Device for surge protection for protected object

Abstract

The present disclosure relates to a device for surge protection against a protected object. The equipment comprises a power supply protection device, the power supply protection device comprises a first asymmetric conduction characteristic unit, the positive electrode of the first asymmetric conduction characteristic unit is electrically connected with the power supply end of a protected object and the negative electrode of a second asymmetric conduction characteristic unit, and the negative electrode of the first asymmetric conduction characteristic unit is electrically connected with the first end of a surge protection device; the positive electrode of the second asymmetric conduction characteristic unit is electrically connected with the second end of the surge protection device; the surge protection device and the current discharge device are configured to be electrically connected with the power supply protection device, the surge protection device, a grounding end and a feed end of a protected object so as to form a current discharge path; wherein the reverse conduction voltage of the asymmetric conduction characteristic unit is greater than the forward conduction voltage. According to the scheme, the size of the surge protection equipment can be remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to the field of surge protection technology, and in particular, to a device for surge protection for a protected object. BACKGROUND

[0002] In the application scenario of photovoltaic inverters, the lightning protection of direct current interfaces is particularly important, especially for systems with multiple input channels. Factors to be considered for lightning surge protection include voltage level, current bearing capacity, response time, and environmental adaptability. Moreover, the lightning protection scheme for multiple direct current interfaces needs to take into account system safety and economy.

[0003] Surge protection devices are indispensable protection equipment in direct current systems. Lightning protection of direct current interfaces, such as lightning protection of multiple direct current interfaces, usually adopts a modular metal oxide varistor as the main protection scheme. However, under the long-term action of direct current voltage, impurity ions inside the metal oxide varistor (MOV) crystal grains will migrate to the depletion layer, causing the PN junction voltage between the crystal grains to decrease in one direction, resulting in polarization of the metal oxide varistor. Polarization problems can increase the leakage current of the metal oxide varistor, leading to exponential development of the deterioration of the metal oxide varistor, and eventually leading to failure or even burning of the metal oxide varistor. Moreover, as the power of the equipment increases, the number of photovoltaic channels input will also increase accordingly, which means that more protection devices (such as metal oxide varistors) are needed to ensure the safe operation of the system. However, as the number of protection devices increases, the size and cost of the surge protection device also increase. CONTENT OF THE UTILITY MODEL

[0004] The present disclosure provides a device for surge protection for a protected object, which can significantly reduce the size of the surge protection device.

[0005] According to one aspect of the present disclosure, there is provided an apparatus for surge protection for a protected object. The apparatus comprises: a power protection device comprising: a first asymmetric conduction characteristic unit, a positive pole of the first asymmetric conduction characteristic unit being electrically connected with a power supply end of the protected object and a negative pole of a second asymmetric conduction characteristic unit, a negative pole of the first asymmetric conduction characteristic unit being electrically connected with a first end of a surge protection device; and the second asymmetric conduction characteristic unit, a positive pole of the second asymmetric conduction characteristic unit being electrically connected with a second end of the surge protection device; the surge protection device being configured to conduct when a voltage between the first end and the second end of the surge protection device is greater than a threshold voltage; the surge protection device comprising a clamping unit; and a current discharge device being electrically connected with the power protection device, the surge protection device, a ground end and a feeding end of the protected object so as to form a current discharge path; wherein a reverse conduction voltage of the asymmetric conduction characteristic unit is greater than a forward conduction voltage; the power supply end of the protected object is a power supply positive pole or a power supply negative pole of the protected object; the power supply negative pole has a lower level relative to the feeding end, and the power supply positive pole has a higher level relative to the feeding end.

[0006] In some embodiments, the current discharge device comprises a feeding protection device, the feeding protection device comprising: a third asymmetric conduction characteristic unit, a positive pole of the third asymmetric conduction characteristic unit being electrically connected with the feeding end of the protected object and a negative pole of a fourth asymmetric conduction characteristic unit, a negative pole of the third asymmetric conduction characteristic unit being electrically connected with the first end of the surge protection device; and the fourth asymmetric conduction characteristic unit, a positive pole of the fourth asymmetric conduction characteristic unit being electrically connected with the second end of the surge protection device.

[0007] In some embodiments, the current discharge device further comprises a ground protection device, the ground protection device comprising: a fifth asymmetric conduction characteristic unit, a positive pole of the fifth asymmetric conduction characteristic unit being electrically connected with the ground end and a negative pole of a sixth asymmetric conduction characteristic unit, a negative pole of the fifth asymmetric conduction characteristic unit being electrically connected with the first end of the surge protection device; and the sixth asymmetric conduction characteristic unit, a positive pole of the sixth asymmetric conduction characteristic unit being electrically connected with the second end of the surge protection device.

[0008] In some embodiments, the asymmetric conduction characteristic unit comprises an asymmetric gas discharge tube, the negative pole of the asymmetric gas discharge tube comprises a curved surface portion, the positive pole of the asymmetric gas discharge tube comprises a needle electrode, a tip of the needle electrode is configured to be aligned with an inner surface of the curved surface portion, and there is a predetermined distance between the tip of the needle electrode and the inner surface of the curved surface portion.

[0009] In some embodiments, the tip of the needle electrode is configured to be aligned with the center of the inner surface of the dome; the predetermined distance is less than or equal to the height of the dome; the dome is a graphite dome or a metal dome; the asymmetric gas discharge tube further comprises a housing, the tip of the needle electrode and the dome are disposed in a closed cavity enclosed by the housing.

[0010] In some embodiments, the asymmetric conduction characteristic unit comprises at least two sub-units connected in series, wherein each sub-unit comprises: a gas discharge tube, a first end of the gas discharge tube is electrically connected to one end of a resistor, and is configured as a negative electrode of the sub-unit; a resistor, the other end of the resistor is electrically connected to the negative electrode of a diode; a diode, the positive electrode of the diode is electrically connected to the second end of the gas discharge tube, and is configured as a positive electrode of the sub-unit; wherein the resistance values of the first resistors in different sub-units are not equal.

