CN113884777A - Open-phase detection method, circuit and device of three-phase alternating-current power supply and electrical equipment - Google Patents
Open-phase detection method, circuit and device of three-phase alternating-current power supply and electrical equipment Download PDFInfo
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Abstract
The invention is suitable for the technical field of electrical equipment, and provides a method, a circuit and a device for detecting the phase failure of a three-phase alternating current power supply and electrical equipment, wherein the method comprises the following steps: acquiring sine waveforms of voltages of a second phase and a third phase of the three-phase alternating-current power supply after the three-phase alternating-current power supply is electrified; calculating a time difference between adjacent peaks of the sinusoidal waveform; comparing the time difference with a preset time difference threshold value; and when the time difference is larger than the time difference threshold value, determining that the phase is open. In the embodiment of the invention, whether the voltage is in phase failure is judged by acquiring the two-phase sine waves and calculating the time difference between adjacent wave crests, the detection method is simple, the functions of voltage detection and phase failure detection can be realized simultaneously by using only one single chip microcomputer pin, and the detection cost is reduced.
Description
Technical Field
The invention belongs to the technical field of electrical equipment, and particularly relates to a method, a circuit and a device for detecting the phase failure of a three-phase alternating current power supply, electrical equipment and a computer readable storage medium.
Background
The voltage phase-loss detection of the three-phase alternating current power supply is to detect whether a certain phase circuit of the input power supply has voltage loss or not, thereby realizing the phase-loss protection of load equipment.
The current phase-lack detection method utilizes the optical coupling principle, when the sine wave voltage is large to a certain degree, the optical coupler is driven to be conducted, the optical coupler outputs square waves, the phase sequence can be measured by measuring the time difference of every two square waves, and whether the phase is lacked or not can be measured by measuring whether each output square wave exists or not, but the detection circuit adopted by the method is complex in structure and high in cost.
Disclosure of Invention
The embodiment of the invention provides a method, a circuit and a device for detecting the phase loss of a three-phase alternating current power supply and electrical equipment, and aims to solve the problems that a detection circuit in the prior art is complex in structure and high in cost.
The embodiment of the invention is realized in such a way that a phase-lack detection circuit of a three-phase alternating-current power supply is provided, and the circuit comprises: the device comprises a switching power supply, a sampling unit and a control unit;
the switching power supply is respectively connected with the control unit, the first phase of the three-phase alternating current power supply and a zero line and is used for supplying power to the control unit;
the sampling unit is respectively connected with the control unit and the second phase and the third phase of the three-phase alternating-current power supply, and is used for acquiring the sine waveforms of the voltages of the second phase and the third phase of the three-phase alternating-current power supply and sending the sine waveforms to the control unit;
and the control unit is used for judging whether the phase is lost or not according to the sine waveform.
A method for detecting the open phase of a three-phase alternating current power supply is applied to a control unit in the open phase detection circuit of the three-phase alternating current power supply, and comprises the following steps:
acquiring sine waveforms of voltages of a second phase and a third phase of the three-phase alternating-current power supply after the three-phase alternating-current power supply is electrified;
calculating a time difference between adjacent peaks of the sinusoidal waveform;
comparing the time difference with a preset time difference threshold value;
and when the time difference is larger than the time difference threshold value, determining that the phase is open.
A phase loss detection apparatus for a three-phase ac power supply, the apparatus comprising:
the sinusoidal waveform acquisition module is used for acquiring sinusoidal waveforms of voltages of a second phase and a third phase of the three-phase alternating-current power supply after the three-phase alternating-current power supply is electrified;
a time difference calculation module for calculating a time difference between adjacent peaks of the sinusoidal waveform;
the comparison module is used for comparing the time difference with a preset time difference threshold value; and
and the phase-lack judging module is used for judging that the phase is lacked when the time difference is greater than the time difference threshold value.
An electrical device, the computer device comprising a processor for executing a computer program stored in a memory to implement the steps of the above method.
