Solid-state relay control circuit with load monitoring and hot standby functions

Abstract

The invention discloses a solid-state relay control circuit with load monitoring and hot standby functions, and the circuit comprises a control circuit which is used for controlling the start and stop of a relay; the input end of the MCU module is connected with the output end of the control circuit, and the MCU module is used for receiving a starting signal of the control circuit and monitoring an output load in real time; the input end of the driving circuit is connected with the output end of the MCU module, and the driving circuit is used for performing zero-cross detection on voltage waveforms and triggering conduction and cut-off of the bidirectional silicon controlled rectifier; the input end of the silicon controlled rectifier circuit is connected with the output end of the driving circuit and is used for controlling cut-off and conduction of the driving circuit; the input end of the sampling circuit is connected with the output end of the silicon controlled rectifier circuit, the output end of the sampling circuit is connected with the MCU module, and the sampling circuit is used for monitoring loads in different states in real time. According to the circuit, the load channel can be rapidly switched, real-time hot backup of the load is realized under the condition of no shutdown, the cost is reduced, and the safety and stability of equipment operation are improved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a solid-state relay control circuit with load monitoring and hot standby functions. Background Art

[0002] SSR (soild state relay) is a contactless switch with isolation function composed of solid-state electronic components. It uses isolation devices to achieve isolation between the control end and the load end. When in use, a small control signal is added to the input end to directly drive a large current load. SSR is generally divided into two types: DC solid-state relay and AC solid-state relay according to the application. DC output usually uses bipolar devices or power field effect tubes, and AC output usually uses two thyristors or one bidirectional thyristor.

[0003] Solid-state relays have long service life, no sparks when switching, high reliability, fast switching speed, and strong anti-interference ability. They are widely used in temperature control systems, lighting control systems, industrial automation devices, etc. However, the tube voltage drop after the output is turned on is large. The forward voltage drop of thyristors or bidirectional thyristors can reach 1-2V, and the saturation voltage drop of high-power transistors is also between 1-2V, which further leads to large power consumption and heat generation during operation, and a proper heat sink is required when using it.

[0004] Ordinary solid-state relays are single actuators and do not have logic judgment and control functions. In some equipment systems, the upper controller is often required to monitor the working status of the solid-state relay and its load to achieve the purpose of early detection and troubleshooting. However, if the system is large, it will be costly, controller resources are scarce, and wiring is complicated to monitor each relay actuator.

[0005] In some occasions, such as constant temperature heating system, the reliability requirements for solid state relays and their loads are high. Once a fault occurs and the system stops, it will cause product defects and great economic losses. Therefore, customers need a set of hot backup relays and loads to ensure the normal operation of the equipment without stopping. Summary of the invention

[0006] The present application provides a solid-state relay control circuit with load monitoring and hot standby functions, which is used to solve the technical problem in the prior art that ordinary solid-state relays cannot have both logical judgment and control capabilities, resulting in the inability to timely discover and eliminate faults.

[0007] In the first aspect, the present application provides a solid-state relay control circuit with load monitoring and hot standby functions, the circuit comprising: a control circuit, an MCU module, a drive circuit, a thyristor circuit, and a sampling circuit; the control circuit is used to control the start and stop of the relay; the input end of the MCU module is connected to the output end of the control circuit, for receiving the start signal of the control circuit, and balancing the running time of the load according to the running time of the thyristor; the input end of the drive circuit is connected to the output end of the MCU module, for detecting the zero crossing of the voltage waveform, and triggering the conduction and cutoff of the bidirectional thyristor; the input end of the thyristor circuit is connected to the output end of the drive circuit, for controlling the cutoff and conduction of the drive circuit; the input end of the sampling circuit is connected to the output end of the thyristor circuit, and the output end of the sampling circuit is connected to the MCU module, for real-time sampling and monitoring of loads in different states.

[0008] In an implementation of the first aspect, the control circuit includes: an isolation optocoupler and a current limiting resistor; the input end of the isolation optocoupler is connected to the positive pole of the voltage, and the output end of the isolation optocoupler is connected to the input end of the MCU module; the input end of the current limiting resistor is connected to the negative pole of the voltage, and the output end of the current limiting resistor is connected to the input end of the isolation optocoupler.

[0009] In an implementation of the first aspect, the driving circuit includes: a thyristor driving optocoupler and a driving resistor group; one end of the thyristor driving optocoupler is connected to the output end of the MCU module, and the other end of the thyristor driving optocoupler is connected to one end of the driving resistor group; the other end of the driving resistor group is connected to one end of the bidirectional thyristor.