[0011] In some embodiments, the asymmetric conduction characteristic unit comprises a diode.

[0012] In some embodiments, the surge protection device comprises a clamping unit comprising a pressure-sensitive resistor and / or a transient voltage suppressor; the surge protection device further comprises a switching unit connected in series with the clamping unit, the switching unit comprising a gas discharge tube and / or a semiconductor discharge tube.

[0013] In some embodiments, the number of first asymmetric conduction characteristic units is at least two, and the at least two first asymmetric conduction characteristic units are connected in parallel; the number of second asymmetric conduction characteristic units is at least two, and the at least two second asymmetric conduction characteristic units are connected in parallel; the number of third asymmetric conduction characteristic units is at least two, and the at least two third asymmetric conduction characteristic units are connected in parallel; the number of fourth asymmetric conduction characteristic units is at least two, and the at least two fourth asymmetric conduction characteristic units are connected in parallel; the number of fifth asymmetric conduction characteristic units is at least two, and the at least two fifth asymmetric conduction characteristic units are connected in parallel; the number of sixth asymmetric conduction characteristic units is at least two, and the at least two sixth asymmetric conduction characteristic units are connected in parallel.

[0014] In some embodiments, the number of power supply protection devices is multiple, and each of the multiple power supply protection devices is electrically connected to a power supply end of the protected object.

[0015] The device for surge protection for a protected object of the embodiment of the present disclosure comprises a power protection device, a surge protection device and a current discharge device. The power protection device comprises a first asymmetric conduction characteristic unit and a second asymmetric conduction characteristic unit. The positive electrode of the first asymmetric conduction characteristic unit is electrically connected with the power supply end of the protected object and the negative electrode of the second asymmetric conduction characteristic unit, and the negative electrode of the first asymmetric conduction characteristic unit is electrically connected with the first end of the surge protection device; the positive electrode of the second asymmetric conduction characteristic unit is electrically connected with the second end of the surge protection device. The surge protection device is configured to be turned on when the voltage between the first end and the second end of the surge protection device is greater than a threshold voltage. The current discharge device is configured to be electrically connected with the power protection device, the surge protection device, a ground end and the power supply end of the protected object, so as to form a current discharge path. Wherein, the reverse conduction voltage of the asymmetric conduction characteristic unit is greater than the forward conduction voltage; the power supply end of the protected object is the power supply positive electrode or the power supply negative electrode of the protected object. Therefore, the device for surge protection for a protected object of the embodiment of the present disclosure can significantly reduce the volume of the surge protection device.

[0016] The utility summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. The utility summary is not intended to identify key or essential features of the disclosure, nor is it intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 A structural schematic diagram of a surge protection device is shown.

[0018] Figure 2 A block schematic diagram of the device for surge protection for a protected object of the embodiment of the present disclosure is shown.

[0019] Figure 3 A structural schematic diagram of the device for surge protection for a protected object of the embodiment of the present disclosure is shown.

[0020] Figure 4 A sectional schematic diagram of the asymmetric gas discharge tube of the embodiment of the present disclosure is shown.

[0021] Figure 5 A sectional schematic diagram of the asymmetric gas discharge tube of the embodiment of the present disclosure is shown.

[0022] Figure 6 A structural schematic diagram of the surge protection device of the embodiment of the present disclosure is shown.

[0023] Figure 7 A structural schematic diagram of the device for surge protection for a protected object of the embodiment of the present disclosure is shown.

[0024] Figure 8 A structural diagram of an asymmetric conduction characteristic unit of an embodiment of the present disclosure is shown.

[0025] Figure 9 A structural diagram of an apparatus for surge protection for a protected object of an embodiment of the present disclosure is shown. In various drawings, the same or corresponding reference numbers represent the same or corresponding parts. DETAILED DESCRIPTION

[0026] Preferred embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0027] The term "comprising" and variations thereof as used herein are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Unless otherwise specified, the term "or" as used herein is intended to mean "and / or". The term "based on" means "based, at least in part, on". The terms "one example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "a first", "a second", etc. can refer to different or the same objects.

[0028] As described previously, as the power of the device increases, the number of photovoltaic input lines also increases accordingly, which means that more protection devices (e.g. varistors) are needed to ensure the safe operation of the system. However, as the number of protection devices increases, the size and cost of the surge protection device also increase.

[0029] For example, Figure 1 A structural diagram of a surge protection apparatus 100 is shown. The surge protection apparatus 100 includes a plurality of first surge protection units 102, which are respectively electrically connected to a plurality of positive power supply terminals (e.g. PV1+, PV2+, PV3+, PV4+, etc.) of a protected object. Moreover, the plurality of first surge protection units 102 are respectively electrically connected to a second surge protection unit 104, which is electrically connected to a ground terminal PE. The surge protection apparatus 100 further includes, for example, a third surge protection unit 106, which is electrically connected to the second surge protection unit 104 and the plurality of first surge protection units 102, and is further electrically connected to a feed terminal RTN of the protected object.

[0030] The surge protection unit employed by the surge protection device 100 includes a varistor. It should be understood that for each positive pole of the power supply, the surge protection device 100 is provided with a corresponding first surge protection unit 102. As the power of the device increases, the number of photovoltaic input lines also increases, and the number of corresponding positive poles of the power supply also increases, which means that more surge protection units (e.g., varistors) are needed to ensure the safe operation of the system. However, as the number of surge protection units increases, the size and cost of the surge protection device also increase.

