CN205157656U - Three -phase inverter output open -phase detecting device and three -phase inverter - Google Patents
Three -phase inverter output open -phase detecting device and three -phase inverter Download PDFInfo
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- CN205157656U CN205157656U CN201520971200.1U CN201520971200U CN205157656U CN 205157656 U CN205157656 U CN 205157656U CN 201520971200 U CN201520971200 U CN 201520971200U CN 205157656 U CN205157656 U CN 205157656U
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Abstract
The utility model discloses a three -phase inverter output open -phase detecting device. The device includes: a balanced load comprises the three load that has the same impedance with three -phase inverter output star connection, the 2nd balanced load comprises the three load that has the same impedance with load input star connection, signal detecting element for voltage signal to between a balanced load mid point and the 2nd balanced load mid point detects. The utility model also discloses a three -phase inverter. The utility model discloses an artificially making the mid point at outlet side and load side, working as and lack the phase time, very big change can appear in two balanced load mid point current potentials, and voltage signal determines whether take place scarce looks trouble between two mid points through detecting, and the sensor need not exported to the realization of this method, and the circuit is simple, the realization is with low costs, does not receive the influence of load size, judges that the degree of accuracy is high, can also protect the connecting circuit between two sets of balanced load wiring points.
Description
Technical field
The utility model relates to electric and electronic technical field, particularly relates to a kind of three-phase inverter and exports pile defection device.
Background technology
Along with the modernization sustainable development of society, increasing power electronic product has been applied in the daily productive life of people, inverter is an important application in power electronics industry, its Main Function is by converting direct-current power into alternating-current power, and present widely used variable-frequency power sources, inverter are all its application.Direct current to be converted to three-phase alternating current (three-phase three-wire system), shore electric power, UPS etc. are the application of this function, to be its output characteristics be a voltage source and export without N line the feature of this power supply, power supply institute bringing onto load can be balanced load also can be unbalance load, in use because the connection between power supply with load occurs that abnormal can causing a certainly exports deficient phenomena mutually, i.e. so-called output open-phase fault, it is abnormal that phase shortage can cause load equipment input voltage to occur, light then quit work, seriously device damage may be caused, so general power supply all can with output default-phase protection function to protect load equipment safety in this case.
Judge that open-phase fault has a lot of method, general people can judge whether to there occurs output phase shortage by using current sensor to detect outgoing side three-phase current, as shown in Figure 1, when detecting that certain phase output current is less than a threshold value, just think that this there occurs output phase shortage mutually, thus realize protection or other control strategies, but there is a problem in the method, that is exactly the selection of threshold value, if load is fixing, when certain phase load diminishes, this corresponding output current also diminishes, if now threshold value is too high, and erroneous judgement situation will occur, if and threshold value is too low, due to the existence of sampling error, also likely occur phase shortage occurring and not protecting, another kind method is at load end voltage sensor sampling three-phase line voltage respectively, as shown in Figure 2, by judging that line voltage swing can judge whether to have occurred open-phase fault accurately, this method needs sampling three-route voltage, and need control chip computing or complex hardware circuit judges to realize, cost is higher.
Utility model content
Technical problem to be solved in the utility model is to overcome prior art deficiency, provides a kind of three-phase inverter to export pile defection device, has higher accuracy in detection, and circuit is simple simultaneously, to realize cost low.
The utility model specifically solves the problems of the technologies described above by the following technical solutions:
Three-phase inverter exports method for detecting open phase, has the load of same impedance, as the first balanced load three-phase inverter output terminal Y-connection three; There is the load of same impedance, as the second balanced load load input terminal Y-connection three; Judge that described three-phase inverter exports whether phase shortage by the voltage signal detected between the first balanced load mid point and the second balanced load mid point.
Three-phase inverter exports pile defection device, comprising:
First balanced load, is made up of three loads with same impedance with the Y-connection of three-phase inverter output terminal;
Second balanced load, is made up of three loads with same impedance with load input terminal Y-connection;
Detecting signal unit, for detecting the voltage signal between the first balanced load mid point and the second balanced load mid point.