[0010] In an implementation of the first aspect, the thyristor circuit includes: a bidirectional thyristor and a load; the control electrode of the bidirectional thyristor is connected to the output end of the drive circuit, and the first anode and the second anode of the bidirectional thyristor are connected to the load; the port of the first anode is connected to the live wire, and the port of the second anode is connected to one end of the load; the other end of the load is connected to the neutral wire; when in the initial state, when the voltage is applied to the first anode and the second anode of the bidirectional thyristor, the bidirectional thyristor is in a cut-off state; when the drive circuit is working, after a forward voltage is generated between the first anode and the second anode of the bidirectional thyristor, the bidirectional thyristor is in a conducting state.

[0011] In an implementation of the first aspect, the sampling circuit includes: a first sampling circuit, a second sampling circuit, a third sampling circuit and a fourth sampling circuit; the first sampling circuit and the third sampling circuit are working state sampling monitoring circuits, which are used to monitor the load operation state in the working state; the second sampling circuit and the fourth sampling circuit are stop state sampling monitoring circuits, which are used to monitor the stop state of the load in the stop state.

[0012] In an implementation of the first aspect, the first sampling circuit includes: a first bidirectional input optocoupler, a first sampling current limiting resistor, and a first sampling resistor; the third sampling circuit includes: a third bidirectional input optocoupler, a third sampling current limiting resistor, and a third sampling resistor; wherein one end of the first sampling current limiting resistor is connected to the drive circuit, and the other end of the first sampling current limiting resistor is connected to the first input end of the first bidirectional input optocoupler; the second input end of the first bidirectional input optocoupler is connected to the drive circuit; the ground end of the first bidirectional input optocoupler is connected to one end of the first sampling resistor; the other end of the first sampling resistor is grounded; and

[0013] One end of the third sampling current limiting resistor is connected to the driving circuit, and the other end of the third sampling current limiting resistor is connected to the first input end of the third bidirectional input optocoupler; the second input end of the third bidirectional input optocoupler is connected to the driving circuit; the ground end of the third bidirectional input optocoupler is connected to one end of the third sampling resistor; and the other end of the third sampling resistor is grounded.

[0014] In an implementation of the first aspect, the second sampling circuit includes: a first operational amplifier, a first high-voltage isolation resistor group, and a second sampling resistor; the positive input terminal and the negative input terminal of the first operational amplifier are both connected to one end of the first high-voltage isolation resistor group; the other end of the first high-voltage isolation resistor group is connected to a bidirectional thyristor; the output end of the first operational amplifier is connected to one end of the second sampling resistor; and the other end of the second sampling resistor is respectively connected to the output end and the ground end of the MCU module.

[0015] In an implementation of the first aspect, the fourth sampling circuit includes: a second operational amplifier, a second high-voltage isolation resistor group, and a fourth sampling resistor; the positive input terminal and the negative input terminal of the second operational amplifier are both connected to one end of the second high-voltage isolation resistor group; the other end of the second high-voltage isolation resistor group is connected to a bidirectional thyristor; the output end of the second operational amplifier is connected to one end of the fourth sampling resistor; and the other end of the fourth sampling resistor is respectively connected to the output end and the ground end of the MCU module.

[0016] In an implementation of the first aspect, it also includes: a power supply circuit, which is used to provide power supply to each module; the power supply circuit includes: a first capacitor group, a power supply control module, a first inductor, a first resistor group, and a second capacitor group; wherein, the input end of the first capacitor group is connected to the output end of the direct current, and the output end of the first capacitor group is connected to the input end of the power supply control module; the output end of the power supply control module is connected to one end of the first inductor; the other end of the first inductor is respectively connected to one end of the first resistor group and the second capacitor group, and the other end of the first resistor group is grounded; the other end of the second capacitor group is grounded.

[0017] In an implementation of the first aspect, it also includes: a fault feedback circuit, used to feed back a fault signal to a host computer; the fault feedback circuit includes: a feedback current limiting resistor group and a transistor; one end of the feedback current limiting resistor group is connected to the MCU module, and the other end of the feedback current limiting resistor group is connected to the base of the transistor; the emitter collector of the transistor is grounded, and the emitter collector of the transistor receives fault information.

[0018] As described above, the solid-state relay control circuit with load monitoring and hot standby functions described in the present application has the following beneficial effects:

[0019] The solid-state relay control circuit with load monitoring and hot standby functions provided by the present application, and the solid-state relay module designed by the present application, have both load monitoring function and load hot standby function. In some use occasions, the load is a wearing part and requires regular maintenance. For example, photovoltaic production equipment cannot be shut down for maintenance at will during the process of using a controller to control the solid-state relay heating resistor. If the heating load is damaged, the use of this type of solid-state relay module can quickly switch the load channel, and achieve real-time hot backup of the load without shutting down, avoiding economic losses. At the same time, the module designed by this circuit also has fault feedback and load balancing operation functions, which can reduce the maintenance times of the equipment load by multiples, bringing convenience and economy to equipment maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Shown is a schematic diagram of the overall framework structure of a solid-state relay control circuit with load monitoring and hot standby functions as described in an embodiment of the present application.

