Three-phase protection device based on MCU and isolation detection

Abstract

The utility model provides a three-phase protection device based on an MCU and isolation detection. The three-phase protection device comprises an electrical parameter isolation acquisition circuit, a phase sequence determination circuit, an MCU protection module, a switch and an external interface. The input ends of the electrical parameter isolation acquisition circuit and the phase sequence judgment circuit are respectively connected with three-phase four wires, and three live wires in the three-phase four wires are connected with electric equipment through switches; the output end of a switch control signal of the MCU protection module controls and connects the switch to control the on-off of the switch; the electrical parameter isolation acquisition circuit is connected with the input end of the MCU protection module through a first bus; the phase sequence judgment circuit is connected with the input end of the MCU protection module through a TTL serial port signal; the output end of the MCU protection module is connected to an external interface through a second bus. According to the utility model, detection and protection of three-phase four-wire input electrical parameters of the low-voltage power supply and distribution system are realized.

Description

Technical Field

[0001] The utility model relates to the technical field of intelligent low-voltage power supply and distribution, in particular to a three-phase protection device based on MCU and isolation detection. Background Art

[0002] The input protection technology in the low-voltage power distribution system covers three aspects: input voltage, current, and phase sequence. The devices used in practice include circuit breakers, over- and under-voltage protection devices, phase sequence protectors, etc. The devices currently used can only achieve a single protection function in a targeted manner. Therefore, in actual applications, they can only be selected and used according to specific circumstances among devices with different specifications and parameters. According to the existing actual situation, since the protection parameters cannot be adjusted, in many cases, they cannot meet the special requirements of users. Utility Model Content

[0003] To solve the above problems, the utility model provides a three-phase protection device based on MCU and isolation detection, which can appropriately adjust the effective protection parameters, effectively realize input over-voltage and under-voltage protection, input overload protection and input phase mismatch protection, and meet the use requirements of different occasions.

[0004] The utility model provides a three-phase protection device based on MCU and isolation detection. The specific technical solution is as follows:

[0005] The device includes an electrical parameter isolation acquisition circuit, a phase sequence judgment circuit, an MCU protection module, a switch and an external interface;

[0006] The input ends of the electrical parameter isolation acquisition circuit and the phase sequence judgment circuit are respectively connected to three-phase four-wire, and the three live wires of the three-phase four-wire are connected to the electrical equipment through a switch;

[0007] The output end of the switch control signal of the MCU protection module is connected to the switch control unit, and the switch control unit is connected to the switch control to control the switch on and off;

[0008] The electrical parameter isolation acquisition circuit is connected to the input end of the MCU protection module through a first bus;

[0009] The phase sequence judgment circuit is connected to the input end of the MCU protection module through a TTL serial port signal;

[0010] The output end of the MCU protection module is connected to the external interface through the second bus.

[0011] Furthermore, the specific connection structure of the output end of the switch control signal of the MCU protection module is as follows:

[0012] The live wire in the three-phase four-wire is also connected to the MCU protection module through a switch control unit, and the neutral wire in the three-phase four-wire is connected to the MCU protection module.

[0013] Furthermore, the electrical parameter isolation acquisition circuit includes an electrical parameter acquisition module, a power module, an LDO voltage regulator module and a photoelectric coupler; the electrical parameter acquisition module adopts BL0942-SSOP10L;

[0014] The photoelectric coupler comprises a first photoelectric coupler and a second photoelectric coupler;

[0015] The second photoelectric coupler is connected between the SCLK, SEL, RX / SDI pins of the electrical parameter acquisition module and the ground terminal; the first photoelectric coupler is connected between the TX / SDO pin of the electrical parameter acquisition module and the ground terminal of the LDO voltage regulator module;

[0016] A resistor and a capacitor are connected in parallel between the IP and IN pins of the electrical parameter acquisition module, and resistors are connected in series to the IP and IN pins respectively, and the series resistors are connected between the parallel resistor and the capacitor;

[0017] A filter circuit is provided between the VP pin of the electrical parameter acquisition module and the ground terminal.