Following technical scheme can also be obtained according to identical utility model thinking:
A kind of three-phase inverter, comprises inversion unit, control module, and for the linkage unit that is connected with load unit by inversion unit be used for exporting to three-phase inverter the pile defection unit that phase shortage detects, described pile defection unit comprises:
First balanced load, is formed by with three loads with same impedance of linkage unit by the Y-connection of inversion unit side;
Second balanced load, is formed by with three loads with same impedance of linkage unit by the Y-connection of load unit side;
Detecting signal unit, for detecting the voltage signal between the first balanced load mid point and the second balanced load mid point, its signal output part is connected with control module.
Compared to existing technology, the utility model has following beneficial effect:
The utility model is by artificially manufacturing mid point at outgoing side and load-side, when there is broken string or other problem and cause phase shortage in connection when between outgoing side and load-side, two place's balanced load midpoint potentials there will be very large change, judge whether to there occurs open-phase fault by the method detecting the voltage signal between two mid points, the realization of this method does not need output transducer, circuit is simple, realize cost low, and it is not by the impact of load, the judgement accuracy of phase shortage is high, not easily report by mistake, the connecting circuit between two groups of balanced load wiring points can be protected.
Accompanying drawing explanation
Fig. 1 is a kind of principle schematic of existing pile defection scheme;
Fig. 2 is the principle schematic of another kind of existing pile defection scheme;
Fig. 3 is principle schematic of the present utility model;
Fig. 4 is voltage oscillogram when there is open-phase fault between two mid points;
Fig. 5 by embodiment the structural representation of employing detecting signal unit.
Embodiment
Below in conjunction with accompanying drawing, the technical solution of the utility model is described in detail:
Fig. 3 shows ultimate principle of the present utility model.As shown in Figure 3, A, B, C three-phase alternating current that inversion unit exports exports load unit to via linkage unit, and control module controls inversion unit.Described linkage unit can be switch, cable, contactor etc.As shown in Figure 3, the triple-phase line between inversion unit and linkage unit is connected to three loads Z1, Z2, Z3 of Y-connection, and its mid point is N1; Triple-phase line between load unit and linkage unit is connected to three loads Z4, Z5, Z6 of Y-connection, and its mid point is N2.The impedance of load Z1, Z2, Z3 is identical, a common formation balanced load; The impedance of load Z4, Z5, Z6 is identical, common another balanced load of formation.Two balanced load mid points N1, N2 are connected with detecting unit; detecting unit detects the voltage signal between N1, N2 and exports testing result to control module; the output signal that control module reception detecting unit is sent here judges whether to there occurs phase shortage; and as required to controls such as inversion unit quit work, realize protection.Load Z1, Z2, Z3, Z4, Z5, Z6 can be resistance, electric capacity or other loads.
For the ease of public understanding, below the principle of technical solutions of the utility model is described in detail.
As shown in Figure 3, balanced load Z1, Z2, Z3 adopt Y-connection mode to be connected between inversion unit and linkage unit, the impedance Z 1=Z2=Z3=Zm of balanced load Z1, Z2, Z3.Balanced load Z4, Z5, Z6 adopt Y-connection mode to be connected between linkage unit and load unit, the impedance Z 4=Z5=Z6=Zn of balanced load Z4, Z5, Z6.
When linkage unit normally works, take N1 as voltage reference points, U
n1=0V, because inversion unit is voltage source, exports as amplitude is equal, the three-phase alternating voltage that phase is 120 °, if U
aN1=U
a ' N2=Umsin ω t, U
bN1=U
b ' N2=Umsin (ω t-120 °), U
cN1=U
c ' N2=Umsin (ω t+120 °), frequency of operation is f, and so because Z1, Z2, Z3 are balanced load, Z4, Z5, Z6 are also balanced load, now U
n2=0V, the voltage U between balanced load mid point N1 and N2 2
n1N2=0V.
When linkage unit breaks down, causing A, B, C three-phase to have and wherein one to be connected disconnection, when not being connected to load unit, take fault phase as A phase is example, now:
Then:
Now voltage U
n1N2waveform as shown in Figure 4, namely when open-phase fault occurs A phase, voltage U between balanced load mid point N1, N2
n1N2can become an amplitude from 0V is phase voltage half, phase place and U
aN1differ the sinusoidal voltage of 180 °.
