CN101819261A - Three-phase source phase failure and power failure detection circuit - Google Patents

Abstract

The invention discloses a three-phase power supply phase loss detection circuit, comprising a working power supply, a phase loss detection module (1) for performing rectification sampling detection on the three-phase power supply and outputting a phase loss detection signal (VO), and a three-phase power supply A power-down detection module (2) for sampling and detecting each phase and outputting power-down detection signals (VA, VB, VC), and a detection result output module (3) for receiving phase-loss detection signals and power-down detection signals and outputting detection results ; The output signal (VOUT) of the detection result output module (3) is sent to the external actuator. Compared with the existing technology, it can accurately detect the failure of three-phase power supply phase loss and power failure within 10 milliseconds of the input voltage between 323 volts and 480 volts, and output an alarm signal, and the alarm signal remains at least 20 milliseconds .

Description

A three-phase power supply phase loss detection circuit

technical field

The invention relates to a power supply detection circuit, in particular to a three-phase power supply phase loss detection circuit.

Background technique

With the rapid development of science and technology, the three-phase power system is becoming more and more complex. There are more and more demands for three-phase power from all walks of life, and the adaptability of electrical equipment to the power grid is also getting higher and higher. Therefore, the power detection circuit Higher requirements have also been put forward, requiring it to have very good timeliness and a wide range of input detection capabilities. The detection circuit should detect the power supply phase loss and power failure as quickly and accurately as possible, and then issue a series of alarms and protection actions. At present, the detection circuit used to detect the lack of phase and power failure of the three-phase power supply, one is to sample and analyze the three-phase power supply after full-bridge rectification; the other is to sample each phase of the three-phase power supply and then process and analyze it. However, none of them can meet the requirement of quickly detecting phase loss in an environment with a large fluctuation range of the input voltage.

Contents of the invention

The present invention is to solve the defect that the existing detection circuit cannot quickly detect the lack of phase and power failure of the three-phase power supply, and proposes a phase loss detection module and a power failure detection module, which can quickly detect the lack of phase and power failure of the three-phase power supply detection circuit.

In order to solve the technical problem, the technical solution proposed by the present invention is: a three-phase power supply phase loss detection circuit, including a working power supply, a phase loss detection module that rectifies, samples and detects the three-phase power supply and outputs a phase loss detection signal , respectively sample and detect each phase of the three-phase power supply and output the power-down detection module of the power-down detection signal, receive the phase-loss detection signal and the power-down detection signal and output the detection result output module of the detection result; the output signal of the detection result output module Send to external actuator.

In one embodiment, the phase loss detection module includes a rectification module that rectifies the three-phase power supply, a rectification signal sampling module that samples the output voltage of the rectification module and outputs a sampling signal, and is connected to the output terminal of the rectification signal sampling module to filter the rectification signal And output the filter circuit of the rectified real-time signal, connect the output terminal of the rectified signal sampling module to perform peak-hold processing on the rectified signal and output the peak-hold circuit of the rectified variable reference signal, compare and analyze the rectified real-time signal and the rectified variable reference signal and output The rectification signal analysis module of the lack of phase detection signal. The power-down detection module includes a phase A power-down detection sub-module, a phase B power-down detection sub-module that samples and detects the signal of a single phase of the three-phase power supply and outputs the A-phase power-down detection signal, the B-phase power-down detection signal and the C-phase power-down detection signal correspondingly. The electrical detection sub-module and the C-phase power-down detection sub-module; the three sub-modules all include a signal sampling module for sampling a single phase of the power supply, and an absolute value processing module connected to the output of the signal sampling module to perform absolute value processing on the sampled signal, Connected to the output terminal of the absolute value processing module to filter the absolute value signal and output the filter circuit of the real-time signal; A signal analysis module that performs comparative analysis with the variable reference signal and outputs the power-down detection signal.

Compared with the prior art, the three-phase power supply phase loss detection circuit disclosed by the present invention has a phase loss detection module and a power failure detection module. volts, within 10 milliseconds of a fault, it can accurately detect a three-phase power supply phase loss fault, and output an alarm signal, and the alarm signal remains at least 20 milliseconds.

