CN215772959U - High-low voltage automatic switching circuit of isolation transformer - Google Patents
High-low voltage automatic switching circuit of isolation transformer Download PDFInfo
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- CN215772959U CN215772959U CN202121671698.1U CN202121671698U CN215772959U CN 215772959 U CN215772959 U CN 215772959U CN 202121671698 U CN202121671698 U CN 202121671698U CN 215772959 U CN215772959 U CN 215772959U
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Abstract
The utility model discloses a high-low voltage automatic switching circuit of an isolation transformer, which comprises at least two transformers, wherein a switch circuit comprises a primary side first switch circuit and a secondary side first switch circuit which are connected in series between the output end and the input end of the adjacent transformers, a primary side second switch circuit and a secondary side second switch circuit which are connected with the input end of the transformer in parallel, and a primary side third switch circuit and a secondary side third switch circuit which are connected with the output end of the transformer in parallel; one end of the input voltage is connected with the input end of the primary coil of the first transformer and the primary second switch circuit, and the other end of the input voltage is connected with the output end of the primary coil of the last transformer and the primary third switch circuit; one end of the output voltage is connected with the input end of the secondary coil of the first transformer and the secondary second switch circuit, and the other end of the output voltage is connected with the output end of the secondary coil of the last transformer and the secondary third switch circuit; the control circuit is connected with the switch circuit in a control mode.
Description
Technical Field
The utility model belongs to commercial power supply equipment with wide voltage input, and particularly relates to a high-low voltage automatic switching circuit of an isolation transformer.
Background
In the prior art, if an isolation transformer is needed to be used in different input voltage areas, under the same power, when the transformer works in a low-voltage area, the current is large, and the loss of a transformer copper wire is increased. When the transformer works in a high-voltage area, the magnetic core of the transformer is easy to saturate. Therefore, two schemes for solving the problem are provided, 1, the wire diameter and the number of turns of the transformer are increased, and the main defects are that the size of the transformer is large and the cost is high. The advantage is that no manual operation is needed, and the voltage is switched. 2. The transformer coil is made into a series-parallel switching design, the transformer has the advantages of cost saving and small volume, and has the defects of manual switching, inconvenient maintenance and risk of burning equipment if the switching is wrong.
Disclosure of Invention
Aiming at the technical problem, the utility model discloses a high-low voltage automatic switching circuit of an isolation transformer, which has a stable and reliable circuit structure.
In order to achieve the purpose, the utility model adopts the technical scheme that: the high-low voltage automatic switching circuit of the isolation transformer mainly comprises a switching circuit, a control circuit and a transformer;
the transformer comprises at least two transformers, and each transformer comprises a primary coil and a secondary coil which correspond to each other;
the switch circuit comprises a primary side first switch circuit and a secondary side first switch circuit which are connected in series between the output end and the input end of the adjacent transformer, a primary side second switch circuit and a secondary side second switch circuit which are connected with the input end of the transformer in parallel, and a primary side third switch circuit and a secondary side third switch circuit which are connected with the output end of the transformer in parallel;
one end of the input voltage is connected with the input end of the primary coil of the first transformer and the primary second switch circuit, and the other end of the input voltage is connected with the output end of the primary coil of the last transformer and the primary third switch circuit;
one end of the output voltage is connected with the input end of the secondary coil of the first transformer and the secondary second switch circuit, and the other end of the output voltage is connected with the output end of the secondary coil of the last transformer and the secondary third switch circuit;
the control circuit is connected with the switch circuit in a control mode.
Further, the switch circuit comprises a single-pole single-throw relay, and the relay can be controlled to be in an open state or a closed state through the control circuit. The control circuit signal samples the voltage value of the input voltage.
Further, the switching circuit further comprises a first triode Q1, the first triode Q1 is connected with the relay K1 in series, and a resistor R1 is arranged in front of the first triode Q1. R1 is used for limiting current, when the first triode Q1 is conducted, the voltage of PIN1-2 is 0.7V, and the control signal voltage can be prevented from being pulled down by the increasing resistor R1.