A computer-readable storage medium, on which a computer program (instructions) is stored, characterized in that the computer program (instructions), when executed by a processor, implements the steps of the above-mentioned method.
According to the phase-loss detection method of the three-phase alternating-current power supply, whether the voltage is in phase loss or not is judged by obtaining the two-phase sine waves and calculating the time difference between adjacent wave crests, the detection method is simple, the functions of voltage detection and phase loss detection can be achieved simultaneously only by using one single-chip microcomputer pin, and the detection cost is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only embodiments of the invention, and that other drawings can be derived from the provided drawings by a person skilled in the art without inventive effort.
Fig. 1 is a schematic diagram of a phase-loss detection circuit of a three-phase ac power supply according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a three-phase voltage sine wave waveform during normal operation;
FIG. 3 is a schematic diagram of a portion of a waveform of a two-phase voltage sine wave during normal operation;
fig. 4 is a flowchart of a method for detecting a phase failure of a three-phase ac power supply according to an embodiment of the present invention;
FIG. 5 is a flow chart of another method for detecting a phase loss in a three-phase AC power source according to an embodiment of the present invention;
fig. 6 is a flowchart of a method for detecting a phase failure of a three-phase ac power supply according to an embodiment of the present invention;
fig. 7 is a block diagram of a phase loss detection apparatus for a three-phase ac power supply according to an embodiment of the present invention;
fig. 8 is a block diagram of another phase loss detection apparatus for a three-phase ac power supply according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the prior art, a detection circuit for detecting the phase failure of the three-phase alternating-current power supply is complex in structure and high in cost.
In order to solve the above problems, the present invention provides a method and a circuit for detecting the phase failure of a three-phase ac power supply, which are applied to electrical equipment.
Fig. 1 shows a schematic circuit diagram of a phase loss detection circuit for a three-phase ac power supply, which is suitable for use in an embodiment of the present invention, the circuit including: the device comprises a switching power supply 1, a sampling unit 2 and a control unit 3; the switching power supply 1 is respectively connected with the control unit 3, a first phase of a three-phase alternating current power supply and a zero line and is used for supplying power to the control unit 3; the sampling unit 2 is respectively connected with the control unit 3 and the second phase and the third phase of the three-phase alternating-current power supply, and is used for acquiring the sine waveforms of the voltages of the second phase and the third phase of the three-phase alternating-current power supply and sending the sine waveforms to the control unit 3; and the control unit 3 is used for judging whether the phase is lack or not according to the sine waveform.
In the embodiment of the present invention, the sampling unit 2 and the switching power supply 1 are respectively connected to three phases of a three-phase ac power supply. For example, when the switching power supply 1 is connected to a first phase, the sampling unit 2 is connected to the second phase and a third phase, and when the switching power supply 1 is connected to the second phase, the sampling unit 2 is connected to the first phase and the third phase. When the switching power supply 1 is connected with the first phase, electricity is taken on the zero line and the first phase, when the first phase is in phase failure, the switching power supply 1 is powered off, the sampling unit and the control unit 3 which are powered by the switching power supply 1 are powered off simultaneously, and the whole system does not work, namely, the phase failure does not need protection, and can be understood as the automatic detection of the phase failure of the first phase connected with the switching power supply 1. When the first phase is normally powered, the sampling unit 2 collects sinusoidal waveforms of voltages of a second phase and a third phase of the three-phase alternating-current power supply and sends the sinusoidal waveforms to the control unit 3, the control unit 3 obtains the time corresponding to the peak values of the voltages of the second phase and the third phase, and the time interval between two adjacent peak values is calculated according to the corresponding time. The normal waveform diagram of the three-phase ac power source is shown in fig. 2, and the first phase, the second phase and the third phase may correspond to the U phase, the V phase and the W phase in the diagram, respectively, where the time interval between adjacent peaks of the U phase and the V phase is T1, the time interval between adjacent peaks of the U phase and the W phase is T2, and the time interval between adjacent peaks of the same phase is T3. For convenience of understanding, T1, T2 and T3 are used herein only for describing time intervals and do not refer to a fixed time value specifically, and the time values of T1, T2 and T3 are determined according to the frequency of the three-phase ac power source in operation and are not limited herein. In normal operation, the time interval between any two adjacent peaks of the three-phase ac power is T1 or T2, and as shown in fig. 3, when the control unit 3 detects that the time interval between any two adjacent peaks is T3 and is greater than T1 or T2, it determines that the phase is open.
