CN217689137U - Three-phase voltage detection system - Google Patents
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- CN217689137U CN217689137U CN202221434998.2U CN202221434998U CN217689137U CN 217689137 U CN217689137 U CN 217689137U CN 202221434998 U CN202221434998 U CN 202221434998U CN 217689137 U CN217689137 U CN 217689137U
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Abstract
The embodiment of the application provides a three-phase voltage detection system which comprises a first detection module, a second detection module and a third detection module; two detection pins of each detection module are respectively connected with two phases of three-phase power, the output end of each detection module is connected with a controller, and the controller acquires the voltage measured by each detection module. Therefore, six voltage values among three phases can be automatically obtained, manual operation is not needed, and the automation degree is high; the detection module adopts a single-phase alternating current contactor inside, has the functions of overcurrent, short-circuit protection, filtering and the like, and can well ensure the stability of equipment operation.
Description
Technical Field
The utility model relates to an electric power detects technical field, especially relates to a three-phase voltage detecting system.
Background
The change of alternating current three-phase voltage can influence the work of consumer, if break down can cause the damage, so the condition that has the voltage of measuring between the three-phase of three-phase electricity. At present, a voltage sensor or other measuring instrument is generally used to sample the voltage between each two phases. However, the voltage sensor has the problems of low automation degree, poor real-time performance, incapability of transmitting fault signals to workers at the first time and the like in measurement, and elements of the voltage sensor are easy to damage under the fault condition, so that serious influence can be caused in the fields of subways, high-speed rails and the like with higher requirements on safety.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, an embodiment of the present application provides a three-phase voltage detection system. The three-phase voltage detection system is based on the single-phase alternating current contactor, can realize automatic voltage detection between each two phases of three-phase electricity, has overcurrent and short-circuit protection functions, and ensures the safety of equipment.
In a first aspect, an embodiment of the present application provides a three-phase voltage detection system, which includes a first detection module, a second detection module, and a third detection module;
the signal input end of the first detection module is used for being connected with a U phase of three-phase power, a first detection pin of the first detection module is used for being connected with a V phase of the three-phase power, and a second detection pin of the first detection module is used for being connected with a W phase of the three-phase power;
the signal input end of the second detection module is used for being connected with the V phase of the three-phase power, the first detection pin of the second detection module is used for being connected with the U phase of the three-phase power, and the second detection pin of the second detection module is used for being connected with the W phase of the three-phase power;
the signal input end of the third detection module is used for being connected with the W phase of the three-phase power, the first detection pin of the third detection module is used for being connected with the V phase of the three-phase power, and the second detection pin of the third detection module is used for being connected with the U phase of the three-phase power.
In one embodiment, the three-phase voltage detection system further comprises a first controller, a second controller, and a third controller;
the output end of the first detection module is connected with a first controller, the first controller is used for acquiring a first potential difference between a U phase and a V phase of the three-phase power, and the first controller is also used for acquiring a second potential difference between the U phase and the W phase of the three-phase power;
the output end of the second detection module is connected with a second controller, the second controller is used for acquiring a third potential difference between the V phase and the U phase of the three-phase power, and the second controller is also used for acquiring a fourth potential difference between the V phase and the W phase of the three-phase power;
the output end of the third detection module is connected with a third controller, the third controller is used for acquiring a fifth electric potential difference between the W phase and the V phase of the three-phase electricity, and the third controller is also used for acquiring a sixth electric potential difference between the W phase and the U phase of the three-phase electricity.
In one embodiment, the first detection module includes a single-phase ac contactor installed inside the chassis, and the second and third detection modules have the same structure as the first detection module.