[0031] In addition, it should be understood that in order to avoid polarization, the DC breakdown voltage of the varistor needs to be increased. However, this can result in a higher residual voltage, so when selecting a varistor, it must be ensured that its residual voltage rating is lower than the withstand voltage level of the protected circuit to ensure that the latter circuit is fully protected. Specifically, the DC breakdown voltage of the varistor refers to the voltage value at which it begins to conduct under DC voltage. When this voltage value is increased, the varistor will not conduct under normal operating voltage, thereby avoiding unnecessary current flow. However, once an overvoltage situation occurs, the varistor needs to be activated at a higher voltage to initiate protection, which results in an increase in voltage. The residual voltage refers to the voltage across the varistor after it is turned on, and if the residual voltage is too high, the latter circuit will still be subjected to a high voltage after the varistor activates protection, thereby failing to obtain effective protection. Therefore, when it comes to surge protection devices, it is necessary to balance the increase in DC breakdown voltage and the decrease in residual voltage in order to ensure the safe and stable operation of the circuit.

[0032] To at least partially solve one or more of the above problems and other potential problems, example embodiments of the present disclosure propose a device for surge protection of a protected object, the device comprising a power protection apparatus, a surge protection apparatus, and a current discharge apparatus. The power protection apparatus comprises a first asymmetric conduction characteristic unit and a second asymmetric conduction characteristic unit. A positive pole of the first asymmetric conduction characteristic unit is electrically connected to a power supply end of the protected object and a negative pole of the second asymmetric conduction characteristic unit, and a negative pole of the first asymmetric conduction characteristic unit is electrically connected to a first end of the surge protection apparatus. A positive pole of the second asymmetric conduction characteristic unit is electrically connected to a second end of the surge protection apparatus. The surge protection apparatus is configured to conduct when a voltage between the first end and the second end of the surge protection apparatus is greater than a threshold voltage. The current discharge apparatus is configured to be electrically connected to the power protection apparatus, the surge protection apparatus, a ground end, and a power feeding end of the protected object to form a current discharge path. The reverse breakdown voltage of the asymmetric conduction characteristic unit is greater than the forward breakdown voltage. The power supply end of the protected object is a positive pole or a negative pole of the power supply of the protected object. Therefore, the device for surge protection of a protected object of the example embodiments of the present disclosure can significantly reduce the size of the surge protection device.

[0033] The following illustrates an apparatus for surge protection for a protected object according to an embodiment of the present disclosure with reference to the accompanying drawings. Figure 2 A block schematic diagram of an apparatus 200 for surge protection for a protected object according to an embodiment of the present disclosure is shown. The apparatus 200 comprises, for example, a power protection device 202, a surge protection device 204, and a current leakage device 206. The apparatus 200 is electrically connected to, for example, a protected object 205 for surge protection of the protected object 205. The power protection device 202 is electrically connected to, for example, a power terminal of the protected object 205. The current leakage device 206 is electrically connected to, for example, the power protection device 202, the surge protection device 204, a ground terminal PE, and a feed terminal RTN of the protected object 205.

[0034] The power protection device 202 comprises a first asymmetric conduction characteristic unit and a second asymmetric conduction characteristic unit. The positive terminal of the first asymmetric conduction characteristic unit is electrically connected to the power terminal of the protected object 205 and the negative terminal of the second asymmetric conduction characteristic unit, and the negative terminal of the first asymmetric conduction characteristic unit is electrically connected to a first terminal of the surge protection device 204; the positive terminal of the second asymmetric conduction characteristic unit is electrically connected to a second terminal of the surge protection device 204. The reverse conduction voltage of the asymmetric conduction characteristic unit is greater than the forward conduction voltage.

[0035] The surge protection device 204 is configured to conduct when the voltage between the first terminal and the second terminal of the surge protection device is greater than a threshold voltage.

[0036] The current leakage device 206 is configured to be electrically connected to the power protection device 202, the surge protection device 204, the ground terminal PE, and the feed terminal RTN of the protected object 205 to form a current leakage path.

[0037] In some embodiments, the current leakage device 206 comprises a feed protection device, and the feed protection device comprises a third asymmetric conduction characteristic unit and a fourth asymmetric conduction characteristic unit. The positive terminal of the third asymmetric conduction characteristic unit is electrically connected to the feed terminal of the protected object and the negative terminal of the fourth asymmetric conduction characteristic unit, and the negative terminal of the third asymmetric conduction characteristic unit is electrically connected to the first terminal of the surge protection device; the positive terminal of the fourth asymmetric conduction characteristic unit is electrically connected to the second terminal of the surge protection device.

[0038] In some embodiments, the current leakage device 206 further comprises a ground protection device, which comprises a fifth asymmetric conduction characteristic unit and a sixth asymmetric conduction characteristic unit. The positive pole of the fifth asymmetric conduction characteristic unit is electrically connected with the ground terminal and the negative pole of the sixth asymmetric conduction characteristic unit, and the negative pole of the fifth asymmetric conduction characteristic unit is electrically connected with the first end of the surge protection device; the positive pole of the sixth asymmetric conduction characteristic unit is electrically connected with the second end of the surge protection device.

[0039] The protected object 205 is, for example, a direct current system. The protected object 205 is, for example, an alternating current system. The protected object 205, for example, comprises a photovoltaic inverter. The protected object 205, for example, comprises a direct current interface of a multi-path inverter. The protected object 205, for example, comprises a three-phase alternating current interface.

[0040] As an example, the protected object 205 can comprise a photovoltaic device and a power converter, the power supply end of the protected object 205 (for example, the power supply positive pole of the protected object 205) can be the output end of the photovoltaic device, the feeder end RTN of the protected object 205 can be the feeder end of the power converter, and the ground terminal PE can be the ground terminal of the photovoltaic device.

[0041] Figure 3 A structural schematic diagram of the device 300 for surge protection for a protected object of an embodiment of the present disclosure is shown. Among them, the power supply protection device 202 comprises a first asymmetric conduction characteristic unit (for example, a fourth asymmetric gas discharge tube G4) and a second asymmetric conduction characteristic unit (for example, an eleventh asymmetric gas discharge tube G11). The positive pole of the first asymmetric conduction characteristic unit is electrically connected with the power supply end (for example, the power supply positive pole PV3+) of the protected object 205 and the negative pole of the second asymmetric conduction characteristic unit, and the negative pole of the first asymmetric conduction characteristic unit is electrically connected with the first end of the surge protection device 204; the positive pole of the second asymmetric conduction characteristic unit is electrically connected with the second end of the surge protection device 204.