In summary, whether the voltage is open-phase or not is judged by obtaining two-phase sine waves and calculating the time difference between adjacent wave crests, the detection method is simple, the voltage detection function and the open-phase detection function can be simultaneously realized by only using one single chip microcomputer pin, and the detection cost is reduced.
As an embodiment of the present invention, as shown in fig. 1, the sampling unit 2 of the open-phase detection circuit of the three-phase ac power supply is composed of a first resistor R1, a second resistor R2, a third resistor R3, a capacitor C1, a first diode D1, and a second diode D2; the second phase of the three-phase alternating current power supply is connected with the control unit 3 through a first diode D1 and a first resistor R1 in sequence, and the third phase of the three-phase alternating current power supply is connected with the control unit 3 through a second diode D2 and a second resistor R2 in sequence; the first resistor R1 is grounded through the third resistor R3, and the second resistor R2 is grounded through a capacitor.
In the embodiment of the invention, the U-phase and the V-phase are respectively input to the control unit 3 through the same node after passing through the first diode D1 and the second diode D2, which is equivalent to combining the voltage waveforms of the two-phase power supply and then inputting the combined voltage waveforms to the control unit 3, the circuit structure is simple, and only 1 connection point of the control unit is needed. For example, when the control unit 3 is a single chip microcomputer, the open-phase detection function can be realized only by occupying 1 pin of the single chip microcomputer.
Fig. 4 shows a flowchart of a method for detecting a phase loss of a three-phase ac power supply, which is applicable to the control unit 3 in the phase loss detection circuit of the three-phase ac power supply according to an embodiment of the present invention, and the method includes the following steps:
step S101, acquiring sine waveforms of voltages of the second phase and the third phase of the three-phase ac power supply after energization.
The phase voltage waveform of the three-phase alternating current in normal operation is a regular periodic repeated waveform, taking a 50Hz three-phase sine alternating current which is common in life as an example, the phase voltage waveform is a repeated sine wave, and the duration of one period of the sine wave is 0.02 second. The sinusoidal waveforms of the voltages of the second phase and the third phase of the three-phase alternating-current power supply after being energized are obtained, and the second phase and the third phase are not referred to as a fixed phase and are only distinguished for convenience of understanding and distinguishing from the first phase of the power supply of the switching power supply 1. For example, when the switching power supply 1 is powered by a U-phase, the first phase represents the U-phase, and the second phase and the third phase may correspond to a V-phase and a W-phase, respectively, or a W-phase and a V-phase, respectively; when the switching power supply 1 is supplied with a V-phase, the first phase represents the V-phase, and the second phase and the third phase may correspond to a U-phase and a W-phase, respectively, or a W-phase and a U-phase, respectively.
In step S102, a time difference between adjacent peaks of the sinusoidal waveform is calculated.
Sine wave waveforms of three-phase alternating current in normal operation are shown in fig. 2 and fig. 3, and two peaks, namely a positive peak and a negative peak, exist in one cycle of the single-phase sine wave waveform, and for convenience of understanding, only the positive peak is taken as an example for description, and the principle of the negative peak is the same as that of the positive peak. The time difference between any two adjacent peaks is T1 or T2, for example, the time interval between U-phase and V-phase adjacent peaks is T1, the time interval between U-phase and W-phase adjacent peaks is T2, and the time interval between the same phase adjacent peaks is T3. For convenience of understanding, T1, T2 and T3 are used herein only for describing time intervals and do not refer to a fixed time value specifically, and the time values of T1, T2 and T3 are determined according to the frequency of the three-phase ac power source in operation and are not limited herein.
