A direct current contactless contactor

Abstract

The application relates to a direct-current non-contact contactor, belonging to the technical field of non-contact contactors. The direct-current non-contact contactor comprises a microprocessor, a main contact loop and an auxiliary contact, is further provided with a short-circuit self-locking module, a direct-current power supply is connected in series with the main contact loop and the short-circuit self-locking module to form a power supply loop of a load, and is characterized in that a fault feedback unit is arranged, a signal output end of the short-circuit self-locking module is connected with an input end of the fault feedback unit, an output end of the fault feedback unit is connected with an input end of the microprocessor, and the output end of the fault feedback unit outputs a control signal for controlling the microprocessor to send a reset control signal to the auxiliary contact. In the direct-current non-contact contactor, a high-level signal is fed back to the microprocessor after the short-circuit self-locking module triggers disconnection, the auxiliary contact is driven to reset, intermediate loop action caused by self-action of the auxiliary contact during the fault is avoided, and a safety hazard is eliminated.

Description

Technical Field

[0001] A DC contactless contactor belongs to the field of contactless contactor technology. Background Technology

[0002] Contactless contactors (also known as solid-state contactors) are increasingly widely used due to their advantages such as no mechanical contacts, rapid response, and long lifespan. In contactless contactors, power switching devices are used as the main contacts to control the power supply circuit between the load and the power source. Traditional contactless contactors, especially DC contactless contactors, often lack protection mechanisms; a short circuit at the load end can directly damage the contactor itself.

[0003] With the continuous development of technology, some contactless contactors (or contactless relays) with short-circuit protection have appeared on the market. These relays cut off the main circuit after a short circuit occurs at the load end, thus providing short-circuit protection. For example, the technical solution described in Chinese invention patent application number 201811446093.5, filed on November 29, 2018, entitled "An IGBT High-Voltage DC Solid-State Relay Circuit with Short-Circuit Protection," is an example. However, this solution has a drawback: the main contacts themselves do not have a locking function, resulting in automatic conduction when the main contacts bottom out. Once the load circuit fault is cleared, power will automatically be supplied to the load, posing a certain safety hazard.

[0004] Some contactless contactors (or contactless relays) with locking functions have also appeared on the market. For example, the technical solution described in Chinese invention patent application number 202310878465.6, filed on July 18, 2023, entitled "A High-Voltage High-Current DC Solid-State Relay with Short-Circuit Protection," has the following drawback: the overcurrent signal is first sent to the controller, which then performs the main contact cut-off and locking functions. Because the controller needs to make a judgment, the execution process of the protection is relatively time-consuming. If the load short-circuit current is high, it can still easily damage the control circuit, including the main contacts. The technical solution described in Chinese invention patent application number 202222597255.3, filed on September 29, 2022, entitled "An Intelligent High-Voltage DC Solid-State Relay," also has the following drawback: the self-locking function is originally achieved through overload energy accumulation, which still results in a long execution time.

[0005] Therefore, designing a technical solution that can quickly turn off the main contacts after a short circuit and lock the off state to minimize damage to the internal circuitry of the contactor has become an urgent problem to be solved in this field. Utility Model Content

[0006] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a DC contactless contactor that, by setting a fault feedback unit, feeds a high-level signal to the microprocessor after the short-circuit self-locking module is triggered to disconnect, drives the auxiliary contacts to reset, avoids the intermediate circuit operation caused by the auxiliary contacts operating on their own during the fault, and eliminates safety hazards.

[0007] The technical solution adopted by this utility model to solve its technical problem is as follows: The DC contactless contactor includes a microprocessor, a main contact circuit, and auxiliary contacts. The control signal output terminal of the microprocessor is connected to the control signal input terminals of the main contact circuit and the auxiliary contacts respectively. A short-circuit self-locking module is also provided. A DC power supply is connected in series with the main contact circuit and the short-circuit self-locking module to form a power supply circuit for the load. The feature is that a fault feedback unit is provided. The signal output terminal of the short-circuit self-locking module is connected to the input terminal of the fault feedback unit. The output terminal of the fault feedback unit is connected to the input terminal of the microprocessor. The output terminal of the fault feedback unit outputs a control signal for controlling the microprocessor to send a reset control signal to the auxiliary contacts.

[0008] Preferably, the fault feedback unit includes a voltage comparison module and an optocoupler trigger module. The signal output terminal of the short-circuit self-locking module is connected to the signal input side of the optocoupler trigger module. The voltage comparison module is a voltage comparator. The output side of the optocoupler trigger module is connected to the trigger voltage and the voltage input terminal of the voltage comparator. The output terminal of the voltage comparator is connected to the input terminal of the microprocessor.