[0042] Among them, the current leakage device 206 comprises a feeder protection device 262. In some embodiments, the current leakage device 206 further comprises a ground protection device 264.

[0043] The feeder protection device 262 comprises a third asymmetric conduction characteristic unit (for example, a seventh asymmetric gas discharge tube G7) and a fourth asymmetric conduction characteristic unit (for example, an eighth asymmetric gas discharge tube G8). The positive pole of the third asymmetric conduction characteristic unit is electrically connected with the feeder end RTN of the protected object 205 and the negative pole of the fourth asymmetric conduction characteristic unit, and the negative pole of the third asymmetric conduction characteristic unit is electrically connected with the first end of the surge protection device 204; the positive pole of the fourth asymmetric conduction characteristic unit is electrically connected with the second end of the surge protection device 204.

[0044] The ground protection device 264 includes a fifth asymmetric conduction characteristic unit (e.g., the first asymmetric gas discharge tube G1) and a sixth asymmetric conduction characteristic unit (e.g., the fourteenth asymmetric gas discharge tube G14). The positive electrode of the fifth asymmetric conduction characteristic unit is electrically connected with the ground terminal PE and the negative electrode of the sixth asymmetric conduction characteristic unit, and the negative electrode of the fifth asymmetric conduction characteristic unit is electrically connected with the first terminal of the surge protection device; the positive electrode of the sixth asymmetric conduction characteristic unit is electrically connected with the second terminal of the surge protection device.

[0045] The power terminals of the protected object 205 include, for example, a plurality of power terminals corresponding to the plurality of interfaces respectively. As an example, Figure 3 In some embodiments, the power terminals of the protected object 205 are power negative terminals (PV-) of the protected object 205, which have a lower level relative to the feed terminals RTN of the protected object 205. Accordingly, the number of the power protection devices 202 is a plurality, and the plurality of power protection devices 202 are electrically connected with the plurality of power terminals of the protected object 205 respectively. The plurality of power protection devices 202 include, for example, a power protection device composed of the second asymmetric gas discharge tube G2 and the thirteenth asymmetric gas discharge tube G13 (electrically connected with PV1+), a power protection device composed of the third asymmetric gas discharge tube G3 and the twelfth asymmetric gas discharge tube G12 (electrically connected with PV2+), a power protection device composed of the fifth asymmetric gas discharge tube G5 and the tenth asymmetric gas discharge tube G10 (electrically connected with PV4+), a power protection device composed of the sixth asymmetric gas discharge tube G6 and the ninth asymmetric gas discharge tube G9 (electrically connected with PV5+), and the like.

[0046] It is worth mentioning that the asymmetric conduction characteristic units employed in the device 300 include asymmetric gas discharge tubes. Figure 4 A cross-sectional schematic diagram of an asymmetric gas discharge tube 400 of an embodiment of the present disclosure is shown. Figure 5 A partial cross-sectional schematic diagram of the asymmetric gas discharge tube 400 of an embodiment of the present disclosure is shown. The negative electrode of the asymmetric gas discharge tube 400 includes a curved surface portion 402. As an example, Figure 3 In some embodiments, the curved surface portion 402 is represented by a circular arc. The positive electrode of the asymmetric gas discharge tube 400 includes a needle-shaped electrode 404. As an example, Figure 3The needle electrode 404 is represented by an arrow. The tip of the needle electrode 404 is configured to be aligned with the inner surface of the dome 402, and there is a predetermined distance D between the tip of the needle electrode 404 and the inner surface of the dome 402. The asymmetric gas discharge tube 400 further includes a housing 406, the dome 402 and the tip of the needle electrode 404 are disposed in a closed cavity enclosed by the housing 406. The negative electrode of the asymmetric gas discharge tube 400 further includes a negative electrode pin 410, one end of the negative electrode pin 410 is electrically connected to the outer surface of the dome 402, and the other end of the negative electrode pin 410 is led out to the outside of the housing 406. The positive electrode of the asymmetric gas discharge tube 400 further includes a positive electrode pin 408, one end of the positive electrode pin 408 is electrically connected to the needle electrode 404, and the other end of the positive electrode pin 408 is led out to the outside of the housing 406. In some embodiments, the needle electrode 404 and the positive electrode pin 408 are an integral structure, i.e., formed by the same metal structure.

[0047] In some embodiments, the tip of the needle electrode 404 is configured to be aligned with the center of the inner surface of the dome 402. In some embodiments, the predetermined distance D is less than or equal to the height H of the dome 402. In some embodiments, the dome 402 is a graphite dome, i.e., the dome 402 is made of graphite material. In some embodiments, the dome 402 is a metal dome, i.e., the dome 402 is made of metal material.

[0048] It is worth noting that according to the sharp tip discharge effect, the voltage required for the needle electrode 404 to discharge to one side of the dome 402 (i.e., the forward conduction voltage) is less than the voltage required for the dome 402 to discharge to one side of the needle electrode 404 (i.e., the reverse conduction voltage). The dome 402 and the needle electrode 404 form a structure similar to an umbrella. The curvature, diameter, etc. of the dome 402 can be reasonably set according to requirements. The predetermined distance D between the tip of the needle electrode 404 and the inner surface of the dome 402 can be reasonably set according to requirements. It is worth noting that factors such as the curvature, diameter of the dome 402, the predetermined distance D between the tip of the needle electrode 404 and the inner surface of the dome 402, the material of the dome 402, etc. can affect the forward conduction voltage and the reverse conduction voltage of the asymmetric gas discharge tube 400. In some embodiments, the reverse conduction voltage of the asymmetric gas discharge tube 400 is twice or more than the forward conduction voltage.

[0049] Regarding the surge protection device 204, it for example includes a surge protection device including a clamping unit, the clamping unit including a pressure-sensitive resistor. In some embodiments, the clamping unit can also include a TVS (Transient Voltage Suppressors).

