Adjustable large current generator based on self-coupling voltage regulator
By adding a fixed coil to the autovoltage regulator and connecting it in series with the original adjustable coil and adjusting the number of turns of the primary coil, the problems of large current generator such as large size, heavy weight and small current adjustment range are solved, and the effect of easy mobility, large current adjustment range and low cost is achieved.
Patent Information
- Application Number
- CN202511017803.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-23
- Publication Date
- 2025-09-19
AI Technical Summary
Existing large current generators are large in size and heavy in weight, making them inconvenient to carry. They also have a small current adjustment range and are expensive, making it difficult to meet diverse usage and testing needs.
On the basis of the autovoltage regulator, a fixed coil is added in series with the original adjustable coil. By adjusting the voltage regulating knob to change the number of turns of the primary coil, stepless regulation of current is achieved, and the primary coil and secondary coil are isolated from each other to ensure safety.
The large current generator is miniaturized and lightweight, easy to move, has a large current adjustment range, low cost, and high safety, meeting diverse usage and testing needs.
Smart Images
Figure CN120674205A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to electrical equipment, in particular to an adjustable high current generator based on an auto-coupling voltage regulator. Background Art
[0002] A high current generator is an electrical device that can generate low voltage and high current. It is one of the common devices used for relay protection in power systems. The core of a high current generator is a current-boosting transformer (the reverse application of a current transformer). Its working principle is based on Faraday's law of electromagnetic induction and the transformer current conversion relationship. Assume that the input current is I1 and the number of winding turns is N1; the output current is I2 and the number of winding turns is N2. Then I2=(N2 / N1)×I1 By adjusting the input / output winding turns ratio N1 / N2, different levels of current can be obtained on the output side. For example, when N1 / N2 = 100 / 1, the output current can reach 100 times the input current.
[0003] The high-current generator's primary application scenarios include providing quick-trip protection for switches in relay protection devices and simulating bypass currents in real distribution networks. It first regulates voltage using an autovoltage regulator, then uses a current-boosting transformer to generate low-voltage, high-current, simulating the current environment the device might experience in actual operation.
[0004] Existing high-current generators offer some convenience when used in fixed locations like laboratories. However, their bulk and weight make them difficult to transport, making them inconvenient for conducting field tests on immovable electrical equipment. Furthermore, they suffer from a limited current adjustment range and high cost, making them difficult to meet diverse usage and testing needs. Summary of the Invention
[0005] The purpose of the present invention is to provide an adjustable high current generator based on an autocoupler voltage regulator, which is small in size, light in weight, easy to carry, has a large current adjustment range, is lower in cost, and can meet diverse usage and testing requirements.
[0006] The technical solution of the present invention is: it includes an autocoupler voltage regulator body, an annular iron core is provided on the autocoupler voltage regulator body, a plurality of turns of adjustable coils are wound on the annular iron core, a voltage regulating knob is rotatably mounted on the autocoupler voltage regulator body, the voltage regulating knob is provided with a sliding contact that is in sliding contact with each adjustable coil, a plurality of turns of fixed coils that are not in contact with the sliding contacts are wound on the annular iron core, one end of the fixed coil is connected to one end of the adjustable coil according to polarity, the coil between the other end of the fixed coil and the sliding contact constitutes a primary coil, and a low-voltage, high-current secondary coil is wound on the annular iron core.
[0007] The technical effects of the present invention are: it simplifies the structure of the existing large current generator, is smaller in size, lighter in weight, and more convenient to carry; it has a larger current adjustment range, lower cost, and can meet diverse usage and testing requirements.
[0008] advantage: 1. Compared with the conventional high current generator composed of an auto-voltage regulator and a current-boosting transformer, it is smaller in size, lighter in weight, and easier to move; 2. Its primary coil and secondary coil are isolated from each other, and the output voltage is within the human body safety voltage range, making it safer to use; 3. On the basis of the original adjustable coil of the autotransformer, a fixed coil is added and connected in series with the original adjustable coil. By adjusting the voltage regulating knob to change the number of turns of the primary coil, the secondary current can be adjusted, which is more convenient to operate.
