CN212572444U - Generator exciting transformer - Google Patents
Generator exciting transformer Download PDFInfo
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- CN212572444U CN212572444U CN202021558457.1U CN202021558457U CN212572444U CN 212572444 U CN212572444 U CN 212572444U CN 202021558457 U CN202021558457 U CN 202021558457U CN 212572444 U CN212572444 U CN 212572444U
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Abstract
The utility model provides a generator exciting transformer, including transformer T1, concatenate fuse F1, current transformer L1, rectifier BD1, voltage stabilizing circuit, isolation control circuit, bidirectional thyristor D4 and current-limiting resistor in transformer T1 input public end line major loop. When the transformer T1 of the utility model is powered on, the current limiting function of the current limiting resistor reduces the starting instantaneous current to the bearable range of the fuse F1, thus avoiding the large impact current generated by the transformer T1 to burn the fuse F1 at the moment of starting the generator; after the excitation of the transformer T1 is established, the isolation control circuit controls the conduction of the bidirectional thyristor D4 to short-circuit the current-limiting resistor, thereby avoiding the generation of potential difference on the current-limiting resistor and reducing the input voltage of the transformer T1 to cause abnormal output.
Description
Technical Field
The utility model relates to a transformer technical field especially relates to a generator exciting transformer.
Background
The generator exciting transformer is used for reducing the voltage of the alternating current output by the generator end, and the reduced alternating current is rectified by the rectifier to provide exciting current for an exciting winding of the generator. The generator exciting transformer is usually in a structure form with a closed magnetic circuit, the electrified exciting impact current is large and is often several times of rated current, a fuse is easily damaged by large current at the moment of starting the generator, and if the fuse with the larger rated current value is selected, the power of the transformer needs to be increased, so that the cost of the exciting transformer is increased. In view of the above, it is desirable to design a generator exciting transformer capable of suppressing the instantaneous large current generated when the transformer is turned on, that is, preventing the instantaneous large current from burning out the fuse of the transformer, thereby reducing the failure rate of the transformer and avoiding the high cost caused by the increase of the power of the transformer.
SUMMERY OF THE UTILITY MODEL
In view of this the utility model provides a generator exciting transformer to solve traditional generator exciting transformer and start the problem that the fuse is damaged by the instantaneous heavy current of start easily in the twinkling of an eye at the generator.
The technical scheme of the utility model is realized like this: a generator exciting transformer comprises a transformer T1 and a fuse F1 connected in series in a main circuit of an input public end connecting line of the transformer T1, and further comprises a current transformer L1, a rectifier BD1, a voltage stabilizing circuit, an isolation control circuit, a bidirectional thyristor D4 and a current limiting resistor;
the primary side of a current transformer L1 is connected in series in a main circuit of an input public end connecting line of a transformer T1, two ends of the secondary side of the current transformer L1 are respectively connected with two alternating current input ends of a rectifier BD1, and the direct current output end of the rectifier BD1 is connected with the input end of an isolation control circuit through a voltage stabilizing circuit;
the output end of the isolation control circuit is connected with the control end of the bidirectional thyristor D4, and the isolation control circuit is used for controlling the conduction of the bidirectional thyristor D4 after the excitation of the generator exciting transformer is established;
the current limiting resistor is connected in series in a main circuit of an input public end connecting line of the transformer T1 and is connected in series with the fuse F1, and the bidirectional thyristor D4 is connected in parallel with the current limiting resistor.