[0050] Figure 6A structural diagram of a surge protection device 204 of an embodiment of the present disclosure is shown. The surge protection device 204 includes, for example, a clamping unit 242, a first switching unit 244, and a second switching unit 246 in series. The clamping unit 242 includes, for example, a varistor, and the second switching unit 246 includes, for example, a gas discharge tube (GDT). It is worth mentioning that the gas discharge tube GDT has a large current-carrying capacity, that is, among other protective devices such as a TVS (Transient Voltage Suppressor), a MOV (Metal Oxide Varistor), a TSS (Thyristor Surge Suppressors), and the like, the gas discharge tube GDT has the largest current-carrying capacity per unit area, and thus the gas discharge tube GDT has a higher cost performance. In some embodiments, the second switching unit 246 includes, for example, a TSS (Thyristor Surge Suppressors).

[0051] The main function of the surge protection device 204 is to provide lightning protection, and in order to ensure its effectiveness, a suitable surge protection device 204 can need to be selected according to various parameters such as its current-carrying capacity, operating voltage, and the like. This can ensure that the circuit can be fully protected in the face of extreme weather conditions such as lightning.

[0052] When the protected object 205 is in an abnormal operating state, for example, a surge occurs due to lightning or the like, the power supply positive terminal and / or the feed terminal RTN of the protected object 205 can surge with an overvoltage, and the device 300 acts due to the overvoltage to provide a large current discharge path to ground, limit the amplitude of the temporary overvoltage, and protect the subsequent circuit in the protected object 205 from the surge. Regarding the working principle of the device 300, taking the lightning path in the direction from the power supply positive terminal PV1+ to the feed terminal RTN as an example, when a surge is injected from the power supply positive terminal PV1+, the second asymmetric gas discharge tube G2 conducts (for example, the second asymmetric gas discharge tube G2 breaks down). Subsequently, the surge current causes the surge protection device 204 to conduct (for example, the surge protection device 204 breaks down), and finally the eighth asymmetric gas discharge tube G8 conducts (for example, the eighth asymmetric gas discharge tube G8 breaks down), so the surge current is guided to the feed terminal RTN.

[0053] In addition, the seventh asymmetric gas discharge tube G7, the surge protection device 204, and the thirteenth asymmetric gas discharge tube G13 also provide a path for discharging the surge current from the feed terminal RTN to the power supply positive terminal PV1+.

[0054] Similarly, the second asymmetric gas discharge tube G2, the surge protection device 204, and the fourteenth asymmetric gas discharge tube G14 also provide a path for discharging the surge current from the power supply positive terminal PV1+ to the ground terminal PE.

[0055] The first asymmetric gas discharge tube G1, the surge protection device 204 and the thirteenth asymmetric gas discharge tube G13 further provide a path for discharging a surge current from the ground terminal PE to the positive power supply terminal PV1+.

[0056] The seventh asymmetric gas discharge tube G7, the surge protection device 204 and the fourteenth asymmetric gas discharge tube G14 further provide a path for discharging a surge current from the feed terminal RTN to the ground terminal PE.

[0057] The first asymmetric gas discharge tube G1, the surge protection device 204 and the eighth asymmetric gas discharge tube G8 further provide a path for discharging a surge current from the ground terminal PE to the feed terminal RTN.

[0058] In some embodiments, the number of ground protection devices 264 is at least two, and the at least two ground protection devices 264 are connected in parallel. That is, the number of first asymmetric gas discharge tubes G1 is at least two, and the at least two first asymmetric gas discharge tubes G1 are connected in parallel, and the number of fourteenth asymmetric gas discharge tubes G14 is at least two, and the at least two fourteenth asymmetric gas discharge tubes G14 are connected in parallel. The number of first asymmetric gas discharge tubes G1 and the number of fourteenth asymmetric gas discharge tubes G14 may, for example, be equal.

[0059] In some embodiments, the number of power supply protection devices 202 is at least two for a same power supply terminal of the protected object 205, and the at least two power supply protection devices 202 are connected in parallel. For example, the number of fourth asymmetric gas discharge tubes G4 is at least two, and the at least two fourth asymmetric gas discharge tubes G4 are connected in parallel, and the number of eleventh asymmetric gas discharge tubes G11 is at least two, and the at least two eleventh asymmetric gas discharge tubes G11 are connected in parallel. The number of fourth asymmetric gas discharge tubes G4 and the number of eleventh asymmetric gas discharge tubes G11 may, for example, be equal.

[0060] In some embodiments, the number of feed protection devices 262 is at least two, and the at least two feed protection devices 262 are connected in parallel. For example, the number of seventh asymmetric gas discharge tubes G7 is at least two, and the at least two seventh asymmetric gas discharge tubes G7 are connected in parallel, and the number of eighth asymmetric gas discharge tubes G8 is at least two, and the at least two eighth asymmetric gas discharge tubes G8 are connected in parallel. The number of seventh asymmetric gas discharge tubes G7 and the number of eighth asymmetric gas discharge tubes G8 may, for example, be equal.

[0061] Therefore, the occurrence of the surge causes the power protection device 202, the surge protection device 204 and the current discharge device 206 of the surge protection device to conduct, and the device 300 can release the surge energy into the ground (e.g. the grounding terminal PE) and / or the feed terminal RTN. When the surge energy is released, or the overvoltage disappears, the device 300 returns to the off state again. The device 300 can significantly reduce the size of the surge protection device.

[0062] Figure 7 A structural schematic diagram of a device 700 for surge protection for a protected object according to an embodiment of the present disclosure is shown. The power protection device 202 includes a first asymmetric conduction characteristic unit and a second asymmetric conduction characteristic unit. The positive electrode of the first asymmetric conduction characteristic unit is electrically connected to the power terminal of the protected object 205 and the negative electrode of the second asymmetric conduction characteristic unit, and the negative electrode of the first asymmetric conduction characteristic unit is electrically connected to the first end of the surge protection device 204; the positive electrode of the second asymmetric conduction characteristic unit is electrically connected to the second end of the surge protection device 204. As an example, Figure 7 In some embodiments, the power terminal of the protected object 205 is the positive electrode (PV+) of the protected object 205, and the positive electrode of the protected object 205 has a higher level relative to the feed terminal RTN of the protected object 205.

