High-voltage high-power anti-backflow solid relay

Abstract

The invention discloses a high-voltage high-power anti-backflow solid relay, which comprises a main power switch circuit, a current detection circuit, a short-circuit tripping judgment circuit, a tripping locking circuit, an overcurrent delay protection circuit, a tripping state indication circuit and a power switch driving circuit, the current detection circuit is connected with the main power switch circuit and collects current signals of the main power switch circuit. According to the invention, basic functions of a traditional electromechanical contactor can be realized, functions of state monitoring, over-current protection and short-circuit protection are realized, electric load non-arc control, over-current protection and short-circuit protection are realized, the reliability of a system and a product is improved, health management requirements of electric equipment are met, the service life is prolonged, and the cost is reduced. Volume and weight of finished products are reduced.

Description

Technical Field

[0001] The invention relates to the field of high-voltage and high-power solid relay circuits, in particular to a high-voltage and high-power backflow prevention solid relay. Background Art

[0002] Traditional electromechanical DC high-power contactors are large in size and weight, and are prone to arcing when the contacts are in motion, which will have a certain impact on the power load and the power grid. In addition, contactors are short-lived electromechanical components and require regular maintenance, which seriously affects product quality, resulting in high product maintenance costs and low overall reliability, which is not conducive to the development of modern advanced equipment. Summary of the invention

[0003] The purpose of the present invention is to provide a high-voltage and high-power anti-backflow solid-state relay to solve the problems proposed in the above background technology that the contactor needs regular maintenance, has a short service life and affects product quality, has high maintenance costs and low overall reliability.

[0004] To achieve the above object, the present invention provides the following technical solutions: A high-voltage and high-power backflow prevention solid-state relay, comprising: Main power switching circuit, A current detection circuit, wherein the current detection circuit is connected to the main power switch circuit and collects a current signal of the main power switch circuit; A short-circuit tripping judgment circuit, wherein the short-circuit tripping judgment circuit is connected to the current detection circuit and receives a current signal; A trip lock circuit, the trip lock circuit is connected to the short circuit trip judgment circuit; An overcurrent delay protection circuit, wherein the overcurrent delay protection circuit is connected to the current detection circuit and the trip lock circuit respectively; A trip state indicating circuit, wherein the trip state indicating circuit is connected to the short circuit trip judgment circuit; A power switch driving circuit, wherein the power switch driving circuit is connected to the main power switch circuit and the trip lock circuit respectively; Wherein, the input end of the trip lock circuit is connected to a command control circuit, and the command control circuit sends an on / off control command to the power switch drive circuit.

[0005] Furthermore, the instruction control circuit includes a photocoupler G1 and a resistor R7, the input end of the photocoupler G1 inputs the control instruction CON1, the control instruction CON1 is connected to one end of the resistor R7, the other end of the resistor R7 is connected to pin No. 1 of the photocoupler G1, and pin No. 2 of the photocoupler G1 is connected to the ground of the control instruction CON1.

[0006] Furthermore, the overcurrent delay protection circuit includes a resistor R1, a resistor R4, a resistor R9, a resistor R11, a resistor R15, a capacitor C1, a capacitor C5 and a voltage comparator U3A, wherein the resistor R1 is connected to the resistor R4, the other end of the resistor R4 is connected to the capacitor C1, one end of the resistor R4 is also connected to the four-pin end of the voltage comparator U3A, the capacitor C1 is connected to the power ground GND1, the five-pin end of the voltage comparator U3A is respectively connected to the resistor R9 and the resistor R11, the other end of the resistor R9 is connected to the power supply VCC, the other end of the resistor R11 is connected to the power ground GND1, the twelve-pin end of the voltage comparator U3A is connected to the power ground, and the three-pin end of the voltage comparator U3A is connected to the power supply VCC.

