Three-phase input open-phase detection system

Abstract

The utility model relates to a three-phase input open-phase detection system, which solves the problem that motor faults caused by input open-phase or input undervoltage cannot be distinguished in the prior art, and adopts the technical scheme that the three-phase input open-phase detection system comprises a voltage detection device, and is characterized by further comprising a circuit detection device and an MCU (Microprogrammed Control Unit) system, and the MCU system is in signal connection with the voltage detection device and the circuit detection device, and is used for receiving voltages output by the voltage detection device and the circuit detection device to judge three-phase input phase loss. The method has the advantages that input phase loss or input undervoltage can be distinguished, related personnel can perform targeted repair, the motor can work normally, the fault detection and maintenance efficiency can be improved, and the workload of fault detection and maintenance can be reduced.

Description

Technical Field

[0001] The utility model relates to the field of power equipment detection, in particular to a three-phase input open-phase detection system. Background Art

[0002] As one of the important support technologies in modern industry and life, the motor technology plays an indispensable role in modern industry, science and technology, and daily life. During the operation of a three-phase motor, due to certain reasons, one or more phases of the power supply may be missing or abnormal, resulting in the motor being unable to work properly or running unstably. This kind of fault is called input open-phase.

[0003] Input open-phase is a problem that needs to be highly emphasized. At present, the most commonly used method for detecting input open-phase faults is to measure the bus voltage. After input open-phase occurs, the bus voltage will decrease, and thus the fault is judged. However, input undervoltage will also cause the bus voltage to decrease. Therefore, the method of judging the fault by simply measuring the bus voltage cannot distinguish these two faults. The current method is to regard these two faults as the same fault and report the same fault code. This method is not only inaccurate but also adds a lot of workload to the subsequent motor fault detection and maintenance. Summary of the Invention

[0004] The purpose of the utility model is to solve the above problems existing in the prior art and provide a three-phase input open-phase detection system. A voltage detection device and a circuit detection device are set to detect the bus voltage or the levels of each phase wire in the bus on the power equipment (such as a motor, hereinafter the motor is used to replace the power equipment for description). The MCU system receives the voltage or level signal and conducts analysis and judgment, and can distinguish whether there is a problem of three-phase input open-phase or input undervoltage in the power equipment, guiding relevant staff to carry out more targeted repair work according to input open-phase or input undervoltage respectively, enabling the power equipment to work normally, thus being beneficial to improving the efficiency of fault detection and maintenance, and being beneficial to reducing the workload of fault detection and maintenance.

[0005] The above technical object of the present utility model is mainly solved by the following technical solutions: A three-phase input open-phase detection system includes a voltage detection device, and is characterized by further comprising a circuit detection device and an MCU system. The MCU system is signal-connected to the voltage detection device and the circuit detection device, and is used to receive the voltage output by the voltage detection device and the level output by the circuit detection device to determine three-phase input open-phase or input undervoltage. In this technical solution, a voltage detection device and a circuit detection device are provided to detect the bus voltage or the level of each phase wire in the bus on an electrical equipment (such as a motor). The MCU system receives the voltage or level signal and performs analysis and judgment, and can accurately distinguish whether there is a three-phase input open-phase problem or an input undervoltage problem in the electrical equipment, and form a corresponding three-phase input open-phase prompt or input undervoltage prompt, so as to guide relevant staff to carry out more targeted repair work according to the input open-phase or input undervoltage respectively, make the electrical equipment work normally, which is beneficial to improving the efficiency of fault detection and repair, and is also beneficial to reducing the workload of fault detection and repair.