[0063] In some embodiments, the current discharge device 206 further includes a ground protection device 264.

[0064] Figure 8 A structural schematic diagram of an asymmetric conduction characteristic unit 701 according to an embodiment of the present disclosure is shown. The asymmetric conduction characteristic unit 701 used in the device 700 includes, for example, at least two sub-units connected in series, wherein each sub-unit includes: a gas discharge tube, a first end of the gas discharge tube is electrically connected to one end of a resistor, and is configured as a negative electrode of the sub-unit; a resistor, the other end of the resistor is electrically connected to the negative electrode of a diode; a diode, the positive electrode of the diode is electrically connected to the second end of the gas discharge tube, and is configured as a positive electrode of the sub-unit; wherein the resistance values of the first resistors in different sub-units are not equal. Figure 8The asymmetric conduction characteristic unit 701 shown includes two sub-units, a first sub-unit 702 and a second sub-unit 703, which are connected in series. In some embodiments, the asymmetric conduction characteristic unit 701 can include three or more sub-units, and the sub-units are connected in series.

[0065] The asymmetric conduction characteristic unit 701 used in the device 700 includes the first sub-unit 702 and the second sub-unit 703, which are connected in series. The negative electrode of the first sub-unit 702 is the negative electrode of the asymmetric conduction characteristic unit 701, the positive electrode of the first sub-unit 702 is electrically connected to the negative electrode of the second sub-unit 703, and the positive electrode of the second sub-unit 703 is the positive electrode of the asymmetric conduction characteristic unit 701. For example, the first sub-unit 702 includes a first gas discharge tube 711, a first diode 712, and a first resistor 715; and the second sub-unit 703 includes a second gas discharge tube 713, a second diode 714, and a second resistor 716.

[0066] The first end of the first gas discharge tube 711 is electrically connected to one end of the first resistor 715, and is configured as the negative electrode of the first sub-unit 702, which is the negative electrode of the asymmetric conduction characteristic unit 701. The other end of the first resistor 715 is electrically connected to the negative electrode of the first diode 712. The positive electrode of the first diode 712 is electrically connected to the second end of the first gas discharge tube 711, and is configured as the positive electrode of the first sub-unit 702; the first end of the second gas discharge tube 713 is electrically connected to one end of the second resistor 716 and the second end of the first gas discharge tube 711, and is configured as the negative electrode of the second sub-unit 703, the second end of the second gas discharge tube 713 is configured as the positive electrode of the second sub-unit 702, which is the positive electrode of the asymmetric conduction characteristic unit 701; the other end of the second resistor 716 is electrically connected to the negative electrode of the second diode 714. The positive electrode of the second diode 714 is electrically connected to the second end of the second gas discharge tube 713. The resistance value of the first resistor 715 is not equal to the resistance value of the second resistor 716.

[0067] It is worth mentioning that the asymmetric conduction characteristic unit 701 adopts two or more standard GDT elements (for example, the first gas discharge tube 711, the second gas discharge tube 713, and the like) to realize the surge protection function characteristic of the device 700 by means of a trigger circuit. The trigger circuit, for example, includes a diode (for example, the first diode 712, the second diode 714). The trigger circuit, for example, also includes a resistor (for example, the first resistor 715, the second resistor 716) connected in series with the diode. Among them, the trigger circuit uses the unidirectional conductivity of the diode to set a specific conduction direction for the surge path. In addition, by configuring the first resistor 715 and the second resistor 716 to have unequal resistance values, the conduction timing of the GDT in parallel with the trigger circuit can be adjusted, so that the two GDTs in series can conduct in a predetermined order, thereby effectively reducing the single-direction conduction voltage. For example, in some embodiments, the resistance value of the first resistor 715 is greater than the resistance value of the second resistor 716, and then the first gas discharge tube 711 conducts first and the second gas discharge tube 713 conducts later. In some embodiments, the resistance value of the first resistor 715 is less than the resistance value of the second resistor 716, and then the second gas discharge tube 713 conducts first and the first gas discharge tube 711 conducts later. If the surge path is consistent with the off direction of the diode, the breakdown voltage in this direction will be the sum of the breakdown voltages of the multiple GDTs.

[0068] In some embodiments, the number of ground protection devices 264 is at least two, and the at least two ground protection devices 264 are connected in parallel.

[0069] Figure 9 A structural schematic diagram of a device 900 for surge protection for a protected object according to an embodiment of the present disclosure is shown. Among them, the power protection device 202 includes a first asymmetric conduction characteristic unit and a second asymmetric conduction characteristic unit. The positive electrode of the first asymmetric conduction characteristic unit is electrically connected with the power supply end of the protected object 205 and the negative electrode of the second asymmetric conduction characteristic unit, the negative electrode of the first asymmetric conduction characteristic unit is electrically connected with the first end of the surge protection device 204; the positive electrode of the second asymmetric conduction characteristic unit is electrically connected with the second end of the surge protection device 204. The power supply end of the protected object 205, for example, is multiple, and the multiple power supply ends, for example, respectively correspond to multiple interfaces of the protected object 205. The multiple power supply ends of the protected object 205, for example, are PV1+, PV2+, PV11+, PV12+, and the like. In some embodiments, the multiple power supply ends of the protected object 205, for example, are multiple power supply negative electrodes of the protected object 205.

[0070] Correspondingly, the number of the power protection devices 202 is multiple, and the multiple power protection devices 202 are respectively electrically connected with multiple power terminals of the protected object 205. The multiple power protection devices 202 for example include a power protection device composed of the third diode D3 and the tenth diode D12 (electrically connected with PV1+), a power protection device composed of the fourth diode D4 and the eleventh diode D11 (electrically connected with PV2+), a power protection device composed of the fifth diode D5 and the twelfth diode D10 (electrically connected with PV11+), a power protection device composed of the sixth diode D6 and the ninth diode D9 (electrically connected with PV12+), and the like.