[0009] 4. It can obtain a larger secondary side induced current, a wider current adjustment range, and can also achieve stepless current adjustment. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 This is a circuit diagram of an embodiment of the present invention; Figure 2 This is a three-dimensional structural diagram of embodiment 1 of the present invention; Figure 3 This is a three-dimensional structural diagram of embodiment 2 of the present invention. DETAILED DESCRIPTION
[0011] Example 1, as Figure 1 、 Figure 2 As shown, it includes an autovoltage regulator body 1, an annular iron core 2 is provided on the autovoltage regulator body 1, a plurality of turns of adjustable coils 3 are wound on the annular iron core 2, a voltage regulating knob 4 is rotatably mounted on the autovoltage regulator body 1, the voltage regulating knob 4 is provided with a sliding contact 5 that is in sliding contact with each adjustable coil 3, a plurality of turns of fixed coils 6 that are not in contact with the sliding contacts 5 are wound on the annular iron core 2, one end of the fixed coil 6 is connected to one end of the adjustable coil 3 according to polarity, and the coil between the other end of the fixed coil 6 and the sliding contact 5 constitutes a primary coil, and a low-voltage, high-current secondary coil 7 is wound on the annular iron core 2.
[0012] The adjustable coil 3 is wound circumferentially in a single layer on the outside of the entire annular iron core 2. The fixed coil 6 is located outside one end of the adjustable coil 3 and is wound around the outside of the adjustable coil 3 and the annular iron core 2. An insulating layer 8 is provided between the fixed coil 6 and the adjustable coil 3 for phase insulation isolation. The low-voltage and high-current secondary coil 7 is located at the position of the fixed coil 6 and is wound around the outside of the fixed coil 6, the adjustable coil 3 and the annular iron core 2 to prevent the low-voltage and high-current secondary coil 7 from affecting the sliding contact cooperation between the sliding contact 5 and the adjustable coil 5.
[0013] The low-voltage, high-current secondary coil 7 is a turn of thick wire wound around the outside of the fixed coil 6 . The outside of the low-voltage, high-current secondary coil 7 is wrapped with an insulating jacket 71 that is insulated and isolated from the fixed coil 6 .
[0014] The section of the adjustable coil 3 covered by the fixed coil 6 is incompatible with the sliding contact 5 and thus constitutes a portion of the fixed coil 6. To maintain the adjustable range of the primary coil, the number of turns of the later-wound fixed coil 6 needs to be reduced to meet the required turns ratio of the effective number of turns of the adjustable coil 3 (the number of turns of the adjustable coil 3 that can engage the sliding contact) to the effective number of turns of the fixed coil 6 (the number of turns of the later-wound fixed coil 6 plus the number of turns of the adjustable coil 3 that cannot engage the sliding contact 5).
[0015] This high current generator is a modification of the existing autovoltage regulator. Since the fixed coil 6 is wrapped around the original adjustable coil 3, it covers a portion of the adjustable coil 3. The covered portion of the adjustable coil 3 where it mates with the sliding contact 5 requires proper insulation treatment.
[0016] Example 2, as Figure 3 As shown, the difference from Example 1 is that the adjustable coil 3 is wound in a single layer circumferentially on the outside of most of the surface of the annular core 2, the fixed coil 6 is wound in multiple layers circumferentially on the outside of the other small part of the surface of the annular core 2 outside the adjustable coil 3, and the low-voltage and high-current secondary coil 7 is located in the position of the fixed coil 6 and is wound on the outside of the fixed coil 6 and the annular core 2 to avoid affecting the cooperation between the sliding contact 5 and the adjustable coil 3.