[0007] Furthermore, the current detection circuit includes an operational amplifier U1B, an operational amplifier U1A, a resistor R5, a resistor R6, a resistor R10, a resistor R14, a capacitor C3 and three groups of resistors R16-R18. The seven-pin end of the operational amplifier U1B is connected to the resistor R1 in the overcurrent delay protection circuit, and the six-pin end of the operational amplifier U1B is connected to the resistor R5 and the resistor R6 respectively. The other end of the resistor R5 is connected to the power ground GND1, and the other end of the resistor R6 is connected to the reference power supply; the five-pin end of the operational amplifier U1B is connected to the capacitor C3 and the resistor R10 respectively, the other end of the capacitor C3 is connected to the power ground GND1, and the other end of the resistor R10 is connected to the operational amplifier U1A, the resistor R14, and the capacitor C4 respectively, and the other end of the resistor R14 is connected to the other end of the capacitor C3 and the two-pin end of the operational amplifier U1A respectively.

[0008] Furthermore, the three pins of the operational amplifier U1A are respectively connected to resistors R16 and R18, the other end of the resistor R16 is connected to the power ground GND1, the two pins of the operational amplifier U1A are connected to resistor R17, the other ends of resistors 17 and R18 are connected to the main power switch circuit, the eight pins of the operational amplifier U1A are connected to the power supply VCC, and the four pins of the operational amplifier U1A are connected to the power ground GND1.

[0009] Furthermore, the main power switch circuit includes resistor R26, resistor R27, resistor R34, resistor R37, resistor R41, shunt resistor RS1, four groups of resistors R19-R22, two groups of capacitors C6-C7, three groups of diodes D2-D4, two groups of transistors T2-T3, two groups of transistors T5-T6 and four groups of field effect transistors M1-M4, one end of the shunt resistor RS1 is respectively connected to resistor 17 and resistor R18, and one end of the capacitor C7 is respectively connected to the anode of diode D4 and the high-voltage power supply ground PGND.

[0010] Furthermore, the short-circuit trip judgment circuit includes a voltage comparator U2A, a resistor R2, a resistor R5, a resistor R8, a resistor R12, a resistor R13, a capacitor C2 and a transistor T1. One pin of the voltage comparator U2A is respectively connected to the resistor R1 and the resistor R13, and eight pins of the voltage comparator U2A are respectively connected to the power supply Vcc, the capacitor C2 and the resistor R12.

[0011] Furthermore, the trip state indication circuit includes a voltage comparator U2B, a resistor R24, a resistor R25, a resistor R35, a resistor R33, a resistor R28, a transistor T4 and a photocoupler G2, wherein the second pin of the photocoupler G2 is connected to the third pin of the transistor T4; the second pin of the transistor T4 is connected to the power ground GND1.

[0012] Furthermore, the power switch driving circuit includes a transistor T7, a transistor T8, a diode V1, a voltage regulator diode Z1, a voltage regulator diode Z2, a resistor R39, a resistor R40 and a capacitor C8. The three pins of the transistor T7 are connected to the power supply Vcc, and the two pins of the transistor T7 are respectively connected to the two pins of the transistor T8, the anode of the voltage regulator diode Z1, the resistor R19 in the main power switch circuit, the resistor R20, the resistor R21, the resistor R22, one pin of the transistor T5, one pin of the transistor T2, and one pin of the transistor T3.

[0013] Furthermore, the trip lock circuit includes four groups of resistors R29-R32, a resistor R23, a resistor R36, a resistor R38, a diode D1, a voltage comparator U3B, a voltage comparator U3C and a voltage comparator U3D. One end of the resistor R8 is respectively connected to the thirteenth pin of the voltage comparator U3D, the resistor R39 and the resistor R40 in the power switch drive circuit, the resistor R31, and one pin of the voltage comparator U3B. The other end of the resistor R31 is respectively connected to the seven-pin end of the voltage comparator U3B, the resistor R15 in the overcurrent delay protection circuit, the two-pin end of the voltage comparator U3A, the three-pin end of the transistor T1 in the short-circuit trip judgment circuit, and the resistor R24 ​​in the trip status indication circuit.