[0021] Figure 2 Shown is a schematic diagram of the structural composition architecture of a solid-state relay control circuit with load monitoring and hot standby functions described in an embodiment of the present application.

[0022] Figure 3 Shown is a schematic diagram of the overall circuit structure of a solid-state relay control circuit with load monitoring and hot standby functions described in an embodiment of the present application.

[0023] Figure 4 Shown is a schematic diagram of a power supply circuit described in an embodiment of the present application.

[0024] Figure 5 Shown is a schematic diagram of the control circuit described in an embodiment of the present application.

[0025] Figure 6 Shown is a schematic diagram of a first driving circuit, a first sampling circuit, and a second sampling circuit according to an embodiment of the present application.

[0026] Figure 7 Shown is a schematic diagram of the second driving circuit, the third sampling circuit and the fourth sampling circuit according to an embodiment of the present application.

[0027] Figure 8 Shown is a schematic diagram of a fault feedback circuit described in an embodiment of the present application.

[0028] Description of Figure Numbers:

[0029] Serial number name

[0030] 1 Solid-state relay control circuit with load monitoring and hot standby functions

[0031] 11 Power Circuit

[0032] 111 First capacitor group

[0033] 112 Power Control Module

[0034] 113 First Inductor

[0035] 114 Second resistor group

[0036] 12 Control Circuit

[0037] 121 Isolation Optocoupler

[0038] 122 Current limiting resistor

[0039] 13 MCU module

[0040] 14. Driving Circuit

[0041] 141 SCR drive optocoupler

[0042] Serial number name

[0043] 142 drive resistor group

[0044] 15. SCR circuit

[0045] 151 Bidirectional thyristor

[0046] 152 Load

[0047] 16 Sampling Circuit

[0048] 161 First Sampling Circuit

[0049] 162 Second sampling circuit

[0050] 163 Third sampling circuit

[0051] 164 Fourth sampling circuit

[0052] 17 Fault feedback circuit

[0053] 171 First fault feedback circuit

[0054] 172 Second fault feedback circuit DETAILED DESCRIPTION

[0055] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0056] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application, and thus the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0057] In addition, in this application, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0058] The solid-state relay control circuit with load monitoring and hot standby functions provided in the following embodiments of the present application solves the problem in the prior art that ordinary solid-state relays cannot have both logical judgment and control capabilities, which leads to the inability to timely detect and eliminate faults; even in certain occasions, when a fault occurs and the machine stops, it is easy to cause damage to the product or equipment, resulting in excessive costs.

[0059] The embodiment of the present application provides a solid-state relay control circuit with load monitoring and hot standby functions. The solid-state relay module designed by the present application has both load monitoring function and load hot standby function. In some use scenarios, the load is a consumable part and requires regular maintenance. For example, photovoltaic production equipment cannot be shut down for maintenance at will during the process of using a controller to control the solid-state relay heating resistor. If the heating load is damaged, the use of this type of solid-state relay module can quickly switch the load channel, and achieve real-time hot backup of the load without shutting down, avoiding economic losses. At the same time, the module designed by this circuit also has fault feedback and load balancing operation functions, which can reduce the maintenance times of the equipment load by multiples, bringing convenience and economy to equipment maintenance.

[0060] The following will describe in detail the implementation principle of a solid-state relay control circuit with load monitoring and hot standby functions of this embodiment in conjunction with the accompanying drawings, so that those skilled in the art can understand the solid-state relay control circuit with load monitoring and hot standby functions of this embodiment without creative work.

[0061] See also Figure 1 and Figure 2 .

[0062] The solid-state relay control circuit 1 with load monitoring and hot standby functions includes: a power supply circuit 11, a control circuit 12, an MCU module 13, a drive circuit 14, a thyristor circuit 15, a sampling circuit 16, and a fault feedback circuit 17. The control circuit 12 is used to control the start and stop of the relay; the input end of the MCU module 13 is connected to the output end of the control circuit 12, and is used to receive the start signal of the control circuit 12, and balance the running time of the load according to the running time of the thyristor; the input end of the drive circuit 14 is connected to the output end of the MCU module 13, and is used to detect the zero crossing of the voltage waveform and trigger the conduction and cutoff of the bidirectional thyristor 151; the input end of the thyristor circuit 15 is connected to the output end of the drive circuit 14, and is used to control the cutoff and conduction of the drive circuit 14; the input end of the sampling circuit 16 is connected to the output end of the thyristor circuit 15, and the output end of the sampling circuit 16 is connected to the MCU module 13, and is used to perform real-time sampling and monitoring of loads in different states. The solid-state relay control circuit 1 with load monitoring and hot standby functions combines the solid-state relay and the logic control into a package to design an intelligent solid-state relay module, which can be directly used in the control system, simplifying electrical connections, reducing costs, and improving system reliability. This solid-state relay module with load monitoring and hot standby can be used in photovoltaic heating, glass bending, ceramic heating, injection molding flow channel control and other equipment.