Step S103, comparing the time difference with a preset time difference threshold.
The frequency of a three-phase alternating current power supply in normal operation is fixed, the time interval between adjacent peak values of each phase waveform is fixed, and the time interval between any waveform peak values can be determined by recording the corresponding time of the waveform peak values. For comparison, the time difference threshold is preset, and is determined according to the frequency of the three-phase power supply, which is not limited in the present invention. For example, when the frequency of the three-phase ac power supply is 50Hz, the wavelength of the single-phase waveform is 0.02s, T3 is 0.02s, T1 is one third of T3, and T2 is two thirds of T3. The time difference threshold may be set to 0.02s, or may be set to a value equal to or slightly larger than T1 or T2, and when the time difference threshold is set to a value equal to or slightly larger than T1, the time difference between adjacent peaks of any two-phase waveform is absolute, regardless of the time sequence in which the waveform peaks appear, as shown in fig. 3, although the time interval between the waveform peak of the second period of the U-phase and the waveform peak of the first period of the W-phase is T2, the time interval between the waveform peak of the second period of the U-phase and the waveform peak of the first period of the W-phase is T1. In the embodiment of the invention, after the time difference threshold is preset according to the frequency of the three-phase alternating current power supply, the time difference between adjacent peak values of the two-phase power supply waveform to be detected can be compared with the time difference threshold.
And step S104, when the time difference is larger than the time difference threshold value, determining that the phase is open.
And when the time difference between adjacent peak values of the two-phase waveform is greater than a preset time difference threshold value, determining that the two-phase waveform is open-phase. For example, when the time difference is equal to T1 or T2, it may be determined that the sampling power is normally supplied according to the above analysis; when the time difference is greater than T1 or T2, equal to T3, it can be determined that the detected two-phase power has a phase failure.
Preferably, whether the phase sequence of the sampling unit 2 connected with any two phases of the three-phase alternating-current power supply is correct can be judged through the time difference between the adjacent peak values of the two-phase waveforms. Taking the U-phase and the V-phase as an example, as shown in fig. 1, if the first diode D1 and the second diode D2 are connected to the U-phase and the V-phase, respectively, it is detected that the time difference between the adjacent peaks of the two-phase waveforms is T1, and if the time difference between the adjacent peaks of the two-phase waveforms is T2, it is explained that the first diode D1 and the second diode D2 are connected to the V-phase and the U-phase, respectively.
In the embodiment of the invention, whether the voltage is in phase failure is judged by acquiring the two-phase sine waves and calculating the time difference between adjacent wave crests, the detection method is simple, the functions of voltage detection and phase failure detection can be realized simultaneously by using only one single chip microcomputer pin, and the detection cost is reduced.
Fig. 5 is a flowchart illustrating another phase loss detection method for a three-phase ac power supply, which is applicable to the embodiment of the present invention, where the step S102 includes the following steps:
in step S1021, peak time of two adjacent peaks of the sine waveform is acquired.
As shown in fig. 2, the waveform of a normally operating three-phase ac power supply varies with time, and the voltage amplitude varies alternately, a sine wave with the time axis as the direction is formed in one period, and two peak values, namely a positive peak value and a negative peak value, appear in one period. The sampling unit 2 transmits the acquired two-phase voltage to the control unit 3, the control unit 3 detects an instantaneous voltage value changing along with a time period, and when a voltage peak value is detected, a time value corresponding to the peak time is recorded and stored, and all peak time of the sampling waveform is recorded in the mode.
In step S1022, the time difference between the peak time of two adjacent peaks is calculated.
