CN111208360A - Detection circuit, system and consumer - Google Patents
Detection circuit, system and consumer Download PDFInfo
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- CN111208360A CN111208360A CN202010186301.3A CN202010186301A CN111208360A CN 111208360 A CN111208360 A CN 111208360A CN 202010186301 A CN202010186301 A CN 202010186301A CN 111208360 A CN111208360 A CN 111208360A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/16—Measuring asymmetry of polyphase networks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/30—Structural combination of electric measuring instruments with basic electronic circuits, e.g. with amplifier
Abstract
The disclosure discloses a detection circuit, a detection system and electric equipment, and relates to the field of circuits. The detection circuit includes: the logic judgment circuit is configured to compare the voltage output by the rectification circuit with a reference voltage and output a comparison result, wherein the reference voltage is greater than 0 and smaller than a threshold value; and a processor configured to determine that a phase-lack fault exists in the three-phase alternating current in a case where the comparison result is that the voltage output by the rectification circuit is less than the reference voltage. According to the method, when the three-phase rectifying circuit is used for two-phase rectification, the characteristic that the output voltage crosses zero is utilized, and the processor can detect whether the three-phase alternating current has a phase-lack fault in real time by setting the logic judgment circuit to compare the voltages.
Description
Technical Field
The present disclosure relates to the field of circuits, and in particular, to a detection circuit, a detection system, and an electrical device.
Background
For the application occasion adopting the uncontrollable rectification of the diode, if any one phase of three-phase alternating current input voltages L1, L2 and L3 is lacked, at the moment, the rectifier bridge works in a two-phase rectification mode, the input current and the output current of the rectifier bridge are doubled compared with the input current and the output current of the rectifier bridge during three-phase rectification, and the peak current is doubled. Under the condition of no protection, the rectifier bridge cannot reach the derating use standard, even the current on the rectifier bridge can exceed the rated value in a specification, if the rectifier bridge works under the condition, the rectifier bridge generates heat seriously, the rectifier bridge is easy to damage, and the reliability can be greatly reduced.
Disclosure of Invention
One technical problem to be solved by the present disclosure is to provide a detection circuit, a system and an electric device capable of detecting whether a phase-lack fault exists in a three-phase alternating current in real time.
According to an aspect of the present disclosure, a detection circuit is provided, including: the logic judgment circuit is configured to compare the voltage output by the rectification circuit with a reference voltage and output a comparison result, wherein the reference voltage is greater than 0 and smaller than a threshold value; and a processor configured to determine that a phase-lack fault exists in the three-phase alternating current in a case where the comparison result is that the voltage output by the rectification circuit is less than the reference voltage.
In some embodiments, a voltage dividing circuit configured to divide a voltage output by the rectifying circuit; the logic judgment circuit is configured to compare the voltage output by the rectifying circuit after voltage division processing with a reference voltage; and the processor is configured to determine that the three-phase alternating current has a phase-lack fault in the case that the comparison result is that the voltage output by the rectifying circuit is less than the reference voltage after voltage division processing.
In some embodiments, the reference voltage is greater than 0 and less than the voltage output by the voltage divider circuit when three-phase alternating current is not open-phase.
In some embodiments, the logic determination circuit is a comparator or an operational amplifier.
In some embodiments, the input terminal of the voltage divider circuit is connected with the output terminal of the rectifier circuit; the first input end of the logic judgment circuit is connected with the first output end of the voltage division circuit, the second input end of the logic judgment circuit is connected with the reference voltage, the grounding end of the logic judgment circuit is connected with the second output end of the voltage division circuit, and the output end of the logic judgment circuit outputs a comparison result.
In some embodiments, the first input is a non-inverting input; the second input end is an inverted input end; under the condition that the voltage output by the voltage division circuit is greater than the reference voltage, the output end of the logic judgment circuit outputs a high-level signal, and the processor determines that the three-phase alternating current is normal; and under the condition that the voltage output by the voltage division circuit is less than the reference voltage, the output end of the logic judgment circuit outputs a low-level signal, and the processor determines that the three-phase alternating current has a phase-lack fault.