[0018] Furthermore, the electrical parameter isolation acquisition circuit is connected to the three-phase four-wire through the JL23-24 connector.

[0019] Further, the phase sequence judgment circuit is composed of two dual D flip-flops and two operational amplifiers, namely a first flip-flop, a second flip-flop, a first operational amplifier and a second operational amplifier;

[0020] The data input terminal D of the first trigger is connected to a 5V voltage input, and the clock terminal CLK is connected to a live wire A of a three-phase four-wire;

[0021] The original code output terminal Q of the first trigger is connected to the data input terminal D of the second trigger;

[0022] The clock terminal CLK of the second trigger is connected to the B live wire of the three-phase four-wire, and the original code output terminal Q is connected to the reverse input terminal of the second operational amplifier;

[0023] The reset terminals R of the first trigger and the second trigger are connected in series with resistors and capacitors and then connected to the live wire C of the three-phase four-wire. The reset terminals R are also connected in series with a resistor and a diode connected in parallel to ground.

[0024] The first operational amplifier is connected in series with the second operational amplifier, and the first operational amplifier is connected to a 5V voltage input via a filter circuit.

[0025] Furthermore, the phase sequence judgment circuit is connected to the three-phase four-wire through the JL23-14 connector.

[0026] Furthermore, the MCU protection module includes a single-chip minimum processing system, a rectifier filter circuit and a 485 isolation circuit;

[0027] The phase sequence judgment circuit and three groups of electrical parameter isolation acquisition circuits are connected through the single chip microcomputer minimum processing system.

[0028] Furthermore, the single-chip microcomputer minimum processing system is also connected to a Darlington output unit and an optocoupler input unit.

[0029] Furthermore, the single chip microcomputer minimum processing system is connected to two groups of the rectification and filtering circuits.

[0030] Furthermore, the single-chip microcomputer minimum processing system adopts stm32f103rc as a core processor.

[0031] The beneficial effects of the utility model are as follows:

[0032] The device of the utility model can reasonably adjust parameters according to actual conditions in view of the differences in voltage levels in different occasions. In occasions where the grid voltage is high / low, normal power consumption can be achieved without damaging electrical equipment, and power supply interruptions due to slight abnormalities in the grid voltage will not have an adverse effect on production. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall module structure of the device.

[0034] Figure 2 It is a schematic diagram of the electrical parameter isolation acquisition circuit.

[0035] Figure 3 It is a schematic diagram of the phase sequence judgment circuit.

[0036] Figure 4 It is a schematic diagram of the processor pin connection of the minimum processing system of the microcontroller.

[0037] Figure 5 This is a schematic diagram of the pin connection of the rectifier and filter circuit.

[0038] Figure 6 This is a schematic diagram of the pin connection of the 485 isolation circuit.

[0039] Figure 7 This is a schematic diagram of the pin connection of the phase sequence judgment circuit.

[0040] Figure 8 This is a schematic diagram of the pin connections of the electrical parameter isolation acquisition circuit.

[0041] Fig. 9This is a diagram of the Darlington output unit pin connections.

[0042] Fig.10 This is a schematic diagram of the pin connection of the optocoupler input unit.

[0043] Fig.11 This is a diagram of the pin connections of the JL23-24 connector.

[0044] Fig.12 This is a diagram of the pin connections of the JL23-20 connector. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0046] In the description of the embodiments of the present utility model, it should be noted that the indicated orientation or position relationship is based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, or the orientation or position relationship commonly understood by those skilled in the art, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0047] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] Example 1

[0049] Embodiment 1 of the present utility model discloses a three-phase protection device based on MCU and isolation detection, such as Figure 1 As shown, the details are as follows:

[0050] The device includes an electrical parameter isolation acquisition circuit, a phase sequence judgment circuit, an MCU protection module, a switch and an external interface;

[0051] The input ends of the electrical parameter isolation acquisition circuit and the phase sequence judgment circuit are respectively connected to the three-phase four-wire, and the three live wires A, B and C in the three-phase four-wire are connected to the electrical equipment through a switch;

[0052] The output end of the switch control signal of the MCU protection module is connected to the switch control unit, and the switch control unit is connected to the switch control to control the switch on and off;

[0053] In this embodiment, the live wire A in the three-phase four-wire is also connected to the MCU protection module through a switch control unit, and the neutral wire N in the three-phase four-wire is connected to the MCU protection module.

