Photovoltaic direct-current isolating switch

Abstract

The invention relates to the technical field of disconnecting switches, in particular to a photovoltaic direct-current disconnecting switch which comprises a shell, an input terminal, an output terminal, an air pipe, an adjusting mechanism, an adjusting disc, a connecting block, a variable resistance mechanism and an output disc, the input terminal is installed on the left side of the shell, the output terminal is installed on the right side of the shell, the air pipe is installed on the shell, and the adjusting disc is installed on the right side of the shell. The adjusting mechanism is installed at the air pipe, the adjusting disc is installed between the input terminal and the output terminal, the connecting block is located at the input terminal, the variable resistance mechanism is installed on the adjusting disc, the output disc is installed at the output terminal, and when the temperature rises, the air pipe drives the adjusting disc to rotate through the adjusting mechanism. When the adjusting disc rotates, the variable resistance mechanism increases the resistance between the connecting block and the output disc, and through the thermal expansion and cold contraction principle of nitrogen, the resistance at the switch can be gradually increased when the temperature rises, so that the stability of output current is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of isolating switches, in particular to a photovoltaic direct current isolating switch. Background Art

[0002] The photovoltaic DC isolating switch is a safety device used in photovoltaic systems. Its function is to cut off the DC circuit in the event of maintenance or failure to ensure the safety of the system. Its principle is to interrupt the current by physically separating the contact points in the circuit.

[0003] During the use of photovoltaic DC circuits, after the isolating switch is connected to the circuit between the photovoltaic module and the inverter, when the power system fails, the following situations exist: when the circuit is broken, the internal current is transmitted to the switch, and the resistance at the switch is constant. At this time, the temperature will gradually rise. At this time, the continuous output current will cause arcing at the switch, which is easy to cause a fire, and then lead to a larger range of paralysis of the power system and damage to power equipment; second, when the circuit is short-circuited, the current is not affected by the resistance, and the current continues to increase, causing the temperature to rise, further affecting the entire circuit system; therefore, when the power system fails, the temperature at the switch will continue to rise, and the resistance of the resistor will decrease with the increase in temperature, causing the current to gradually increase, affecting the normal use of the output current.

[0004] In order to solve the above problems, a variety of solutions have been proposed in the prior art, such as a photovoltaic DC fast isolating switch with patent number CN219180380U, which detects the surface temperature of the moving contact and the static contact in real time through a thermistor. When the temperature detected by the thermistor is higher than the set value, the single-chip microcomputer controls the operating mechanism to separate the static contact and the moving contact to disconnect the circuit, thereby reducing the occurrence of fires caused by power system failures; however, the set value of the thermistor is a fixed value. When the circuit is damaged and the current gradually increases, the thermistor has not reached the set value, and the current at the output end has exceeded the required current, thereby affecting the normal use of the power system.

[0005] Based on this, in order to solve the problem of how to keep the current stable as the internal temperature gradually increases when a power system fails, the present invention designs a photovoltaic DC isolation switch. Summary of the invention

[0006] A photovoltaic DC isolating switch provided by the present invention is designed to solve the problem of how to keep the current stable as the internal temperature gradually increases when a power system fails. The thermal expansion and contraction principle of nitrogen is used to adjust the resistance at the switch. When the temperature rises, the resistance at the switch can be gradually increased, thereby changing the current at the output end. The nitrogen is simultaneously used to block the current protection circuit to ensure the stability of the output current.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A photovoltaic DC isolating switch provided by the present invention comprises a housing, an input terminal, an output terminal, an air pipe, an adjustment mechanism, an adjustment disk, a connecting block, a variable resistance mechanism, and an output disk, wherein the input terminal is installed on the left side of the housing, the output terminal is installed on the right side of the housing, the air pipe is installed on the housing, the adjustment mechanism is installed at the air pipe, the adjustment disk is installed between the input terminal and the output terminal, the connecting block is located at the input terminal, the variable resistance mechanism is installed on the adjustment disk, and the output disk is installed at the output terminal, when the temperature rises, the air pipe drives the adjustment disk to rotate through the adjustment mechanism, and when the adjustment disk rotates, the variable resistance mechanism increases the resistance between the connecting block and the output disk;

[0009] The regulating mechanism uses the principle of thermal expansion and contraction to drive the slider crank transmission, and the variable resistance mechanism uses the principle of sliding rheostat to adjust the resistance. The two cooperate with each other to achieve synchronous change of the output current as the temperature changes, thereby improving the stability of the current.