And calculating the time difference between two adjacent waveform peaks according to the occurrence time of the recorded waveform peaks. For example, when U-phase and V-phase voltages are collected by the sampling unit 2, during normal operation, the peak time of the voltage appearing in the first two periods is sequentially Tu1, Tv1, Tu2, Tv2, Tu1 and Tv1, Tv1 and Tu2, Tu2 and Tv2 are three adjacent peaks in the two periods, Tu1 and Tv1, Tu2 and Tv2 are time differences T1 between U-phase and V-phase peaks in the first two periods, which are equal in value and same in property, and Tv1 and Tu2 are also adjacent peak time, but are respectively the peak time of the V-phase first period and the peak time of the V-phase second period, and the time difference T2 is twice the time difference T1 between Tu1 and Tv 1. When V is cancelled, the voltage waveform acquired by the sampling unit 2 is only a U-phase waveform, and then the control unit 3 can only record the two time instants Tu1, Tu2 when the peak value of the U-phase voltage waveform appears in the previous two periods, and the time difference between Tu1 and Tu2 is T3, which is the waveform period of the phase voltage.
Fig. 6 shows a flowchart of a method for detecting phase loss of a three-phase ac power supply according to an embodiment of the present invention, which includes the following steps:
step S201, a voltage value of the three-phase ac power supply is calculated from a peak value of the sine waveform.
In the embodiment of the invention, the voltage value of the three-phase alternating-current power supply is calculated according to the acquired sinusoidal waveform peak value of the three-phase alternating-current power supply in operation. The waveform peak value recorded by the control unit 3 is an instantaneous value, in actual production life, people adopt an effective value of a three-phase alternating-current power supply, and a mature method and a formula are adopted for conversion between the peak value and the effective value, and are not detailed here.
As shown in fig. 6, the method further comprises the following steps:
step S202, open-phase protection is carried out.
In the embodiment of the invention, after the three-phase power supply is judged to be out of phase through the steps, the corresponding protection signal is output, and equipment is driven to carry out-of-phase protection, such as equipment shutdown and the like, so that the damage caused by long-time out-of-phase operation of the equipment is avoided.
Preferably, when the phase loss is judged, an alarm signal can be output to give an alarm to remind maintenance personnel to check or process in time.
Fig. 7 is a block diagram showing a phase loss detection apparatus for a three-phase ac power supply according to an embodiment of the present invention, the apparatus including:
and a sine waveform obtaining module 701, configured to obtain sine waveforms of voltages of the second phase and the third phase of the three-phase ac power supply after the three-phase ac power supply is powered on.
The phase voltage waveform of the three-phase alternating current in normal operation is a regular periodic repeated waveform, taking a 50Hz three-phase sine alternating current which is common in life as an example, the phase voltage waveform is a repeated sine wave, and the duration of one period of the sine wave is 0.02 second. The sinusoidal waveform obtaining module 701 obtains the sinusoidal waveforms of the voltages of the second phase and the third phase of the three-phase ac power supply after being powered on, where the second phase and the third phase do not refer to a fixed phase, and are only distinguished for convenience of understanding and distinguishing from the first phase of the power supplied by the switching power supply 1. For example, when the switching power supply 1 is powered by a U-phase, the first phase represents the U-phase, and the second phase and the third phase may correspond to a V-phase and a W-phase, respectively, or a W-phase and a V-phase, respectively; when the switching power supply 1 is supplied with a V-phase, the first phase represents the V-phase, and the second phase and the third phase may correspond to a U-phase and a W-phase, respectively, or a W-phase and a U-phase, respectively.
A time difference calculation module 702 for calculating a time difference between adjacent peaks of the sinusoidal waveform.