Optionally, the voltage stabilizing circuit includes diodes D1-D2, resistors R1-R5, a PNP transistor Q1, NPN transistors Q2-Q4, and a capacitor C2;
the direct current output positive electrode of the rectifier BD1 is grounded through a collector electrode of a triode Q3, an emitter electrode of a triode Q3, a resistor R3 and a resistor R4 in sequence, the common end of the direct current output positive electrode of the rectifier BD1 and the collector electrode of a triode Q3 is connected with a collector electrode of a triode Q2, and the emitter electrode of the triode Q2 is connected with a base electrode of a triode Q3;
the common end of the direct current output anode of the rectifier BD1 and the collector of the triode Q3 is further grounded through the anode of a diode D1, the cathode of a diode D1, the anode of a diode D2, the cathode of a diode D2 and a resistor R1 in sequence, the cathode of a diode D2 and the common end of a resistor R1 are connected with the base of a triode Q1, the common end of the direct current output anode of the rectifier BD1 and the collector of a triode Q3 is further connected with the emitter of a triode Q1 through the resistor R2, the collector of the triode Q1 is grounded through a capacitor C2, and the collector of a triode Q1 and the common end of a capacitor C2 are connected with the base of a triode Q2;
the common end of the resistor R3 and the resistor R4 is connected with the base electrode of the triode Q4, the collector electrode of the triode Q4 is connected with the base electrode of the triode Q2, and the emitter electrode of the triode Q4 is grounded through the resistor R5;
the common end of the emitter of the triode Q3 and the resistor R3 is connected with the anode of the input end of the isolation control circuit, and the common end of the resistor R3 and the resistor R4 is also connected with the cathode of the input end of the isolation control circuit.
Optionally, the isolation control circuit includes an optocoupler U1 and resistors R9 to R10;
the positive pole of opto-coupler U1 emitting diode is connected with the common terminal of triode Q3 emitter and resistance R3, the negative pole of opto-coupler U1 emitting diode is connected with the common terminal of resistance R3 and resistance R4, the collecting electrode of opto-coupler U1 phototriode is connected through resistance R9 to the one end of current-limiting resistance, the other end of current-limiting resistance is connected through resistance R10 to the emitter of opto-coupler U1 phototriode, the control end of bidirectional thyristor D4 is connected to the collecting electrode of opto-coupler U1 phototriode.
Optionally, the isolation control circuit further includes a diode D3, and the diode D3 is connected in inverse parallel to two ends of the light emitting diode of the optocoupler U1.
Optionally, the current-limiting resistor includes resistors R6 to R7, and the resistor R7 is connected in series with the resistor R6 and then connected in parallel with the triac D4.
Optionally, the generator exciting transformer further comprises a buffer absorption circuit, and the buffer absorption circuit is connected in parallel with the triac D4.
Optionally, the snubber circuit includes a resistor R8 and a capacitor C3, and the resistor R8 is connected in series with the capacitor C3 and then connected in parallel with the triac D4.
The utility model discloses a generator exciting transformer has following beneficial effect for prior art:
(1) when the transformer T1 is powered on, most of input voltage is loaded on the current-limiting resistor, and a small part of voltage is loaded on the coil winding of the transformer T1, so that the starting instantaneous current is reduced to a bearable range of the fuse F1 through the current-limiting function of the current-limiting resistor, and the fuse F1 is prevented from being burnt by large impact current generated by the transformer T1 at the starting moment of the generator; after the excitation of the transformer T1 is established, the isolation control circuit controls the conduction of the bidirectional thyristor D4 to short-circuit the current-limiting resistor, thereby avoiding the generation of potential difference on the current-limiting resistor and reducing the input voltage of the transformer T1 to cause abnormal output;
(2) when the output voltage of the voltage stabilizing circuit is influenced by certain factors and is higher than a constant value, the base voltage of the triode Q4 is increased under the partial pressure of the series resistors R3 and R4, the conduction of the triode Q4 is increased, the push current flowing to the triodes Q2 and Q3 is reduced, and the output voltage of the voltage stabilizing circuit is reduced; on the contrary, when the output voltage is lower than a constant value, the base voltage of the triode Q4 is reduced under the partial pressure of the series resistors R3 and R4, the conduction of the triode Q4 is reduced, the push current flowing to the triodes Q2 and Q3 is increased, the output voltage of the voltage stabilizing circuit is increased, and therefore the output voltage of the voltage stabilizing circuit can be always kept at the constant value.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used 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 some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a circuit diagram of the generator exciting transformer of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work all belong to the protection scope of the present invention.