[0063] See also Figures 3 to 8 .

[0064] The power supply circuit 11 is used to provide power supply to each module.

[0065] The power supply circuit 11 includes: a first capacitor group 111, a power supply control module 112, a first inductor 113, a first resistor group 114, and a second capacitor group 115. The input end of the first capacitor group 111 is connected to the output end of the direct current, and the output end of the first capacitor group 111 is connected to the input end of the power supply control module 112; the output end of the power supply control module 112 is connected to one end of the first inductor 113; the other end of the first inductor 113 is connected to one end of the first resistor group 114 and the second capacitor group 115 respectively, the other end of the first resistor group 114 is grounded; the other end of the second capacitor group 115 is grounded.

[0066] In this embodiment, the power supply circuit 11 preferably adopts a DC-DC BUCK circuit, which allows a wide voltage power input (5-40VDC).

[0067] Specifically, the power supply circuit 11 includes: a first capacitor group 111, a power control module 112, a first inductor 113, a first resistor group 114, and a second capacitor group 115. The first capacitor group 111 includes: a capacitor C101 and a capacitor C102, that is, the input power passes through two capacitors C101 and C102 for filtering and smoothing the input voltage. The input end of the power control module 112 is connected to one end of the capacitor C102; and the BOOT pin of the power control module 112 is connected to the capacitor C100 for driving the gate drive voltage of the high-side switch; the switch pin of the power control module 112 is connected to one end of the first inductor L100 for current conversion. At the same time, the other end of the first inductor L100 is connected to one end of the first resistor group R102, and the resistor R102 and the resistor R105 are connected in series and then grounded. C103 of the second capacitor group is connected in parallel to the resistor R102, and one end of the capacitor C104 is grounded.

[0068] Please continue reading Figure 3 and Figure 5 .

[0069] The control circuit 12 includes: an isolation optocoupler 121 and a current limiting resistor 122. The input end of the isolation optocoupler 121 is connected to the positive pole of the voltage, and the output end of the isolation optocoupler 121 is connected to the input end of the MCU module 13; the input end of the current limiting resistor 122 is connected to the negative pole of the voltage, and the output end of the current limiting resistor 122 is connected to the input end of the isolation optocoupler 121.

[0070] In this embodiment, the solid-state relay control terminal input generally has two modes: a constant current mode and a current limiting mode, which are used to start and stop the relay.

[0071] The control end of this circuit uses an isolated optocoupler IC105 (for example: EL357) and a current-limiting resistor R152 (for example: 2K), which can not only realize the electrical isolation between the external control end and this module, but also realize wide voltage signal control (4-32VDC, corresponding to a current of about 1.3~15mA, which meets the working conditions of the isolated optocoupler of this circuit).

[0072] See also Figure 3 , Figure 6 to Figure 7 .

[0073] The driving circuit 14 includes a thyristor driving optocoupler 141 and a driving resistor group 142 .

[0074] One end of the thyristor driving optocoupler 141 is connected to the output end of the MCU module 13 , and the other end of the thyristor driving optocoupler 141 is connected to one end of the driving resistor group 142 ; the other end of the driving resistor group 142 is connected to one end of the bidirectional thyristor 151 .

[0075] In this embodiment, the driving circuit 14 includes: a first driving circuit and a second driving circuit.

[0076] The first driving circuit includes: a first thyristor driving optocoupler U100, and a first driving resistor group (driving resistor R103, driving resistor R108). Among them, one end of the first thyristor driving optocoupler U100 is connected to the output end of the MCU module 13, and the other end of the first thyristor driving optocoupler U100 is connected to one end of the resistor R103 in the first driving resistor group; the other end of the resistor R103 is connected to one end of the resistor R108, and the other end of the resistor R108 is connected to one end of the bidirectional thyristor Q100.

[0077] Similarly, the second driving circuit includes: a second thyristor driving optocoupler, a second driving resistor group (driving resistor R116, driving resistor R122). Among them, one end of the second thyristor driving optocoupler U102 is connected to the output end of the MCU module 13, and the other end of the second thyristor driving optocoupler U102 is connected to one end of the resistor R116 in the second driving resistor group; the other end of the resistor R116 is connected to one end of the resistor R122, and the other end of the resistor R122 is connected to one end of the bidirectional thyristor Q101.

[0078] Furthermore, in order to adapt to some inductive and capacitive load occasions, an RC absorption circuit R101 is added at both ends of the bidirectional thyristor Q100, and an RC absorption circuit R115 is added at both ends of the bidirectional thyristor Q101 to absorb the switching peak voltage.