Sine wave waveforms of three-phase alternating current in normal operation are shown in fig. 2 and fig. 3, and two peaks, namely a positive peak and a negative peak, exist in one cycle of the single-phase sine wave waveform, and for convenience of understanding, only the positive peak is taken as an example for description, and the principle of the negative peak is the same as that of the positive peak. The time difference calculation module 702 calculates the time difference between adjacent peaks of the sinusoidal waveform. The time difference between any two adjacent peaks is T1 or T2, for example, the time interval between U-phase and V-phase adjacent peaks is T1, the time interval between U-phase and W-phase adjacent peaks is T2, and the time interval between the same phase adjacent peaks is T3. For convenience of understanding, T1, T2 and T3 are used herein only for describing time intervals and do not refer to a fixed time value specifically, and the time values of T1, T2 and T3 are determined according to the frequency of the three-phase ac power source in operation and are not limited herein.
A comparing module 703, configured to compare the time difference with a preset time difference threshold.
The frequency of a three-phase alternating current power supply in normal operation is fixed, the time interval between adjacent peak values of each phase waveform is fixed, and the time interval between any waveform peak values can be determined by recording the corresponding time of the waveform peak values. For comparison, the time difference threshold is preset, and is determined according to the frequency of the three-phase power supply, which is not limited in the present invention. For example, when the frequency of the three-phase ac power supply is 50Hz, the wavelength of the single-phase waveform is 0.02s, T3 is 0.02s, T1 is one third of T3, and T2 is two thirds of T3. The time difference threshold may be set to 0.02s, or may be set to a value equal to or slightly larger than T1 or T2, and when the time difference threshold is set to a value equal to or slightly larger than T1, the time difference between adjacent peaks of any two-phase waveform is absolute, regardless of the time sequence in which the waveform peaks appear, as shown in fig. 3, although the time interval between the waveform peak of the second period of the U-phase and the waveform peak of the first period of the W-phase is T2, the time interval between the waveform peak of the second period of the U-phase and the waveform peak of the first period of the W-phase is T1. In the embodiment of the present invention, after the time difference threshold is preset according to the frequency of the three-phase ac power, the comparing module 703 compares the time difference between adjacent peaks of the two-phase power waveform to be detected with the time difference threshold.
And a phase loss determining module 704, configured to determine that a phase is lost when the time difference is greater than the time difference threshold.
The phase-missing determination module 704 may determine that the phase is missing when the time difference between adjacent peaks of the two-phase waveform is greater than a preset time difference threshold. For example, when the time difference is equal to T1 or T2, it may be determined that the sampling power is normally supplied according to the above analysis; when the time difference is greater than T1 or T2, equal to T3, it can be determined that the detected two-phase power has a phase failure.
Preferably, the phase-loss detection apparatus for a three-phase ac power supply further includes a phase sequence detection module 705, and the phase sequence detection module 705 can determine whether the phase sequence of the connection between the sampling unit 2 and any two phases of the three-phase ac power supply is correct according to the time difference between adjacent peak values of the two-phase waveforms. Taking the U-phase and the V-phase as an example, as shown in fig. 1, if the first diode D1 and the second diode D2 are connected to the U-phase and the V-phase, respectively, it is detected that the time difference between the adjacent peaks of the two-phase waveforms is T1, and if the time difference between the adjacent peaks of the two-phase waveforms is T2, it is explained that the first diode D1 and the second diode D2 are connected to the V-phase and the U-phase, respectively.
In the embodiment of the invention, the open-phase detection device of the three-phase alternating-current power supply judges whether the voltage is open-phase or not by acquiring the two-phase sine waves and calculating the time difference between adjacent wave crests, the detection method is simple, the functions of voltage detection and open-phase detection can be realized simultaneously by using only one single chip microcomputer pin, and the detection cost is reduced.
Fig. 8 is a block diagram showing a structure of another phase-loss detection apparatus for a three-phase ac power supply according to an embodiment of the present invention, where the time difference calculation module 702 includes a peak value acquisition unit 7021 and a time difference calculation unit 7022:
peak acquiring unit 7021 is configured to acquire peak time instants of two adjacent peaks of the sinusoidal waveform.