In some embodiments, the voltage dividing circuit includes a first resistor and a second resistor, and the rectifying circuit includes a first output terminal and a second output terminal; the first end of the first resistor is connected with the first output end of the rectifying circuit, and the second end of the first resistor is connected with the first end of the second resistor; the first end of the second resistor is a first output end of the voltage division circuit, and the second end of the second resistor is a second output end of the voltage division circuit and is connected with the second output end of the rectification circuit.
In some embodiments, the processor is further configured to control to cut off the three-phase alternating current input to the rectification circuit when there is a phase-lack fault in the three-phase alternating current.
In some embodiments, the alarm circuit is configured to output an alarm signal when the three-phase alternating current has a phase-lack fault.
According to another aspect of the present disclosure, there is also provided a protection system, including: the above-described detection circuit; and the input end of the rectifying circuit is connected with a three-phase alternating current power supply.
In some embodiments, the input of the rectifier circuit is connected to the three-phase ac power supply through a resistor.
According to another aspect of the present disclosure, there is also provided an electric device, including: the protection system is described above.
According to the embodiment of the invention, by utilizing the characteristic that the output voltage crosses zero when the three-phase rectification circuit is used for carrying out two-phase rectification and arranging the logic judgment circuit, whether the three-phase alternating current has a phase-lack fault or not can be detected by the processor in real time.
Other features of the present disclosure and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.
The present disclosure may be more clearly understood from the following detailed description, taken with reference to the accompanying drawings, in which:
fig. 1 is a schematic structural diagram of some embodiments of a detection circuit of the present disclosure.
Fig. 2 is a schematic structural diagram of another embodiment of the detection circuit of the present disclosure.
Fig. 3 is a schematic structural diagram of some embodiments of the protection system of the present disclosure.
Fig. 4 is a waveform diagram of three-phase alternating current without a phase-loss fault.
Fig. 5 is a waveform diagram when a phase-lack fault exists in three-phase alternating current.
Detailed Description
Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise.
Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description.
The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.
Fig. 1 is a schematic structural diagram of some embodiments of a detection circuit of the present disclosure. The detection circuit includes a logic decision circuit 120 and a processor 130.
The logic determination circuit 120 is configured to compare the magnitude of the voltage output by the rectifier circuit with a reference voltage, and output a comparison result, where the reference voltage is greater than 0 and less than a threshold.
When the three-phase alternating current is not in phase failure, the rectifying circuit outputs relatively stable direct-current voltage. When the three-phase alternating current is in a phase failure, the voltage output by the rectifying circuit is 0 at a certain moment, so the reference voltage is more than 0 and less than the voltage output by the rectifying circuit when the three-phase alternating current is not in a phase failure.
In some embodiments, the logic determining circuit 120 is, for example, a comparator or an operational amplifier. Since the dc voltage output from the rectifying circuit is generally hundreds of volts, and the comparator and the operational amplifier cannot operate at a high voltage, it is necessary to divide the voltage output from the rectifying circuit.
In some embodiments, as shown in fig. 2, the detection circuit further includes a voltage dividing circuit 110, and the voltage dividing circuit 110 is disposed between the rectifying circuit and the logic determination circuit 120 and configured to divide the voltage output by the rectifying circuit. The divided voltage is input to the logic determining circuit 120. At this time, the reference voltage is set to be greater than 0 and less than the voltage output by the voltage-dividing circuit when the three-phase alternating current is not open-phase. The logic determining circuit 120 compares the voltage output by the voltage dividing circuit with a reference voltage to output a high level signal or a low level signal.
The processor 130 is connected to the logic judgment circuit 120 and configured to determine that a phase-lack fault exists in the three-phase alternating current when the comparison result is that the voltage output by the rectification circuit is smaller than the reference voltage. If the voltage divider circuit 110 is disposed in the detection circuit, the processor 130 determines that the three-phase ac power has a phase-missing fault when the voltage output by the rectifier circuit is smaller than the reference voltage after voltage division processing.
