Three-phase three-wire system open-phase detection circuit and method

Abstract

The invention relates to the technical field of electrical variable measurement, in particular to a three-phase three-wire system phase loss detection circuit and method, and the circuit comprises a diode D01, a resistor R01, an optocoupler OP1, a resistor R02, a diode D02, a resistor R03, an optocoupler OP2, a resistor R04, a diode D03, a resistor R05, a resistor R06, a diode D04 and a microcontroller U1. Two groups of half-wave rectification circuits are constructed through a diode D01, a resistor R01, an optocoupler OP1, a resistor R02, a diode D02, a resistor R03, an optocoupler OP2, a resistor R04, a diode D03, a resistor R05, a resistor R06 and a diode D04, a three-phase sine alternating current electric signal is converted into a square wave signal which is subjected to optoelectronic isolation, and whether the three-phase alternating current is open-phase or not is identified according to the square wave signal; the circuit is simple and reliable, parameter adjustment is not needed, which path of the three-phase alternating current has the power supply open phase can be flexibly identified, and information support is provided for rapid troubleshooting and open phase positioning.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring electric variables, and in particular to a three-phase three-wire phase loss detection circuit and method. Background Art

[0002] High-power power supply products usually use three-phase AC power supply. The three-phase AC power supply is composed of three AC potentials with the same frequency, equal amplitude, and phase difference of 120°. In order to protect the power supply products, it is necessary to detect whether the three-phase AC power is missing in real time.

[0003] The current existing method for detecting phase loss of three-phase AC power is mainly through a phase loss detection circuit. Although the existing phase loss detection circuit can detect whether the three-phase AC power is missing a phase, it cannot identify which power supply is missing a phase, resulting in insufficient accuracy in phase loss detection of three-phase AC power. Summary of the invention

[0004] The object of the present invention is to provide a three-phase three-wire phase loss detection circuit and method, which can detect which circuit of the three-phase alternating current has a power supply phase loss and improve the detection accuracy.

[0005] To achieve the above-mentioned object, in a first aspect, the present invention provides a three-phase three-wire phase loss detection circuit, including a diode D01, a resistor R01, an optical coupler OP1, a resistor R02, a diode D02, a resistor R03, an optical coupler OP2, a resistor R04, a diode D03, a resistor R05, a resistor R06, a diode D04 and a microcontroller U1;

[0006] One end of the resistor R01 is connected to the cathode of the diode D01, and the other end is connected to pin 1 of the optocoupler OP1; pin 3 of the optocoupler OP1 is grounded; one end of the resistor R02 is connected to pin 2 of the optocoupler OP1; the anode of the diode D02 is connected to the resistor R02; one end of the resistor R03 is connected to pin 4 of the optocoupler OP1; pin 3 of the optocoupler OP2 is grounded; one end of the resistor R04 is connected to pin 1 of the optocoupler OP2; the cathode of the diode D03 is connected to the resistor R04; one end of the resistor R06 is connected to pin 2 of the optocoupler OP2; the anode of the diode D04 is connected to the resistor R05; the input port IO1 of the microcontroller U1 is connected to pin 4 of the optocoupler OP1, and the input port IO2 of the microcontroller U1 is connected to pin 4 of the optocoupler OP2.

[0007] In a second aspect, the present invention further provides a three-phase three-wire phase loss detection method, comprising:

[0008] Connect phase A of the three-phase AC power to the positive electrode of diode D01, phase B of the three-phase AC power to the negative electrode of diode D02 and the negative electrode of diode D04 at the same time, and phase C of the three-phase AC power to the positive electrode of diode D03;

[0009] In a sinusoidal AC cycle, the optocoupler OP1 conducts for half a cycle and generates a square wave Pab through the resistor R03;

[0010] In a sinusoidal AC cycle, the optocoupler OP2 conducts for half a cycle, generating a square wave Pbc through the resistor R06;

[0011] Detect square wave Pab and square wave Pbc in real time, and identify whether the three-phase AC power is missing a phase based on the square wave signal.