Description of drawings

The present invention is described in detail below in conjunction with accompanying drawing and embodiment, wherein:

Fig. 1 is a functional block diagram of a preferred embodiment of the present invention;

Fig. 2 is the circuit diagram of preferred embodiment of the present invention;

Figure 3 is a waveform diagram of phase loss when the rectified wave is connected to the peak;

Figure 4 is a waveform diagram of phase loss when the rectified wave enters the trough;

Figure 5 is a waveform diagram of phase loss detection;

Figure 6 is a waveform diagram of power-down detection.

Detailed ways

The present invention includes a working power supply VCCP, a phase loss detection module 1 that rectifies, samples and detects the three-phase power supply and outputs a phase loss detection signal VO, samples and detects each phase of the three-phase power supply separately, and outputs power-down detection signals VA, VB, VC The power failure detection module 2 receives the phase loss detection signal and the power failure detection signal and outputs the detection result output module 3 of the detection result; the output signal VOUT of the detection result output module 3 is sent to the external execution device.

Referring to Fig. 1, in a preferred embodiment of the present invention, the lack of phase detection module 1 includes a rectification module 4 that rectifies the three-phase power supply, and a rectification signal sampling module 5 that samples the output voltage of the rectification module 4 and outputs a sampling signal, connected to The output end of the rectification signal sampling module 5 filters the rectification signal and outputs the filter circuit 6 of the rectified real-time signal, and is connected to the output end of the rectification signal sampling module 5 to perform peak hold processing on the rectification signal and output the peak hold circuit 7 of the rectification variable reference signal, A rectification signal analysis module 8 that compares and analyzes the rectification real-time signal and the rectification variable reference signal and outputs a phase loss detection signal. Referring to Fig. 2, rectification signal sampling module 5 comprises the isolated follower that is made of integrated operational amplifier; Rectification signal analysis module 8 is the open-loop comparator that integrated operational amplifier forms; The inverting input terminal of the ring comparator is connected with the rectified variable reference signal.

Referring to Fig. 1, in a preferred embodiment of the present invention, the power-down detection module 2 includes sampling and detecting the signals of a single phase of the three-phase power supply and correspondingly outputting the A-phase power-down detection signal VA, the B-phase power-down detection signal VB and the C-phase A-phase power-failure detection sub-module, B-phase power-failure detection sub-module and C-phase power-failure detection sub-module of power-failure detection signal VC; all three sub-modules include signal sampling modules 9, 10, 11 for sampling single-phase power supply , connected to the output terminals of the signal sampling modules 9, 10, 11 for absolute value processing modules 12, 13, 14 that perform absolute value processing on the sampled signals, connected to the output terminals of the absolute value processing modules 12, 13, 14 to filter and output the absolute value signals The filter circuits 15, 16, 17 of real-time signals are connected to the output terminals of the absolute value processing modules 12, 13, 14 to carry out peak-hold processing of the absolute value signals and output the peak-hold circuits 18, 19, 20 of the variable reference signal, for the real-time signals Signal analysis modules 21 , 22 , 23 for comparing and analyzing the variable reference signal and outputting power-down detection signals VA, VB, and VC. Referring to Fig. 2, the signal sampling modules 9, 10, 11 include an isolation follower made of an integrated operational amplifier, and the single-phase signal of the three-phase power supply is connected to the inverting input of the isolation follower; the absolute value processing module 12, 13, 14 includes The absolute value circuit formed by the integrated operational amplifier, the sampling signal is connected to the non-inverting input terminal of the absolute value circuit; the signal analysis modules 21, 22, 23 are open-loop comparators formed by the integrated operational amplifier; wherein the non-inverting input terminal of the open-loop comparator is connected to the real-time signal, The inverting input of the open-loop comparator is connected to a variable reference signal.