[0010] Preferably, the adjustment mechanism includes a conduction rod, a piston, a connecting rod, and a shift block, one end of the conduction rod is installed at the end of the input terminal, the other end of the conduction rod is connected to the air pipe, the piston is located in the air pipe, the connecting rod is installed at the end of the piston, the shift block is installed in a groove on the adjustment disk, and the connecting rod is connected to the shift block; attention should be paid to the extreme position of the slider crank during transmission to avoid locking of the slider during transmission, and it is necessary to ensure that its stroke is within 180 degrees, thereby improving the stability of the transmission.

[0011] Preferably, the variable resistance mechanism includes a conductor, a resistor, an insulator and a fixed block, and the conductor, resistor and insulator are all installed on an adjusting disk, and the conductor, resistor and insulator are arranged in sequence and are all arc-shaped. The circle formed by the three is concentric with the adjusting disk, and the fixed block is installed between the adjusting disk and the output disk; when the temperature gradually increases, it means that the current at the input terminal is too large. At this time, the piston will drive the adjusting disk to rotate, and the adjusting disk rotates to the resistor. During the current flow, the resistance at this place is increased, thereby reducing the current at the output terminal, so that the current at the output terminal is always maintained below the threshold range.

[0012] Preferably, an expansion airbag is installed between the piston and the inner wall of the trachea, and a compression airbag is installed on the other side of the bottom of the piston. An air outlet is provided on the compression airbag, and both the expansion airbag and the compression airbag are filled with nitrogen. The compression airbag is filled with nitrogen, and during the movement of the piston, the compression airbag will be squeezed, so that the gas in the compression airbag flows into the shell from the air outlet, thereby reducing the internal current propagation.

[0013] Preferably, a rotating shaft is installed at the center of the adjusting disk, and a motor driving the adjusting disk to rotate is installed at the input end of the rotating shaft. The adjusting disk is a symmetrical structure, and the length ratio of the conductor, resistor and insulator is 1:6:2, ensuring that the piston drives the adjusting disk to rotate within a certain range. The rotating shaft is fixed to the adjusting disk, and the motor here can be a brushless DC motor, and the rotating shaft of the brushless DC motor can rotate freely when it is not powered. Because the brushless DC motor does not rely on brushes and commutators to change the direction of the current, but electronically controls the current in the stator winding, thereby changing the direction of the magnetic field to drive the rotor. When the motor is not powered, there is no magnetic field acting on the rotor, so the rotating shaft can rotate freely and will not be locked by the magnetic field inside the motor.

[0014] Preferably, a round ball is installed on the fixed block, the round ball is in contact with the adjustment disk, a reed is installed between the round ball and the fixed block, the reed is a conductive material, and the interior of the fixed block is connected to the compressed airbag; on the one hand, the reed can support the round ball, and on the other hand, the reed can block the current transmission when the round ball is suspended in the air.

[0015] Preferably, the back of the adjusting disk is stepped, and the position of the adjusting disk back corresponding to the insulator does not contact the ball; when the adjusting disk rotates to the extreme position, the ball is not squeezed, and the reed separates the ball from the output disk through its own deformation, thereby achieving secondary circuit breaking.

[0016] Preferably, the output disk is in a circular ring shape, a variable resistor is installed on the output disk, a metal strip connected to the output terminal is installed on the output disk, a fixed resistor is installed on the output disk symmetrically to the variable resistor, a conductive sheet is installed between the variable resistor and the metal strip, and the conductive sheet is connected to the adjustment disk through an insulating rod; as the adjustment disk rotates, the insulating rod will drive the conductive sheet to gradually move to the right, at this time, like a sliding rheostat, the resistance of the variable resistor gradually increases, which will drive the overall resistance of the output disk to gradually increase.