In one embodiment, the single-phase alternating current contactor comprises a starting circuit, a driving circuit, a detection circuit, a switching circuit and an overcurrent protection circuit which are connected in sequence;
the starting circuit comprises a first input end and a second input end, the first input end is used for accessing a starting signal, and the starting circuit is used for outputting a driving signal according to the starting signal;
the driving circuit is used for providing driving current to control the switch circuit to be switched on when receiving the driving signal;
the signal input end of the switching circuit is used for inputting an alternating current signal, and the signal output end of the switching circuit is used for outputting the alternating current signal;
the detection circuit is used for detecting the current value in the single-phase alternating current contactor and outputting an overcurrent signal when the current value is greater than an overcurrent threshold value;
one end of the overcurrent protection circuit is connected with the detection circuit, the other end of the overcurrent protection circuit is connected with the second input end of the starting circuit, the overcurrent protection circuit is further connected with the first public end, and the overcurrent protection circuit is used for outputting a protection signal when receiving the overcurrent signal.
In an embodiment, the start circuit includes a not gate and an and gate, one end of the not gate is connected to the second input terminal, the other end of the not gate is connected to the and gate, the and gate is further connected to the first input terminal, and the other end of the and gate is connected to the driving circuit.
In one embodiment, the driving circuit includes a driving chip, and the driving chip is connected to the switching circuit.
In one embodiment, the switching circuit comprises a first driving resistor, a second driving resistor, a first thyristor and a second thyristor;
the first driving resistor is connected with the first controllable silicon;
and the second driving resistor is connected with the second controllable silicon.
In one embodiment, the detection circuit comprises a current transformer and a comparison module, wherein one end of the current transformer is connected with the driving circuit, and the other end of the current transformer is connected with the comparison module;
the comparison module comprises a first comparator and a second comparator, and the first comparator is connected with the second comparator in parallel;
the negative input end of the first comparator is connected with the current transformer, and the positive input end of the first comparator is connected with a first reference value;
and the positive input end of the second comparator is connected with the current transformer, and the negative input end of the second comparator is connected with a second reference value.
In one embodiment, the overcurrent protection circuit comprises an optical coupler and a self-locking module, wherein one end of the optical coupler is connected with the comparison module, and the other end of the optical coupler is connected with the self-locking module;
the optocoupler is used for conducting when receiving the overcurrent signal, and the self-locking module is used for outputting a protection signal when receiving the overcurrent signal.
In one embodiment, the self-locking module comprises: the protection circuit comprises a first diode, a first protection resistor, a second protection resistor, a first triode and a second triode;
the anode of the first diode is connected with the optocoupler, and the cathode of the first diode is connected with the base electrode of the first triode;
an emitter of the first triode is connected with a first common end, and a collector of the first triode is connected with a base of the second triode through the first protection resistor;
and the collector of the second triode is connected with the first common end through the second protection resistor, and the emitter of the second triode is connected with the second common end.
The application provides a three-phase voltage detection system has following beneficial effect:
the embodiment of the application provides a three-phase voltage detection system which comprises a first detection module, a second detection module and a third detection module; two detection pins of each detection module are respectively connected with two phases of three-phase power, the output end of each detection module is connected with a controller, and the controller acquires the voltage measured by each detection module. Therefore, six voltage values among three phases can be automatically acquired, manual operation is not needed, the automation degree is high, and whether a fault exists in the loop can be found at the first time. The detection module adopts a single-phase alternating current contactor, has the functions of overcurrent, short-circuit protection, filtering and the like, and can well ensure the stability of equipment operation.
Drawings
In order to more clearly explain the technical solutions of the present application, the drawings needed to be used in the embodiments are briefly introduced below, and it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope of protection of the present application. Like components are numbered similarly in the various figures.
FIG. 1 is a schematic diagram illustrating a three-phase voltage detection system according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a single-phase ac contactor according to an embodiment of the present application;
fig. 3 shows a schematic circuit diagram of a single-phase ac contactor according to an embodiment of the present application.
200-single phase ac contactor; 210-a start-up circuit; 220-a drive circuit; 230-a switching circuit; 240-detection circuit; 250-overcurrent protection circuit.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments.