[0012] The specific steps of detecting the square wave Pab and the square wave Pbc in real time and identifying whether the three-phase AC power is missing a phase according to the square wave signal include:

[0013] Real-time detection of square wave Pab and square wave Pbc. If both square wave Pab and square wave Pbc exist, it means that the three-phase AC power supply is normal and there is no phase loss.

[0014] The square wave Pab does not exist, but the square wave Pbc exists, indicating that the A phase AC power supply is missing.

[0015] The specific steps of detecting the square wave Pab and the square wave Pbc in real time and identifying whether the three-phase AC power is missing a phase according to the square wave signal also include:

[0016] The square wave Pab exists but the square wave Pbc does not exist, which means that the C phase AC power supply is missing.

[0017] The specific steps of detecting the square wave Pab and the square wave Pbc in real time and identifying whether the three-phase AC power is missing a phase according to the square wave signal also include:

[0018] The square wave Pab does not exist, and the square wave Pbc does not exist, indicating that the B phase AC power supply is missing.

[0019] The present invention discloses a three-phase three-wire phase loss detection circuit and method. When performing phase loss detection on a three-phase alternating current, the phase A of the three-phase alternating current is connected to the positive electrode of a diode D01, the phase B of the three-phase alternating current is simultaneously connected to the negative electrode of a diode D02 and the negative electrode of a diode D04, and the phase C of the three-phase alternating current is connected to the positive electrode of a diode D03; the power supply of the phase A and the phase B is passed through the diode D01, the diode D02, the resistor R01, the resistor R02, and the light-emitting diode inside the optical coupler OP1 to form a half-wave rectification circuit. In a sinusoidal alternating current cycle, the optical coupler OP1 is turned on for half a cycle, and the optical coupler OP1 is turned on for half a cycle. One end of OP1 generates a square wave Pab through the resistor R03, and the square wave Pab is sent to the input port IO1 of the microcontroller U1. The microcontroller U1 detects the square wave signal Pab in real-time level detection. When the input port IO1 can collect a low level within the specified time, it means that the square wave Pab exists; when the input port IO1 cannot collect a low level within the specified time, it means that the square wave Pab does not exist; determine whether the loop formed by phase A and phase B is missing: if the square wave Pab exists normally, it indicates that the power supply of phase A and phase B is normal; if there is no square wave Pab, it indicates that the power supply of phase A and phase B is abnormal. Similarly, the power supply of phase C and phase B passes through the diode D03, the diode D04, the resistor R04, the resistor R05, and the light-emitting diode inside the optocoupler OP2 to form a half-wave rectifier circuit; within a sinusoidal AC power cycle, the optocoupler OP2 is turned on for half a cycle, and a square wave Pbc is generated at one end of the optocoupler OP2 through the resistor R06, and the square wave Pbc is sent to the input port IO2 of the microcontroller U1. The microcontroller U1 detects the square wave signal Pbc in real-time level detection. When the input port IO2 can collect a low level within the specified time, it means that the square wave Pbc exists; when the input port IO2 cannot collect a low level within the specified time, it means that the square wave Pbc does not exist; it is determined whether the circuit formed by phase C and phase B is missing: if the square wave Pbc exists normally, it indicates that the power supply of phase C and phase B is normal; if there is no square wave Pbc, it indicates that the power supply of phase C and phase B is abnormal. By utilizing the digital and intelligent processing capabilities of the microcontroller U1 and comprehensively processing the square wave signals generated by the two half-wave rectifier circuits, it is possible to identify which power supply phase is missing.Specifically as follows: when the microcontroller U1 input port IO1 and input port IO2 have low levels, it indicates that both square wave Pab and square wave Pbc exist, indicating that the three-phase AC power supply is normal and there is no phase loss; when the microcontroller U1 input port IO1 only has a high level, it indicates that square wave Pab does not exist, square wave Pbc exists, indicating that the A phase AC power supply has a phase loss; when the microcontroller U1 input port IO2 only has a high level, it indicates that square wave Pab exists, square wave Pbc does not exist, indicating that the C phase AC power supply has a phase loss; when the microcontroller U1 input port IO1 and input port IO2 only have high levels, it indicates that square wave Pab does not exist, square wave Pbc does not exist, indicating that the B phase AC power supply has a phase loss. The circuit of the present invention is simple and reliable, does not require parameter adjustment, can flexibly identify which three-phase AC power supply has a phase loss, and provides information support for rapid troubleshooting and positioning of phase loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0021] Figure 1 The invention discloses a circuit diagram of a three-phase three-wire phase loss detection circuit.