[0009] Preferably, the fault feedback unit further includes an optocoupler feedback module, the output of the voltage comparator is connected to the input and output sides of the optocoupler feedback module, and the output side of the optocoupler feedback module is connected to the input of the microprocessor.

[0010] Preferably, a communication module is also connected to the input / output port of the microprocessor.

[0011] Preferably, the short-circuit self-locking module includes a MOSFET, and the output terminal of the main contact circuit is connected to a protection transistor through a voltage divider circuit. The protection transistor is connected to the gate of the MOSFET.

[0012] Preferably, the protection tube is a transistor, the voltage output by the voltage divider circuit is connected to the base of the transistor, the collector of the transistor is connected to the gate of the MOSFET, and a Zener diode is connected in parallel between the collector and emitter of the transistor.

[0013] Compared with the prior art, the beneficial effects of this utility model are: In the DC contactless contactor of this application, by setting a fault feedback unit, after the short-circuit self-locking module is triggered to disconnect, a high-level signal is fed back to the microprocessor to drive the auxiliary contact to reset, thereby avoiding the intermediate circuit from being activated by the auxiliary contact on its own during the fault and eliminating safety hazards.

[0014] In the DC contactless contactor of this application, when a short circuit fault occurs on the load side, the overcurrent signal first triggers the short circuit self-locking module. After the short circuit self-locking module is triggered, the power supply circuit of the load is connected to avoid damage to the contactor. The short circuit self-locking module always remains locked in the open state until the load side fault is restored and the contactor is de-energized and reset before it can be connected again.

[0015] A communication module is also provided at the signal input / output port of the microprocessor. The communication module enables communication with the microprocessor, so as to configure the microprocessor and read and write data (such as fault data). Attached Figure Description

[0016] Figure 1 This is a block diagram illustrating the principle of a DC contactless contactor.

[0017] Figure 2 This is a circuit diagram of the short-circuit self-locking module, optocoupler triggering module, voltage comparison module, and optocoupler feedback module in a DC contactless contactor.

[0018] Figure 3 This is a circuit diagram of the communication module in a DC contactless contactor. Detailed Implementation

[0019] Figures 1-3 This is the preferred embodiment of the present invention, which is described below in conjunction with the appendix. Figures 1-3 The present invention will be further described below.

[0020] like Figure 1 As shown, a DC contactless contactor (hereinafter referred to as the contactor) includes a microprocessor. The control signal input terminal of the microprocessor is connected to the control signal input terminal of the main contact circuit. The main contact circuit is connected in series in the DC power supply. The microprocessor controls the on / off state of the main contact circuit to realize the on / off state of the power supply circuit between the DC power supply and the load. As is common knowledge in the art, the main contact circuit of this contactor can be implemented using an H-bridge circuit composed of switching transistors. Its circuit structure and control principle will not be described in detail here.

[0021] This contactor also includes auxiliary contacts (including normally open and normally closed contacts). The control signal output of the microprocessor is connected to the control signal input of the auxiliary contacts, and the microprocessor controls the opening and closing of the auxiliary contacts. The auxiliary contacts are also implemented using circuits known in the art, such as the auxiliary contact implementation scheme described in Chinese Utility Model Patent Application No. 201520089392.3, filed on February 9, 2015, entitled "A Contactless Contactor with Jog Controllable".

[0022] A short-circuit self-locking module is connected to the output terminal (negative terminal) of the main contact circuit. This module is connected in series between the main contact circuit and the load, i.e., in the load's power supply circuit. The control signal output terminal of the short-circuit self-locking module is connected to the control signal input terminal of the optocoupler trigger module. The output terminal of the optocoupler module is connected to the input terminal of the voltage comparator module. The output terminal of the voltage comparator module is connected to the input terminal of the optocoupler feedback module. The output terminal of the optocoupler feedback module is connected to the signal input terminal of the microprocessor.

[0023] When a short-circuit fault occurs on the load side, the overcurrent signal first triggers the short-circuit self-locking module. After triggering, the short-circuit self-locking module connects the power supply circuit to the load, preventing damage to the contactor. The short-circuit self-locking module remains locked in the open state until the load-side fault is resolved and the contactor is de-energized and reset before it can be reconnected. After being triggered by the short-circuit signal, the short-circuit self-locking module triggers the optocoupler triggering module. The optocoupler triggering module then introduces the trigger voltage connected to its input terminal into the voltage comparator module. Since the trigger voltage is greater than the reference voltage connected to the voltage comparator module, the voltage comparator module outputs a high-level signal and triggers the optocoupler feedback module. After the optocoupler feedback is triggered, it sends a high-level signal to the microprocessor, which controls the auxiliary contacts to reset; that is, normally open contacts return to the open state, and normally closed contacts return to the closed state, until the load-side fault is resolved.