[0071] The current discharge device 206 includes the power feeding protection device 262. In some embodiments, the current discharge device 206 further includes the grounding protection device 264. In some embodiments, the number of the grounding protection device 264 is at least two, and the at least two grounding protection devices 264 are in parallel. In some embodiments, the number of the power feeding protection device 262 is at least two, and the at least two power feeding protection devices 262 are in parallel. In some embodiments, the number of the surge protection device 204 is at least two, and the at least two surge protection devices 204 are in parallel. The surge protection device 204 for example includes the first clamping unit 243, the second clamping unit 245, and the switching unit 245 in series.

[0072] The asymmetric conduction characteristic unit adopted in the device 900 for example is a diode, wherein the positive electrode of the diode is the positive electrode of the asymmetric conduction characteristic unit, and the negative electrode of the diode is the negative electrode of the asymmetric conduction characteristic unit.

[0073] It is worth mentioning that the diodes as the first asymmetric conduction characteristic unit and the second asymmetric conduction characteristic unit form a half-bridge structure, which forms a lightning protection shunt branch. Specifically, the cathode of the first diode in the half-bridge structure is connected to the first end of the surge protection device 204 (for example, the positive electrode of the surge protection device 204), and the anode of the second diode in the half-bridge structure is connected to the second end of the surge protection device 204 (for example, the negative electrode of the surge protection device 204). The middle connection point of the two diodes is directly connected to the input end of the circuit branch to be protected. It is worth mentioning that in the device 900, the diode as the asymmetric conduction characteristic unit can be a general diode, but also can be a TSS (Thyristor Surge Suppressors, surge suppression thyristor). It should be understood that the semiconductor discharge tube is a voltage switch type transient voltage suppression diode, also known as a solid discharge tube, a surge suppression thyristor, and is a PNPN junction four-layer structure device made of semiconductor technology. In addition, the diode as the asymmetric conduction characteristic unit can also be a TVS (Transient Voltage Suppressors, transient voltage suppressor), also known as an avalanche breakdown diode, which is a high-efficiency circuit protection device, mainly for protecting the circuit from the impact of transient high-voltage spike pulses (static electricity or lightning surge).

[0074] The core function of the surge protection device 204 is to provide reliable lightning protection. In order to ensure its effectiveness, the lightning protection device can be carefully selected according to key parameters such as current-carrying capacity and operating voltage, so as to ensure that the circuit is fully protected under extreme weather conditions such as lightning.

[0075] When the protected object 205 is in an abnormal working state, for example, a surge occurs due to lightning, the power supply positive terminal and / or the feed terminal RTN of the protected object 205 will surge into an overvoltage, and the device 900 will act due to the overvoltage to provide a large current discharge path to the ground, limit the amplitude of the temporary overvoltage, and protect the subsequent circuit in the protected object 205 from the influence of the surge. Regarding the working principle of the device 900, taking the lightning path in the direction from the power supply positive terminal PV1+ to the feed terminal RTN as an example, when the surge is injected from the power supply positive terminal PV1+, the third diode D3 is turned on. Subsequently, the surge current causes the surge protection device 204 to be turned on (for example, the surge protection device 204 breaks down), and finally the eighth diode D8 is turned on, so that the surge current is guided to the feed terminal RTN.

[0076] In addition, the seventh diode D7, the surge protection device 204, and the tenth diode D12 also provide a path for discharging the surge current from the feed terminal RTN to the power supply positive terminal PV1+.

[0077] Similarly, the third diode D3, the surge protection device 204, and the fourteenth diode D14 also provide a path for discharging surge current from the power supply positive pole PV1+ to the ground PE.

[0078] The first diode D1, the surge protection device 204, and the tenth diode D12 also provide a path for discharging surge current from the ground PE to the power supply positive pole PV1+.

[0079] The seventh diode D7, the surge protection device 204, and the fourteenth diode D14 also provide a path for discharging surge current from the feed end RTN to the ground PE.

[0080] The first diode D1, the surge protection device 204, and the eighth diode D8 also provide a path for discharging surge current from the ground PE to the feed end RTN.

[0081] In some embodiments, the number of the ground protection devices 264 is at least two, and the at least two ground protection devices 264 are connected in parallel. For example, the first diode D1 and the second diode D2 are connected in parallel, and the fourteenth diode D14 and the thirteenth diode D13 are connected in parallel.

[0082] In some embodiments, the number of the power supply protection devices 202 corresponding to the same power supply end of the protected object 205 is at least two, and the at least two power supply protection devices 202 are connected in parallel. For example, the number of the fourth diodes D4 is at least two, and the at least two fourth diodes D4 are connected in parallel, and the number of the eleventh diodes D11 is at least two, and the at least two eleventh diodes D11 are connected in parallel. The number of the fourth diodes D4 and the number of the eleventh diodes D11 may, for example, be equal.

[0083] In some embodiments, the number of the feed protection devices 262 is at least two, and the at least two feed protection devices 262 are connected in parallel. For example, the number of the seventh diodes D7 is at least two, and the at least two seventh diodes D7 are connected in parallel, and the number of the eighth diodes D8 is at least two, and the at least two eighth diodes D8 are connected in parallel. The number of the seventh diodes D7 and the number of the eighth diodes D8 may, for example, be equal.

[0084] Therefore, the occurrence of the surge causes the power supply protection device 202, the surge protection device 204, and the current discharge device 206 of the surge protection device to be turned on, and the device 900 can release the surge energy into the ground (for example, the ground PE) and / or the feed end RTN. After the surge energy is released, or after the overvoltage disappears, the device 900 returns to the off state again. The device 900 can significantly reduce the size of the surge protection device.