Referring to Fig. 2, in a preferred embodiment of the present invention, the detection result output module 3 includes a comparator composed of an integrated operational amplifier; wherein the inverting input terminal of the comparator is connected to the phase loss detection signal VO and the power failure detection signal VA, VB, VC, the noninverting input terminal of the comparator is connected in series with the common terminal of two voltage dividing resistors R813 and R823 between the working power supply VCCP and the ground.

When working, the rectifier module 4 rectifies the three-phase power supply, and the rectified voltage waveform is divided and sampled and passed through the isolation follower composed of U801, so that there will be no gap between the virtual ground rectified by the neutral line and the virtual ground of the module. Voltage drift, one path of the signal at the output of U801 passes through the filter circuit 6 composed of R806 and C797 to become a real-time signal, and is sent to the non-inverting input of the comparator U803 in the rectified signal analysis module; the other path of the signal at the output of U801 passes through R801, R802, and C799 The formed peak hold circuit 7 becomes a rectified variable reference signal, which is sent to the inverting input terminal of U803. U803 output level VO is high level when there is no fault, and low level when there is a phase loss fault. A, B, and C phase power-down detection sub-modules are three parallel and independent branches with the same parameters. Now take the A-phase power failure detection sub-module as an example for illustration. The signal sampling module 9 composed of U806 and other components samples the A-phase power supply. The absolute value processing module 12 composed of U804 performs absolute value processing on the signal. One path of the signal at the U804 output terminal becomes a real-time signal through the filter circuit 15 composed of R812 and C794, and is sent to the non-inverting input terminal of the comparator U805 in the signal analysis module; the other path of the signal at the U804 output terminal passes through the peak value formed by R817, R819, and C795 The holding circuit 18 becomes a variable reference signal, which is sent to the inverting input terminal of U805. U805 output level VA is high level when there is no fault, and low level when there is a phase loss fault.

According to the principle of vector superposition, it can be known that the ripple of the three phases is relatively small when the full bridge is rectified. Once one phase is missing, the ripple will become very large. This invention uses this principle to obtain the sampling signal, but the phase loss , the influence of the phase of the phase on the ripple is different, as can be seen from Figures 3 and 4. Curve D in the figure is the waveform after three-phase rectification, and curves D' and D" are rectification waveforms after phase loss, which are sent to the non-inverting input terminal of comparator U803 in the rectification signal analysis module as real-time signals. For this Uncertain influence, it is impossible for the comparator to detect the fault quickly when the input voltage fluctuation range is large by adopting the general constant reference. The present invention adopts the peak hold circuit, and the reference signal is processed as a variable variable of real-time tracking. Reference signal E. In this way, this uncertain factor and the influence of the large fluctuation range of the input voltage can be basically shielded, so as to achieve the purpose of quickly detecting the phase loss fault. Referring to the phase loss detection waveform diagram shown in Figure 5, the rectified variable reference signal E After the phase loss fault occurs, the amplitude increases greatly, and it is sent to the inverting input terminal of the comparator U803 of the rectification signal analysis module, and the output terminal VO is turned from high level to low level, and the low level is sent to the detection result output module The comparator U810, the VOUT at the output end of U810 changes from low level to high level, and sends out a fault signal.

When the three phases are missing when the power is lost, only using the phase loss detection module 1 will not be able to detect the power failure in the cycle after the first frequency multiplication according to the ripple. Power-down detection module 2 for sampling detection. After power failure, if there is a capacitor between the three phases, there will be a certain residual voltage, but since the phase sequence difference is 120 degrees, there must be at least one capacitor with little energy storage. As shown in Figure 6, G is the real-time signal when no fault occurs, G' is the real-time signal after a fault occurs, F is a variable reference signal, and F' is a variable reference signal after a fault occurs. , the comparator compares the real-time signal G' with the variable reference signal F', so that the potential at the output terminal of the comparator is flipped from high to low, and the flip time depends on the point where the real-time signal G' first crosses with the variable reference signal F' The time of appearance also determines which one of VA, VB, and VC is flipped. Therefore, this module can accurately detect the phase loss and power failure of the three-phase power supply within 10 milliseconds of the input voltage between 323 volts and 480 volts, and output an alarm signal, and the alarm signal remains at least 20 milliseconds.