[0014] The beneficial effects of the present invention are as follows: the present invention can realize the basic functions of traditional electromechanical contactors, and at the same time has status monitoring, overcurrent protection, and short-circuit protection functions, realize arc-free control and overcurrent protection and short-circuit protection of electrical loads, improve the reliability of systems and products, meet the health management needs of electrical equipment, protect electrical equipment, and use solid relays to achieve high-voltage and high-power control to avoid the influence of arcs during switching, increase service life, reduce the volume and weight of finished products, and prevent the reverse input of electrical energy to the subsequent load after shutdown, which is conducive to the promotion and use of the high-voltage and high-power anti-backflow solid relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a principle block diagram of the high-voltage and high-power backflow prevention solid-state relay of the present invention; Figure 2 A combined circuit diagram of the present invention without connecting the current detection circuit and the main power switch circuit; Figure 3 It is a combined circuit diagram of the current detection circuit and the main power switch circuit of the present invention.

[0016] In the figure: 1 command control circuit, 2 trip lock circuit, 3 overcurrent delay protection circuit, 4 power switch drive circuit, 5 short circuit trip judgment circuit, 6 trip state indication circuit, 7 current detection circuit, 8 main power switch circuit. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1-3, which provides a technical solution for the present invention, a high-voltage and high-power backflow prevention solid relay, including a main power switch circuit 8, a current detection circuit 7, a short-circuit trip judgment circuit 5, a trip lock circuit 2, an overcurrent delay protection circuit 3, a trip state indication circuit 6 and a power switch drive circuit 4; the current detection circuit 7 is connected to the main power switch circuit 8 and collects the current signal of the main power switch circuit 8, the current detection circuit 7 includes an operational amplifier U1B, an operational amplifier U1A, a resistor R5, a resistor R6, a resistor R10, a resistor R14, a capacitor C3 and three groups of resistors R16-R18, the seven-pin end of the operational amplifier U1B is connected to the resistor R1 in the overcurrent delay protection circuit 3, the six-pin end of the operational amplifier U1B is respectively connected to the resistor R5 and the resistor R6, and the other end of the resistor R5 is connected to the power ground GND1 The five-pin end of the operational amplifier U1B is connected to the capacitor C3 and the resistor R10 respectively, the other end of the capacitor C3 is connected to the power ground GND1, and the other end of the resistor R10 is connected to the operational amplifier U1A, the resistor R14, and the capacitor C4 respectively, and the other end of the resistor R14 is connected to the other end of the capacitor C3 and the two-pin end of the operational amplifier U1A respectively; the three-pin end of the operational amplifier U1A is connected to the resistor R16 and the resistor R18 respectively, the other end of the resistor R16 is connected to the power ground GND1, the two-pin end of the operational amplifier U1A is connected to the resistor R17, and the other ends of the resistors 17 and R18 are connected to the main power switch circuit 8, the eight-pin end of the operational amplifier U1A is connected to the power supply VCC, and the four-pin end of the operational amplifier U1A is connected to the power ground GND1.

[0019] It should be noted that the seven-pin end of the operational amplifier U1B is connected to the other end of the resistor R1; the six-pin end of the operational amplifier U1B is respectively connected to one end of the resistor R5 and the resistor R6; the other end of the resistor R5 is connected to the source ground GND1; the other end of the resistor R6 is connected to the reference power supply; the five-pin end of the operational amplifier U1B is respectively connected to one end of the capacitor C3 and the resistor R10; the other end of the capacitor C3 is connected to the power ground GND1; the other end of the resistor R10 is respectively connected to one pin end of the operational amplifier U1A, the resistor R14, and one end of the capacitor C4; the other end of the resistor R14 is respectively connected to the capacitor C14, the two-pin end of the operational amplifier U1B, and one end of the resistor R17; the three-pin end of the operational amplifier U1A is respectively connected to one end of the resistor R16 and the resistor R18; the eight-pin end of the operational amplifier U1A is connected to the power supply Vcc; the four-pin end of the operational amplifier U1A is connected to the power ground GND1.