As shown in fig. 2, the waveform of a normally operating three-phase ac power supply varies with time, and the voltage amplitude varies alternately, a sine wave with the time axis as the direction is formed in one period, and two peak values, namely a positive peak value and a negative peak value, appear in one period. The sampling unit 2 transmits the acquired two-phase voltage to the control unit 3, the control unit 3 detects an instantaneous voltage value varying with a time period, a time value corresponding to a peak time is recorded and stored when a voltage peak value is detected, and the peak acquisition unit 7021 records all peak times of the sampling waveform in this way.
And a time difference calculation unit 7022 configured to calculate a time difference between peak time instants of two adjacent peaks.
From the aforementioned recorded times at which the waveform peaks occur, time difference calculation unit 7022 calculates the time difference between two adjacent waveform peaks. For example, when U-phase and V-phase voltages are collected by the sampling unit 2, during normal operation, the peak time of the voltage appearing in the first two periods is sequentially Tu1, Tv1, Tu2, Tv2, Tu1 and Tv1, Tv1 and Tu2, Tu2 and Tv2 are three adjacent peaks in the two periods, Tu1 and Tv1, Tu2 and Tv2 are time differences T1 between U-phase and V-phase peaks in the first two periods, which are equal in value and same in property, and Tv1 and Tu2 are also adjacent peak time, but are respectively the peak time of the V-phase first period and the peak time of the V-phase second period, and the time difference T2 is twice the time difference T1 between Tu1 and Tv 1. When V is cancelled, the voltage waveform acquired by the sampling unit 2 is only a U-phase waveform, and then the control unit 3 can only record the two time instants Tu1, Tu2 when the peak value of the U-phase voltage waveform appears in the previous two periods, and the time difference between Tu1 and Tu2 is T3, which is the waveform period of the phase voltage.
Preferably, the device for detecting the phase failure of the three-phase ac power supply further includes a voltage calculating module 706, configured to calculate a voltage value of the three-phase ac power supply according to a peak value of the sinusoidal waveform.
In the embodiment of the present invention, the voltage calculating module 706 calculates the voltage value of the three-phase ac power according to the obtained sinusoidal waveform peak value of the three-phase ac power in operation. The waveform peak value recorded by the control unit 3 is an instantaneous value, in actual production life, people adopt an effective value of a three-phase alternating-current power supply, and a mature method and a formula are adopted for conversion between the peak value and the effective value, and are not detailed here.
Preferably, the open-phase detection apparatus for a three-phase ac power supply further includes an open-phase protection module 707 for performing open-phase protection.
In the embodiment of the present invention, after the three-phase power supply is determined to be open-phase through the above steps, the open-phase protection module 707 outputs a corresponding protection signal to drive the device to perform open-phase protection, such as shutdown of the device, so as to avoid damage to the device due to long-time open-phase operation.
Preferably, when the phase loss is judged, an alarm signal can be output to give an alarm to remind maintenance personnel to check or process in time.
The electrical equipment provided by the embodiment of the invention further comprises a memory. Illustratively, a computer program can be partitioned into one or more modules, which are stored in memory and executed by a processor to implement the present invention. One or more of the modules may be a series of computer program instruction segments capable of performing certain functions, the instruction segments being used to describe the execution of the computer program in the electrical device.
Those skilled in the art will appreciate that the above description of an electrical device is by way of example only and is not intended to be limiting of electrical devices, and that it may include more or less components than those described, or some components may be combined, or different components may include, for example, input output devices, network access devices, buses, etc.
The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Micro Control Unit (MCU), a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, a discrete Gate or transistor logic device, a discrete hardware component, etc. The general purpose processor may be a microprocessor or the processor may be any conventional processor or the like, which is the control center for the electrical apparatus described above, with various interfaces and lines connecting the various parts of the overall electrical apparatus.
The memory may be used to store the computer programs and/or modules, and the processor may implement the various functions of the electrical device by running or executing the computer programs and/or modules stored in the memory, and calling the data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function (such as a sound playing function, an image playing function, etc.), and the like. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.