[0024] A communication module is also provided at the signal input / output port of the microprocessor. The communication module enables communication with the microprocessor, so as to configure the microprocessor and read data (such as fault data).

[0025] As described above, in this contactor, after a short-circuit fault occurs on the load side, the main circuit of the load is immediately disconnected by driving the short-circuit self-locking module, ensuring the safety of equipment and personnel, and simultaneously preventing damage to the contactor. Then, the fault signal is fed back to the microprocessor through the optocoupler trigger module, voltage comparison module, and optocoupler feedback module, thereby further resetting the auxiliary contacts. The microprocessor maintains the reset state of the auxiliary contacts until the load-side fault is cleared. This also avoids the intermediate circuit from operating automatically during a fault, eliminating potential safety hazards.

[0026] like Figure 2As shown, the power supply (positive terminal) from the self-contained contact circuit is connected to the input terminal of chip D3. Chip D3 is a Schottky chip with a dual-transistor structure, model MBR60200PT. The positive terminal of the power supply is also connected to the anode of the two transistors inside chip D3. The output terminal of chip D3 is connected to capacitor C3, one end of resistors R13~R14, one end of resistor R19, and the drain of MOSFET M1. The source of MOSFET M1 is connected to one end of resistors R17~R18. The other end of resistor R17 is grounded, and the other end of resistor R18 is connected to the other end of capacitor C3.

[0027] The other ends of resistors R13-R14 are connected to one end of resistors R15-R16 and the base of transistor T1. The other ends of resistors R15-R16 and the emitter of transistor T1 are grounded. The collector of transistor T1 is connected to the cathode of Zener diode D4, the gate of MOSFET M1, and one end of resistors R9-R12. Resistors R11-R12 and the anode of Zener diode D4 are grounded. Pin 1 of optocoupler chip U3 (model TY29AHE) is connected to the other end of resistor R19. Pin 2 of optocoupler chip U3 is connected to the other end of resistors R11-R12. Pin 4 of optocoupler chip U3 is connected to a 12V power supply, which is the trigger voltage mentioned above.

[0028] Pin 3 of optocoupler chip U3 is connected in series with resistor R8, and then simultaneously connected to resistor R6, resistor R1, one end of capacitors C1~C2, and pin 2 of integrated chip U1. The other end of resistor R1 and capacitor C2 is grounded. The other end of capacitor C1 is connected to the other end of resistor R6, one end of resistor R7, the anode of diode D1, and pin 3 of integrated chip U1. The other end of resistor R7 is grounded.

[0029] The integrated chip U1 uses an integrated operational amplifier chip of model PL6258S. The integrated chip U1 contains two integrated operational amplifiers U1-1 to U1-2 (not shown in the figure). The integrated chip U1-1 and its peripheral circuits form a voltage comparator, namely the voltage comparison module mentioned above. The integrated chip U1-2 provides a reference voltage for the integrated chip U1-1.

[0030] Pin 1 of integrated chip U1 (the output of integrated operational amplifier U1-1, and also the output of the voltage comparator) is connected to the cathode of diode D1, one end of resistor R3, and the other ends of resistors R9-R10. Pin 4 of integrated chip U1 is grounded. Pin 5 of integrated chip U1 is connected to pin 2 and also to the cathode of diode D2. Pin 6 of integrated chip U1 is connected to the anode of diode D1. Pin 7 of integrated chip U1 is connected in series with resistor R2, then connected to one end of resistor R5 and the anode of diode D2. The other end of resistor R5 is grounded. Pin 8 of integrated chip U1 is connected to a 12V power supply.

[0031] The voltage output from pin 7 of integrated chip U1 (output terminal of integrated operational amplifier U1-2) is divided by resistors R2 and R5 and then used as a reference voltage to be connected to pin 3 of integrated chip U1 (inverting input terminal of integrated operational amplifier U1-1) so as to be compared with the trigger voltage of pin 2 of integrated chip U1 (non-inverting input terminal of integrated operational amplifier U1-1).

[0032] The other end of resistor R3 is connected to pin 1 of optocoupler chip U2 (model PC817). Pins 2 and 3 of optocoupler chip U2 are grounded. Pin 4 of optocoupler chip U2 is connected to a 5V power supply via series resistor R4. Pin 4 of optocoupler chip U2 is also connected to the signal input terminal of the microprocessor.