Further, the control circuit comprises a rectifier diode, the rectifier diode is connected with input voltage and is communicated with a voltage comparator, and the voltage comparator is connected with the second triode Q2.
Furthermore, voltage dividing resistors R2, R3 and R4 are arranged between the rectifier diode and the voltage comparator, and voltage division is realized by R2, R3 and R4 and is compared with reference voltage VREF.
Further, R4 is connected in parallel with the first filter capacitor C1.
Furthermore, the voltage comparator is connected with the primary side first switch circuit through a third control signal end, and the fourth control signal end is connected with the secondary side first switch circuit.
Furthermore, a delay circuit composed of R7 and a second filter capacitor C2 is arranged between the third control signal end and the fourth control signal end. The time delay circuit is used for preventing the primary coil from being closed firstly, so that voltage spike or voltage drop occurs in the later stage.
Further, the second filter capacitor C2 is connected to the primary side second switch circuit and the primary side third switch circuit through the first control signal terminal; the second control signal end is connected with the secondary side second switch circuit and the secondary side third switch circuit.
Furthermore, a delay circuit composed of R8 and a second filter capacitor C3 is arranged between the first control signal end and the second control signal end. The time delay circuit is used for preventing the primary coil from being closed firstly, so that voltage spike or voltage drop occurs in the later stage.
When the voltage is higher than VREF, the input voltage AC can be judged to be high voltage, the third control circuit signal and the fourth control signal are high level, the primary side first switch circuit and the secondary side first switch circuit are closed, other switches are opened, and the two coils are connected in series for use.
When the voltage is lower than VREF, the input voltage AC can be judged to be low voltage, the control circuit outputs low level, after the phase inversion of the control signal is carried out by the second triode Q2, the control signals 1 and 2 are high level, the primary side second switch circuit, the primary side third switch circuit, the secondary side second switch circuit and the secondary side third switch circuit are closed, other switches are opened, and the transformer coils are connected in parallel for use.
The utility model has the following beneficial effects: according to the high-low voltage automatic switching circuit of the isolation transformer, the control circuit and the switch circuit are added, so that automatic switching of coils is realized, and manual operation errors caused by manual switching are avoided. And when the circuit fails, the parallel connection mode can be automatically changed or the transformer connection can be disconnected, so that the effect of protecting the copper wires of the transformer and load equipment is achieved.
Drawings
Fig. 1 is a structural diagram of an isolation transformer high-low voltage automatic switching circuit according to an embodiment of the present invention.
Fig. 2 is a circuit diagram of the switch circuit of the high-low voltage automatic switching circuit of the isolation transformer according to the embodiment of the utility model.
Fig. 3 is a structural diagram of a control circuit of the high-low voltage automatic switching circuit of the isolation transformer according to the embodiment of the utility model.
Detailed Description
In order to facilitate understanding of those skilled in the art, the present invention will be further described with reference to the following embodiments and accompanying drawings.
The high-low voltage automatic switching circuit of the isolation transformer mainly comprises three parts, namely a switching circuit, a detection circuit and a transformer. The specific structural block diagram is shown in figure 1.
Circuit principle of transformer regulation:
in the embodiment, the number of the transformers is two, and each transformer comprises a primary coil and a secondary coil which correspond to each other;
the switch circuit comprises a switch circuit 2 (a primary side first switch circuit), a switch circuit 5 (a secondary side first switch circuit) which are connected in series between the output end and the input end of the adjacent transformer, a switch circuit 1 (a primary side second switch circuit) and a switch circuit 4 (a secondary side second switch circuit) which are connected with the input end of the transformer in parallel, a switch circuit 3 (a primary side third switch circuit) and a switch circuit 6 (a secondary side third switch circuit) which are connected with the output end of the transformer in parallel;
one end of the input voltage is connected with the input end of the primary coil of the first transformer and the switch circuit 1, and the other end of the input voltage is connected with the output end of the primary coil of the last transformer and the switch circuit 3;
one end of the output voltage is connected with the input end of the secondary coil of the first transformer and the switch circuit 4, and the other end of the output voltage is connected with the output end of the secondary coil of the last transformer and the switch circuit 6;
the control circuit is connected with the switch circuit in a control mode.
