CN211377885U - Output switching circuit - Google Patents
Output switching circuit Download PDFInfo
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- CN211377885U CN211377885U CN202020457640.6U CN202020457640U CN211377885U CN 211377885 U CN211377885 U CN 211377885U CN 202020457640 U CN202020457640 U CN 202020457640U CN 211377885 U CN211377885 U CN 211377885U
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Abstract
An output switching circuit relates to a power output circuit and comprises two independent power conversion unit branches 1 and 2 and two switch isolation branches, wherein each switch isolation branch comprises an isolation diode and a capacitor, and the capacitors are output capacitors of the two switch isolation branches; the switch isolation branches also comprise a switch respectively; the positive pole output of the branch circuit is respectively connected with the output load through the isolating diode, the negative pole output of the branch circuit 1 is connected with the positive pole output of the other branch circuit through one of the switches and is connected with the negative pole of the load through the other switch, and the negative pole of the branch circuit 2 is connected with the negative pole of the output load. The high-voltage output and low-voltage output conversion can be realized through switch control, so that wide-range constant power output is obtained; moreover, the two isolation diodes have the functions of partial switching circuits, and the effects of reducing cost and volume and the outstanding advantages are obtained while the efficiency is not sacrificed.
Description
Technical Field
The present invention relates to power output circuits, and more particularly to an output switching circuit.
Background
With the development of science and technology, high-power conversion devices are applied more and more, and a constant-power supply with continuously adjustable output wide range is a special application in a plurality of application fields of switching power supplies. Among them, the problem that prior art exists:
the output rectifying part in the wide-range constant power output module increases the volume and cost and reduces the efficiency due to the selection of high-voltage-resistant and high-current rectifying diodes;
and the secondary winding of the transformer can not be fully utilized due to high voltage and large current and the like.
These are problems that those skilled in the art are demanding to solve.
For example, as shown in fig. 3, it is a schematic diagram of a conventional output switching circuit. For the output switching circuit, the output switching circuit K1 is switched on, when K2 and K3 are switched off, the branch 1 is connected with the branch 2 in series, and the output switching circuit can work in a high-voltage state; when K1 is turned off and K2 and K3 are turned on, the circuits are connected in parallel, and the circuit works in a low-voltage state at the moment and can output large current.
Wherein the diode D1 plays a role of preventing reverse flow. The circuit functions as output switching and comprises three switches.
When the circuit outputs high voltage, the current is small, and when the circuit outputs low voltage, the current is large.
For example: the output power is constant as P, the output power P is 20kW, the output voltage range is 300-1000V,
when the output is 400V, when K1 is turned off, K2 and K3 are turned on,
when the output current I0 is 20k/400 is 50A,
because the type selection of a single high-current diode is difficult, 2 diodes are needed to be connected in parallel at the position D1, and the problem of poor current-sharing performance exists when the 2 diodes are connected in parallel.
When 800V is output, K1 is turned on, K2 and K3 are turned off,
when the output current I0 is 20k/800 to 25A,
the D1 can work normally only by connecting 1 diode in parallel, and the D1 is actually connected by connecting 2 diodes in parallel, which also has the problem of poor current-sharing performance.
SUMMERY OF THE UTILITY MODEL
To solve the above problems, an object of the present invention is to provide an output switching circuit
The utility model provides an output switching circuit, it contains two independent power conversion units: branch 1 and branch 2(Ua and Ub), and two switch isolation branches;
the switch isolation branches respectively comprise an isolation diode (D1, D2) and a capacitor (CD1, CD2), and the capacitors are output capacitors of the two switch isolation branches respectively; in addition, the switch isolation branches also comprise a switch (V1, V2); the positive pole outputs of the branches are respectively connected with the output load through the isolation diodes (D1 and D2), the negative pole output of the branch 1 is connected with the positive pole output of the other branch through one switch V1 and is connected with the negative pole of the load through the other switch V2, and the negative pole of the branch 2 is connected with the negative pole of the output load.
Preferably, the two switches are interlocked, and preferably the switches may be constituted by MOS or IGBT or a transformer.
In addition, when the switch adopts MOS or IGBT, the first switch (V1) needs the source to be connected with the positive terminal of CD 2; when the second switch (V2) is turned on, the V1 is controlled to be turned off; when the V1 is conducted, the V1 can be naturally conducted through the internal parasitic diode, and when the V1 is conducted in a controlled mode, the loss of the V1 can be reduced, and the efficiency can be improved.