The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application.
Hereinafter, the terms "including", "having", and their derivatives, which may be used in various embodiments of the present application, are intended to indicate only specific features, numbers, steps, operations, elements, components, or combinations of the foregoing, and should not be construed as first excluding the existence of, or adding to, one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.
Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application belong. The terms (such as terms defined in a commonly used dictionary) will be construed to have the same meaning as the contextual meaning in the related art and will not be construed to have an idealized or overly formal meaning unless expressly so defined in various embodiments of the present application.
Referring to fig. 1, a schematic structural diagram of a three-phase voltage detection system provided in the embodiment of the present application is shown: the three-phase voltage detection system comprises a first detection module, a second detection module and a third detection module; the signal input end of the first detection module is used for being connected with a U phase of three-phase power, a first detection pin of the first detection module is used for being connected with a V phase of the three-phase power, and a second detection pin of the first detection module is used for being connected with a W phase of the three-phase power; the signal input end of the second detection module is used for being connected with the V phase of the three-phase power, the first detection pin of the second detection module is used for being connected with the U phase of the three-phase power, and the second detection pin of the second detection module is used for being connected with the W phase of the three-phase power; the signal input end of the third detection module is used for being connected with the W phase of the three-phase power, the first detection pin of the third detection module is used for being connected with the V phase of the three-phase power, and the second detection pin of the third detection module is used for being connected with the U phase of the three-phase power. The first, second and third detection modules are ACT1, ACT2 and ACT3 in fig. 1, respectively. A first detection pin of the first detection module is a pin marked by a reference numeral 1 in fig. 1, and a second detection pin is a pin marked by a reference numeral 2 in fig. 1; the second detection module and the third detection module have the same structure as the first detection module, and are not described herein again.
The output end of the first detection module is connected with a first controller, the first controller is used for acquiring a first potential difference between a U phase and a V phase of the three-phase electricity, and the first controller is also used for acquiring a second potential difference between the U phase and the W phase of the three-phase electricity; the output end of the second detection module is connected with a second controller, the second controller is used for acquiring a third potential difference between the V phase and the U phase of the three-phase power, and the second controller is also used for acquiring a fourth potential difference between the V phase and the W phase of the three-phase power; the output end of the third detection module is connected with a third controller, the third controller is used for acquiring a fifth electric potential difference between the phase W and the phase V of the three-phase electricity, and the third controller is also used for acquiring a sixth electric potential difference between the phase W and the phase U of the three-phase electricity. Vin in fig. 1 is an input terminal, and Vout is an output terminal.
Thus, each detection module detects 2 voltages between two phases, and the three detection modules can simultaneously detect 6 voltages between three phases of electricity; meanwhile, the potential between the phase lines can be judged according to the positive and negative of the detection value, so that the functions of good real-time performance and comprehensive data acquisition are realized.
In one embodiment, the first detection module includes a single-phase ac contactor installed inside the chassis, and the second and third detection modules have the same structure as the first detection module.
In one embodiment, please refer to fig. 2, which is a schematic structural diagram of a single-phase ac contactor 200 according to an embodiment of the present disclosure. Illustratively, the single-phase ac contactor 200 includes a start circuit 210, a drive circuit 220, a switching circuit 230, a detection circuit 240, and an overcurrent protection circuit 250. Specifically, the starting circuit 210, the driving circuit 220, the switching circuit 230, the detection circuit 240 and the overcurrent protection circuit 250 are connected in sequence, and the overcurrent protection circuit 250 is connected to the first common terminal. The starting circuit 210 is connected to the first input end, and is configured to receive a starting signal and output a driving signal; the driving circuit 220 is used for receiving the driving signal and controlling the switch circuit 230 to be turned on according to the driving signal; the switching circuit 230 is connected to the input and output terminals of the three-phase power; the detection circuit 240 is used for detecting a current value in the loop of the single-phase alternating current contactor 200 and judging whether to output an overcurrent signal to the overcurrent protection circuit 250 according to the current value; the overcurrent protection circuit 250 is turned on after receiving the overcurrent signal and outputs a protection signal, and the second input terminal of the start circuit 210 controls the switching-off of the switching circuit 230 after receiving the protection signal, thereby performing the function of overall overcurrent protection on the single-phase ac contactor 200.