[0022] Figure 2 The present invention is a flow chart of a three-phase three-wire phase loss detection method.

[0023] Figure 3 It is a flow chart of the present invention for detecting square wave Pab and square wave Pbc in real time and identifying whether three-phase alternating current is missing a phase according to the square wave signal. DETAILED DESCRIPTION

[0024] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0025] In the first aspect, the present invention provides a three-phase three-wire phase loss detection circuit, see Figure 1 ,in, Figure 1 The invention discloses a circuit diagram of a three-phase three-wire phase loss detection circuit.

[0026] The present invention provides a three-phase three-wire phase loss detection circuit, comprising a diode D01, a resistor R01, an optical coupler OP1, a resistor R02, a diode D02, a resistor R03, an optical coupler OP2, a resistor R04, a diode D03, a resistor R05, a resistor R06, a diode D04 and a microcontroller U1; the above scheme can detect which circuit of the three-phase alternating current has a power supply phase loss, thereby improving the detection accuracy.

[0027] For this specific implementation, one end of the resistor R01 is connected to the cathode of the diode D01, and the other end is connected to pin 1 of the optocoupler OP1; pin 3 of the optocoupler OP1 is grounded; one end of the resistor R02 is connected to pin 2 of the optocoupler OP1; the anode of the diode D02 is connected to the resistor R02; one end of the resistor R03 is connected to pin 4 of the optocoupler OP1; pin 3 of the optocoupler OP2 is grounded; one end of the resistor R04 is connected to pin 1 of the optocoupler OP2; the cathode of the diode D03 is connected to the resistor R04; one end of the resistor R06 is connected to pin 2 of the optocoupler OP2; the anode of the diode D04 is connected to the resistor R05; the input port IO1 of the microcontroller U1 is connected to pin 4 of the optocoupler OP1, and the input port IO2 of the microcontroller U1 is connected to pin 4 of the optocoupler OP2. The optocoupler OP1 and the optocoupler OP2 are both composed of a light emitting diode and an optocoupler transistor. Pin 1 of the optocoupler OP1 and the optocoupler OP2 is the positive electrode of the light emitting diode, pin 2 is the negative electrode of the light emitting diode, pin 3 is the emitter of the optocoupler transistor, and pin 4 is the collector of the optocoupler transistor.

[0028] When performing three-phase AC power phase loss detection, phase A of the three-phase AC power is connected to the positive electrode of diode D01, phase B of the three-phase AC power is connected to the negative electrode of diode D02 and the negative electrode of diode D04 at the same time, and phase C of the three-phase AC power is connected to the positive electrode of diode D03; phase A and phase B power are supplied through the diode D01, the diode D02, the resistor R01, the resistor R02, and the light-emitting diode inside the optocoupler OP1 to form a half-wave rectification circuit. In a sinusoidal AC power cycle, the optocoupler OP1 is turned on for half a cycle, and the resistor is turned on at one end of the optocoupler OP1. R03 generates a square wave Pab, which is sent to the input port IO1 of the microcontroller U1. The microcontroller U1 detects the square wave signal Pab in real-time by detecting the level. When the input port IO1 can collect a low level within the specified time, it indicates that the square wave Pab exists. When the input port IO1 cannot collect a low level within the specified time, it indicates that the square wave Pab does not exist. It determines whether the circuit formed by phases A and B is missing a phase: if the square wave Pab exists normally, it indicates that the power supply of phases A and B is normal. If there is no square wave Pab, it indicates that the power supply of phases A and B is abnormal.