[0017] Preferably, the maximum resistance of the variable resistor is equal to that of the fixed resistor, and when the conductive sheet slides and the variable resistor is close to one side of the connecting block, the current does not pass through the fixed resistor; when the adjusting disk is rotated to the extreme position, the parallel resistance is equal to half of the resistance of the fixed resistor, thereby forming triple protection for the circuit.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. A photovoltaic DC isolating switch proposed in the present invention uses the thermal expansion and contraction principle of nitrogen and an adjusting mechanism to control the rotation of an adjusting disk, so that the variable resistance mechanism on the adjusting disk can increase its own resistance as the heat increases, thereby compensating for the resistance reduction caused by the temperature increase, thereby reducing the increase in output current caused by the resistance reduction, and thus improving the stability of the output current.

[0020] 2. A photovoltaic DC isolating switch proposed in the present invention, when the temperature gradually rises, the piston will drive the adjusting disk to rotate, and the adjusting disk will rotate to the resistor. During the current flow, the resistance at this place is increased, and then the current at the output terminal is reduced, so that the current at the output terminal is always maintained below the threshold range; and as the temperature gradually rises, the adjusting disk is gradually rotated under the influence of the piston and the connecting rod, and the insulator on the adjusting disk is connected to the connecting block. At this time, the current flowing into the input terminal is isolated by the insulator. At this time, the entire circuit is broken, and overheating protection is formed. At the same time, the specific position of the switch break can be known according to the circuit connection between different switches, which is convenient for locating the position of the temperature increase area, thereby providing convenience for circuit maintenance and improving the stability of current transmission.

[0021] 3. The photovoltaic DC isolating switch proposed by the present invention has a ball that can always be rotatably connected to the adjustment disk, and at this time the current can also be transmitted to the output disk through the ball, and the reed can be squeezed. On the one hand, the reed can support the ball, and on the other hand, the reed can block the current transmission when the ball is suspended in the air, and the gas in the compressed airbag is conducted to between the reed and the output disk. When the piston suddenly moves to the rightmost end, the compressed airbag is completely squeezed, and a part of the gas in the compressed airbag flows from the air outlet to the inside of the shell, and the other part will enter between the reed and the output disk, thereby blocking the ball and the output disk, avoiding the transmission of current and improving the current overload protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation mode of the present invention or the technical solution in the prior art, the drawings required for use in the specific implementation mode or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are one implementation mode of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 is a schematic diagram of the appearance of the switch of the present invention;

[0024] Figure 2 is a partial cross-sectional view of the switch of the present invention;

[0025] Figure 3 is a schematic diagram of the adjustment mechanism of the present invention;

[0026] Figure 4 It is a state diagram of the connection between the connection block and the resistor body of the present invention;

[0027] Figure 5 It is a state diagram of the connection block and the insulator of the present invention being connected;

[0028] Figure 6 is a schematic diagram of the motor of the present invention;

[0029] Figure 7 is a schematic diagram of the variable resistance mechanism of the present invention;

[0030] Figure 8 It is an exploded view of the adjusting disk and the output disk of the present invention.

[0031] In the figure: 1. shell; 2. input terminal; 3. output terminal; 4. air pipe; 41. expansion airbag; 42. compression airbag; 421. air outlet; 5. adjustment mechanism; 51. conduction rod; 52. piston; 53. connecting rod; 54. dial block; 6. adjustment disk; 61. rotating shaft; 62. motor; 7. connecting block; 8. variable resistance mechanism; 81. conductor; 82. resistor; 83. insulator; 84. fixed block; 841. ball; 842. reed; 9. output disk; 91. variable resistor; 92. metal strip; 93. fixed resistor; 94. conductive sheet; 95. insulating rod. DETAILED DESCRIPTION