[0079] Specifically, the driving circuit 14 is mainly composed of the thyristor driving optocouplers U100 and U102 (for example: MOC3083) with zero-crossing detection and driving resistors R103 (for example: 150Ω), R108 (for example: 22Ω) and R116 and R122 resistors. In order to adapt to some inductive and capacitive load occasions, RC absorption circuits R101, R115 (for example: 47Ω) and C105, C110 (for example: 10nF) are added at both ends of the thyristor to absorb the switching peak voltage.

[0080] Please continue reading Figure 6 to Figure 7 .

[0081] The thyristor circuit 15 includes a bidirectional thyristor 151 and a load 152 .

[0082] The control electrode of the bidirectional thyristor 151 is connected to the output end of the driving circuit 14, and the first anode and the second anode of the bidirectional thyristor 151 are connected to the load 152; the port of the first anode is connected to the live wire, and the port of the second anode is connected to one end of the load 152; the other end of the load 152 is connected to the neutral wire.

[0083] When voltage is applied to both ends of the first anode and the second anode of the bidirectional thyristor 151 in the initial state, the bidirectional thyristor 151 is in the cut-off state; when the drive circuit 14 is working, after a forward voltage is generated between the first anode and the second anode of the bidirectional thyristor 151, the bidirectional thyristor 151 is in the on state.

[0084] In this embodiment, the thyristor circuit 15 is composed of a bidirectional thyristor 151 (such as BTA20) and a load 152 (such as a heating wire). In the initial state, the voltage is applied to the A and K terminals of the thyristor, and the thyristor is in the cut-off state. When the drive circuit 14 is working, a forward voltage is generated between the G and K terminals of the thyristor, and the thyristor is in the on state. Port T1 is used to connect the live wire, ports L1 and L2 are used to connect one end of the load 152, and the other end of the load 152 is connected to the neutral wire.

[0085] The sampling circuit 16 includes: a first sampling circuit 161 , a second sampling circuit 162 , a third sampling circuit 163 and a fourth sampling circuit 164 .

[0086] The first sampling circuit 161 and the third sampling circuit 163 are working state sampling monitoring circuits, which are used to monitor the operating state of the load 152 in the working state; the second sampling circuit 162 and the fourth sampling circuit 164 are stopping state sampling monitoring circuits, which are used to monitor the stopping state of the load 152 in the stopping state.

[0087] In this embodiment, the first sampling circuit 161 includes: a first bidirectional input optocoupler, a first sampling current limiting resistor, and a first sampling resistor.

[0088] One end of the first sampling current limiting resistor is connected to the driving circuit 14, and the other end of the first sampling current limiting resistor is connected to the first input end of the first bidirectional input optocoupler; the second input end of the first bidirectional input optocoupler is connected to the driving circuit 14; the ground end of the first bidirectional input optocoupler is connected to one end of the first sampling resistor; the other end of the first sampling resistor is grounded.

[0089] Specifically, the first sampling circuit 161 includes: a first bidirectional input optocoupler IC101, a first sampling current limiting resistor R107, and a first sampling resistor R111. Among them, one end of the first sampling resistor R111 is connected to the emitter of the first bidirectional input optocoupler IC101, and the other end is grounded. The collector of the first bidirectional input optocoupler IC101 is connected to the positive power supply terminal to provide voltage; the first input end of the first bidirectional input optocoupler IC101 is connected to one end of the first sampling current limiting resistor R107, and the two input ends of the first bidirectional input optocoupler IC101 are connected in parallel to the driving resistor R103.

[0090] The second sampling circuit 162 includes: a first operational amplifier, a first high-voltage isolation resistor group, and a second sampling resistor.

[0091] The positive input terminal and the negative input terminal of the first operational amplifier are both connected to one end of the first high-voltage isolation resistor group; the other end of the first high-voltage isolation resistor group is connected to the bidirectional thyristor 151; the output end of the first operational amplifier is connected to one end of the second sampling resistor; the other end of the second sampling resistor is respectively connected to the output end and the ground end of the MCU module 13.

[0092] Specifically, the second sampling circuit 162 includes: a first operational amplifier IC102A, a first high-voltage isolation resistor group, and a second sampling resistor R134. The positive input terminal of the first operational amplifier IC102A is connected to one end of the resistor R135 of the first high-voltage isolation resistor group, and the resistors R135, R129, and R136 are connected in series in sequence, and the other end of the resistor R136 is connected to one end of the bidirectional thyristor Q100; the negative input terminal of the first operational amplifier IC102A is connected to one end of the resistor R137 in the first high-voltage isolation resistor group, and the resistors R137, R130, and R138 are connected in series, and the other end of the resistor R138 is connected to the live wire T1. One end of the second sampling resistor R134 is connected to the MCU module 13 and the ground terminal respectively, and the other end of the second sampling resistor R134 is connected to the output end of the first operational amplifier IC102A.