[0020] In this embodiment, the short-circuit trip judgment circuit 5 is connected to the current detection circuit 7 and receives the current signal; the trip lock circuit 2 is connected to the short-circuit trip judgment circuit 5, the input end of the trip lock circuit 2 is connected to the command control circuit 1, and the command control circuit 1 sends an on / off control command to the power switch drive circuit 4; the command control circuit 1 includes a photocoupler G1 and a resistor R7, the input end of the photocoupler G1 inputs the control command CON1, the control command CON1 is connected to one end of the resistor R7, and the other end of the resistor R7 It is connected to pin No. 1 of the photocoupler G1, and pin No. 2 of the photocoupler G1 is connected to the ground of the control instruction CON1; the input control instruction CON1 is connected to one end of the resistor R7, and the other end of the resistor R7 is connected to one pin of the photocoupler G1, the second pin of the photocoupler G1 is connected to the ground of the control instruction CON1, the third pin is connected to the ground of the power switch drive circuit 4, the fourth pin is connected to one end of the resistor R29 and the eighth pin of the voltage comparator U3C; the other end of the resistor R29 is connected to the power supply Vcc.

[0021] Among them, the trip lock circuit 2 includes four groups of resistors R29-R32, a resistor R23, a resistor R36, a resistor R38, a diode D1, a voltage comparator U3B, a voltage comparator U3C and a voltage comparator U3D. One end of the resistor R8 is respectively connected to the thirteenth pin of the voltage comparator U3D, the resistor R39 and the resistor R40 in the power switch drive circuit 4, the resistor R31, and one pin of the voltage comparator U3B. The other end of the resistor R31 is respectively connected to the seven-pin end of the voltage comparator U3B, the resistor R15 in the overcurrent delay protection circuit 3, the two-pin end of the voltage comparator U3A, the three-pin end of the transistor T1 in the short-circuit trip judgment circuit 5, and the resistor R24 ​​in the trip state indication circuit 6.

[0022] It should be noted that one end of the resistor R29 is connected to the power supply Vcc, and the other end is connected to the eight-pin end of the voltage comparator; the nine-pin end of the voltage comparator U3B is connected to one end of the resistor R30 and to the reference voltage source Vref, and the fourteen-pin end of the voltage comparator U3B is connected to one end of the resistor R36, to one end of the resistor R32, and to the cathode of the diode D1; the other end of the resistor R30 is connected to one end of the resistor R23, to the anode of the diode D1, and to the six-pin end of the voltage comparator U3B; the other end of the resistor R36 is connected to the power supply Vcc, to one end of the resistor R38, and to one pin end of the diode V1; The other end of the resistor R23 is connected to the power ground GND1; the other end of the resistor R38 is connected to the thirteenth pin of the voltage comparator U3D, to one end of the resistor R39, and to one end of the resistor R40; the tenth pin of the voltage comparator U3D is connected to the reference voltage source Vref, and the eleventh pin is connected to the other end of the resistor R32, to one end of the resistor R31, and to one pin of the voltage comparator U3B; the other end of the resistor R31 is connected to the seven-pin of the voltage comparator U3B, to one end of the resistor R15, to the two-pin of the voltage comparator U3A, to the three-pin of the transistor T1, and to one end of the resistor R24.

[0023] In this embodiment, the overcurrent delay protection circuit 3 mentioned is respectively connected to the current detection circuit 7 and the trip lock circuit 2. The overcurrent delay protection circuit 3 includes a resistor R1, a resistor R4, a resistor R9, a resistor R11, a resistor R15, a capacitor C1, a capacitor C5 and a voltage comparator U3A. The resistor R1 is connected to the resistor R4, and the other end of the resistor R4 is connected to the capacitor C1. One end of the resistor R4 is also connected to the four-pin end of the voltage comparator U3A, and the capacitor C1 is connected to the power ground GND1. The five-pin end of the voltage comparator U3A is respectively connected to the resistor R9 and the resistor R11. The other end of the resistor R9 is connected to the power supply VCC, and the other end of the resistor R11 is connected to the power ground GND1. , the twelve-pin end of the voltage comparator U3A is connected to the power ground, and the three-pin end of the voltage comparator U3A is connected to the power supply VCC; wherein, one end of the resistor R1 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to one end of the capacitor C1 and to the four-pin end of the voltage comparator U3A; the other end of the capacitor C1 is connected to the power ground GND1; the five-pin end of the power comparator U3A is connected to one end of the resistor R9 and to one end of the resistor R11; the other end of the resistor R9 is connected to the power supply Vcc; the other end of the resistor R11 is connected to the power ground GND1; the twelve-pin end of the voltage comparator U3A is connected to the power ground; the three-pin end of the voltage comparator U3A is connected to the power supply Vcc.