[0032] In order to better understand the above solution, the above technical solution is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0033] like Figure 1-2 As shown, a photovoltaic DC isolating switch provided by the present invention comprises a housing 1, an input terminal 2, an output terminal 3, an air pipe 4, an adjustment mechanism 5, an adjustment disk 6, a connecting block 7, a variable resistance mechanism 8, and an output disk 9. The input terminal 2 is installed on the left side of the housing 1, and the output terminal 3 is installed on the right side of the housing 1. The input terminal 2 and the output terminal 3 are respectively connected to external lines. The air pipe 4 is installed on the housing 1. The outer shell of the air pipe 4 and the housing 1 are both made of insulating materials. The adjustment mechanism 5 is installed at the air pipe 4. The adjustment disk 6 is installed between the input terminal 2 and the output terminal 3. The adjustment disk 6 is equivalent to a sliding variable resistance. During the rotation of the adjusting disk 6, the current is connected from the input terminal 2 to the connecting block 7, and then the current flows from the connecting block 7 into the adjusting disk 6, and the current is transmitted on the adjusting disk 6 until it is introduced into the output disk 9, and is transmitted to the output terminal 3 through the output disk 9. The connecting block 7 is located at the input terminal 2, the variable resistance mechanism 8 is installed on the adjusting disk 6, and the output disk 9 is installed at the output terminal 3, where the output disk 9 is equivalent to a parallel sliding rheostat; when the temperature rises, the air pipe 4 drives the adjusting disk 6 to rotate through the adjusting mechanism 5, and when the adjusting disk 6 rotates, the variable resistance mechanism 8 increases the resistance between the connecting block 7 and the output disk 9.

[0034] During the current transmission process, if the temperature is too high, the adjustment disk 6 will be adjusted to the insulator 83. At this time, the current will be blocked by the insulator 83, and the current will stop flowing, thereby gradually reducing the temperature and the adjustment disk 6 will rotate to the resistor 82.

[0035] like Figure 3 As shown, the adjustment mechanism 5 includes a conduction rod 51, a piston 52, a connecting rod 53, and a shifting block 54. One end of the conduction rod 51 is mounted at the end of the input terminal 2, and the other end of the conduction rod 51 is connected to the air pipe 4. The piston 52 is located in the air pipe 4, the connecting rod 53 is mounted at the end of the piston 52, and the shifting block 54 is mounted in the groove on the adjustment disk 6, and the connecting rod 53 is connected to the shifting block 54. The conduction rod 51 can be made of ceramic material to achieve heat conduction without conducting electricity.

[0036] Under the action of the conduction rod 51, the temperature of the input terminal 2 is transmitted to the inside of the air pipe 4, and then the nitrogen inside expands due to the heat, which will push the piston 52 to move to the right. At this time, the piston 52 will drive the shift block 54 to rotate around the center of the circle of the adjustment disk 6 through the connecting rod 53. The piston 52 is rotationally connected to the connecting rod 53, and the connecting rod 53 is also rotationally connected to the shift block 54. The shift block 54 is fixedly connected to the adjustment disk 6, and then the piston 52 will drive the adjustment disk 6 to rotate. The rotation angle of the adjustment disk 6 at this place is limited by the movement of the piston 52. In order to avoid the phenomenon of jamming, the process of the piston 52 driving the adjustment disk 6 to rotate should be kept within 180 degrees, and the connecting rod 53 cannot coincide with the connecting line between the shift block 54 and the circle of the adjustment disk 6. On this basis, the piston 52 can drive the connecting rod 53 to the greatest extent, thereby driving the normal operation of the adjustment disk 6 to rotate. When the temperature drops, the nitrogen shrinks at this time, which will make the adjustment disk 6 follow the previous process range. At this time, the return angle of the adjustment disk 6 is consistent with the process angle.

[0037] Through the thermal expansion and contraction principle of nitrogen, the adjustment disk 6 can increase its resistance as the heat increases, so that the resistance value reduced due to the temperature increase is compensated, thereby reducing the increase in output current caused by the reduction in resistance, thereby improving the stability of the output current.

[0038] like Figure 3-5As shown, the variable resistance mechanism 8 includes a conductor 81, a resistor 82, an insulator 83 and a fixed block 84. The conductor 81, the resistor 82 and the insulator 83 are all installed on the adjustment disk 6. The conductor 81, the resistor 82 and the insulator 83 are arranged in sequence and are all arc-shaped. The circle formed by the three is concentric with the adjustment disk 6. The fixed block 84 is installed between the adjustment disk 6 and the output disk 9. When the temperature does not rise, the piston 52 is not affected by the gas and moves. The conductor 81 on the adjustment disk 6 is connected to the connecting block 7. At this time, the current flows normally, and the current at the input terminal 2 and the output terminal 3 is the same; when the temperature gradually rises, it means that the current at the input terminal 2 is too large. At this time, the piston 52 will drive the adjustment disk 6 to rotate, and the adjustment disk 6 rotates to the resistor 82 At this point, during the current flow, the resistance at this point is increased, thereby reducing the current at the output terminal 3, so that the current at the output terminal 3 is always maintained below the threshold range. As the temperature gradually increases, the adjustment disk 6 is gradually rotated under the influence of the piston 52 and the connecting rod 53, and the insulator 83 on the adjustment disk 6 is turned to be connected to the connecting block 7. At this time, the current flowing into the input terminal 2 is isolated by the insulator 83. At this time, the entire circuit is broken, thereby forming an overheating protection. Before the fuse blows, the circuit has been cut off, thereby reducing the frequency of fuse blowing. At the same time, it can be known which switch is broken according to the circuit connection between different switches (only supporting parallel circuits), thereby facilitating the location of the temperature rising area, thereby providing convenience for circuit maintenance.