As shown in fig. 3, the single-phase ac contactor 200 includes: the start circuit 210, the drive circuit 220, the switch circuit 230, the detection circuit 240 and the overcurrent protection circuit 250 are connected in sequence; all VSS in fig. 3 represent the first common terminal and all GND represent ground.
The starting circuit comprises a first input end and a second input end, the first input end is used for accessing a starting signal, and the starting circuit is used for outputting a driving signal according to the starting signal;
in an embodiment, the start circuit includes a not gate and an and gate, one end of the not gate is connected to the second input terminal, the other end of the not gate is connected to the and gate, the and gate is further connected to the first input terminal, and the other end of the and gate is connected to the driving circuit.
As shown in fig. 3, U2 in fig. 3 is the not gate, the level states of the input terminal and the output terminal of the not gate are always in opposite phase, when the input terminal inputs a high level, the output terminal outputs a low level, and conversely, when the input terminal inputs a low level, the output terminal outputs a high level; for convenience of description, the high level is represented by a logic 1 and the low level is represented by a logic 0 in the present embodiment.
The and gate U3 comprises two inputs, one output. The AND gate outputs a logic 1 only when the input levels of the two input ends are the same, otherwise, the AND gate outputs a logic 0. One of the input ends of the AND gate U3 is connected with the output end of the NAND gate U2, and the other input end is connected with an external signal source and used for receiving an externally input starting signal SW ARM. In one embodiment, the external signal source may be a single chip.
When the start signal SW ARM is logic 1 and the protection signal FAULT is 0 at the same time, that is, the circuit is not over-current, the not gate U2 outputs logic 1, and the and gate U3 outputs logic 1, and is connected to the driving circuit via the fifth resistor R5. In one embodiment, the and gate is further connected to the first common terminal via a first capacitor, and the and gate is further connected to the first common terminal via a third protection resistor R3. In one embodiment, the first common terminal is a common ground terminal VSS.
The driving circuit is used for providing driving current to control the switch circuit to be switched on when receiving the driving signal; the signal input end of the switching circuit is used for inputting an alternating current signal, and the signal output end of the switching circuit is used for outputting the alternating current signal; the driving circuit comprises a driving chip, and the driving chip is connected with the switching circuit. It should be noted that the single-phase ac contactor provided in this embodiment is used to control the on/off of the ac circuit, the ac signal is not divided into positive and negative, and the description of the signal input end and the signal output end of the switching circuit is only used to distinguish the wiring, and is not used to limit the flow direction of the electrical signal. In one embodiment, the signal input terminal of the switching circuit is 440VI in fig. 3, and the signal output terminal of the switching circuit is 440VO in fig. 3.
The switching circuit comprises a first driving resistor, a second driving resistor, a first controllable silicon and a second controllable silicon; the first driving resistor is connected with the first controllable silicon; and the second driving resistor is connected with the second controllable silicon.
In one embodiment, as shown in fig. 3, the driver chip U1 is an optical isolator FOD4118, and the driver chip U1 includes pins 1, 2, 3, 4, 5, and 6. Pin 1 of the driving chip U1 is connected with the output end of the gate U3 through a fifth resistor R5, and pin 2 of the driving chip U1 is connected with the first common end; when the pin 6 and the pin 4 of the driving chip U1 detect that the alternating current voltage in the single-phase alternating current contactor passes through a zero point, the pin 6 is conducted with the pin 4, the driving current flows through the first driving resistor, and the driving voltage is generated to drive the first controllable silicon D1 to be conducted; the driving current flows through the second driving resistor to generate driving voltage to drive the second silicon controlled rectifier D2 to be conducted; thus, the drive circuit is turned on and the single-phase ac contactor is turned on. The driving circuit further comprises a fourth resistor R4 and a second capacitor C2 which are connected in series, and a branch where the fourth resistor R4 and the second capacitor C2 are located is connected in parallel with a branch where the first controllable silicon D1 and the second controllable silicon D2 are located, so that a filtering effect is achieved. The negative pole of the second controllable silicon D2 is connected with the signal input end of the external alternating current through a fuse F1.