[0017] This high current generator is not a modification of an existing autocoupler voltage regulator. Its adjustable coil 3 and fixed coil 6 are respectively wound at different positions on the annular iron core 2. The fixed coil 6 does not cover the adjustable coil 3, does not affect the sliding contact and cooperation between the sliding contact 5 and the adjustable coil 3, and does not waste the effective number of turns of the adjustable coil 3.
[0018] The autovoltage regulator body 1 is provided with a first terminal 11 and a second terminal 12 connected to the two ends of the fixed coil 6 via wires respectively. One end of the adjustable coil 3 is connected to the first terminal 11 via a wire according to polarity. The autovoltage regulator body 1 is provided with a third terminal 13 connected to the sliding contact 5 via a wire. The third terminal 13 and the second terminal 12 constitute the primary terminal.
[0019] The autovoltage regulator body 1 is provided with two output terminals 14 and 15 connected to the two ends of the low-voltage and high-current secondary coil 7 respectively, forming secondary terminal terminals.
[0020] Design and working principle: To meet the experimental requirements for high secondary current output, the secondary coil consists of a thick, high-current-carrying wire wrapped around the transformer core. The primary coil is connected to a 220V power frequency voltage. By adjusting the contact position between the sliding contact and the adjustable coil using the voltage adjustment knob, the number of energized turns in the primary coil can be changed. This, in turn, also changes the induced voltage in the secondary coil, thereby adjusting the secondary voltage by adjusting the number of turns in the primary coil. For a given secondary coil resistance, a higher secondary output voltage results in a higher output current.
[0021] Select the secondary coil according to the required current. In the experiment, the cross-sectional area S of the secondary coil wire is 30 mm², the length L is 6 m, and the maximum current that can pass is 150 A. According to the resistance calculation formula R = ρL / S The secondary conductor self-resistance, or the resistance in the loop, is 3.4 mΩ. This resistance is the self-resistance of the secondary conductor and the primary resistance in the secondary loop. (A copper conductor with a cross-sectional area of 30 mm² can withstand the long-term, stable flow of 150 A current, ensuring that the conductor does not overheat and melt or the insulation fails during the experiment.) The purpose of adding several turns of fixed coil to the primary adjustable coil of the autovoltage regulator is to make the secondary voltage adjustable within a certain range, and thus the secondary current adjustable. Let n be the number of turns of the adjustable coil and n1 be the number of turns of the fixed coil. When the input voltage is constant at 220 V AC, the more turns of coil connected to the primary, the smaller the voltage induced by the thick wire on the secondary, that is, the smaller the secondary current. Therefore, the maximum secondary current I 2max When only the fixed coil is working on the primary side, it is: I 2max =U1 / (n1×R) in R The secondary wire self-resistance is determined when the number of turns of the fixed coil is determined. When the number of turns of the primary adjustable coil connected to the loop is increased, the secondary current decreases. When all the adjustable coils are connected, the secondary current reaches the minimum value i 2max , the expression is: I 2min =U1 / [(n+n1)×R)] It can be seen that the range in which the secondary current can be changed is limited by the number of turns of the primary adjustable coil connected to the loop. The adjustment range of the number of turns of the primary coil determines the range of change of the secondary current.
[0022] For example, if the maximum secondary current is 150A, i.e., i2 = 150A and U2 = 0.51V, then n' = U1 / U2 ≈ 432 turns. Therefore, the number of additional turns of the series-connected fixed coil is 432. The total number of turns, N, equals n + n'. When all 300 turns of the adjustable coil are connected to the primary, the secondary current is: I2 = U1 / (N × R) ≈ 88.40A. In this case, the secondary current ranges from 88.4A to 150A.
[0023] If the fixed coil is wound outside the adjustable coil, so that part of the adjustable coil cannot contact the sliding contact, the original entire adjustable coil can no longer be used as the number of turns of the adjustable coil. n still represents the number of turns of the original adjustable coil, but n' no longer represents the number of turns of the wound fixed coil, but represents the number of turns connected to the primary circuit, including the number of turns of the wound fixed coil n. c and the number of turns n of the adjustable coil covered by the fixed coil b , n a Indicates the number of turns of the original transformer coil that is not covered and can still be changed through contacts to determine whether it is connected to the primary side.