[0006] As a further improvement and supplement to the above technical solution, the present utility model adopts the following technical measures: The circuit detection device includes three-way level detection circuits. The input end of each level detection circuit is respectively used to connect an output end of a phase power supply of the three-phase power supply on the device to be detected. The output end of each level detection circuit is connected to the electrical signal receiving end on the MCU system, and is used to receive the voltage signal of the corresponding phase wire to judge whether there is a fault or undervoltage input in the corresponding phase wire. When the corresponding phase wire in the bus is normal, the level detection circuit connected to this path outputs a low-level signal, and the MCU system receives the low-level signal. Similarly, it is judged whether the other two-way level detection circuits output low-level signals. If all output low-level signals, the bus is normal. At this time, if the motor cannot run normally, it indicates that there is an input undervoltage situation. On the contrary, when there is a fault in the corresponding phase wire in the bus, the MCU system receives a high-level signal, and at this time, the motor may have a three-phase input open-phase problem. Therefore, this technical solution can clearly distinguish whether the motor has an input undervoltage or input open-phase problem.

[0007] Preferably, a transistor output optocoupler, a first voltage-dividing current-limiting resistor connected in series with the anode on the transistor output optocoupler, an avalanche diode connected in parallel with the anode and cathode of the transistor output optocoupler, and a DC power supply for supplying power to the collector of the transistor output optocoupler are provided on the level detection circuit. The electrical signal receiving end on the MCU system is connected to the collector of the transistor output optocoupler, and the emitter of the transistor output optocoupler is grounded. The first voltage-dividing current-limiting resistor is used to limit the voltage and current entering the level detection circuit of this path, reducing the voltage and current after limiting and voltage division to within the tolerable range of each electronic component (such as the transistor output optocoupler (which can be simply referred to as an optocoupler), the avalanche diode, and the chips and various electronic components in the MCU system). The avalanche diode is provided to protect the optocoupler and allow the alternating current to flow in one direction to the optocoupler. Taking the level detection circuit connected to a phase line as an example, when the No. 1 pin (anode) of the optocoupler is powered on, the photosensitive device (such as a light-emitting diode) inside the optocoupler conducts and emits light, and the secondary side of the optocoupler is turned on by light (that is, the No. 3 pin (collector) and the No. 4 pin (emitter) are turned on). Since the collector is grounded (GND), the current input from the DC power supply (which can be a 3.3V DC power supply or a DC power supply with other voltage parameters) enters the secondary side of the optocoupler from the No. 4 pin and is output to GND from the No. 3 pin, pulling down the signal on this line to a low level. Therefore, the signal received by the MCU system is a low level. When the AC power input is disconnected, the photosensitive device inside the optocoupler does not conduct, and the photosensitive device on the secondary side also does not conduct. The No. 3 pin and the No. 4 pin are internally disconnected, and the current input from the DC power supply cannot flow to GND. At this time, the signal on this line is a high level, and the signal received by the MCU system is also a high level. The MCU system determines whether the phase line is open by judging whether the output end of the level detection circuit outputs a high level or a low level. When it is open, there may be a fault of input phase loss. When it is not open, there is a fault of input undervoltage.

[0008] Preferably, a second voltage-dividing current-limiting resistor is provided on the level detection circuit. The input end of the second voltage-dividing current-limiting resistor is connected to the DC power supply, and the output end of the second voltage-dividing current-limiting resistor is connected in parallel with the electrical signal receiving end on the MCU system and the collector of the transistor output optocoupler. The function and effect of the second voltage-dividing current-limiting resistor are similar to those of the first voltage-dividing current-limiting resistor, and it is also used for current limiting and voltage division, which is beneficial to protecting each electronic component.

[0009] Preferably, the DC power supply is 3.3V.