[0029] Similarly, the power supply of phase C and phase B passes through the diode D03, the diode D04, the resistor R04, the resistor R05, and the light-emitting diode inside the optocoupler OP2 to form a half-wave rectifier circuit; within a sinusoidal AC power cycle, the optocoupler OP2 is turned on for half a cycle, and a square wave Pbc is generated at one end of the optocoupler OP2 through the resistor R06, and the square wave Pbc is sent to the input port IO2 of the microcontroller U1. The microcontroller U1 detects the square wave signal Pbc in real-time level detection. When the input port IO2 can collect a low level within the specified time, it means that the square wave Pbc exists; when the input port IO2 cannot collect a low level within the specified time, it means that the square wave Pbc does not exist; it is determined whether the circuit formed by phase C and phase B is missing: if the square wave Pbc exists normally, it indicates that the power supply of phase C and phase B is normal; if there is no square wave Pbc, it indicates that the power supply of phase C and phase B is abnormal. By utilizing the digital and intelligent processing capabilities of the microcontroller U1, the square wave signals generated by the two half-wave rectifier circuits are comprehensively processed to identify which power supply is missing a phase. The details are as follows:

[0030] When the input ports IO1 and IO2 of the microcontroller U1 are at low level, it indicates that both the square wave Pab and the square wave Pbc exist, indicating that the three-phase AC power supply is normal and there is no phase loss;

[0031] When the input port IO1 of the microcontroller U1 has only a high level, it indicates that the square wave Pab does not exist, and the square wave Pbc exists, indicating that the phase A AC power supply is missing;

[0032] When the input port IO2 of the microcontroller U1 has only a high level, it indicates that the square wave Pab exists, but the square wave Pbc does not exist, indicating that the phase C AC power supply is missing;

[0033] When only high level exists at the input port IO1 and the input port IO2 of the microcontroller U1, it indicates that the square wave Pab does not exist and the square wave Pbc does not exist, indicating that the B phase AC power supply is missing.

[0034] A three-phase three-wire phase-loss detection circuit of the present invention constructs two groups of half-wave rectifier circuits through the diode D01, the resistor R01, the optical coupler OP1, the resistor R02, the diode D02, the resistor R03, the optical coupler OP2, the resistor R04, the diode D03, the resistor R05, the resistor R06 and the diode D04, converts the three-phase sinusoidal AC power signal into a square wave signal after photoelectric isolation, and sends it to the microcontroller U1, which performs data processing through software to identify the three-phase AC power supply phase-loss information; the circuit of the present invention is simple and reliable, does not require parameter adjustment, can flexibly identify which circuit of the three-phase AC power has a power supply phase loss, and the microcontroller U1 reports the power input power supply phase-loss status information to the system through the power communication bus, providing information support for rapid troubleshooting and positioning of phase loss.

[0035] Second, see Figure 2-Figure 3 ,in, Figure 2 is a flow chart of a three-phase three-wire phase loss detection method of the present invention, Figure 3 The present invention is a flow chart for detecting square waves Pab and Pbc in real time and identifying whether three-phase AC power is missing phase according to square wave signals; the present invention also provides a three-phase three-wire missing phase detection method, comprising:

[0036] S1 connects the A phase of the three-phase AC power to the positive electrode of the diode D01, the B phase of the three-phase AC power to the negative electrode of the diode D02 and the negative electrode of the diode D04 at the same time, and the C phase of the three-phase AC power to the positive electrode of the diode D03;

[0037] In the embodiment of the present invention, the optocoupler OP1 and the optocoupler OP2 are both composed of a light emitting diode and an optocoupler transistor, pin 1 of the optocoupler OP1 and the optocoupler OP2 is the positive electrode of the light emitting diode, pin 2 is the negative electrode of the light emitting diode, pin 3 is the emitter of the optocoupler transistor, pin 4 is the collector of the optocoupler transistor, and the microcontroller U1 is connected to pin 4 of the optocoupler OP1 and pin 4 of the optocoupler OP2; when performing three-phase alternating current phase loss detection, phase A of the three-phase alternating current is connected to the positive electrode of the diode D01, phase B of the three-phase alternating current is simultaneously connected to the negative electrode of the diode D02 and the negative electrode of the diode D04, and phase C of the three-phase alternating current is connected to the positive electrode of the diode D03.