In some embodiments, the processor 130 is, for example, a DSP (Digital Signal Processing).
In some embodiments, the processor 130 is further configured to control to cut off the three-phase alternating current input to the rectification circuit when there is a phase-lack fault in the three-phase alternating current. For example, a relay is provided between the rectifier circuit and the three-phase alternating-current power supply, and the processor sends a signal to the relay so that a circuit between the three-phase alternating-current power supply and the rectifier circuit is broken.
In the embodiment, when the three-phase rectifying circuit is used for rectifying two phases, the characteristic that the output voltage crosses zero is utilized, and the logic judgment circuit is arranged, so that the processor can detect whether the three-phase alternating current has a phase-lack fault in real time.
In some embodiments, the detection circuit may further include an alarm circuit 140, connected to the processor 130, configured to output an alarm signal when there is a phase-loss fault in the three-phase ac power.
Fig. 3 is a schematic structural diagram of some embodiments of the protection system of the present disclosure. The protection system comprises a detection circuit and a rectification circuit, wherein the detection circuit comprises a voltage division circuit, a logic judgment circuit and a processor, and the logic judgment circuit is introduced by taking a comparator as an example.
The rectifier circuit D is, for example, a bridge rectifier circuit, and six diodes are provided therein. The voltage dividing circuit includes a first resistor R1 and a second resistor R2. The comparator U includes a first input terminal, a second input terminal, a ground terminal, a voltage terminal, and an output terminal, wherein the first input terminal is exemplified by a non-inverting input terminal, and the second input terminal is exemplified by an inverting input terminal.
The input end of the rectifying circuit D is connected with a three-phase alternating current power supply. As shown in fig. 3, the three-phase ac power supply outputs three-phase ac power of L1 phase, L2 phase, and L3 phase, and the three-phase ac power is stepped down and limited in current by resistors R3, R4, and R5, respectively, and then input to the rectifier circuit D.
For example, the rectifier circuit D includes diodes VD1-VD6, wherein cathodes of the diodes VD1, VD3 and VD5 are connected, anodes of the diodes VD2, VD4 and VD6 are connected, an anode of the diode VD1 is connected to a cathode of the diode VD2, an anode of the diode VD3 is connected to a cathode of the diode VD4, and an anode of the diode VD5 is connected to a cathode of the diode VD6, wherein the cathode of the VD5 serves as a first output terminal of the rectifier circuit D, and the anode of the VD6 serves as a second output terminal of the rectifier circuit D. The anode of the diode VD1 is connected with one end of a resistor R3, and the other end of the resistor R3 is used for connecting the L1 end of a three-phase alternating current power supply; the anode of the diode VD3 is connected with one end of a resistor R4, and the other end of the resistor R4 is used for connecting the L2 end of a three-phase alternating current power supply; the anode of the diode VD5 is connected to one end of the resistor R5, and the other end of the resistor R5 is used to connect to the L3 end of the three-phase ac power supply. The rectifier circuit D is used only for checking signals, so that a rectifier bridge with a large current and a high voltage is not selected, and specific voltage and current values are selected according to the resistance values of the resistors R3, R4 and R5. The resistors R3, R4, R5 may be selected according to the voltage resistance and power of the resistors.
A first end of the first resistor R1 is connected to a first output end of the rectifying circuit D, and a second end of the first resistor R1 is connected to a first end of the second resistor R2; a first end of the second resistor R2 is a first output end of the voltage dividing circuit, i.e., connected to a first input end of the comparator U, a second end of the second resistor R2 is a second output end of the voltage dividing circuit, i.e., connected to a ground end of the comparator U, and a second end of the second resistor R2 is further connected to a second output end of the rectifying circuit D. The first resistor R1 and the second resistor R2 are connected in a loop to meet the power level requirement.
The second input terminal of the comparator U is connected to a reference voltage Vref, which is a relatively low voltage such as 2V, 3V, 10V, etc. The output end of the comparator U is connected with the processor C.