[0039] In addition, during the rotation of the adjustment disk 6, the resistance on the output disk 9 is also adjusted through the insulating rod 95, so that a parallel resistance is formed on the output disk 9, thereby achieving double protection, improving the stability of the output current, and avoiding the output current overload affecting daily use.

[0040] like Figure 3 As shown, an expansion airbag 41 is installed between the piston 52 and the inner wall of the air pipe 4, and a compression airbag 42 is installed on the other side of the piston 52. The compression airbag 42 is provided with an air outlet 421. Both the expansion airbag 41 and the compression airbag 42 are filled with nitrogen.

[0041] The expansion airbag 41 can push the piston 52 forward more stably. At the same time, when resetting, the airbag can pull the piston 52 inward to shrink, thereby improving the stability of the adjustment mechanism 5. The compression airbag 42 is filled with nitrogen. During the movement of the piston 52, the compression airbag 42 will be squeezed, so that the gas in the compression airbag 42 flows into the shell 1 from the outlet 421, thereby reducing the internal current propagation (nitrogen has insulating properties). As the nitrogen wraps the connecting block 7 and the adjustment disk 6, the flow of current is reduced, thereby protecting the circuit.

[0042] like Figure 6 As shown, a rotating shaft 61 is installed at the center of the adjusting disk 6, and a motor 62 is installed at the input end of the rotating shaft 61 to drive the adjusting disk 6 to rotate. The adjusting disk 6 is a symmetrical structure, and the length ratio of the conductor 81, the resistor 82 and the insulator 83 is 1:6:2; but when the switch needs to be turned off, the motor 62 is adjusted by the electric control, and the motor 62 drives the adjusting disk 6 to rotate through the rotating shaft 61 to realize the current cutoff of the switch. When the motor 62 rotates to the set limit position, the position of the shift block 54 at this time is symmetrical with the position where the piston 52 drives the connecting rod 53 to drive the shift block 54 before. The two are symmetrical about the center of the adjusting disk 6, and because the progress of the two must be kept within 180 degrees, the length ratio of the conductor 81, the resistor 82 and the insulator 83 is set to 1:6:2. It is only necessary to keep the initial connection block 7 at the center of the conductor 81, and then move clockwise until it contacts the insulator 83, that is, travel to 130 degrees to 150 degrees. The limit process, the counterclockwise process is the same, the calculation method is to split the whole circle into two 180°, because the length ratio of the conductor 81, the resistor 82 and the insulator 83 is 1:6:2, and the single ratio is 20 degrees, it can be seen that the upper and lower parts of the conductor 81 are ten degrees, and when the connecting block 7 reaches the insulator 83, the circuit can be broken, so it is only necessary to ensure that the rotation angle of the adjustment disk 6 is greater than 130 degrees to achieve the circuit break, so the limit process is set between 130 degrees and 150 degrees, thereby ensuring the stability of the piston 52 driving the adjustment disk 6.

[0043] When the piston 52 drives the adjusting disk 6, the motor 62 is a permanent magnet synchronous motor or a brushless DC motor. When the motor 62 is not powered, the adjusting disk 6 can rotate clockwise and counterclockwise, and the adjusting disk 6 rotates synchronously with the rotating shaft 61, so it will not be affected by the motor 62 and will not be locked.