[0010] Preferably, the voltage detection device includes a rectifier bridge and a current-limiting filter circuit connected in series. The input end of the rectifier bridge is electrically connected to the three-phase power lines of the device to be detected. The negative pole of the output end of the current-limiting filter circuit is grounded, and the positive pole of the output end of the current-limiting filter circuit is connected to the electrical signal receiving end on the MCU system. The rectifier bridge is used to convert the input alternating current into direct current. The current-limiting filter circuit is used to correct the current and voltage rectified by the rectifier bridge, minimize the AC component in the pulsating DC voltage as much as possible, retain its DC component, reduce the ripple coefficient of the output voltage and make the waveform smoother, and form a voltage output signal. The MCU system receives the voltage output signal and judges the voltage output signal. When the voltage output signal decreases, it indicates that the bus voltage decreases and the motor fails. At this time, the MCU system makes the circuit detection device work. The MCU system receives the levels on each phase line transmitted by the circuit detection device. If it is a high level, it indicates an input phase loss fault and forms an input phase loss fault signal. If it is a low level, it indicates input undervoltage and forms an input undervoltage fault signal.

[0011] The beneficial effects of the present utility model are as follows: The circuit detection device respectively connected to each line detects the output level signal. Since the voltage detection device connected to the bus outputs a voltage signal, the MCU system is respectively connected to the voltage detection device and the circuit detection device to receive the level or voltage signal. After processing and judgment, an input phase loss fault signal or an input undervoltage fault signal of the bus is formed, so that relevant personnel can quickly distinguish whether there is a three-phase input phase loss problem or an input undervoltage problem in the electrical equipment, which is beneficial for relevant staff to carry out more targeted repair work according to the input phase loss or input undervoltage respectively, enabling the electrical equipment to work normally, thus being beneficial to improving the fault detection and repair efficiency and reducing the workload of fault detection and repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic flow structure diagram of the present utility model.

[0013] Figure 2 is a schematic circuit structure diagram of the voltage detection device involved in the present utility model.

[0014] Figure 3 is a schematic circuit structure diagram of the voltage detection device involved in the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The technical solutions of the present utility model will be further specifically described below through embodiments in conjunction with the drawings.

[0016] Embodiment: As Figures 1 - 3As shown in the figure, a three-phase input open-phase detection system includes a voltage detection device, a circuit detection device, and an MCU system (in this embodiment, the MCU system is the MCU, which is a microcontroller). The MCU system is signal-connected to the voltage detection device and the circuit detection device, and is used to receive the voltage output by the voltage detection device and the level output by the circuit detection device to determine whether there is a three-phase input open-phase or input undervoltage. Among them, the voltage detection device detects the bus voltage by detecting the voltage, and the circuit detection device detects the hardware circuit by detecting the level. The MCU system (abbreviated as MCU) processes and judges the level and voltage signals to determine the fault.

[0017] In this technical solution, the voltage detection device can be started first to detect the bus voltage, and then the circuit detection device can be started to detect the level of each phase line in the bus. Vice versa, that is, the circuit detection device can be started first to detect the level of each phase line in the bus, and then the voltage detection device can be started to detect the bus voltage.

[0018] In this technical solution, the function of the MCU system is to receive the voltage signal output by the voltage detection device and the level signal output by the circuit detection device, and then judge and analyze the voltage signal and the level signal, and form a corresponding bus input open-phase fault signal or bus input undervoltage fault signal.

[0019] Among them, the process and technical means for the MCU system to judge and analyze the voltage signal and the level signal and form a bus input open-phase fault signal or bus input undervoltage fault signal are prior art. For those skilled in the art, through the disclosure of the foregoing technical solution, the MCU system completes the work of judging and analyzing the voltage signal and the level signal and forming a bus input open-phase fault signal or bus input undervoltage fault signal.

[0020] The detection principle and technical effect of this technical solution are as follows: A voltage detection device and a circuit detection device are set to detect the bus voltage or the level of each phase line in the bus of an electrical equipment (such as a motor) respectively. The MCU system receives the voltage or level signal and conducts analysis and judgment, and can accurately distinguish whether there is a three-phase input open-phase problem or an input undervoltage problem in the electrical equipment, and form a corresponding three-phase input open-phase prompt or input undervoltage prompt, so as to guide the relevant staff to carry out more targeted repair work according to the input open-phase or input undervoltage respectively, make the electrical equipment work normally, which is beneficial to improving the fault detection and repair efficiency, and is also beneficial to reducing the workload of fault detection and repair.