[0024] In this embodiment, the trip state indication circuit 6 mentioned is connected to the short-circuit trip judgment circuit 5, and the short-circuit trip judgment circuit 5 includes a voltage comparator U2A, a resistor R2, a resistor R5, a resistor R8, a resistor R12, a resistor R13, a capacitor C2 and a transistor T1. One pin of the voltage comparator U2A is respectively connected to the resistor R1 and the resistor R13, and the eight pins of the voltage comparator U2A are respectively connected to the power supply Vcc, the capacitor C2 and the resistor R12, and the other end of the resistor R13 is connected to one pin of the transistor T1; the two pins of the transistor T1 are connected to the power ground GND1; the trip state indication circuit 6 includes a voltage comparator U2B, a resistor R24, a resistor R25, a resistor R35, a resistor R33, a resistor R28, a transistor T4 and a photoelectric coupler G2, and the photoelectric coupler G The second pin of resistor R24 ​​is connected to the third pin of transistor T4; the second pin of transistor T4 is connected to the power ground GND1; the other end of resistor R24 ​​is connected to the sixth pin of voltage comparator U2B; one end of resistor R25 is connected to the reference power supply; the other end of resistor R25 is connected to one end of resistor R28 and to the fifth pin of voltage comparator U2B; the other end of resistor R28 is connected to the power ground GND1; the seventh pin of voltage comparator U2B is connected to one end of resistor R33 and to one pin of transistor T4; the other end of resistor R33 is connected to the power supply Vcc and to one end of resistor R35; the other end of resistor R35 is connected to one pin of photoelectric coupler G2; the second pin of photoelectric coupler G2 is connected to the third pin of transistor T4; the second pin of transistor T4 is connected to the power ground GND1.

[0025] In this embodiment, the power switch driving circuit 4 is respectively connected to the main power switch circuit 8 and the trip lock circuit 2; the power switch driving circuit 4 includes a transistor T7, a transistor T8, a diode V1, a voltage regulator diode Z1, a voltage regulator diode Z2, a resistor R39, a resistor R40 and a capacitor C8, the three pins of the transistor T7 are connected to the power supply Vcc, the two pins of the transistor T7 are respectively connected to the two pins of the transistor T8, the anode of the voltage regulator diode Z1, the resistor R19, the resistor R20, the resistor R21, the resistor R22, one pin of the transistor T5, one pin of the transistor T2, and one pin of the transistor T3 in the main power switch circuit 8; the two pins of the diode V1 are connected to one end of the resistor R39, and the three pins of the diode V1 are connected to the three pins of the transistor T8. One pin end of the transistor T7 is connected, the three pin ends of the transistor V1 are connected to one pin end of the transistor T8, the three pin ends of the transistor V1 are connected to the other end of the resistor R40, and the three pin ends of the transistor V1 are connected to one end of the capacitor C8; the three pin ends of the transistor T7 are connected to the power supply Vcc, the two pin ends of the three pin ends of the transistor T7 are connected to the two pin ends of the transistor T8, the three pin ends of the transistor T7 are connected to the anode of the voltage-stabilizing diode Z1, the three pin ends of the transistor T7 are connected to one end of the resistor R19 in the main power switch circuit 8, the three pin ends of the transistor T7 are connected to one end of the resistor R20, to one end of the resistor R21, to one end of the resistor R22, to one pin end of the transistor T5, to one pin end of the transistor T2, and to one pin end of the transistor T3.

[0026] In this embodiment, the main power switch circuit 8 mentioned includes resistor R26, resistor R27, resistor R34, resistor R37, resistor R41, shunt resistor RS1, four groups of resistors R19-R22, two groups of capacitors C6-C7, three groups of diodes D2-D4, two groups of transistors T2-T3, two groups of transistors T5-T6 and four groups of field effect transistors M1-M4. One end of the shunt resistor RS1 is respectively connected to the resistor 17 and the resistor R18, and one end of the capacitor C7 is respectively connected to the anode of the diode D4 and the high-voltage power supply ground PGND.