Under the condition that the three-phase alternating current has no phase failure, namely L1, L2 and L3 are normal, the three-phase alternating current waveform is as No. 1 waveform in FIG. 4, and the No. 2 waveform is a six-wave-head 300HZ direct current voltage which is output by the three-phase alternating current through the rectifying circuit D, namely fluctuates between 150V and 250V and is a relatively stable direct current voltage. Since the voltage at the first input terminal of the comparator U is always higher than the voltage at the second input terminal, the output terminal of the comparator U always outputs a high level signal as shown by the waveform No. 3, for example, the voltage at the voltage terminal of the comparator U is 3.3V, and the output terminal of the comparator U always outputs 3.3V. And the processor C receives the high-level signal, determines that the three-phase alternating current has no open-phase fault, the unit can normally operate, and the alarm circuit does not perform alarm processing.
When the three-phase alternating current has a phase-missing fault, the three-phase alternating current has a waveform shown as No. 1 in FIG. 5, the voltage output by the rectifying circuit D has 0V at a certain moment, for example, a waveform shown as No. 2, the output voltage of the rectifying circuit can fluctuate between 0V and 300V, the voltage of the first input end of the comparator U is lower than the voltage of the second input end, and at the moment, as shown by a waveform shown as No. 3, the output end of the comparator U can output a low-level signal at some moment. And when the processor C receives the low-level signal, the processor C determines that the three-phase alternating current has a phase-lack fault, can perform shutdown protection at the moment, and can output an alarm signal by the alarm circuit.
In the above embodiment, when utilizing three-phase rectifier circuit to carry out two-phase rectification, the characteristics of output voltage zero passage, carry out logic judgement through setting up the comparator, can discern whether the three-phase alternating current appears lacking the looks condition, this circuit structure is simple, the device that uses is few, do not need to develop a board alone, with the direct board of circuit carry on the mainboard can, and the space that needs is very little, the cost is extremely low, this circuit has isolation function, can solve whether the three-phase alternating current appears lacking the looks when, rectifier circuit work is in two-phase rectification mode, because of overheated problem of damaging, three-phase rectifier circuit's reliability has been improved.
In some embodiments, if the first input terminal of the comparator is a negative input terminal and the second input terminal is a positive input terminal, the comparator outputs a high level signal when the three-phase alternating current has a phase-missing fault, and outputs a low level signal when the three-phase alternating current does not have the phase-missing fault.
In some embodiments, if the logic determination circuit is an operational amplifier, not only the comparison function can be implemented, but also some more precise control can be implemented, that is, a voltage value with a finer granularity is output compared with the amplifier, so that the processor can implement fine-grained control.
In other embodiments of the present disclosure, a user equipment is also protected, and the user equipment comprises the protection system, wherein the user equipment is, for example, an air conditioner, a refrigerator, a washing machine and the like.
Thus far, the present disclosure has been described in detail. Some details that are well known in the art have not been described in order to avoid obscuring the concepts of the present disclosure. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.
The methods and apparatus of the present disclosure may be implemented in a number of ways. For example, the methods and apparatus of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order for the steps of the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above unless specifically stated otherwise. Further, in some embodiments, the present disclosure may also be embodied as programs recorded in a recording medium, the programs including machine-readable instructions for implementing the methods according to the present disclosure. Thus, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.
Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.
Claims (12)
1. A detection circuit, comprising:
the logic judgment circuit is configured to compare the voltage output by the rectification circuit with a reference voltage and output a comparison result, wherein the reference voltage is greater than 0 and smaller than a threshold value; and
a processor configured to determine that there is a phase-lack fault in the three-phase alternating current in a case where the comparison result is that the voltage output by the rectification circuit is less than the reference voltage.
2. The detection circuit of claim 1, further comprising:
a voltage dividing circuit configured to divide a voltage output from the rectifying circuit;
the logic judgment circuit is configured to compare the voltage output by the rectifying circuit after voltage division processing with the reference voltage; and
the processor is configured to determine that a phase-lack fault exists in the three-phase alternating current when the comparison result is that the voltage output by the rectifying circuit is subjected to voltage division processing and then is smaller than the reference voltage.