As shown in fig. 1, the generator exciting transformer of the present embodiment includes a transformer T1, a fuse F1 connected in series in the main circuit of the input common terminal connection of the transformer T1, a current transformer L1, a rectifier BD1, a voltage stabilizing circuit, an isolation control circuit, a triac D4, and a current limiting resistor. The primary side of the current transformer L1 is connected in series in the input common end connecting line main loop of the transformer T1, the two ends of the secondary side of the current transformer L1 are respectively connected with the two alternating current input ends of the rectifier BD1, and the direct current output end of the rectifier BD1 is connected with the input end of the isolation control circuit through a voltage stabilizing circuit. The output end of the isolation control circuit is connected with the control end of the bidirectional thyristor D4, and the isolation control circuit is used for controlling the conduction of the bidirectional thyristor D4 after the excitation of the generator exciting transformer is established. The current limiting resistor is connected in series in a main circuit of an input public end connecting line of the transformer T1 and is connected in series with the fuse F1, and the bidirectional thyristor D4 is connected in parallel with the current limiting resistor.
In this embodiment, the current transformer L1 is used to obtain energy required by the operation of the subsequent circuit from the serial transformer T1 input common terminal connection line, and after the transformer T1 is powered on, the current transformer L1 converts the starting current into proportional voltage to provide power output for the subsequent circuit. The primary side and the secondary side of the current transformer L1 carry out energy transfer through the change of the magnetic field and form effective and reliable electrical isolation. Because the current transformer L1 is connected in series with the common end connecting line in the actual working process and forms a series connection relation with the primary winding of the transformer T1, when current flows, the current transformer acquires energy and also divides a part of voltage, so that the voltage of two ends of the winding of the transformer T1 is reduced, and a certain current inhibiting effect is achieved. The rectifier BD1 is used for converting alternating current obtained by the current transformer L1 from a connection line of an input common end of the transformer T1 into direct current, and the output end of the rectifier BD1 is connected with the electrolytic capacitor C1 in parallel, so that the load characteristic of the rectifying circuit is improved, and stable voltage output is provided for a post-stage voltage stabilizing circuit. The voltage stabilizing circuit is used for performing voltage stabilizing output on the direct current to supply to the isolation control circuit. When the transformer T1 is powered on, most of input voltage is loaded on the current-limiting resistor, and a small part of voltage is loaded on the coil winding of the transformer T1, so that the starting instantaneous current is reduced to a bearable range of the fuse F1 through the current-limiting function of the current-limiting resistor, and the phenomenon that the fuse F1 is burnt by large impact current generated by the transformer T1 at the starting moment of a generator is avoided. After the excitation of the transformer T1 is established, the bidirectional thyristor D4 is controlled to be turned on by the isolation control circuit to short-circuit the current-limiting resistor, so that the voltages at the two ends of the input common terminal connecting line of the transformer T1 and the corresponding voltage tap connecting line are all loaded to the two ends of the primary coil of the transformer T1, and the main loop voltage of the input common terminal connecting line at the input end of the transformer T1 is recovered, so that the transformer T1 is in a normal working state, thereby ensuring the reliable output of the transformer T1, avoiding the generation of a potential difference on the current-limiting resistor, and reducing the input voltage of the transformer T1 to cause abnormal output.
Specifically, as shown in fig. 1, the voltage regulator circuit of this embodiment includes diodes D1-D2, resistors R1-R5, a PNP transistor Q1, NPN transistors Q2-Q4, and a capacitor C2. The direct current output positive electrode of the rectifier BD1 is grounded through a collector electrode of the triode Q3, an emitter electrode of the triode Q3, a resistor R3 and a resistor R4 in sequence, the common end of the direct current output positive electrode of the rectifier BD1 and the collector electrode of the triode Q3 is connected with a collector electrode of the triode Q2, and the emitter electrode of the triode Q2 is connected with a base electrode of the triode Q3. The common end of the direct current output anode of the rectifier BD1 and the collector of the triode Q3 is further grounded through the anode of a diode D1, the cathode of a diode D1, the anode of a diode D2, the cathode of a diode D2 and a resistor R1 in sequence, the cathode of a diode D2 and the common end of a resistor R1 are connected with the base of a triode Q1, the common end of the direct current output anode of the rectifier BD1 and the collector of a triode Q3 is further connected with the emitter of a triode Q1 through the resistor R2, the collector of the triode Q1 is grounded through a capacitor C2, and the collector of a triode Q1 and the common end of a capacitor C2 are connected with the base of a triode Q2. The common end of the resistor R3 and the resistor R4 is connected with the base electrode of the triode Q4, the collector electrode of the triode Q4 is connected with the base electrode of the triode Q2, and the emitter electrode of the triode Q4 is grounded through the resistor R5. The common end of the emitter of the triode Q3 and the resistor R3 is connected with the anode of the input end of the isolation control circuit, and the common end of the resistor R3 and the resistor R4 is also connected with the cathode of the input end of the isolation control circuit.
