitive element is 5 times larger than that of the first sub-branch; the high-frequency impedance mode of the first sub-branch is 5 times larger than that of the first capacitive element;
the impedance branch circuit with the minimum high-frequency impedance mode comprises a second capacitive element, wherein two ends of the second capacitive element are respectively and electrically connected with two ends of the corresponding switch-type devices; the capacitance value of the first capacitive element is equal to the capacitance value of the second capacitive element.
3. The discharge circuit according to claim 2, wherein the impedance branch with the smallest high-frequency impedance mode further comprises a second sub-branch, the second sub-branch is connected in series with the second capacitive element, and two ends of the series connection are electrically connected to two ends of the corresponding switching device respectively;
the second sub-branch comprises at least one of a second resistive element and a second inductive element, and a high-frequency impedance mode of the first sub-branch is larger than a high-frequency impedance mode of the second sub-branch.
4. The discharge circuit of claim 3, wherein the first sub-branch comprises a first resistive element, wherein the second sub-branch comprises a second resistive element,
sequencing according to the sizes of the high-frequency impedance modes of the impedance branches, wherein in two impedance branches with adjacent serial numbers, the resistance value of the resistor in the impedance branch with the large high-frequency impedance mode is 5 times larger than that of the resistor in the impedance branch with the small high-frequency impedance mode;
5. The discharge circuit of claim 3 wherein the first sub-branch comprises a first inductive element, the second sub-branch comprises a second inductive element,
sequencing according to the sizes of the high-frequency impedance modes of the impedance branches, wherein in two impedance branches adjacent to the sequence number, the inductance value of the inductor in the impedance branch with the large high-frequency impedance mode is 5 times larger than that of the inductor in the impedance branch with the small high-frequency impedance mode;
6. The discharge circuit of claim 1, wherein the switching device comprises: gas discharge tubes, semiconductor discharge tubes, air gaps, graphite gaps, or spark gaps.
7. The discharge circuit of claim 1, wherein the number of switching devices is three, and the high frequency impedance mode of the impedance branch corresponding to the switching device connected in series in the middle is the smallest.
8. The discharge circuit of claim 1, wherein the switching device comprises a gas discharge tube,
the discharge circuit further comprises K second gas discharge tubes and K third capacitors, wherein K is an integer greater than or equal to 2, and the K second gas discharge tubes are connected in series to form a first series branch;
the K second gas discharge tubes are connected in series to form K +1 first nodes, the other K first nodes except the first node connected with the first end of the first series branch are in one-to-one correspondence with the K third capacitors, and any one first node is electrically connected with the first end of the first series branch through the corresponding third capacitor;
two ends of the at least two switching devices which are connected with the first series branch in series are respectively and electrically connected with the first end and the second end of the discharge circuit;
the direct current breakdown voltage of the second gas discharge tube is smaller than the direct current breakdown voltage of the switching device.
9. The discharge circuit of claim 1, wherein the high frequency is greater than or equal to 25000Hz and the power frequency is less than or equal to 68Hz.
10. A surge protection circuit comprising a discharge circuit according to any of claims 1-9.
11. An ignition circuit comprising a discharge circuit as claimed in any one of claims 1 to 9.
12. An electronic device, characterized in that it comprises a discharge circuit according to any of claims 1-9.
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| PCT/CN2021/125461 WO2022083709A1 (en) | 2020-10-22 | 2021-10-22 | Discharge circuit, surge protection circuit, ignition circuit and electronic apparatus |
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| CN109217275A (en) * | 2018-08-22 | 2019-01-15 | 深圳市瑞隆源电子有限公司 | High voltage bearing anti-thunder surge suppression circuit, device and power supply adaptor |
| CN111490672A (en) * | 2020-02-28 | 2020-08-04 | 深圳市槟城电子有限公司 | Power protection circuit, power supply and electronic equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| NL8701238A (en) * | 1987-05-22 | 1988-12-16 | Smit Transformatoren Bv | FREQUENCY-DEPENDENT OVERVOLTAGE PROTECTION FOR HIGH-VOLTAGE DEVICES. |
| DE102015108652A1 (en) * | 2015-06-01 | 2016-12-01 | Ebm-Papst Mulfingen Gmbh & Co. Kg | Overvoltage protection circuit |
| CN109546637A (en) * | 2018-11-28 | 2019-03-29 | 厦门赛尔特电子有限公司 | A kind of surge protection device and system |
| CN109904847B (en) * | 2019-01-23 | 2020-03-17 | 西安交通大学 | Multi-stage series discharge gap with frequency selection characteristic and working method thereof |
| CN111276957A (en) * | 2020-03-20 | 2020-06-12 | 深圳市槟城电子有限公司 | Overvoltage protection device and electronic equipment |
| CN112332396A (en) * | 2020-10-22 | 2021-02-05 | 马鞍山市槟城电子有限公司 | Discharge circuit, surge protection circuit, ignition circuit, and electronic device |
| CN112332395B (en) * | 2020-10-22 | 2022-11-29 | 马鞍山市槟城电子有限公司 | Discharge circuit, surge protection circuit, ignition circuit, and electronic device |
| CN112332394A (en) * | 2020-10-22 | 2021-02-05 | 马鞍山市槟城电子有限公司 | Surge protection circuit and electronic equipment |
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2020
- 2020-10-22 CN CN202011140519.1A patent/CN112332395B/en active Active
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109217275A (en) * | 2018-08-22 | 2019-01-15 | 深圳市瑞隆源电子有限公司 | High voltage bearing anti-thunder surge suppression circuit, device and power supply adaptor |
| CN111490672A (en) * | 2020-02-28 | 2020-08-04 | 深圳市槟城电子有限公司 | Power protection circuit, power supply and electronic equipment |
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| 从电梯主板被烧毁谈接口电路的防浪涌保护;陈辉;《中国电梯》;20191201(第23期);第50-53页 * |
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