The detection circuit is used for detecting the current value in the single-phase alternating current contactor and outputting an overcurrent signal when the current value is larger than an overcurrent threshold value.
In one embodiment, the detection circuit includes a current transformer and a comparison module, one end of the current transformer is connected to the switch circuit, and the other end of the current transformer is connected to the comparison module.
In one embodiment, the current transformer U4 is L18P060D15, pin 6 of the current transformer U4 is connected to the positive electrode of the first thyristor D1, pin 5 is connected to the output terminal of the external alternating current, pin 4 is connected to the comparison module, and pin 4 is also grounded via the sixth resistor R6; and pin 1 of the current transformer U4 is also connected with an external first level, pin 2 is grounded, pin 3 is connected with an external second level, a third capacitor C3 is connected between pin 1 and pin 2, and a fourth capacitor C4 is connected between pin 2 and pin 3. The third capacitor C3 and the fourth capacitor C4 function as filtering. In one embodiment, the first level is 15V and the second level is-15V.
In one embodiment, the comparison module includes a first comparator U6 and a second comparator U7, the first comparator U6 being connected in parallel with the second comparator U7; the negative input end of the first comparator U6 is connected with the current transformer U4, and the positive input end of the first comparator U6 is connected with a first reference value REF-; the positive input end of the second comparator U7 is connected to the current transformer, and the negative input end of the second comparator U7 is connected to a second reference value REF +. The first reference value REF-is the lowest current value, the second reference value REF + is the highest reference value, namely the overcurrent threshold, and the lowest reference value REF-and the highest reference value REF + are set according to actual conditions based on the conditions that the equipment can normally operate and the safety can be guaranteed.
In one embodiment, the output terminal of the first comparator U6 is connected to the anode of the third diode D5, the cathode of the third diode D5 is connected to the overcurrent protection module, the output terminal of the second comparator U7 is connected to the anode of the fourth diode D6, and the cathode of the fourth diode D6 is connected to the overcurrent protection module. When the current value in the loop is between the lowest reference value REF-and the highest reference value REF +, the first comparator U6 outputs low level, the second comparator U7 outputs low level, and the optical coupler keeps off state.
In one embodiment, the comparing module is connected to the optocoupler via a ninth resistor R9, and the comparing module is further connected to ground via the ninth resistor R9 and a fifth capacitor C5.
One end of the overcurrent protection circuit is connected with the detection circuit, the other end of the overcurrent protection circuit is connected with the second input end of the starting circuit, the overcurrent protection circuit is also connected with the first public end, and the overcurrent protection circuit is used for outputting a protection signal when receiving the overcurrent signal.
In one embodiment, the overcurrent protection circuit comprises an optical coupler and a self-locking module, one end of the optical coupler is connected with the comparison module, and the other end of the optical coupler is connected with the self-locking module;
the optical coupler is used for being conducted when receiving the overcurrent signal, and the self-locking module is used for outputting a protection signal when receiving the overcurrent signal.