[0044] like Figure 7-8 As shown, a ball 841 is installed on the fixed block 84, and the ball 841 contacts the adjustment disk 6. A reed 842 is installed between the ball 841 and the fixed block 84, and the reed 842 is made of conductive material. The interior of the fixed block 84 is connected to the compressed air bag 42;

[0045] During the rotation of the adjusting disk 6, the fixed block 84 is connected to the adjusting disk 6 for rotation, and the fixed block 84 is relatively fixed to the output disk 9. In order to reduce the wear during the rotation, the ball 841 is set so that the ball 841 can always be connected to the adjusting disk 6 for rotation. At this time, the current can also be transmitted to the output disk 9 through the ball 841, and the reed 842 can be squeezed. On the one hand, the reed 842 can support the ball 841, and on the other hand, the reed 842 can block the current transmission when the ball 841 is suspended in the air, and conduct the gas in the compressed air bag 42 to between the reed 842 and the output disk 9. When the piston 52 suddenly moves to the rightmost end, the compressed airbag 42 is completely squeezed. A part of the gas in the compressed airbag 42 flows into the interior of the housing 1 from the air outlet 421, and the other part enters between the reed 842 and the output disk 9, thereby blocking the ball and the output disk 9 to avoid the transmission of current. At this time, the current is bound to increase suddenly, and when the compressed airbag 42 is slowly squeezed, the gas will be discharged from the air outlet 421 first (low pressure). Therefore, this place is overload protected against the sudden increase in temperature, and then cooperates with the adjustment disk 6 to improve the stability of the current output.

[0046] like Figure 7 As shown, the back of the adjusting disk 6 is stepped, and the position of the adjusting disk 6 back corresponding to the insulator 83 is not in contact with the ball 841; when the adjusting disk 6 is not rotating, the ball 841 is squeezed by the protrusion of the adjusting disk 6 back corresponding to the conductor 81, and then squeezes the reed 842. At this time, the reed 842 is squeezed to the limit position, and the current is transmitted to the reed 842 through the ball 841. At this time, the reed 842 can transmit the complete current, thereby improving the stability of the current; after the adjusting disk 6 rotates, the ball 841 is squeezed by the protrusion of the adjusting disk 6 back corresponding to the resistor 82. Compared with the previous level, the protrusion is shorter, and the bending degree of the reed 842 is reduced, but the reed 842 is still in contact with the output disk 9, which will not affect the transmission of the current by the reed 842. At this time, the current can still be transmitted to the reed 842 and the output disk 9 through the ball 841;

[0047] However, when the adjusting disk 6 rotates to the extreme position (insulator 83 contacts connecting block 7), the ball 841 is not squeezed, and the reed 842 separates the ball 841 from the output disk 9 through its own deformation, thereby achieving secondary circuit breaking and improving circuit protection at the switch.

[0048] like Figure 8As shown, the output disk 9 is annular, a variable resistor 91 is mounted on the output disk 9, a metal strip 92 connected to the output terminal 3 is mounted on the output disk 9, a fixed resistor 93 is mounted on the output disk 9 at a position symmetrical to the variable resistor 91, a conductive sheet 94 is mounted between the variable resistor 91 and the metal strip 92, the conductive sheet 94 can be telescopic, or can slide on the metal strip 92, the conductive sheet 94 is connected to the adjustment disk 6 through an insulating rod 95; the maximum resistance of the variable resistor 91 is equal to that of the fixed resistor 93, and when the conductive sheet 94 slides, the variable resistor 91 is close to the connecting block 7, and the current does not pass through the fixed resistor 93.

[0049] During normal circuit flow, the current will be transmitted to the fixed block 84 through the adjustment disk 6, and the fixed block 84 will transmit the current to the output terminal 3 along the metal strip 92. The metal strip 92 is divided into two sections, the upper section of the metal strip 92 is connected to the fixed resistor 93, and the lower section of the metal strip 92 is connected to the variable resistor 91. When the adjustment disk 6 does not rotate, the insulating rod 95 drives the conductive sheet 94 to be located at the leftmost end of the variable resistor 91. At this time, the current will directly reach the output terminal 3 along the conductive sheet 94, and the current will not pass through the upper section of the metal strip 92, so that the current at the output terminal 3 is equal to the current at the fixed block 84. As the adjusting disk 6 rotates, the insulating rod 95 will drive the conductive sheet 94 to gradually move to the right. At this time, like a sliding rheostat, the resistance of the variable resistor 91 gradually increases, which will drive the overall resistance of the output disk 9 to gradually increase. Specifically, the parallel resistance is the product of the two resistances divided by the sum of the two resistances. When the adjusting disk 6 rotates to the extreme position, the parallel resistance is equal to half of the resistance of the fixed resistor 93, thereby forming triple protection for the circuit to prevent the current on the adjusting disk 6 from passing through the insulator 83 and then being transmitted to the fixed block 84 and then directly reaching the output terminal 3, affecting the normal use of the circuit.