[0021] Next, the circuit detection device will be described in detail:

[0022] In practical applications, such as Figure 2As shown, the circuit detection device includes three-level detection circuits. The input end of each level detection circuit is respectively used to connect to one phase power output end of the three-phase power supply on the device to be detected, and the output end of each level detection circuit is connected to the electrical signal receiving end on the MCU system, for receiving the voltage signal of the corresponding phase line to determine whether there is a fault or undervoltage input in the corresponding phase line.

[0023] That is to say, when the corresponding phase line in the bus is normal, the level detection circuit connected to this path outputs a low-level signal, and the MCU system receives the low-level signal. Similarly, check whether the other two level detection circuits output low-level signals. If all output low-level signals, the bus is normal. At this time, if the motor cannot run normally, it indicates that there is an undervoltage input situation. On the contrary, when there is a fault in the corresponding phase line in the bus, the MCU system receives a high-level signal, and at this time, there may be a problem of input phase loss in the motor. Therefore, this technical solution can clearly distinguish whether there is an input undervoltage or input phase loss problem in the motor.

[0024] In practical applications, the level detection circuit is provided with a transistor output optocoupler, a first voltage-dividing and current-limiting resistor R1 connected in series with the anode on the transistor output optocoupler, an avalanche diode D1 connected in parallel with the anode and cathode on the transistor output optocoupler, and a DC power supply (such as Figure 2 3.3V in) for supplying power to the collector of the transistor output optocoupler. The electrical signal receiving end on the MCU system is connected to the collector on the transistor output optocoupler, and the emitter on the transistor output optocoupler is grounded.

[0025] In practical applications, the level detection circuit is provided with a second voltage-dividing and current-limiting resistor R2. The input end of the second voltage-dividing and current-limiting resistor is connected to the DC power supply, and the output end of the second voltage-dividing and current-limiting resistor is connected in parallel with the electrical signal receiving end on the MCU system and the collector of the transistor output optocoupler.

[0026] Among them, the setting of the first voltage-dividing and current-limiting resistor and the second voltage-dividing and current-limiting resistor is used to limit the voltage and current entering the level detection circuit of this path, and reduce the voltage and current after limiting and voltage-dividing to within the tolerable range of each electronic component (such as the transistor output optocoupler (which can be simply referred to as optocoupler), avalanche diode, and chips and various electronic components in the MCU system, etc.). The setting of the avalanche diode is used to protect the optocoupler and make the alternating current flow in one direction to the optocoupler.

[0027] In this embodiment, a level detection circuit connected to one phase line is taken as an example for illustration. When the No. 1 pin (anode) of the optocoupler is powered on, the photosensitive device (such as a light-emitting diode) inside the optocoupler conducts and emits light. The secondary side of the optocoupler is turned on by receiving light (that is, the No. 3 pin (collector) and the No. 4 pin (emitter) are turned on). Since the collector is grounded (GND), the current input from the DC power supply (which can be a 3.3V DC power supply or a DC power supply with other voltage parameters, and preferably a 3.3V DC power supply) enters the secondary side of the optocoupler from the No. 4 pin and is output to GND from the No. 3 pin, pulling down the signal on this line to a low level. Therefore, the signal received by the MCU system is a low level. When the AC power input is disconnected, the photosensitive device inside the optocoupler does not conduct, and the photosensitive device on the secondary side also does not conduct. The No. 3 pin and the No. 4 pin are internally disconnected, and the current input from the DC power supply cannot flow to GND. At this time, the signal on this line is a high level, and the signal received by the MCU system is also a high level. The MCU system determines whether the phase line is open by judging whether the output end of the level detection circuit outputs a high level or a low level. When it is open, there may be a fault of input phase loss. When it is not open, there is a fault of input undervoltage. By analogy, the other two phase lines are detected and judged in the same way.