In one embodiment, the self-locking module comprises: the protection circuit comprises a first diode D3, a first protection resistor R1T, a second protection resistor R2T, a first triode Q1 and a second triode Q2; the positive electrode of the first diode D3 is connected with the optocoupler, and the negative electrode of the first diode D3 is connected with the base electrode of the first triode Q1; an emitter of the first triode Q1 is connected with a first common terminal VSS, and a collector of the first triode Q1 is connected with a base of the second triode Q2 through the first protection resistor R1T; a collector of the second triode Q2 is connected to the first common terminal VSS via the second protection resistor R2T, and an emitter of the second triode Q2 is connected to the second common terminal.
In one embodiment, the optocoupler U5 is a TLP785 model. Pin 1 of the optocoupler U5 is connected with the comparison module, pin 2 is grounded, pin 3 is connected with the first common terminal through a sixth capacitor C6, and pin 4 is connected with the second common terminal. And a pin 3 of the optocoupler U5 is also connected with the self-locking module through a seventh resistor R7. The second common terminal is switched in a third level, which in one embodiment is 5V.
In one embodiment, the optocoupler is further connected to the first input via a second diode D4. The cathode of the first diode D3 is also connected to the input of the nand gate U2 via an eighth resistor R8.
When the detection circuit detects that the current value in the loop is larger than the overcurrent threshold value, the second comparator U7 outputs a high level, the comparison circuit outputs an overcurrent signal to the optocoupler U5, the optocoupler U5 is switched on, the self-locking module outputs the high level, the protection signal is logic 1, the NOT gate U2 outputs logic 0, the AND gate U3 outputs logic 0, the first silicon controlled rectifier D1 and the second silicon controlled rectifier D2 in the driving circuit are switched off, and the single-phase alternating current contactor is switched off. Therefore, when the current value in the loop is detected to be larger than the overcurrent threshold value, the single-phase alternating current contactor can be quickly turned off, the intelligent control of the single-phase alternating current contactor is realized, the informatization and the intellectualization in operation are realized, and the safety of the electrical equipment applying the three-phase voltage detection system is well protected.
The three-phase voltage detection system provided by the embodiment of the application comprises a first detection module, a second detection module and a third detection module; controllers are arranged at the output end of each detection module, and each controller acquires the potential difference between two phases, so that six potential differences between three phases can be acquired, manual operation is not needed, and the automation degree is high; the detection module adopts a single-phase alternating current contactor inside, has the functions of overcurrent, short-circuit protection, filtering and the like, and can well ensure the stability of equipment operation.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrases "comprising a component of' 8230; \8230;" does not exclude the presence of additional like elements in the process, method, article, or terminal that comprises the element.
Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solutions of the present application or portions thereof that contribute to the prior art may be embodied in the form of a software product, which is stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal (which may be a mobile phone, a computer, a server, an air conditioner, or a network device) to execute the method according to the embodiments of the present application.
While the present embodiments have been described with reference to the accompanying drawings, it is to be understood that the invention is not limited to the precise embodiments described above, which are meant to be illustrative and not restrictive, and that various changes may be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A three-phase voltage detection system is characterized by comprising a first detection module, a second detection module and a third detection module;
the signal input end of the first detection module is used for being connected with a U phase of three-phase power, a first detection pin of the first detection module is used for being connected with a V phase of the three-phase power, and a second detection pin of the first detection module is used for being connected with a W phase of the three-phase power;
the signal input end of the second detection module is used for being connected with the V phase of the three-phase power, the first detection pin of the second detection module is used for being connected with the U phase of the three-phase power, and the second detection pin of the second detection module is used for being connected with the W phase of the three-phase power;
the signal input end of the third detection module is used for being connected with the W phase of the three-phase power, the first detection pin of the third detection module is used for being connected with the V phase of the three-phase power, and the second detection pin of the third detection module is used for being connected with the U phase of the three-phase power.