[0054] The electrical parameter isolation acquisition circuit is connected to the input end of the MCU protection module through a first bus;

[0055] The phase sequence judgment circuit is connected to the input end of the MCU protection module through a TTL serial port signal;

[0056] The output end of the MCU protection module is connected to the external interface through the second bus.

[0057] The three-phase voltage / current is sampled in an isolated manner, and the sampled data is transmitted to the MCU protection module through the first bus. After the MCU protection module processes the data, it performs overvoltage, undervoltage, and overcurrent protection according to the set strategy;

[0058] The phase sequence judgment circuit outputs a TTL signal to the MCU protection module, and then the MCU protection module outputs a switch control signal to control the on and off of the switch K1 to perform phase error protection;

[0059] The terminal is connected to the MCU protection module based on the external interface, and the overvoltage, undervoltage and overcurrent protection parameters are customized according to the actual situation to meet the usage requirements in different occasions.

[0060] like Figure 2 As shown, in this embodiment, the electrical parameter isolation acquisition circuit includes an electrical parameter acquisition module, a power supply module, an LDO voltage regulator module and a photoelectric coupler;

[0061] The electrical parameter acquisition module adopts BL0942-SSOP10L;

[0062] The photoelectric coupler adopts EL357N;

[0063] The photoelectric coupler comprises a first photoelectric coupler and a second photoelectric coupler;

[0064] The collector of the second photoelectric coupler is connected between the SCLK, SEL, RX / SDI pins of the electrical parameter acquisition module and the ground terminal, and the emitter is grounded; the anode of the diode of the second photoelectric coupler is connected to the collector of the first photoelectric coupler via a 10K resistor, and the 10K resistor is also connected to an OR resistor for RX output; the cathode of the diode of the second photoelectric coupler is grounded via an OR resistor;

[0065] Among them, the pin SCLK is connected in series with two 10K resistors, and the pin SEL is connected in series with an NC resistor.

[0066] The cathode of the diode of the first photocoupler is connected to the TX / SDO pin of the electrical parameter acquisition module, and the anode is connected to the ground terminal, the VOUT output terminal and the VDD terminal of the electrical parameter acquisition module of the LDO voltage regulator module through a 1K resistor;

[0067] A 100nF capacitor is connected between the VIN terminal and the GND terminal of the LDO voltage regulator module, the VIN terminal is connected to the +VO terminal of the power module, the GND terminal is connected to the +OV terminal of the power module, the VIN terminal and the GND terminal of the power module are connected to the 100nF capacitor, and the GND terminal is connected to the emitter of the first photocoupler;

[0068] Among them, the LDO voltage regulator module adopts XC6206-3.3, and the power supply module adopts BO505S-1WR3.

[0069] A resistor and a capacitor are connected in parallel between the IP and IN pins of the electrical parameter acquisition module, and resistors are connected in series to the IP and IN pins respectively, and the series resistors are connected between the parallel resistor and the capacitor;

[0070] Specifically, two 33nF capacitors are connected between the IP terminal and the IN terminal and a resistor is connected in parallel. The two capacitors are grounded, denoted as EX_GND, and are connected to the emitter of the first photocoupler.

[0071] The IP and IN terminals are also connected to 1K resistors respectively;

[0072] A filter circuit is provided between the VP pin and the ground terminal of the electrical parameter acquisition module;

[0073] Specifically, the VP terminal is connected with a 1K resistor, and the VP terminal and the GND terminal are connected with a parallel resistor and a 33nF capacitor.

[0074] like Figure 8 and Fig.11 As shown, the electrical parameter isolation acquisition circuit is connected to the three-phase four-wire through the JL23-24 connector.

[0075] like Figure 3As shown, in this embodiment, the phase sequence judgment circuit is composed of two dual D flip-flops and two operational amplifiers, which are respectively a first flip-flop, a second flip-flop, a first operational amplifier and a second operational amplifier;

[0076] The dual D flip-flop adopts CD4013, and the operational amplifier adopts Aip258 dual-channel operational amplifier.