[0028] Next, the voltage detection device will be further elaborated:

[0029] In practical applications, as Figure 3 shown, the voltage detection device includes a rectifier bridge and a current-limiting and filtering circuit connected in series. The input end of the rectifier bridge is electrically connected to the power supply three-phase lines on the device to be detected. The negative pole of the output end of the current-limiting and filtering circuit is grounded, and the positive pole of the output end of the current-limiting and filtering circuit is connected to the electrical signal receiving end on the MCU system.

[0030] In this technical solution, taking the same phase line as an example for illustration, after being connected to the AC power supply, the current enters the rectifier bridge. The rectifier bridge rectifies the current, converting the input alternating current into direct current. The current directly rectified by the rectifier bridge is still very large and the voltage is not smooth enough, and it still needs to be corrected by the current-limiting and filtering circuit. The function of the current-limiting and filtering circuit is to minimize the AC component in the pulsating DC voltage as much as possible, retain its DC component, reduce the output voltage ripple coefficient, and make the waveform become relatively smooth. After the three-phase alternating current is rectified, the voltage of this phase line is output from the output end of the voltage detection device (that is, the output end of the current-limiting and filtering circuit). By analogy, the voltages of the corresponding phase lines of the other two phase lines are output from the output end of the voltage detection device (that is, the output end of the current-limiting and filtering circuit). Finally, the MCU system receives the bus voltage and analyzes and judges the change of the bus voltage.

[0031] When the bus voltage drops and the motor fails, the MCU determines the on / off state of the three-phase lines based on the high and low level signals received from the circuit detection device. If the signal transmitted to the MCU system by one or more of the phase lines is high level, an input phase loss fault is reported. If the signals of all three phase lines are low level, an input undervoltage fault is reported.

[0032] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. In the above embodiments, various changes and modifications can be made to the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A three-phase input open-phase detection system, comprising a voltage detection device, characterized in that It also includes a circuit detection device and an MCU system. The MCU system is signal-connected to the voltage detection device and the circuit detection device, and is used to receive the voltage output by the voltage detection device and the level output by the circuit detection device to determine the three-phase input phase loss or input undervoltage; The circuit detection device includes three-way level detection circuits. The input end of each level detection circuit is respectively used to connect to a phase power output end of the three-phase power supply on the device to be detected. The output end of each level detection circuit is connected to the electrical signal receiving end on the MCU system, and is used to receive the voltage signal of the corresponding phase line to determine whether there is a fault or undervoltage input in the corresponding phase line; The level detection circuit is provided with a transistor output optocoupler, a first voltage-dividing current-limiting resistor connected in series with the anode on the transistor output optocoupler, an avalanche diode connected in parallel with the anode and cathode on the transistor output optocoupler, and a DC power supply for supplying power to the collector of the transistor output optocoupler. The electrical signal receiving end on the MCU system is connected to the collector on the transistor output optocoupler, and the emitter on the transistor output optocoupler is grounded.

2. The three-phase input open-phase detection system according to claim 1, wherein The level detection circuit is provided with a second voltage-dividing current-limiting resistor. The input end of the second voltage-dividing current-limiting resistor is connected to the DC power supply, and the output end of the second voltage-dividing current-limiting resistor is connected in parallel with the electrical signal receiving end on the MCU system and the collector of the transistor output optocoupler.

3. The three-phase input open-phase detection system according to claim 2, wherein The DC power supply is 3.3V.

4. The three-phase input open-phase detection system according to any one of claims 1 to 3, characterized in that The voltage detection device includes a rectifier bridge and a current-limiting filter circuit connected in series. The input end of the rectifier bridge is electrically connected to the three-phase power supply lines of the device to be detected. The negative electrode of the output end of the current-limiting filter circuit is grounded, and the positive electrode of the output end of the current-limiting filter circuit is connected to the electrical signal receiving end on the MCU system.

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