[0033] exist Figure 2 In the circuit shown, MOSFET M1 serves as a short-circuit self-locking module, optocoupler chip U3 serves as the aforementioned optocoupler trigger module, integrated chip U1 forms the aforementioned voltage comparison module and provides a reference voltage, and optocoupler chip U2 serves as the aforementioned optocoupler feedback module.

[0034] like Figure 3 As shown, the communication module includes a communication chip U4 (model MAX485-S) to enable communication via the RS485 communication protocol. Pins 1, 2, and 4 of the communication chip U4 are connected to the microprocessor, pin 5 is grounded, and pin 6 is connected to one end of resistors R20-R22. The other end of resistor R21 is connected to a 5V power supply. The other end of resistor R22 is connected to one end of resistors R23-R24 and pin 7 of the communication chip U4. The other end of resistor R23 is grounded, and the other end of resistor R24 ​​is connected to the anode of diode D6, serving as communication port B+. The other end of resistor R20 is connected to the anode of diode D5, serving as communication port A+. The cathodes of diodes D5-D6 are connected together, and pin 8 of the communication chip U4 is connected to a 5V power supply.

[0035] The specific working process and working principle are as follows: When a short circuit fault occurs on the load side, the current in the power supply circuit will increase instantaneously. At this time, the voltage at the output terminal of chip U3 increases. After the voltage is divided by the parallel resistors R13~R14 and the parallel resistors R15~R16, the voltage drives the transistor T1 to conduct. After the transistor T1 conducts, it pulls down the voltage at the gate of MOSFET M1, causing MOSFET M1 to turn off and disconnecting the main power supply circuit of the load.

[0036] Simultaneously, the optocoupler chip U3 is triggered. After the optocoupler chip U3 is triggered, the trigger voltage (12V) is introduced into the integrated chip U1, i.e. the input terminal of the voltage comparator, through the optocoupler chip U3. Since the trigger voltage is greater than the reference voltage, the high level of the output terminal of pin 1 of the integrated chip U1 is introduced into the optocoupler chip U2. After the optocoupler chip U2 is triggered, it conducts and introduces the high level signal into the microprocessor to realize the feedback of the fault signal. After the microprocessor receives the feedback signal from the optocoupler chip U2, it controls the auxiliary contact to reset.

[0037] After the short circuit fault on the load side is cleared, the power supply circuit of this contactor is cut off, and then the MOSFET M1 is reset to turn on the power supply circuit of the load again.

[0038] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its technical solution shall still fall within the protection scope of this utility model.

Claims

1. A DC contactless contactor, comprising a microprocessor, a main contact circuit, and auxiliary contacts, wherein the control signal output terminal of the microprocessor is connected to the control signal input terminals of the main contact circuit and the auxiliary contacts respectively, and a short-circuit self-locking module is further provided; a DC power supply is connected in series with the main contact circuit and the short-circuit self-locking module to form a power supply circuit for the load, characterized in that: A fault feedback unit is provided. The signal output terminal of the short-circuit self-locking module is connected to the input terminal of the fault feedback unit, and the output terminal of the fault feedback unit is connected to the input terminal of the microprocessor. The output terminal of the fault feedback unit outputs a control signal to control the microprocessor to send a reset control signal to the auxiliary contacts.

2. The DC contactless contactor according to claim 1, characterized in that: The fault feedback unit includes a voltage comparison module and an optocoupler trigger module. The signal output terminal of the short-circuit self-locking module is connected to the signal input side of the optocoupler trigger module. The voltage comparison module is a voltage comparator. The output side of the optocoupler trigger module is connected to the trigger voltage and the voltage input terminal of the voltage comparator. The output terminal of the voltage comparator is connected to the input terminal of the microprocessor.

3. The DC contactless contactor according to claim 2, characterized in that: The fault feedback unit also includes an optocoupler feedback module. The output of the voltage comparator is connected to the input and output sides of the optocoupler feedback module, and the output side of the optocoupler feedback module is connected to the input of the microprocessor.

4. The DC contactless contactor according to claim 1, characterized in that: A communication module is also connected to the input / output ports of the microprocessor.

5. The DC contactless contactor according to claim 1, characterized in that: The short-circuit self-locking module includes a MOSFET. The output of the main contact circuit is connected to a protection transistor via a voltage divider circuit, and the protection transistor is connected to the gate of the MOSFET.

6. The DC contactless contactor according to claim 5, characterized in that: The protection transistor is a triode. The voltage output from the voltage divider circuit is connected to the base of the triode, and the collector of the triode is connected to the gate of the MOSFET. A Zener diode is also connected in parallel between the collector and emitter of the triode.

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