In this embodiment, the diodes D1-D2, the resistors R1-R2, and the transistor Q1 form a constant current source circuit, which provides driving current for the voltage-regulating transistors Q2 and Q3. The resistors R3-R5 and the triode Q4 form a voltage fluctuation feedback circuit, and the output voltage of the voltage stabilizing circuit is kept at a constant value through feedback. Normally, the constant current source supplies 2mA to the voltage regulating transistors Q2 and Q3, so that the transistors Q2 and Q3 conduct output current. When the output voltage is influenced by certain factors and is higher than a constant value, the base voltage of the triode Q4 is increased under the partial pressure of the series resistors R3 and R4, the conduction of the triode Q4 is increased, the push current flowing to the triodes Q2 and Q3 is reduced, and the output voltage of the voltage stabilizing circuit is reduced; on the contrary, when the output voltage is lower than a constant value, the base voltage of the triode Q4 is reduced under the partial voltage of the series resistors R3 and R4, the conduction of the triode Q4 is reduced, the push current flowing to the triodes Q2 and Q3 is increased, and the output voltage of the voltage stabilizing circuit is increased. Therefore, the output voltage of the voltage stabilizing circuit can be always kept at a constant value. The capacitor C2 is used for charging and adjusting the time required by the conduction of the triodes Q2 and Q3, and ensures that the voltage stabilizing circuit outputs after the excitation of the transformer T1 is established.
As shown in fig. 1, the isolation control circuit of the present embodiment includes an optocoupler U1, resistors R9 to R10, and a diode D3. The positive pole of opto-coupler U1 emitting diode is connected with the common terminal of triode Q3 emitter and resistance R3, the negative pole of opto-coupler U1 emitting diode is connected with the common terminal of resistance R3 and resistance R4, the collecting electrode of opto-coupler U1 phototriode is connected through resistance R9 to the one end of current-limiting resistance, the other end of current-limiting resistance is connected through resistance R10 to the emitter of opto-coupler U1 phototriode, the control end of bidirectional thyristor D4 is connected to the collecting electrode of opto-coupler U1 phototriode. The diode D3 is connected in reverse parallel with two ends of the light-emitting diode of the optocoupler U1. Diode D3 acts to protect optocoupler U1.
As shown in fig. 1, the current limiting resistor of this embodiment includes resistors R6 to R7, and the resistor R7 is connected in series with the resistor R6 and then connected in parallel with the triac D4. At the moment of electrifying the transformer T1, the voltage at two ends of the current-limiting resistor is higher, in the embodiment, 2 resistors are connected in series to reduce the voltage at two ends of any resistor, and simultaneously, the dissipation power of the resistor is reduced, and the application under the conditions of high power and high voltage is realized by using a low-power device.
Further, the generator exciting transformer of the present embodiment further includes a buffering absorption circuit, as shown in fig. 1, the buffering absorption circuit includes a resistor R8 and a capacitor C3, and the resistor R8 is connected in series with the capacitor C3 and then connected in parallel with the triac D4. The buffer absorption circuit is used for reducing the voltage at two ends of the connecting main loop of the input public end of the controlled silicon D4 before the triodes Q2 and Q3 are conducted when the generator is started so as to protect the connecting main loop of the input public end of the controlled silicon D4 from being damaged.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A generator excitation transformer comprises a transformer T1 and a fuse F1 connected in series in a main circuit of an input public end connecting line of the transformer T1, and is characterized by further comprising a current transformer L1, a rectifier BD1, a voltage stabilizing circuit, an isolation control circuit, a bidirectional thyristor D4 and a current limiting resistor;
the primary side of a current transformer L1 is connected in series in a main circuit of an input public end connecting line of a transformer T1, two ends of the secondary side of the current transformer L1 are respectively connected with two alternating current input ends of a rectifier BD1, and the direct current output end of the rectifier BD1 is connected with the input end of an isolation control circuit through a voltage stabilizing circuit;
the output end of the isolation control circuit is connected with the control end of the bidirectional thyristor D4, and the isolation control circuit is used for controlling the conduction of the bidirectional thyristor D4 after the excitation of the generator exciting transformer is established;
the current limiting resistor is connected in series in a main circuit of an input public end connecting line of the transformer T1 and is connected in series with the fuse F1, and the bidirectional thyristor D4 is connected in parallel with the current limiting resistor.