The invention can be used for detection of three-phase power supply with neutral line, and can also be used for detection of three-phase power supply without neutral line.

The preferred embodiments of the present invention have been described above, but those skilled in the art should understand that these are only examples, and various changes or modifications can be made to these embodiments without departing from the principles and principles of the present invention. substance. All belong to the protection scope of the present invention.

Claims (6)

1. three-phase source phase failure and power failure detection circuit, comprise working power, it is characterized in that also comprising: three-phase supply is carried out the rectification sample detecting and exports the open phase detection module (1) of phase shortage detection signal (VO), to each sample detecting and export the detection of power loss module (2) of detection of power loss signal (VA, VB, VC) respectively mutually of three-phase supply, receive phase shortage detection signal and detection of power loss signal and export the testing result output module (3) of testing result; The output signal (VOUT) of testing result output module (3) is sent outside actuating unit.

2. testing circuit as claimed in claim 1, it is characterized in that: described open phase detection module (1) comprises the rectification module (4) that three-phase supply is carried out rectification, rectification module (4) output voltage is sampled and exported the rectified signal sampling module (5) of sampled signal, connect the filtering circuit (6) that rectified signal sampling module (5) output terminal carries out filtering to rectified signal and exports the rectification live signal, connect rectified signal sampling module (5) output terminal and rectified signal is carried out peak value keep to be handled and the peak holding circuit (7) of output rectification variable reference signal, rectification live signal and rectification variable reference signal are analyzed and export the rectified signal analysis module (8) of described phase shortage detection signal.

3. testing circuit as claimed in claim 1 is characterized in that: described detection of power loss module (2) comprises the single-phase signal sampling of three-phase supply is detected and corresponding output A phase detection of power loss signal (VA), B phase detection of power loss signal (VB) and C A phase detection of power loss submodule, B phase detection of power loss submodule and the C detection of power loss submodule mutually of detection of power loss signal (VC) mutually; Described three submodules all comprise the single-phase signal sampling module (9 of sampling of power supply, 10,11), connect signal sampling module (9,10,11) output terminal carries out the absolute value processing module (12 that absolute value is handled to sampled signal, 13,14), connect absolute value processing module (12,13,14) output terminal carries out filtering to absolute value signal and exports the filtering circuit (15 of live signal, 16,17), connect absolute value processing module (12,13,14) output terminal carries out the peak holding circuit (18 that peak value keeps handling and exporting the variable reference signal to absolute value signal, 19,20), live signal and variable reference signal are analyzed and export described detection of power loss signal (VA, VB, VC) signal analyse block (21,22,23).

4. testing circuit as claimed in claim 1 is characterized in that: described testing result output module (3) comprises the comparer that is made of integrated operational amplifier; Wherein the comparer inverting input connects described phase shortage detection signal (VO) and detection of power loss signal (VA, VB, VC), and the comparer in-phase input end connects on the common port that is connected on two divider resistances between working power and the ground.

5. testing circuit as claimed in claim 2 is characterized in that: described rectified signal sampling module (5) comprises the isolation follower that is made of integrated operational amplifier; The open loop comparer that rectified signal analysis module (8) constitutes for integrated operational amplifier; Wherein open loop comparer in-phase input end connects described rectification live signal, and open loop comparer inverting input connects described rectification variable reference signal.

6. testing circuit as claimed in claim 3 is characterized in that: described signal sampling module (9,10,11) comprises the isolation follower that is made of integrated operational amplifier, and the single-phase signal of described three-phase supply connects isolates the follower inverting input; Described absolute value processing module (12,13,14) comprises the absolute value circuit that is made of integrated operational amplifier, and described sampled signal connects the absolute value circuit in-phase input end; The open loop comparer that signal analyse block (21,22,23) constitutes for integrated operational amplifier; Wherein open loop comparer in-phase input end connects described live signal, and open loop comparer inverting input connects described variable reference signal.

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