[0027] It should be noted that one end of the resistor R19 is respectively connected to one end of the resistor R37, the two-pin end of the transistor T5, and one-pin end of the field effect transistor M3; the other end of the resistor R37 is respectively connected to the three-pin end of the transistor T5, the three-pin end of the transistor T2, the three-pin end of the field effect transistor M3, the three-pin end of the field effect transistor M1, one end of the resistor R26, the end of the shunt resistor RS1, and the other end of the resistor R18; the other end of the resistor R20 is respectively connected to the resistor R26, the two-pin end of the transistor T2, and one-pin end of the field effect transistor M1; the three-pin end of the field effect transistor M1 is respectively connected to the three-pin end of the field effect transistor M3, The cathode of the diode D2, the resistor R4, the capacitor C7, the cathode of the diode D4 and the high voltage power supply Vin are connected; the other end of the resistor R21 is respectively connected to the resistor R27, the second pin end of the transistor T3 and the one pin end of the field effect transistor M2; the other end of the resistor R22 is respectively connected to one end of the resistor R4, the second pin end of the transistor T6 and the one pin end of the field effect transistor M4; the other end of the resistor R27 is respectively connected to the three pin end of the transistor T3, the two pin end of the field effect transistor M2, the shunt resistor RS1, the resistor R17, the resistor R4, the three pin end of the transistor T6 and the two pin end of the field effect transistor M4.

[0028] Among them, the three pins of the field effect tube M2 are respectively connected to the three pins of the field effect tube M4, the cathode of the diode D3, the capacitor C6 and the high-voltage output terminal Vout; the anode of the diode D3 is connected to the high-voltage power supply ground PGND; the other end of the capacitor C6 is respectively connected to the resistor R41 and the anode of the diode D2; the other end of the capacitor C7 is respectively connected to the anode of the diode D4 and the high-voltage power supply ground PGND.

[0029] The high-voltage and high-power backflow prevention solid-state relay, the working process of the instruction control circuit 1: when the small signal instruction CON1 is high level "1", the primary of the photocoupler G1 flows with current, the light-emitting diode works, and the internal photosensitive transistor senses the light emitted by the light-emitting diode, so that the photosensitive transistor is in a conducting state and issues a connection control instruction. Otherwise, the photosensitive transistor is in a cut-off state and issues a cut-off control instruction; the working process of the power switch drive circuit 4: when the control signal CON is "1", the fourteenth pin of the voltage comparator U3C jumps to "1", so that the thirteenth pin of the voltage-relatively strong U3D jumps to '1', and the high-level signal charges the capacitor C8 through the current limiting resistor R40. After the charging voltage is greater than 0.7V, the transistor T7 of the push-to-complete circuit is turned on, the transistor T8 is turned off, and the output power switch is turned on; otherwise, when the control signal CON is "0", the transistor T7 of the push-to-complete circuit is turned off, the transistor T8 is turned on, and the output power switch is turned off.

[0030] The working process of the trip lock circuit 2: When the seventh pin of the voltage comparator U3C receives the overcurrent trip or short circuit trip signal '0', the first pin of the voltage comparator U3B jumps to '0'; at this time, the sixth pin of the voltage comparator U3B is kept higher than the seventh pin through the diode D1, thereby keeping the first pin of the voltage comparator U3B at a low level, and it will not change even if the trip signal returns to '0', thus achieving the purpose of locking.

[0031] The working principle of the overcurrent delay protection circuit 3: the current detection circuit 7 detects the current signal and sends it to the overcurrent delay protection circuit 3, which is delayed by the resistor R1, the resistor R4 and the capacitor C1 and sent to the four-pin end of the voltage comparator U3A; it is compared with the reference voltage at the five-pin end of the voltage comparator U3A. When the overcurrent signal is greater than the reference signal, the two-pin end of the voltage comparator U3A jumps to a low level '0' and is sent to the trip lock circuit 2 to realize the protection function.

[0032] The working principle of the short-circuit trip judgment circuit 5 is as follows: the current detection circuit 7 detects the current signal and sends it to the short-circuit trip judgment circuit 5. If the detected current signal is greater than the current signal reference during the short circuit, the trip lock circuit 2 is triggered to realize the short-circuit trip protection function.