2. The generator exciting transformer according to claim 1, wherein the voltage stabilizing circuit comprises diodes D1-D2, resistors R1-R5, a PNP triode Q1, NPN triodes Q2-Q4, and a capacitor C2;
the direct current output positive electrode of the rectifier BD1 is grounded through a collector electrode of a triode Q3, an emitter electrode of a triode Q3, a resistor R3 and a resistor R4 in sequence, the common end of the direct current output positive electrode of the rectifier BD1 and the collector electrode of a triode Q3 is connected with a collector electrode of a triode Q2, and the emitter electrode of the triode Q2 is connected with a base electrode of a triode Q3;
the common end of the direct current output anode of the rectifier BD1 and the collector of the triode Q3 is further grounded through the anode of a diode D1, the cathode of a diode D1, the anode of a diode D2, the cathode of a diode D2 and a resistor R1 in sequence, the cathode of a diode D2 and the common end of a resistor R1 are connected with the base of a triode Q1, the common end of the direct current output anode of the rectifier BD1 and the collector of a triode Q3 is further connected with the emitter of a triode Q1 through the resistor R2, the collector of the triode Q1 is grounded through a capacitor C2, and the collector of a triode Q1 and the common end of a capacitor C2 are connected with the base of a triode Q2;
the common end of the resistor R3 and the resistor R4 is connected with the base electrode of the triode Q4, the collector electrode of the triode Q4 is connected with the base electrode of the triode Q2, and the emitter electrode of the triode Q4 is grounded through the resistor R5;
the common end of the emitter of the triode Q3 and the resistor R3 is connected with the anode of the input end of the isolation control circuit, and the common end of the resistor R3 and the resistor R4 is also connected with the cathode of the input end of the isolation control circuit.
3. The generator exciting transformer according to claim 2, wherein the isolation control circuit comprises an optocoupler U1 and resistors R9-R10;
the positive pole of opto-coupler U1 emitting diode is connected with the common terminal of triode Q3 emitter and resistance R3, the negative pole of opto-coupler U1 emitting diode is connected with the common terminal of resistance R3 and resistance R4, the collecting electrode of opto-coupler U1 phototriode is connected through resistance R9 to the one end of current-limiting resistance, the other end of current-limiting resistance is connected through resistance R10 to the emitter of opto-coupler U1 phototriode, the control end of bidirectional thyristor D4 is connected to the collecting electrode of opto-coupler U1 phototriode.
4. The generator excitation transformer of claim 3, wherein the isolation control circuit further comprises a diode D3, and a diode D3 is connected in anti-parallel across the light emitting diode of the optocoupler U1.
5. The generator exciting transformer according to claim 1, wherein the current limiting resistor comprises resistors R6-R7, and the resistor R7 is connected in series with the resistor R6 and then connected in parallel with the triac D4.
6. The generator exciter transformer of claim 1, further comprising a snubber circuit connected in parallel with triac D4.
7. The generator excitation transformer of claim 6 wherein the snubber absorption circuit comprises a resistor R8 and a capacitor C3, wherein the resistor R8 is connected in series with the capacitor C3 and then in parallel with the triac D4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021558457.1U CN212572444U (en) | 2020-07-30 | 2020-07-30 | Generator exciting transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021558457.1U CN212572444U (en) | 2020-07-30 | 2020-07-30 | Generator exciting transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212572444U true CN212572444U (en) | 2021-02-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021558457.1U Active CN212572444U (en) | 2020-07-30 | 2020-07-30 | Generator exciting transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN212572444U (en) |
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2020
- 2020-07-30 CN CN202021558457.1U patent/CN212572444U/en active Active
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