3. The detection circuit according to claim 2, wherein the reference voltage is greater than 0 and less than a voltage output by the voltage divider circuit when the three-phase alternating current is not open-phase.
4. The detection circuit of claim 2, wherein the logic decision circuit is a comparator or an operational amplifier.
5. The detection circuit of claim 2,
the input end of the voltage division circuit is connected with the output end of the rectification circuit;
the first input end of the logic judgment circuit is connected with the first output end of the voltage division circuit, the second input end of the logic judgment circuit is connected with the reference voltage, the grounding end of the logic judgment circuit is connected with the second output end of the voltage division circuit, and the output end of the logic judgment circuit outputs the comparison result.
6. The detection circuit of claim 5,
the first input end is a non-inverting input end;
the second input end is an inverted input end;
under the condition that the voltage output by the voltage division circuit is greater than the reference voltage, the output end of the logic judgment circuit outputs a high-level signal, and the processor determines that the three-phase alternating current is normal;
and under the condition that the voltage output by the voltage division circuit is less than the reference voltage, the output end of the logic judgment circuit outputs a low-level signal, and the processor determines that the three-phase alternating current has a phase-lack fault.
7. The detection circuit of claim 5, wherein the voltage divider circuit comprises a first resistor and a second resistor, the rectifier circuit comprises a first output terminal and a second output terminal;
the first end of the first resistor is connected with the first output end of the rectifying circuit, and the second end of the first resistor is connected with the first end of the second resistor;
the first end of the second resistor is the first output end of the voltage division circuit, and the second end of the second resistor is the second output end of the voltage division circuit and is connected with the second output end of the rectification circuit.
8. The detection circuit according to any one of claims 1 to 7,
the processor is further configured to control to cut off the three-phase alternating current input to the rectification circuit when there is a phase-lack fault in the three-phase alternating current.
9. The detection circuit of any of claims 1-7, further comprising:
and the alarm circuit is configured to output an alarm signal when the three-phase alternating current has a phase-lack fault.
10. A protection system, comprising:
the detection circuit of any one of claims 1-9; and
and the input end of the rectifying circuit is connected with a three-phase alternating current power supply.
11. The protection system of claim 10,
the input end of the rectifying circuit is connected with a three-phase alternating current power supply through a resistor.
12. An electrical device comprising:
the protection system of claim 10 or 11.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010186301.3A CN111208360A (en) | 2020-03-17 | 2020-03-17 | Detection circuit, system and consumer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010186301.3A CN111208360A (en) | 2020-03-17 | 2020-03-17 | Detection circuit, system and consumer |
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| CN111208360A true CN111208360A (en) | 2020-05-29 |
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| CN202010186301.3A Pending CN111208360A (en) | 2020-03-17 | 2020-03-17 | Detection circuit, system and consumer |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111999568A (en) * | 2020-09-17 | 2020-11-27 | 杭州益川电子有限公司 | Three-phase input open-phase detection system for variable frequency driver |
| CN113075467A (en) * | 2021-03-17 | 2021-07-06 | 苏州汇川技术有限公司 | Power grid phase loss detection device and method for controlling switch tube in rectifier bridge |
| CN113075467B (en) * | 2021-03-17 | 2024-04-26 | 苏州汇川技术有限公司 | Power grid open-phase detection device and method for controlling switching tube in rectifier bridge |
-
2020
- 2020-03-17 CN CN202010186301.3A patent/CN111208360A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111999568A (en) * | 2020-09-17 | 2020-11-27 | 杭州益川电子有限公司 | Three-phase input open-phase detection system for variable frequency driver |
| CN113075467A (en) * | 2021-03-17 | 2021-07-06 | 苏州汇川技术有限公司 | Power grid phase loss detection device and method for controlling switch tube in rectifier bridge |
| CN113075467B (en) * | 2021-03-17 | 2024-04-26 | 苏州汇川技术有限公司 | Power grid open-phase detection device and method for controlling switching tube in rectifier bridge |
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