[0093] The third sampling circuit 163 includes: a third bidirectional input optocoupler, a third sampling current limiting resistor, and a third sampling resistor.

[0094] One end of the third sampling current limiting resistor is connected to the driving circuit 14, and the other end of the third sampling current limiting resistor is connected to the first input end of the third bidirectional input optocoupler; the second input end of the third bidirectional input optocoupler is connected to the driving circuit 14; the ground end of the third bidirectional input optocoupler is connected to one end of the third sampling resistor; the other end of the third sampling resistor is grounded.

[0095] Specifically, the third sampling circuit 163 includes: a third bidirectional input optocoupler IC103, a third sampling current limiting resistor R121, and a third sampling resistor R125. Among them, one end of the third sampling resistor R111 is connected to the emitter of the third bidirectional input optocoupler IC103, and the other end is grounded. The collector of the third bidirectional input optocoupler IC103 is connected to the positive power supply terminal to provide voltage; the first input end of the third bidirectional input optocoupler IC103 is connected to one end of the third sampling current limiting resistor R121, and the two input ends of the third bidirectional input optocoupler IC103 are connected in parallel to the driving resistor R103.

[0096] The fourth sampling circuit 164 includes: a second operational amplifier, a second high-voltage isolation resistor group, and a fourth sampling resistor.

[0097] The positive input terminal and the negative input terminal of the second operational amplifier are both connected to one end of the second high-voltage isolation resistor group; the other end of the second high-voltage isolation resistor group is connected to the bidirectional thyristor 151; the output end of the second operational amplifier is connected to one end of the fourth sampling resistor; the other end of the fourth sampling resistor is respectively connected to the output end and the ground end of the MCU module 13.

[0098] Specifically, the fourth sampling circuit 164 includes: a second operational amplifier IC102B, a second high-voltage isolation resistor group, and a fourth sampling resistor R147. The positive input terminal of the second operational amplifier IC102B is connected to one end of the resistor R139 of the second high-voltage isolation resistor group, and the resistors R139, R132, and R140 are connected in series in sequence, and the other end of the resistor R140 is connected to one end of the bidirectional thyristor Q101; the negative input terminal of the second operational amplifier IC102B is connected to one end of the resistor R141 in the second high-voltage isolation resistor group, and the resistors R141, R133, and R142 are connected in series, and the other end of the resistor R142 is connected to the T1 live wire. One end of the fourth sampling resistor R147 is connected to the MCU module 13 and the ground terminal respectively, and the other end of the fourth sampling resistor R147 is connected to the output terminal of the second operational amplifier IC102B. At the same time, the negative input terminal and the output terminal of the second operational amplifier IC102B are respectively connected in parallel with a resistor R148 and a capacitor C122.

[0099] In summary, it can be seen that the sampling circuit in the present application is mainly divided into two parts, namely: the first sampling circuit 161 and the third sampling circuit 163 are monitoring circuits for the load in the working state, and the second sampling circuit 162 and the fourth sampling circuit 164 are monitoring circuits for the load in the stopped state.

[0100] Among them, the first sampling circuit 161 and the third sampling circuit 163 are mainly composed of bidirectional input optocouplers IC101, IC103 (such as LTV-214) and current limiting resistors R107, R121 (such as 510Ω). The input end of the optocoupler is connected in parallel to the two ends of the driving resistor R103 or R116. When the thyristor is driven at zero, due to the switching characteristics of the bidirectional thyristor 151, a voltage drop of about 6V will be generated at both ends of the driving resistor, which will last for about 50uS, and can drive the conduction of the sampling optocoupler. If the MCU can detect a pulse signal with a pulse width of 50uS and a period of 10ms, it can be judged that the load operation status is normal, otherwise it will report a corresponding channel fault.

[0101] Furthermore, due to the characteristics of the thyristor, the first sampling circuit 161 and the third sampling circuit 163 can only monitor the state of the load when it is working. If you want to monitor the state when the load stops, you need to cooperate with the second sampling circuit 162 and the fourth sampling circuit 164. It is mainly composed of an operational amplifier circuit (such as: TP2584) and high-voltage isolation resistors R132, R140, R133, R142 (such as: 510K / 400V).

[0102] This differential input amplifier circuit has a gain of about 0.0021 times and a bias voltage of 1.65V, which is compatible with the detection of 80-480VAC load voltage. When the current channel load stops and is in normal state, the operational amplifier will output a 1.65V biased sinusoidal signal, whose Vpp peak-to-peak value is determined by the external grid voltage. Within the allowable operating voltage range, the maximum Vpp does not exceed 3V. If the MCU can normally detect the 20ms sinusoidal signal of the period, it can be judged that the load is normal, otherwise it will report the corresponding channel fault.

[0103] See also Figure 8 .