[0077] The data input terminal D of the first trigger is connected to a 5V voltage input, and the clock terminal CLK is connected to a live wire A of a three-phase four-wire, denoted as PEA;

[0078] The original code output terminal Q of the first trigger is connected to the data input terminal D of the second trigger;

[0079] The clock terminal CLK of the second trigger is connected to the B live wire of the three-phase four-wire, denoted as PEB, and the original code output terminal Q is connected to the reverse input terminal of the second operational amplifier through a 20K resistor, and then connected to ground through a 22uF / 50V polarity capacitor after the 20K resistor;

[0080] The reset terminals R of the first trigger and the second trigger are connected in series with resistors and capacitors and then connected to the live wire C of the three-phase four-wire. The reset terminals R are also connected in series with a resistor and a diode connected in parallel to ground.

[0081] Specifically, the reset terminal R is connected in series with a 100R resistor and a 200p capacitor to the live wire C, recorded as PEC; the reset terminal R is connected in parallel with a diode, a 200K resistor and another 200K resistor connected in series with the 100R resistor to ground.

[0082] The first operational amplifier is connected in series with the second operational amplifier, and the first operational amplifier is connected to a 5V voltage input via a filter circuit;

[0083] Specifically, the positive input terminal of the first operational amplifier is connected to a 5V voltage input via a series resistor, and is grounded via a series resistor and a parallel capacitor and resistor; the negative input terminal of the first operational amplifier is connected to the output terminal, and is connected to the positive input terminal of the second operational amplifier via a resistor; the output of the second operational amplifier is connected to a diode as a PERR.

[0084] like Figure 7 and Fig.12 As shown, the phase sequence judgment circuit is connected to the three-phase four-wire through the JL23-14 connector.

[0085] like Figure 4 As shown, the MCU protection module includes a single-chip minimum processing system, a rectifier filter circuit and a 485 isolation circuit;

[0086] The phase sequence judgment circuit and three groups of electrical parameter isolation acquisition circuits are connected through the single chip microcomputer minimum processing system.

[0087] As a preferred embodiment, the single-chip microcomputer minimum processing system uses stm32f103rc as the core processor;

[0088] like Fig. 9 and Fig.10 As shown, the single-chip microcomputer minimum processing system is also connected to a Darlington output unit and an optocoupler input unit;

[0089] The output of the Darlington output unit is connected with a JL23-20 connector.

[0090] like Figure 5 As shown, the single-chip microcomputer minimum processing system is connected to two groups of the rectification and filtering circuits.

[0091] like Figure 6 As shown, the 485 isolation circuit is connected to a JL23-12 connector.

[0092] Based on the above device, the electrical parameter isolation acquisition circuit is connected to the three-phase four-wire through the Hall sensor circuit, the three-phase four-wire input is connected to the Hall current sensor through the through-core method, and the three-phase voltage is connected to the Hall voltage sensor through the current limiting resistor; the isolated sampling of AC voltage / current is realized through the isolated voltage / current sensor, and the high and low voltage isolation is realized to ensure the safe and reliable operation of the system. The electrical parameter isolation acquisition circuit converts the signal output by the Hall sensor into electrical parameter signals such as voltage and current, and communicates with the MCU protection module through the serial interface.

[0093] The MCU protection module receives signals from the phase sequence detection circuit while performing serial communication (TTL level); the phase sequence detection circuit processes the isolated voltage waveform signal into a phase sequence signal. When the phase sequence is inconsistent, the circuit outputs a high-level signal to indicate a phase error.

[0094] The MCU protection module outputs a switch control signal according to the received detection signal, which can control the on and off of the switch.

[0095] The MCU protection module communicates with the outside world through the RS485 interface to customize parameters.