[0033] The working principle of the tripping status indication circuit 6: when receiving an overcurrent signal or a short-circuit signal, the six-pin end of the trigger voltage comparator U2B jumps to a low level '0', and the 7-pin jumps to a high level '1'. At this time, the transistor T4 is turned on, and the photocoupler G2 outputs a status signal; the working principle of the current detection circuit 7: a differential amplifier is used to collect the potential difference signal across the main power bus shunt resistor, and after the signal is amplified, it is sent to the overcurrent delay protection circuit 3 and the short-circuit trip judgment circuit 5 respectively.

[0034] The working principle of the main power switch circuit 8 is as follows: when receiving a high level '1' signal from the power switch drive circuit 4, the gate-source voltage of the reverse series-connected power switch MOS tubes M1, M2, M3, and M4 is high, and the power switch MOS tubes M1, M2, M3, and M4 are turned on to provide power to the subsequent load; otherwise, the drive circuit output is a low level '0', and the power switch MOS tubes M1, M2, M3, and M4 are turned off to disconnect the power supply to the subsequent load.

[0035] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0036] The above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be understood that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection, or integrated; it can be a mechanical connection; among them, there are many ways of detachable installation, for example, it can be through the method of plug-in and buckle matching, for example, through the method of bolt connection, etc.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high-voltage, high-power, backflow-proof solid-state relay, characterized in that: include: Main power switching circuit, A current detection circuit, wherein the current detection circuit is connected to the main power switch circuit and collects a current signal of the main power switch circuit; A short-circuit tripping judgment circuit, wherein the short-circuit tripping judgment circuit is connected to the current detection circuit and receives a current signal; A trip lock circuit, the trip lock circuit is connected to the short circuit trip judgment circuit; An overcurrent delay protection circuit, wherein the overcurrent delay protection circuit is connected to the current detection circuit and the trip lock circuit respectively; A trip state indicating circuit, wherein the trip state indicating circuit is connected to the short circuit trip judgment circuit; A power switch driving circuit, wherein the power switch driving circuit is connected to the main power switch circuit and the trip lock circuit respectively; Wherein, the input end of the trip lock circuit is connected to a command control circuit, and the command control circuit sends an on / off control command to the power switch drive circuit.

2. The high-voltage, high-power, backflow-proof solid-state relay according to claim 1 is characterized in that: The command control circuit includes a photocoupler G1 and a resistor R7, the input end of the photocoupler G1 inputs a control command CON1, the control command CON1 is connected to one end of the resistor R7, the other end of the resistor R7 is connected to a pin No. 1 of the photocoupler G1, and a pin No. 2 of the photocoupler G1 is connected to the ground of the control command CON1.

3. The high-voltage, high-power, backflow-proof solid-state relay according to claim 1 is characterized in that: The overcurrent delay protection circuit includes a resistor R1, a resistor R4, a resistor R9, a resistor R11, a resistor R15, a capacitor C1, a capacitor C5 and a voltage comparator U3A. The resistor R1 is connected to the resistor R4, the other end of the resistor R4 is connected to the capacitor C1, one end of the resistor R4 is also connected to the four-pin end of the voltage comparator U3A, the capacitor C1 is connected to the power ground GND1, the five-pin end of the voltage comparator U3A is respectively connected to the resistor R9 and the resistor R11, the other end of the resistor R9 is connected to the power supply VCC, the other end of the resistor R11 is connected to the power ground GND1, the twelve-pin end of the voltage comparator U3A is connected to the power ground, and the three-pin end of the voltage comparator U3A is connected to the power supply VCC.