[0104] The circuit further comprises: a fault feedback circuit 17 for feeding back a fault signal to a host computer.

[0105] The fault feedback circuit 17 includes: a feedback current limiting resistor group and a transistor. One end of the feedback current limiting resistor group is connected to the MCU module 13, and the other end of the feedback current limiting resistor group is connected to the base of the transistor; the emitter collector of the transistor is grounded, and the emitter collector of the transistor receives fault information.

[0106] In this embodiment, the fault feedback circuit 17 is mainly an open-drain output circuit composed of a feedback current limiting resistor and an NPN transistor, which is used to feed back fault information to the host computer. The fault feedback circuit 17 includes: a feedback current limiting resistor group and a transistor. Among them, one end of the feedback current limiting resistor group is connected to the MCU module 13, and the other end of the feedback current limiting resistor group is connected to the base of the transistor; the emitter collector of the transistor is grounded, and the emitter collector of the transistor receives fault information.

[0107] Specifically, the fault feedback circuit 17 includes: a first fault feedback circuit 171 and a second fault feedback circuit 172 .

[0108] The first fault feedback circuit 171 includes: a first feedback current limiting resistor group and a first transistor TR101. The first feedback current limiting resistor group includes: a resistor R112 and a resistor R113. Among them, the collector of the first transistor TR101 receives the fault alarm signal, the emitter of the first transistor TR101 is grounded, and the base of the first transistor TR101 is connected to the resistor R112 and the resistor R113 respectively, and the resistor R112 and the resistor R113 are connected in parallel. The other end of the resistor R112 is connected to the MCU module.

[0109] The second fault feedback circuit 172 includes: a second feedback current limiting resistor group and a second triode TR103. The second feedback current limiting resistor group includes: a resistor R118 and a resistor R120. The collector of the second triode TR103 receives the fault alarm signal, the emitter of the second triode TR103 is grounded, and the base of the second triode TR103 is connected to the resistor R118 and the resistor R120 respectively, and the resistor R118 and the resistor R120 are connected in parallel. The other end of the resistor R118 is connected to the MCU module.

[0110] In this application, an intelligent solid-state relay module is designed by solidifying the solid-state relay and logic control combination into a package. This structure can be directly used in the control system, which can simplify electrical connections, reduce costs, and improve system reliability. This solid-state relay module with load monitoring and hot standby can be used in photovoltaic heating, glass bending, ceramic heating, injection molding flow channel control and other equipment.

[0111] In summary, the solid-state relay control circuit with load monitoring and hot standby functions of the present application, the solid-state relay control circuit with load monitoring and hot standby functions, and the solid-state relay module designed by the present application have both load monitoring functions and load hot standby functions. In some use occasions, the load is a consumable part and requires regular maintenance. For example, photovoltaic production equipment cannot be shut down for maintenance at will during the process of using a controller to control the solid-state relay heating resistor. If the heating load is damaged, the use of this type of solid-state relay module can quickly switch the load channel, and achieve real-time hot backup of the load without shutting down, avoiding economic losses. At the same time, the module designed by this circuit also has fault feedback and load balancing operation functions, which can reduce the maintenance times of the equipment load by multiples, bringing convenience and economy to equipment maintenance. At the same time, this solution has strong versatility, a wide range of application, and high practical value.

[0112] The above embodiments are only for explaining the principle and effect of the present application, and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A solid-state relay control circuit with load monitoring and hot standby functions, characterized in that: The circuit includes: a control circuit, an MCU module, a drive circuit, a thyristor circuit, and a sampling circuit; The control circuit is used to control the start and stop of the relay; The input end of the MCU module is connected to the output end of the control circuit, and is used to receive a start signal of the control circuit and balance the operation time of the load according to the operation time of the thyristor; The input end of the driving circuit is connected to the output end of the MCU module, and is used for detecting the zero crossing of the voltage waveform and triggering the conduction and cutoff of the bidirectional thyristor; The input end of the thyristor circuit is connected to the output end of the drive circuit, and is used to control the cut-off and conduction of the drive circuit; The input end of the sampling circuit is connected to the output end of the thyristor circuit, and the output end of the sampling circuit is connected to the MCU module, which is used for real-time sampling and monitoring of loads in different states.

2. The solid-state relay control circuit with load monitoring and hot standby functions according to claim 1, characterized in that: The control circuit includes: an isolation optocoupler and a current limiting resistor; The input end of the isolation optocoupler is connected to the positive pole of the voltage, and the output end of the isolation optocoupler is connected to the input end of the MCU module; The input end of the current limiting resistor is connected to the negative voltage electrode, and the output end of the current limiting resistor is connected to the input end of the isolation optocoupler.