[0050] During normal current flow, the current is transmitted to the inside of the housing 1 through the input terminal 2, transmitted to the adjustment disk 6 through the connecting block 7, and then transmitted from the adjustment disk 6 to the variable resistance mechanism 8, and then transmitted from the output disk 9 to the output terminal 3;

[0051] When the temperature at the input terminal 2 gradually increases, the adjustment mechanism 5 will transfer the temperature to the air pipe 4, and the air pipe 4 will then convert the linear motion into circular motion through the adjustment mechanism 5, thereby driving the adjustment disk 6 to rotate. During the rotation of the adjustment disk 6, the variable resistance mechanism 8 gradually increases the resistance value at the adjustment disk 6, thereby reducing the current flowing there, so that the current at the output terminal 3 remains stable;

[0052] When the temperature at the input terminal 2 reaches the limit, the adjustment mechanism 5 causes the adjustment disk 6 to rotate to the limit position, at which time the limit disk is disconnected, thereby protecting the circuit.

[0053] Specifically, when the temperature at the input terminal 2 gradually increases, the temperature of the input terminal 2 will be transmitted to the inside of the air pipe 4 through the conductive rod 51. At this time, the nitrogen in the expansion airbag 41 will expand due to the heat, which will push the piston 52 to move to the right, and will simultaneously drive the connecting rod 53 to transmit the transmission. Through the shift block 54 connected to the connecting rod 53, the transmission is transmitted to the adjusting disk 6. At this time, as the piston 52 moves, the adjusting disk 6 rotates, and the contact point of the adjusting disk 6 with the connecting block 7 is gradually transferred from the conductor 81 to the resistor 82. As the adjusting disk 6 rotates, the adjusting The resistance at the disk 6 gradually increases, thereby reducing the magnitude of the transmitted current. At the same time, as the adjusting disk 6 rotates, the insulating rod 95 on the back of the adjusting disk 6 drives the conductive sheet 94 to move. At this time, the conductive sheet 94 gradually moves to the right. At this time, the resistance at the lower end of the output disk 9 gradually increases, and the overall resistance of the output disk 9 is also gradually increased due to the influence of the parallel circuit. The current is transmitted to the fixed block 84 through the adjusting disk 6, and then the current transmitted from the fixed block 84 to the output terminal 3 through the metal strip 92 is also reduced, thereby ensuring that the current of the output terminal 3 does not increase.

[0054] When the temperature at the input terminal 2 suddenly reaches the highest value, the piston 52 will suddenly squeeze the compressed airbag 42, and a part of the nitrogen in the compressed airbag 42 will enter the housing 1, and another small part will enter the fixed block 84 connected thereto, thereby pushing the reed 842 away from the output disk 9, and the fixed block 84 itself will be disconnected; at the same time, the nitrogen will form a barrier between the reed 842 and the output disk 9, thereby blocking the transmission of the current. At the same time, the adjustment disk 6 rotates to the extreme position, and the connecting block 7 is connected to the insulator 83, and the disconnection is realized synchronously; and the insulating rod 95 will rotate synchronously with the adjustment disk 6, so that the conductive sheet 94 moves to the rightmost end of the variable resistor 91, and the resistance of the variable resistor 91 is the largest at this time, and is equal to the resistance of the fixed resistor 93. At this time, the resistance of the two in parallel is equal to half of the resistance of the fixed resistor 93, thereby limiting the current and stabilizing the current at the output terminal 3.