The circuit diagram and the working principle of the switching circuit are shown in fig. 2:
the switch circuit further comprises a first triode Q1, the first triode Q1 is connected with a relay K1 in series, a resistor R1 is further arranged in front of the first triode Q1, the resistor R1 is used for limiting current, when the first triode Q1 is conducted, the voltage of the PIN1-2 is 0.7V, and the control signal voltage can be prevented from being pulled down by adding the resistor R1.
The switch circuit uses the relay as the main controller, and the main function is to connect or disconnect the connection between each winding. The relay switch is controlled by a control circuit. The control circuit signal samples the voltage value of the input voltage.
When the AC input is high voltage, the control circuit outputs high level, the primary side coil and the secondary side coil are connected in series, the switch circuit 2 and the switch circuit 5 are closed, and the switch circuit 1, the switch circuit 3, the switch circuit 4 and the switch circuit 6 are disconnected.
When the AC input is low voltage, no signal or low level is output, the primary side coil and the secondary side coil are connected in parallel, the switch circuits 2 and 5 are disconnected, and the switch circuit 1, the switch circuit 3, the switch circuit 4 and the switch circuit 6 are closed. The switch circuit 1 and the switch circuit 3 are controlled by a control signal 1, the switch circuit and the switch circuit 6 are controlled by a control signal 2, the switch circuit 2 is controlled by the control signal 3, and the switch circuit 5 is controlled by a control signal 4.
The circuit diagram and the working principle of the control circuit are shown in fig. 3:
d1 is a rectifier diode, C1 is a filter capacitor, VREF is a reference voltage, U1A is a voltage comparator, and Q2 is a second triode.
The control circuit comprises a rectifier diode, the rectifier diode is connected with input voltage, after the input voltage is divided by R2, R3 and R4, the rectifier diode is communicated with a voltage comparator U1A (compared with reference voltage VREF), and R4 is connected with a first filter capacitor C1 in parallel. The voltage comparator U1A is connected with the second triode Q2, a resistor R5 is arranged between the second triode Q2 and the resistor R5, the current is limited, when the second triode Q2 is conducted, the voltage of the PIN1-2 is 0.7V, and the control signal voltage can be prevented from being pulled down by increasing the resistor.
The voltage comparator is connected with the switch circuit 2 through a third control signal terminal, and the fourth control signal terminal is connected with the switch circuit 5 (the control signal terminal is connected to the control signal of fig. 2). And a delay circuit consisting of R7 and a second filter capacitor C2 is arranged between the third control signal end and the fourth control signal end. Similarly, the second filter capacitor C2 is connected to the switch circuit 1 and the switch circuit 3 through the first control signal terminal; the second control signal terminal is connected with the switch circuit 4 and the switch circuit 6. A delay circuit consisting of R8 and a second filter capacitor C3 is arranged between the first control signal end and the second control signal end.
R6 is a pull-up resistor, and when U1A outputs a low level, Q2 is turned off, and the voltages of control signal 2 and control signal 1 are high level.
1. When the voltage is higher than VREF, the AC input high voltage can be judged, the control circuit signals 3 and 4 are high level, the switch circuits 2 and 5 are closed, other switches are opened, and the two coils are connected in series for use.
2. When the voltage is lower than VREF, the AC input low voltage can be judged, the control circuit outputs low level, after the phase inversion of Q2, the control signals 1 and 2 are high level, the switch circuits 1,3,4 and 6 are closed, other switches are opened, and the two coils are connected in parallel for use.