[0085] In some embodiments, the number of grounding protection devices 264 is at least two, and the at least two grounding protection devices 264 are connected in parallel, so as to enhance the current carrying capacity of the protection branch to ground (for example, the chassis). In some specific application scenarios, it is necessary to meet the lightning test requirements of double-wire-to-ground, and therefore the structure of at least two grounding protection devices 264 connected in parallel can better meet these requirements.

[0086] In addition, it is worth noting that the device 900 is not only suitable for the DC interface of the multi-channel inverter, but also suitable for the three-phase AC interface. Whether it is a DC circuit or an AC circuit, the scheme can play a protective role and ensure the safe and stable operation of the circuit.

[0087] Having described various embodiments of the disclosure, the above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0088] The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements in the technology in the market, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

[0089] The above is only an optional embodiment of the disclosure, and is not used to limit the disclosure. For those skilled in the art, the disclosure can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the disclosure shall be included in the protection scope of the disclosure.

Claims

1. An apparatus for surge protection for a protected object, characterized by The power supply protection device comprises: a first asymmetric conduction characteristic unit, a positive electrode of the first asymmetric conduction characteristic unit being electrically connected to a power supply end of the protected object and a negative electrode of a second asymmetric conduction characteristic unit, and a negative electrode of the first asymmetric conduction characteristic unit being electrically connected to a first end of the surge protection device; and a second asymmetric conduction characteristic unit, a positive electrode of the second asymmetric conduction characteristic unit being electrically connected to a second end of the surge protection device; the surge protection device being configured to be turned on when a voltage between the first end and the second end of the surge protection device is greater than a threshold voltage; the surge protection device comprising a clamping unit; and a current discharge device being electrically connected to the power supply protection device, the surge protection device, a ground end and a power feeding end of the protected object so as to form a current discharge path. The asymmetric conduction characteristic unit has a reverse conduction voltage greater than a forward conduction voltage; the power supply end of the protected object is a power supply positive electrode or a power supply negative electrode of the protected object; the power supply negative electrode has a lower level relative to the power feeding end, and the power supply positive electrode has a higher level relative to the power feeding end. The current discharge device comprises a power feeding protection device, and the power feeding protection device comprises:

2. The apparatus of claim 1, wherein, a third asymmetric conduction characteristic unit, a positive electrode of the third asymmetric conduction characteristic unit being electrically connected to the power feeding end of the protected object and a negative electrode of a fourth asymmetric conduction characteristic unit, and a negative electrode of the third asymmetric conduction characteristic unit being electrically connected to the first end of the surge protection device; and a fourth asymmetric conduction characteristic unit, a positive electrode of the fourth asymmetric conduction characteristic unit being electrically connected to the second end of the surge protection device. The current discharge device further comprises a ground protection device, and the ground protection device comprises:

3. The apparatus of claim 2, wherein, a fifth asymmetric conduction characteristic unit, a positive electrode of the fifth asymmetric conduction characteristic unit being electrically connected to the ground end and a negative electrode of a sixth asymmetric conduction characteristic unit, and a negative electrode of the fifth asymmetric conduction characteristic unit being electrically connected to the first end of the surge protection device; and a sixth asymmetric conduction characteristic unit, a positive electrode of the sixth asymmetric conduction characteristic unit being electrically connected to the second end of the surge protection device. The asymmetric conduction characteristic unit comprises an asymmetric gas discharge tube, a negative electrode of the asymmetric gas discharge tube comprising a curved surface part, and a positive electrode of the asymmetric gas discharge tube comprising a needle-shaped electrode, a tip end of the needle-shaped electrode being configured to be aligned with an inner surface of the curved surface part, and a predetermined distance being provided between the tip end of the needle-shaped electrode and the inner surface of the curved surface part.

4. The apparatus of claim 1, wherein, The tip end of the needle-shaped electrode is configured to be aligned with a center of the inner surface of the curved surface part; the predetermined distance is less than or equal to a height of the curved surface part; and the curved surface part is a graphite curved surface part or a metal curved surface part.

5. The apparatus of claim 4, wherein, The asymmetric gas discharge tube further comprises an outer shell, and the tip end of the needle-shaped electrode and the curved surface part are arranged in a closed cavity surrounded by the outer shell. The asymmetric conduction characteristic unit comprises at least two sub-units connected in series, and each sub-unit comprises:

6. The apparatus of claim 1, wherein, a gas discharge tube, a first end of the gas discharge tube being electrically connected to one end of a resistor, and being configured as a negative electrode of the sub-unit; a resistor, the other end of the resistor being electrically connected to a negative electrode of a diode; a diode, a positive electrode of the diode being electrically connected to a second end of the gas discharge tube, and being configured as a positive electrode of the sub-unit. ​ The resistance values of the resistors in different sub-units are not equal.

7. The apparatus of claim 1, wherein, The asymmetric conduction characteristic unit comprises a diode.

8. The apparatus of claim 1, wherein, The clamping unit comprises a pressure-sensitive resistor and / or a transient voltage suppressor; the surge protection device further comprises a switching unit connected in series with the clamping unit.

9. The apparatus of claim 3, wherein, The number of the first asymmetric conduction characteristic units is at least two, and the at least two first asymmetric conduction characteristic units are connected in parallel. The number of the second asymmetric conduction characteristic units is at least two, and the at least two second asymmetric conduction characteristic units are connected in parallel. The number of the third asymmetric conduction characteristic units is at least two, and the at least two third asymmetric conduction characteristic units are connected in parallel. The number of the fourth asymmetric conduction characteristic units is at least two, and the at least two fourth asymmetric conduction characteristic units are connected in parallel. The number of the fifth asymmetric conduction characteristic units is at least two, and the at least two fifth asymmetric conduction characteristic units are connected in parallel. The number of the sixth asymmetric conduction characteristic units is at least two, and the at least two sixth asymmetric conduction characteristic units are connected in parallel.

10. The apparatus of claim 1, wherein, The number of the power supply protection devices is multiple, and the multiple power supply protection devices are respectively connected with multiple power supply ends of the protected objects.

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