[0055] The basic principles and beneficial effects of the present invention are shown and described above. At the same time, the present invention is not limited to the above embodiments. Without departing from the effects and scope of the present invention, the present invention may have various changes and improvements. These changes and improvements all fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A photovoltaic DC isolating switch, characterized in that: The invention comprises a housing (1), an input terminal (2), an output terminal (3), an air pipe (4), an adjusting mechanism (5), an adjusting disk (6), a connecting block (7), a variable resistance mechanism (8), and an output disk (9); the input terminal (2) is mounted on the left side of the housing (1); the output terminal (3) is mounted on the right side of the housing (1); the air pipe (4) is mounted on the housing (1); the adjusting mechanism (5) is mounted on the air pipe (4); the adjusting disk (6) is mounted between the input terminal (2) and the output terminal (3); the connecting block (7) is located at the input terminal (2); the variable resistance mechanism (8) is mounted on the adjusting disk (6); and the output disk (9) is mounted at the output terminal (3); when the temperature rises, the air pipe (4) drives the adjusting disk (6) to rotate through the adjusting mechanism (5); when the adjusting disk (6) rotates, the variable resistance mechanism (8) increases the resistance between the connecting block (7) and the output disk (9).

2. A photovoltaic DC isolating switch according to claim 1, characterized in that: The regulating mechanism (5) comprises a transmission rod (51), a piston (52), a connecting rod (53), and a shifting block (54); one end of the transmission rod (51) is mounted on the input terminal (2); the other end of the transmission rod (51) is connected to the air pipe (4); the piston (52) is located in the air pipe (4); one end of the connecting rod (53) is mounted on the end of the piston (52); the shifting block (54) is mounted in a groove on the regulating disk (6); and the other end of the connecting rod (53) is connected to the shifting block (54).

3. A photovoltaic DC isolating switch according to claim 2, characterized in that: The variable resistance mechanism (8) comprises a conductor (81), a resistor (82), an insulator (83) and a fixed block (84); the conductor (81), the resistor (82) and the insulator (83) are all mounted on an adjustment disk (6); the conductor (81), the resistor (82) and the insulator (83) are arranged in sequence and are all in an arc shape; a circle formed by the three is concentric with the adjustment disk (6); and the fixed block (84) is mounted between the adjustment disk (6) and an output disk (9).

4. A photovoltaic DC isolating switch according to claim 2, characterized in that: An expansion airbag (41) is installed between the piston (52) and the inner wall of the air pipe (4), and a compression airbag (42) is installed on the other side of the bottom of the piston (52). The compression airbag (42) is provided with an air outlet (421), and both the expansion airbag (41) and the compression airbag (42) are filled with nitrogen.

5. A photovoltaic DC isolating switch according to claim 3, characterized in that: A rotating shaft (61) is installed at the center of the adjusting disk (6), and a motor (62) for driving the rotating shaft (61) to rotate is installed at the input end of the rotating shaft (61). The adjusting disk (6) is a symmetrical structure, and the length ratio of the conductor (81), the resistor (82) and the insulator (83) is 1:6:

2.

6. A photovoltaic DC isolating switch according to claim 3 or 4, characterized in that: A round ball (841) is installed on the fixed block (84), the round ball (841) is in contact with the adjustment disk (6), a reed (842) is installed between the round ball (841) and the fixed block (84), the reed (842) is a conductive material, and the interior of the fixed block (84) is connected to the compressed air bag (42).

7. A photovoltaic DC isolating switch according to claim 6, characterized in that: The back of the adjustment disk (6) is in a stepped shape, and the position of the back of the adjustment disk (6) corresponding to the insulator (83) does not contact the round bead (841).

8. A photovoltaic DC isolating switch according to claim 7, characterized in that: The output disk (9) is annular, a variable resistor (91) is mounted on the output disk (9), a metal strip (92) connected to the output terminal (3) is mounted on the output disk (9), a fixed resistor (93) is mounted on the output disk (9) at a position symmetrical to the center of the variable resistor (91), a conductive sheet (94) is mounted between the variable resistor (91) and the metal strip (92), and an insulating rod (95) is connected between the conductive sheet (94) and the adjustment disk (6).

9. A photovoltaic DC isolating switch according to claim 8, characterized in that: The maximum resistance of the variable resistor (91) is equal to that of the fixed resistor (93), and when the conductive sheet (94) slides to the side of the variable resistor (91) close to the connecting block (7), the current does not pass through the fixed resistor (93).

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