3. The RC time delay circuit is used for preventing the primary coil from being closed firstly, so that voltage spike or voltage drop occurs in the later stage.
The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical solution according to the technical idea of the present invention falls within the protection scope of the present invention.
Claims (10)
1. The utility model provides an isolation transformer high-low voltage automatic switch-over circuit which characterized in that: the device comprises a switching circuit, a control circuit and a transformer;
the transformer comprises at least two transformers, and each transformer comprises a primary coil and a secondary coil which correspond to each other;
the switch circuit comprises a primary side first switch circuit and a secondary side first switch circuit which are connected in series between the output end and the input end of the adjacent transformer, a primary side second switch circuit and a secondary side second switch circuit which are connected with the input end of the transformer in parallel, and a primary side third switch circuit and a secondary side third switch circuit which are connected with the output end of the transformer in parallel;
one end of the input voltage is connected with the input end of the primary coil of the first transformer and the primary second switch circuit, and the other end of the input voltage is connected with the output end of the primary coil of the last transformer and the primary third switch circuit;
one end of the output voltage is connected with the input end of the secondary coil of the first transformer and the secondary second switch circuit, and the other end of the output voltage is connected with the output end of the secondary coil of the last transformer and the secondary third switch circuit;
the control circuit is connected with the switch circuit in a control mode.
2. The high-low voltage automatic switching circuit of the isolation transformer according to claim 1, wherein:
the switch circuit comprises a single-pole single-throw relay, and a control circuit signal samples the voltage value of the input voltage.
3. The high-low voltage automatic switching circuit of the isolation transformer as claimed in claim 2, wherein:
the switch circuit further comprises a first triode Q1, a first triode Q1 is connected with the relay in series, and a resistor R1 is arranged in front of the first triode Q1.
4. The high-low voltage automatic switching circuit of the isolation transformer according to claim 1, wherein:
the control circuit comprises a rectifier diode, the rectifier diode is connected with input voltage and communicated with a voltage comparator, and the voltage comparator is connected with a second triode Q2.
5. The high-low voltage automatic switching circuit of the isolation transformer according to claim 1, wherein:
and voltage dividing resistors R2, R3 and R4 are arranged between the rectifying diode and the voltage comparator.
6. The high-low voltage automatic switching circuit of the isolation transformer of claim 5, wherein:
the divider resistor R4 is connected in parallel with the first filter capacitor C1.
7. The high-low voltage automatic switching circuit of the isolation transformer according to claim 1, wherein:
the voltage comparator is connected with the primary side first switch circuit through a third control signal end, and the fourth control signal end is connected with the secondary side first switch circuit.
8. The high-low voltage automatic switching circuit of the isolation transformer of claim 7, wherein:
and a delay circuit consisting of R7 and a second filter capacitor C2 is arranged between the third control signal end and the fourth control signal end.
9. The high-low voltage automatic switching circuit of the isolation transformer according to claim 1, wherein:
the second filter capacitor C2 is connected with the primary side second switch circuit and the primary side third switch circuit through a first control signal end; the second control signal end is connected with the secondary side second switch circuit and the secondary side third switch circuit.
10. The high-low voltage automatic switching circuit of the isolation transformer of claim 9, wherein:
a delay circuit consisting of R8 and a second filter capacitor C3 is arranged between the first control signal end and the second control signal end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121671698.1U CN215772959U (en) | 2021-07-21 | 2021-07-21 | High-low voltage automatic switching circuit of isolation transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121671698.1U CN215772959U (en) | 2021-07-21 | 2021-07-21 | High-low voltage automatic switching circuit of isolation transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215772959U true CN215772959U (en) | 2022-02-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121671698.1U Active CN215772959U (en) | 2021-07-21 | 2021-07-21 | High-low voltage automatic switching circuit of isolation transformer |
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| Country | Link |
|---|---|
| CN (1) | CN215772959U (en) |
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2021
- 2021-07-21 CN CN202121671698.1U patent/CN215772959U/en active Active
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