2. The three-phase voltage detection system of claim 1, further comprising a first controller, a second controller, and a third controller;
the output end of the first detection module is connected with a first controller, the first controller is used for acquiring a first potential difference between a U phase and a V phase of the three-phase power, and the first controller is also used for acquiring a second potential difference between the U phase and the W phase of the three-phase power;
the output end of the second detection module is connected with a second controller, the second controller is used for acquiring a third potential difference between the V phase and the U phase of the three-phase power, and the second controller is also used for acquiring a fourth potential difference between the V phase and the W phase of the three-phase power;
the output end of the third detection module is connected with a third controller, the third controller is used for acquiring a fifth electric potential difference between the W phase and the V phase of the three-phase electricity, and the third controller is also used for acquiring a sixth electric potential difference between the W phase and the U phase of the three-phase electricity.
3. The three-phase voltage detection system according to claim 1, wherein the first detection module comprises a single-phase alternating current contactor installed inside a cabinet, and the second and third detection modules have the same structure as the first detection module.
4. The three-phase voltage detection system according to claim 3, wherein the single-phase alternating current contactor comprises a starting circuit, a driving circuit, a detection circuit, a switching circuit and an overcurrent protection circuit which are connected in sequence;
the starting circuit comprises a first input end and a second input end, the first input end is used for accessing a starting signal, and the starting circuit is used for outputting a driving signal according to the starting signal;
the driving circuit is used for providing driving current to control the switching circuit to be switched on when receiving the driving signal;
the signal input end of the switching circuit is used for inputting an alternating current signal, and the signal output end of the switching circuit is used for outputting the alternating current signal;
the detection circuit is used for detecting the current value in the single-phase alternating current contactor and outputting an overcurrent signal when the current value is greater than an overcurrent threshold value;
one end of the overcurrent protection circuit is connected with the detection circuit, the other end of the overcurrent protection circuit is connected with the second input end of the starting circuit, the overcurrent protection circuit is also connected with the first public end, and the overcurrent protection circuit is used for outputting a protection signal when receiving the overcurrent signal.
5. The three-phase voltage detection system according to claim 4, wherein the start-up circuit comprises a not gate and an and gate, one end of the not gate is connected to the second input terminal, the other end of the not gate is connected to the and gate, the and gate is further connected to the first input terminal, and the other end of the and gate is connected to the driving circuit.
6. The three-phase voltage detection system of claim 4, wherein the drive circuit comprises a driver chip, the driver chip being coupled to the switching circuit.
7. The three-phase voltage detection system of claim 4, wherein the switching circuit comprises a first drive resistor, a second drive resistor, a first thyristor, and a second thyristor;
the first driving resistor is connected with the first controllable silicon;
and the second driving resistor is connected with the second controllable silicon.
8. The three-phase voltage detection system according to claim 4, wherein the detection circuit comprises a current transformer and a comparison module, one end of the current transformer is connected with the driving circuit, and the other end of the current transformer is connected with the comparison module;
the comparison module comprises a first comparator and a second comparator, and the first comparator is connected with the second comparator in parallel;
the negative input end of the first comparator is connected with the current transformer, and the positive input end of the first comparator is connected with a first reference value;
and the positive input end of the second comparator is connected with the current transformer, and the negative input end of the second comparator is connected with a second reference value.
9. The three-phase voltage detection system according to claim 4, wherein the over-current protection circuit comprises an optocoupler and a self-locking module, one end of the optocoupler is connected to the comparison module, and the other end of the optocoupler is connected to the self-locking module;
the optical coupler is used for being conducted when receiving the overcurrent signal, and the self-locking module is used for outputting a protection signal when receiving the overcurrent signal.
10. The three-phase voltage detection system of claim 9, wherein the self-locking module comprises: the protection circuit comprises a first diode, a first protection resistor, a second protection resistor, a first triode and a second triode;
the anode of the first diode is connected with the optocoupler, and the cathode of the first diode is connected with the base electrode of the first triode;
an emitter of the first triode is connected with a first common end, and a collector of the first triode is connected with a base of the second triode through the first protection resistor;
and the collector of the second triode is connected with the first common end through the second protection resistor, and the emitter of the second triode is connected with the second common end.
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