According to above-mentioned principle, by voltage U
n1N2carry out detection and can realize phase shortage judgement accurately.Such as, can directly by the voltage U shown by oscillograph
n1N2waveform judges, or by detecting U
n1N2differ alternate with inversion unit three judges.But obviously the circuit of such scheme is too complicated, realizes high cost.In order to simplify circuit, reduce costs, the utility model is preferably by detection U
n1N2voltage magnitude or voltage effective value whether be greater than predetermined voltage threshold and judge that described three-phase inverter exports whether phase shortage.Those skilled in the art can choose voltage threshold according to actual conditions, the simplest choosing method is directly using 1/4th of phase voltage amplitude or effective value as the voltage threshold judging voltage magnitude or voltage effective value, also can according to the metrical error selection appropriate threshold of the output pulsation scope of inversion unit and/or detecting unit.
The detection of voltage signal is this area mature technology, and those skilled in the art can build corresponding detecting signal unit according to the actual requirements flexibly.Fig. 5 shows a preferred structure of detecting signal unit, and it comprises the differential sample circuit, the comparator circuit that connect in turn; Differential sample circuit is utilized to carry out sampling filtering to balanced load mid point N1, N2, and compared by comparator circuit and outputed signal, the identification that control module carries out open-phase fault according to the output signal of comparator circuit judges, thus controls inversion unit.
Claims (6)
1. three-phase inverter exports pile defection device, it is characterized in that, comprising:
First balanced load, is made up of three loads with same impedance with the Y-connection of three-phase inverter output terminal;
Second balanced load, is made up of three loads with same impedance with load input terminal Y-connection;
Detecting signal unit, for detecting the voltage signal between the first balanced load mid point and the second balanced load mid point.
2. pile defection device as claimed in claim 1, it is characterized in that, described detecting signal unit is voltage magnitude detecting unit or voltage effective value detecting unit.
3. pile defection device as claimed in claim 1, it is characterized in that, described detecting signal unit comprises the differential sample circuit, the comparator circuit that connect in turn.
4. a three-phase inverter, comprise inversion unit, control module, and for the linkage unit that is connected with load unit by inversion unit be used for exporting to three-phase inverter the pile defection unit that phase shortage detects, it is characterized in that, described pile defection unit comprises:
First balanced load, is formed by with three loads with same impedance of linkage unit by the Y-connection of inversion unit side;
Second balanced load, is formed by with three loads with same impedance of linkage unit by the Y-connection of load unit side;
Detecting signal unit, for detecting the voltage signal between the first balanced load mid point and the second balanced load mid point, its signal output part is connected with control module.
5. three-phase inverter as claimed in claim 4, it is characterized in that, described detecting signal unit is voltage magnitude detecting unit or voltage effective value detecting unit.
6. three-phase inverter as claimed in claim 4, it is characterized in that, described detecting signal unit comprises the differential sample circuit, the comparator circuit that connect in turn.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520971200.1U CN205157656U (en) | 2015-11-30 | 2015-11-30 | Three -phase inverter output open -phase detecting device and three -phase inverter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520971200.1U CN205157656U (en) | 2015-11-30 | 2015-11-30 | Three -phase inverter output open -phase detecting device and three -phase inverter |
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| Publication Number | Publication Date |
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| CN205157656U true CN205157656U (en) | 2016-04-13 |
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| CN201520971200.1U Active CN205157656U (en) | 2015-11-30 | 2015-11-30 | Three -phase inverter output open -phase detecting device and three -phase inverter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105467226A (en) * | 2015-11-30 | 2016-04-06 | 常熟开关制造有限公司(原常熟开关厂） | Three-phase inverter output phase failure detection method, device and three-phase inverter |
-
2015
- 2015-11-30 CN CN201520971200.1U patent/CN205157656U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105467226A (en) * | 2015-11-30 | 2016-04-06 | 常熟开关制造有限公司(原常熟开关厂） | Three-phase inverter output phase failure detection method, device and three-phase inverter |
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| GR01 | Patent grant |