The utility model has the advantages that with the help of the technical proposal, when the high-voltage output is realized, the two independent units are connected in series through the switch control, and when the low-voltage output is realized, the two independent units are connected in parallel through the switch control, thereby obtaining the wide-range constant-power output; moreover, through reasonable selection of the diodes and the switch devices, the two isolation diodes have the functions of partial switching circuits, and the effects of reducing cost and volume and outstanding advantages are achieved while the efficiency is not sacrificed.
Drawings
Fig. 1 shows an output switching circuit according to the present invention.
Fig. 2 is a schematic diagram of an output switching circuit using an electronic switch according to the present invention.
Fig. 3 is a schematic diagram of a conventional output switching circuit.
Detailed Description
In order to embody the above effects and show the advantages thereof, the following embodiments are combined with the accompanying drawings to further specifically describe the technical solution of the present invention. The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention.
As shown in fig. 1, is a schematic diagram of the circuit principle of the present invention. In a specific embodiment of the present invention, the module of the present invention comprises two independent power conversion unit branches 1 and 2(Ua and Ub) and two switch isolation branches, each of which comprises an isolation diode (D1, D2); the two capacitors (CD1, CD2) are output capacitors of the two switch isolation branches, and the switch isolation branches further include two switches V1 and V2, respectively, and the switches may be MOS or IGBT, or may employ a relay.
The positive pole outputs of the branches are respectively connected with the output load through the isolation diodes (D1 and D2), the negative pole output of the branch 1 is connected with the positive pole output of the other branch through one switch V1 and is connected with the negative pole of the load through the other switch V2, and the negative pole of the branch 2 is connected with the negative pole of the output load.
By means of the circuit, the branches (Ua and Ub) can realize constant power output in a full range by switching on and off the two switches, and because the two independent units bear half of the output power respectively, the selection of devices is easy to perform, the power consumption can be reduced, and the efficiency is improved.
The principle of the circuit when working is as follows:
suppose the total output voltage, current is denoted as U0And I0And the output voltage and current of the two branches are respectively expressed as Ua、IaAnd Ub、Ib；
When the constant power outputs high voltage, V1 is conducted, and V2 is disconnected (namely, an interlocking state); after the two independent power units are connected in series through a switch V1, the positive output end is isolated and output through D1, and D2 is reversely biased and naturally cut off. At this time, the two branches bear half of the output voltage respectively, namely:
when constant-power low-voltage output is carried out, the V1 is disconnected, the V2 is closed, the output negative ends of the two independent power units are connected in parallel through the switch V2, and the output positive ends are connected in parallel through the diodes D1 and D2 respectively.
It can be seen that the two branches each carry half of the output current, while V2 is connected in series with branch 1, which has half the output current, i.e. half the output current：
The output positive stage is output in parallel through the isolation diodes D1 and D2, and the two independent power units can realize isolation sampling, so that the current sharing is easy to realize; meanwhile, the two isolation diodes D1 and D2 bear half of output current respectively, so that the loss can be reduced, and the efficiency is improved.
Stress analysis of the circuit:
when the constant-power high-voltage output is carried out, the total power is large, but the output current is small, the switches V1 and D1 are conducted, and the current stress is correspondingly small; v2 is turned off and the voltage across it is Ub(ii) a D2 is turned off and the voltage across the D2 is Ua。
When constant power low voltage is output, V1 is disconnected, V2 is connected, and D1 and D2 are naturally connected; d1, D2, V2 each bear half of the output current; voltage at both ends of V1 is Ub。
Through the analysis, the utility model adds the switches V1 and V2; the wide-range constant power output is realized; meanwhile, the current sharing can be conveniently realized due to the isolation effect of the D1 and D2 diodes;
the following are to be noted:
(1) characteristics of two operating modes
During high-voltage output, two independent branches are connected in series, and the output voltage of each branch bears half of the total output voltage respectively, namely:
Ia＝Ib＝I0；
when the low-voltage output is carried out, the two independent units are connected in parallel through diodes D1 and D2; the output voltage of each of the two independent units is equal to the output voltage, and the output current of each independent unit respectively bears half of the total output current, namely: u shapea＝Ub＝U0、
In a word, the power of two independent branches is half of the total output power respectively no matter the switches are connected in series or in parallel; the electric stress of each independent unit and the series-parallel switch is reduced equivalently, the device is easy to select, the loss can be effectively reduced, and the efficiency is improved.
(2) About switch V1
As shown in fig. 2, the switches V1, V2 may be MOS, IGBT, relay, or the like. Referring to fig. 2, no matter whether the switch V1 is a MOS or IGBT, it is not necessary to use a bidirectional blocking device as long as the source is connected to the positive terminal of CD 2; when the switch V2 is turned on, the switch V1 can be controlled to be turned off; when the V1 is conducted, the V1 can be naturally conducted through the internal parasitic diode, and when the V1 is conducted in a controlled mode, the loss of the V1 can be reduced, and the efficiency can be improved.