The above-described electric device integrated module/unit, if implemented in the form of a software functional unit and sold or used as a separate product, may be stored in a computer-readable storage medium. Based on such understanding, all or part of the functions of the units in the above embodiments may be implemented by a computer program, which may be stored in a computer-readable storage medium and used by a processor to implement the functions of the above embodiments. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A phase loss detection circuit for a three-phase ac power supply, the circuit comprising: the device comprises a switching power supply, a sampling unit and a control unit;
the switching power supply is respectively connected with the control unit, the first phase of the three-phase alternating current power supply and a zero line and is used for supplying power to the control unit;
the sampling unit is respectively connected with the control unit and the second phase and the third phase of the three-phase alternating-current power supply, and is used for acquiring the sine waveforms of the voltages of the second phase and the third phase of the three-phase alternating-current power supply and sending the sine waveforms to the control unit;
and the control unit is used for judging whether the phase is lost or not according to the sine waveform.
2. The open-phase detection circuit of a three-phase ac power supply according to claim 1, wherein said sampling unit is composed of a first resistor, a second resistor, a third resistor, a capacitor, a first diode, and a second diode; a second phase of the three-phase alternating-current power supply is connected with the control unit sequentially through the first diode and the first resistor, and a third phase of the three-phase alternating-current power supply is connected with the control unit sequentially through the second diode and the second resistor; the first resistor is grounded through the third resistor, and the second resistor is grounded through the capacitor.
3. A method for detecting a phase failure of a three-phase ac power supply, applied to a control unit in a phase failure detection circuit of a three-phase ac power supply according to claim 1, the method comprising:
acquiring sine waveforms of voltages of a second phase and a third phase of the three-phase alternating-current power supply after the three-phase alternating-current power supply is electrified;
calculating a time difference between adjacent peaks of the sinusoidal waveform;
comparing the time difference with a preset time difference threshold value;
and when the time difference is larger than the time difference threshold value, determining that the phase is open.
4. The method according to claim 3, wherein the step of calculating the time difference between adjacent peaks comprises:
acquiring peak value moments of two adjacent peaks of the sine waveform;
and calculating the time difference between the peak time moments of the two adjacent peaks.
5. A method of detecting a phase loss in a three-phase ac power supply as claimed in claim 3, further comprising:
and calculating the voltage value of the three-phase alternating current power supply according to the peak value of the sine waveform.
6. A method for detecting a phase failure of a three-phase ac power supply according to claim 3, further comprising, after the step of determining a phase failure:
and carrying out open-phase protection.
7. A phase loss detection apparatus for a three-phase ac power supply, the apparatus comprising:
the sinusoidal waveform acquisition module is used for acquiring sinusoidal waveforms of voltages of a second phase and a third phase of the three-phase alternating-current power supply after the three-phase alternating-current power supply is electrified;
a time difference calculation module for calculating a time difference between adjacent peaks of the sinusoidal waveform;
the comparison module is used for comparing the time difference with a preset time difference threshold value; and
and the phase-lack judging module is used for judging that the phase is lacked when the time difference is greater than the time difference threshold value.
8. The apparatus for detecting a phase loss in a three-phase ac power supply according to claim 7, wherein said time difference calculation module comprises:
a peak value obtaining unit, configured to obtain peak value time of two adjacent peaks of the sinusoidal waveform;
and the time difference calculation unit is used for calculating the time difference between the peak time of the two adjacent peaks.
9. An electrical device, characterized in that the computer device comprises a processor for executing a computer program stored in a memory for implementing the steps of the method according to any one of claims 3-6.
10. A computer-readable storage medium, on which a computer program (instructions) is stored, which, when being executed by a processor, carries out the steps of the method according to any one of claims 3-6.
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| CN117907878A (en) * | 2024-03-15 | 2024-04-19 | 商宇(深圳)科技有限公司 | Method and device for judging power failure of alternating current power supply, electronic equipment and storage medium |
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