3. The solid-state relay control circuit with load monitoring and hot standby functions according to claim 1, characterized in that: The driving circuit includes: a thyristor driving optocoupler and a driving resistor group; One end of the thyristor driving optocoupler is connected to the output end of the MCU module, and the other end of the thyristor driving optocoupler is connected to one end of the driving resistor group; The other end of the driving resistor group is connected to one end of the bidirectional thyristor.

4. The solid-state relay control circuit with load monitoring and hot standby functions according to claim 1, characterized in that: The thyristor circuit comprises: a bidirectional thyristor and a load; The control electrode of the bidirectional thyristor is connected to the output end of the driving circuit, and the first anode and the second anode of the bidirectional thyristor are connected to the load; The port of the first anode is connected to the live wire, and the port of the second anode is connected to one end of the load; The other end of the load is connected to the neutral line; When a voltage is applied to both ends of the first anode and the second anode of the bidirectional thyristor in an initial state, the bidirectional thyristor is in a cut-off state; When the driving circuit is working, after a forward voltage is generated between the first anode and the second anode of the bidirectional thyristor, the bidirectional thyristor is in a conducting state.

5. The solid-state relay control circuit with load monitoring and hot standby functions according to claim 1, characterized in that: The sampling circuit comprises: a first sampling circuit, a second sampling circuit, a third sampling circuit and a fourth sampling circuit; The first sampling circuit and the third sampling circuit are working state sampling monitoring circuits, which are used to monitor the operating state of the load in the working state; The second sampling circuit and the fourth sampling circuit are sampling monitoring circuits in a stopped state, and are used to monitor the stopped state of the load in the stopped state.

6. The solid-state relay control circuit with load monitoring and hot standby functions according to claim 5, characterized in that: The first sampling circuit includes: a first bidirectional input optocoupler, a first sampling current limiting resistor, and a first sampling resistor; The third sampling circuit includes: a third bidirectional input optocoupler, a third sampling current limiting resistor, and a third sampling resistor; wherein, One end of the first sampling current limiting resistor is connected to the driving circuit, and the other end of the first sampling current limiting resistor is connected to the first input end of the first bidirectional input optocoupler; The second input terminal of the first bidirectional input optocoupler is connected to the driving circuit; The ground terminal of the first bidirectional input optocoupler is connected to one end of the first sampling resistor; The other end of the first sampling resistor is grounded; as well as One end of the third sampling current limiting resistor is connected to the driving circuit, and the other end of the third sampling current limiting resistor is connected to the first input end of the third bidirectional input optocoupler; The second input end of the third bidirectional input optocoupler is connected to the driving circuit; The ground terminal of the third bidirectional input optocoupler is connected to one end of the third sampling resistor; The other end of the third sampling resistor is grounded.

7. The solid-state relay control circuit with load monitoring and hot standby functions according to claim 5, characterized in that: The second sampling circuit includes: a first operational amplifier, a first high-voltage isolation resistor group, and a second sampling resistor; The positive input terminal and the negative input terminal of the first operational amplifier are both connected to one end of the first high-voltage isolation resistor group; The other end of the first high-voltage isolation resistor group is connected to a bidirectional thyristor; The output end of the first operational amplifier is connected to one end of the second sampling resistor; The other end of the second sampling resistor is connected to the output end and the ground end of the MCU module respectively.

8. The solid-state relay control circuit with load monitoring and hot standby functions according to claim 5, characterized in that: The fourth sampling circuit includes: a second operational amplifier, a second high-voltage isolation resistor group, and a fourth sampling resistor; The positive input terminal and the negative input terminal of the second operational amplifier are both connected to one end of the second high-voltage isolation resistor group; The other end of the second high-voltage isolation resistor group is connected to the bidirectional thyristor; The output end of the second operational amplifier is connected to one end of the fourth sampling resistor; The other end of the fourth sampling resistor is connected to the output end and the ground end of the MCU module respectively.

9. The solid-state relay control circuit with load monitoring and hot standby functions according to claim 1, characterized in that: Also includes: A power supply circuit, used for providing power supply to each module; The power supply circuit includes: a first capacitor group, a power supply control module, a first inductor, a first resistor group, and a second capacitor group; in, The input end of the first capacitor group is connected to the output end of the direct current, and the output end of the first capacitor group is connected to the input end of the power control module; The output end of the power control module is connected to one end of the first inductor; The other end of the first inductor is connected to one end of the first resistor group and the second capacitor group respectively, and the other end of the first resistor group is grounded; The other end of the second capacitor group is grounded.

10. The solid-state relay control circuit with load monitoring and hot standby functions according to claim 1, characterized in that: Also includes: Fault feedback circuit, used to feed back fault signals to the host computer; The fault feedback circuit comprises: a feedback current limiting resistor group and a triode; One end of the feedback current limiting resistor group is connected to the MCU module, and the other end of the feedback current limiting resistor group is connected to the base of the transistor; The emitter collector of the transistor is grounded, and the emitter collector of the transistor receives fault information.

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