4. The high-voltage, high-power, backflow-proof solid-state relay according to claim 1, characterized in that: The current detection circuit includes an operational amplifier U1B, an operational amplifier U1A, a resistor R5, a resistor R6, a resistor R10, a resistor R14, a capacitor C3 and three groups of resistors R16-R18. The seven-pin end of the operational amplifier U1B is connected to the resistor R1 in the overcurrent delay protection circuit, and the six-pin end of the operational amplifier U1B is connected to the resistor R5 and the resistor R6 respectively. The other end of the resistor R5 is connected to the power ground GND1, and the other end of the resistor R6 is connected to the reference power supply; the five-pin end of the operational amplifier U1B is connected to the capacitor C3 and the resistor R10 respectively, and the other end of the capacitor C3 is connected to the power ground GND1, and the other end of the resistor R10 is connected to the operational amplifier U1A, the resistor R14, and the capacitor C4 respectively, and the other end of the resistor R14 is connected to the other end of the capacitor C3 and the two-pin end of the operational amplifier U1A respectively.

5. The high-voltage, high-power, backflow-proof solid-state relay according to claim 4, characterized in that: The three pins of the operational amplifier U1A are connected to resistors R16 and R18 respectively, the other end of resistor R16 is connected to the power ground GND1, the two pins of the operational amplifier U1A are connected to resistor R17, the other ends of resistors 17 and R18 are connected to the main power switch circuit, the eight pins of the operational amplifier U1A are connected to the power supply VCC, and the four pins of the operational amplifier U1A are connected to the power ground GND1.

6. The high-voltage, high-power, backflow-proof solid-state relay according to claim 1, characterized in that: The main power switch circuit includes resistor R26, resistor R27, resistor R34, resistor R37, resistor R41, shunt resistor RS1, four groups of resistors R19-R22, two groups of capacitors C6-C7, three groups of diodes D2-D4, two groups of transistors T2-T3, two groups of transistors T5-T6 and four groups of field effect transistors M1-M4. One end of the shunt resistor RS1 is respectively connected to resistor 17 and resistor R18, and one end of the capacitor C7 is respectively connected to the anode of diode D4 and the high-voltage power supply ground PGND.

7. The high-voltage, high-power, backflow-proof solid-state relay according to claim 1, characterized in that: The short circuit trip judgment circuit includes a voltage comparator U2A, a resistor R2, a resistor R5, a resistor R8, a resistor R12, a resistor R13, a capacitor C2 and a transistor T1. One pin of the voltage comparator U2A is connected to the resistor R1 and the resistor R13 respectively, and the eight pins of the voltage comparator U2A are connected to the power supply Vcc, the capacitor C2 and the resistor R12 respectively.

8. The high-voltage, high-power, backflow-proof solid-state relay according to claim 1, characterized in that: The trip state indication circuit comprises a voltage comparator U2B, a resistor R24, a resistor R25, a resistor R35, a resistor R33, a resistor R28, a transistor T4 and a photoelectric coupler G2, wherein the two pins of the photoelectric coupler G2 are connected to the three pins of the transistor T4; the two pins of the transistor T4 are connected to the power ground GND1.

9. The high voltage and high power backflow prevention solid state relay according to claim 1, characterized in that: The power switch driving circuit comprises a transistor T7, a transistor T8, a diode V1, a voltage stabilizing diode Z1, a voltage stabilizing diode Z2, a resistor R39, a resistor R40 and a capacitor C8. The three pins of the transistor T7 are connected to the power supply Vcc, and the two pins of the transistor T7 are respectively connected to the two pins of the transistor T8, the anode of the voltage stabilizing diode Z1, the resistor R19, the resistor R20, the resistor R21, the resistor R22, one pin of the transistor T5, one pin of the transistor T2, and one pin of the transistor T3 in the main power switch circuit.

10. The high voltage and high power backflow prevention solid state relay according to claim 1, characterized in that: The trip lock circuit includes four groups of resistors R29-R32, a resistor R23, a resistor R36, a resistor R38, a diode D1, a voltage comparator U3B, a voltage comparator U3C and a voltage comparator U3D. One end of the resistor R8 is respectively connected to the thirteenth pin of the voltage comparator U3D, the resistor R39 and the resistor R40 in the power switch drive circuit, the resistor R31, and one pin of the voltage comparator U3B. The other end of the resistor R31 is respectively connected to the seven-pin end of the voltage comparator U3B, the resistor R15 in the overcurrent delay protection circuit, the two-pin end of the voltage comparator U3A, the three-pin end of the transistor T1 in the short-circuit trip judgment circuit, and the resistor R24 ​​in the trip state indication circuit.

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