[0038] S2 In one sinusoidal AC cycle, the optocoupler OP1 conducts for half a cycle, generating a square wave Pab through the resistor R03;

[0039] In the embodiment of the present invention, the A-phase and B-phase power supplies are supplied through the diode D01, the diode D02, the resistor R01, the resistor R02, and the light-emitting diode inside the optocoupler OP1 to form a half-wave rectifier circuit. In one sinusoidal alternating current cycle, the optocoupler OP1 is turned on for half a cycle, and a square wave Pab is generated at one end of the optocoupler OP1 through the resistor R03, and the square wave Pab is sent to the microcontroller U1.

[0040] S3 In one sinusoidal AC cycle, the optocoupler OP2 conducts for half a cycle, generating a square wave Pbc through the resistor R06;

[0041] In the embodiment of the present invention, the C-phase and B-phase power supplies are supplied through the diode D03, the diode D04, the resistor R04, the resistor R05, and the light-emitting diode inside the optocoupler OP2 to form a half-wave rectifier circuit; in a sinusoidal alternating current cycle, the optocoupler OP2 is turned on for half a cycle, and a square wave Pbc is generated at one end of the optocoupler OP2 through the resistor R06. The square wave is sent to the microcontroller U1.

[0042] S4 detects square wave Pab and square wave Pbc in real time, and identifies whether the three-phase AC power is missing a phase according to the square wave signal;

[0043] The specific steps include:

[0044] S41 detects square wave Pab and square wave Pbc in real time. If both square wave Pab and square wave Pbc exist, it means that the three-phase AC power supply is normal and there is no phase loss.

[0045] S42 square wave Pab does not exist, but square wave Pbc exists, indicating that phase A AC power supply is missing;

[0046] S43 square wave Pab exists, but square wave Pbc does not exist, indicating that the C phase AC power supply is missing;

[0047] S44 square wave Pab does not exist, square wave Pbc does not exist, indicating that the B phase AC power supply is missing;

[0048] In the embodiment of the present invention, a square wave Pab is generated at one end of the optical coupler OP1 through the resistor R03, and the square wave Pab is sent to the input port IO1 of the microcontroller U1. The microcontroller U1 detects the square wave signal Pab in a real-time level detection manner. When the input port IO1 can collect a low level within the specified time, it indicates that the square wave Pab exists; when the input port IO1 cannot collect a low level within the specified time, it indicates that the square wave Pab does not exist; it is determined whether the loop formed by phase A and phase B is missing: if the square wave Pab exists normally, it indicates that the power supply of phase A and phase B is normal; if there is no square wave Pab, it indicates that the power supply of phase A and phase B is abnormal. A square wave Pbc is generated at one end of the optical coupler OP2 through the resistor R06, and the square wave Pbc is sent to the input port IO2 of the microcontroller U1. The microcontroller U1 detects the square wave signal Pbc in real-time level detection. When the input port IO2 can collect a low level within the specified time, it means that the square wave Pbc exists; when the input port IO2 cannot collect a low level within the specified time, it means that the square wave Pbc does not exist; determine whether the loop formed by phase C and phase B is missing: if the square wave Pbc exists normally, it indicates that the power supply of phase C and phase B is normal; if there is no square wave Pbc, it indicates that the power supply of phase C and phase B is abnormal. The details are as follows:

[0049] (1) When the input ports IO1 and IO2 of the microcontroller U1 are at low levels, it indicates that both the square wave Pab and the square wave Pbc exist, indicating that the three-phase AC power supply is normal and there is no phase loss;

[0050] (2) When the input port IO1 of the microcontroller U1 only has a high level, it indicates that the square wave Pab does not exist, and the square wave Pbc exists, indicating that the A phase AC power supply is missing;

[0051] (3) When the input port IO2 of the microcontroller U1 only has a high level, it indicates that the square wave Pab exists and the square wave Pbc does not exist, indicating that the phase C AC power supply is missing;

[0052] (4) When only high level exists at the input port IO1 and the input port IO2 of the microcontroller U1, it indicates that the square wave Pab does not exist and the square wave Pbc does not exist, indicating that the B phase AC power supply is missing.