When V1 is turned on and V2 is turned off, the voltage at port 1 of the diode D2 is U0The voltage at port 2 is U0The diode D2 is subject to a reverse voltage cutoff. Wherein the diode and switch sizing problems can be specifically analyzed by a skilled person according to prior art specific circuits.
As shown in fig. 1, diode D1 only functions here as an anti-backflow; the diode D2 here functions as a reverse-flow prevention and output switching. For D2, due to the characteristic of the diode, which is a natural switch, when the high voltage needs to be output, V1 is turned on, V2 is turned off, the voltage at port 1 of diode D2 is U0, the voltage at port 2 is U0/2, and diode D2 is subjected to back voltage and is cut off.
For example: the output power is constant as P, the output power P is 20kW, the output voltage range is 300-1000V,
when outputting 400V, when V1 is turned off, V2 is turned on,
at this time, the output current I020 k/400-50A, and the currents D1, D2 are I0/2＝25A
The selection of a single high-current diode is difficult, and the method of the utility model makes the current of the diodes D1 and D2 only half of the original current, so that the diode meeting 25A is selected, and the consideration of flow equalization is avoided.
When outputting 800V, V1 is turned on, and V2 is turned off
At this time, the output current I0＝20k/800＝25A，
Only 1 diode is needed at the position D1 to work normally, and actually, only 1 diode is needed at the position D1, so that the current sharing problem of the traditional circuit is avoided. And D2 is now blocked from sustaining the back pressure.
As shown in fig. 2, V1, V2 in the present invention can be MOS, IGBT or relay, D2 is a diode, and compared with the conventional output switching circuit, the present invention has the advantage of solving the current sharing problem.
The utility model discloses compare in traditional output switching circuit, though diode quantity is two, the through flow volume is halved. When using traditional switching circuit in the reality, the diode needs two to be parallelly connected, and the utility model discloses need not parallelly connected, select two independent diodes can, the quantity that the diode was used is the same.
Output switching circuit, only use 2 switches, and traditional output switching circuit needs 3 switches, under the same and switch through-flow also the same condition of the diode through-flow, output switching circuit use a switch less, reduce the circuit control degree of difficulty, reduce cost.
Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can be modified or replaced with other embodiments without departing from the spirit and scope of the present invention, and all such modifications and equivalent substitutions are intended to be encompassed by the scope of the following claims.
Claims (4)
1. An output switching circuit comprising two independent power conversion units: branch 1 and branch 2(Ua and Ub), and two switch isolation branches;
the switch isolation branches respectively comprise an isolation diode (D1, D2) and a capacitor (CD1, CD2), and the capacitors are output capacitors of the two switch isolation branches respectively;
in addition, the switch isolation branches also comprise a switch (V1, V2);
the positive pole outputs of the branches are respectively connected with the output load through the isolation diodes (D1 and D2), the negative pole output of the branch 1 is connected with the positive pole output of the other branch through one switch V1 and is connected with the negative pole of the load through the other switch V2, and the negative pole of the branch 2 is connected with the negative pole of the output load.
2. An output switching circuit according to claim 1, wherein both of said switches are interlocked.
3. An output switching circuit according to claim 1 or 2, wherein the switch is formed by a MOS or IGBT or a relay.
4. An output switching circuit according to claim 3, wherein: the source of the first switch (V1) is connected with the positive terminal of CD 2; when the second switch (V2) is turned on, the V1 is controlled to be turned off; when the first switch (V1) is conducted, the first switch is naturally conducted through the internal parasitic diode, and when the first switch is controlled to be conducted, the loss of the first switch can be reduced, and the efficiency is improved.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020457640.6U CN211377885U (en) | 2020-04-01 | 2020-04-01 | Output switching circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020457640.6U CN211377885U (en) | 2020-04-01 | 2020-04-01 | Output switching circuit |
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| CN211377885U true CN211377885U (en) | 2020-08-28 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112994193A (en) * | 2021-05-06 | 2021-06-18 | 深圳市永联科技股份有限公司 | Charging protection circuit module and related product |
| WO2022165759A1 (en) * | 2021-02-05 | 2022-08-11 | 华为数字能源技术有限公司 | Charging circuit and charging device |
-
2020
- 2020-04-01 CN CN202020457640.6U patent/CN211377885U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022165759A1 (en) * | 2021-02-05 | 2022-08-11 | 华为数字能源技术有限公司 | Charging circuit and charging device |
| CN112994193A (en) * | 2021-05-06 | 2021-06-18 | 深圳市永联科技股份有限公司 | Charging protection circuit module and related product |
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