[0096] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A three-phase protection device based on MCU and isolation detection, characterized in that: The device includes an electrical parameter isolation acquisition circuit, a phase sequence judgment circuit, an MCU protection module, a switch and an external interface; The input ends of the electrical parameter isolation acquisition circuit and the phase sequence judgment circuit are respectively connected to three-phase four-wire, and the three live wires of the three-phase four-wire are connected to the electrical equipment through a switch; The output end of the switch control signal of the MCU protection module is connected to the switch control unit, and the switch control unit is connected to the switch control to control the switch on and off; The electrical parameter isolation acquisition circuit is connected to the input end of the MCU protection module through a first bus; The phase sequence judgment circuit is connected to the input end of the MCU protection module through a TTL serial port signal; The output end of the MCU protection module is connected to the external interface through the second bus.

2. The three-phase protection device of MCU and isolation detection according to claim 1, characterized in that: The specific connection structure of the output terminal of the switch control signal of the MCU protection module is as follows: The live wire in the three-phase four-wire is also connected to the MCU protection module through a switch control unit, and the neutral wire in the three-phase four-wire is connected to the MCU protection module.

3. The three-phase protection device of MCU and isolation detection according to claim 1, characterized in that: The electrical parameter isolation acquisition circuit includes an electrical parameter acquisition module, a power module, an LDO voltage regulator module and a photoelectric coupler; the electrical parameter acquisition module adopts BL0942-SSOP10L; The photoelectric coupler comprises a first photoelectric coupler and a second photoelectric coupler; The second photoelectric coupler is connected between the SCLK, SEL, RX / SDI pins of the electrical parameter acquisition module and the ground terminal; the first photoelectric coupler is connected between the TX / SDO pin of the electrical parameter acquisition module and the ground terminal of the LDO voltage regulator module; A resistor and a capacitor are connected in parallel between the IP and IN pins of the electrical parameter acquisition module, and resistors are connected in series to the IP and IN pins respectively, and the series resistors are connected between the parallel resistor and the capacitor; A filter circuit is provided between the VP pin of the electrical parameter acquisition module and the ground terminal.

4. The three-phase protection device of MCU and isolation detection according to claim 3 is characterized in that: The electrical parameter isolation acquisition circuit is connected to the three-phase four-wire through the JL23-24 connector.

5. The three-phase protection device of MCU and isolation detection according to claim 1, characterized in that: The phase sequence judgment circuit is composed of two dual D flip-flops and two operational amplifiers, namely a first flip-flop, a second flip-flop, a first operational amplifier and a second operational amplifier; The data input terminal D of the first trigger is connected to a 5V voltage input, and the clock terminal CLK is connected to a live wire A of a three-phase four-wire; The original code output terminal Q of the first trigger is connected to the data input terminal D of the second trigger; The clock terminal CLK of the second trigger is connected to the B live wire of the three-phase four-wire, and the original code output terminal Q is connected to the reverse input terminal of the second operational amplifier; The reset terminals R of the first trigger and the second trigger are connected in series with resistors and capacitors and then connected to the live wire C of the three-phase four-wire. The reset terminals R are also connected in series with a resistor and a diode connected in parallel to ground. The first operational amplifier is connected in series with the second operational amplifier, and the first operational amplifier is connected to a 5V voltage input via a filter circuit.

6. The three-phase protection device of MCU and isolation detection according to claim 5, characterized in that: The phase sequence judgment circuit is connected to the three-phase four-wire through the JL23-14 connector.

7. The three-phase protection device of MCU and isolation detection according to claim 1, characterized in that: The MCU protection module includes a single-chip minimum processing system, a rectifier filter circuit and a 485 isolation circuit; The phase sequence judgment circuit and three groups of electrical parameter isolation acquisition circuits are connected through the single chip microcomputer minimum processing system.

8. The three-phase protection device of MCU and isolation detection according to claim 7, characterized in that: The single-chip microcomputer minimum processing system is also connected to a Darlington output unit and an optical coupler input unit.

9. The three-phase protection device of MCU and isolation detection according to claim 7, characterized in that: The single chip microcomputer minimum processing system is connected with two groups of the rectifying and filtering circuits.

10. The three-phase protection device of MCU and isolation detection according to claim 7, characterized in that: The single-chip minimum processing system adopts stm32f103rc as the core processor.

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