[0053] A three-phase three-wire phase loss detection method of the present invention comprises two groups of half-wave rectifier circuits formed by the diode D01, the resistor R01, the optical coupler OP1, the resistor R02, the diode D02, the resistor R03, the optical coupler OP2, the resistor R04, the diode D03, the resistor R05, the resistor R06 and the diode D04, and converts a three-phase sinusoidal alternating current signal into a square wave signal after photoelectric isolation, and sends the signal to a microcontroller U1, which processes the data through software to identify the phase loss information of the three-phase alternating current power supply; the circuit of the present invention is simple and reliable, does not require parameter adjustment, can flexibly identify which circuit of the three-phase alternating current has a power supply phase loss, and provides information support for rapid troubleshooting and positioning of phase loss.

[0054] What is disclosed above is only one or more preferred embodiments of the present application, and cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiments and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A three-phase three-wire phase loss detection circuit, characterized in that: Includes diode D01, resistor R01, optocoupler OP1, resistor R02, diode D02, resistor R03, optocoupler OP2, resistor R04, diode D03, resistor R05, resistor R06, diode D04 and microcontroller U1; One end of the resistor R01 is connected to the cathode of the diode D01, and the other end is connected to pin 1 of the optocoupler OP1; pin 3 of the optocoupler OP1 is grounded; one end of the resistor R02 is connected to pin 2 of the optocoupler OP1; the anode of the diode D02 is connected to the resistor R02; one end of the resistor R03 is connected to pin 4 of the optocoupler OP1; pin 3 of the optocoupler OP2 is grounded; one end of the resistor R04 is connected to pin 1 of the optocoupler OP2; the cathode of the diode D03 is connected to the resistor R04; one end of the resistor R06 is connected to pin 2 of the optocoupler OP2; the anode of the diode D04 is connected to the resistor R05; the input port IO1 of the microcontroller U1 is connected to pin 4 of the optocoupler OP1, and the input port IO2 of the microcontroller U1 is connected to pin 4 of the optocoupler OP2.

2. A three-phase three-wire phase loss detection method, applied to a three-phase three-wire phase loss detection circuit as claimed in claim 1, characterized in that: include: Connect phase A of the three-phase AC power to the positive electrode of diode D01, phase B of the three-phase AC power to the negative electrodes of diodes D02 and D04 at the same time, and phase C of the three-phase AC power to the positive electrode of diode D03; In a sinusoidal AC cycle, the optocoupler OP1 conducts for half a cycle, generating a square wave Pab through the resistor R03; In a sinusoidal AC cycle, the optocoupler OP2 conducts for half a cycle, generating a square wave Pbc through the resistor R06; Detect square waves Pab and Pbc in real time, and identify whether the three-phase AC power is missing a phase based on the square wave signal.

3. A three-phase three-wire phase loss detection method according to claim 2, characterized in that: The specific steps of detecting the square wave Pab and the square wave Pbc in real time and identifying whether the three-phase AC power is missing a phase according to the square wave signal include: Real-time detection of square waves Pab and Pbc. If both are present, it indicates that the three-phase AC power supply is normal and there is no phase loss. If the square wave Pab does not exist but the square wave Pbc exists, it means that the AC power supply phase A is missing.

4. A three-phase three-wire phase loss detection method as claimed in claim 3, characterized in that: The specific steps of detecting the square wave Pab and the square wave Pbc in real time and identifying whether the three-phase AC power is missing a phase according to the square wave signal also include: If the square wave Pab exists but the square wave Pbc does not, it means that the AC power supply phase C is missing.

5. A three-phase three-wire phase loss detection method according to claim 4, characterized in that: The specific steps of detecting the square wave Pab and the square wave Pbc in real time and identifying whether the three-phase AC power is missing a phase according to the square wave signal also include: The square wave Pab and the square wave Pbc do not exist, indicating that the AC power supply phase B is missing.

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