[0024] If n c Unknown, let n1=n b =n c As the independent variable, the maximum secondary current I 2max =U1 / (n1×R), minimum current I 2min = U1 / [(n + n1) × R]. Assuming the fixed coil covers half of the adjustable coil and leaves the original coil uncovered, the effective turns of the variable coil are 150 and 300, respectively. When the fixed coil covers half of the adjustable coil, the number of turns of the fixed coil wound around the outer portion of the adjustable coil is 432 - 150 = 282.
Claims
1. An adjustable high current generator based on an auto-voltage regulator, comprising an auto-voltage regulator body (1), an annular iron core (2) provided on the auto-voltage regulator body (1), a plurality of turns of adjustable coils (3) wound on the annular iron core (2), a voltage regulating knob (4) rotatably mounted on the auto-voltage regulator body (1), and a sliding contact (5) provided on the voltage regulating knob (4) for sliding contact with each adjustable coil (3), characterized in that: A plurality of turns of a fixed coil (6) which does not contact the sliding contact (5) are wound around the annular core (2). One end of the fixed coil (6) is connected to one end of the adjustable coil (3) according to polarity. The other end of the fixed coil (6) and the coil between the sliding contact (5) constitute a primary coil. A low-voltage, high-current secondary coil (7) is wound around the annular core (2).
2. The adjustable high current generator based on the auto-voltage regulator according to claim 1, characterized in that The adjustable coil (3) is wound in a single layer circumferentially around the outside of the entire annular core (2); the fixed coil (6) is located outside one end of the adjustable coil (3) and is wound around the adjustable coil (3) and the outside of the annular core (2); an insulating layer (8) is provided between the fixed coil (6) and the adjustable coil (3) for phase insulation isolation; and the low-voltage, high-current secondary coil (7) is located at the position of the fixed coil (6) and is wound around the outside of the fixed coil (6), the adjustable coil (3) and the annular core (2).
3. The adjustable high current generator based on the auto-voltage regulator according to claim 2, characterized in that The low-voltage, high-current secondary coil (7) is a turn of thick wire wound around the outside of the fixed coil (6), and the outside of the low-voltage, high-current secondary coil (7) is wrapped with an insulating jacket (71) that is insulated and isolated from the fixed coil (6).
4. The adjustable high current generator based on the auto-voltage regulator according to claim 1, characterized in that The adjustable coil (3) is wound in a single circumferential layer around the outside of most of the surface of the annular core (2); the fixed coil (6) is wound in multiple circumferential layers around the outside of a small portion of the surface of the annular core (2) outside the adjustable coil (3); and the low-voltage, high-current secondary coil (7) is located at the position of the fixed coil (6) and is wound around the outside of the fixed coil (6) and the annular core (2).
5. The adjustable high current generator based on the auto-voltage regulator according to claim 4, characterized in that The low-voltage, high-current secondary coil (7) is a turn of thick wire wound around the outside of the fixed coil (6), and the outside of the low-voltage, high-current secondary coil (7) is wrapped with an insulating jacket (71) that is insulated and isolated from the fixed coil (6).
6. The adjustable high current generator based on the auto-voltage regulator according to claim 4, characterized in that The auto-voltage regulator body (1) is provided with a first terminal (11) and a second terminal (12) connected to both ends of the fixed coil (6) through wires, one end of the adjustable coil (3) is connected to the first terminal (11) through a wire according to polarity, and the auto-voltage regulator body (1) is provided with a third terminal (13) connected to the sliding contact (5) through a wire, and the third terminal (13) and the second terminal (12) constitute a primary terminal.
7. The adjustable high current generator based on the auto-voltage regulator according to claim 4, characterized in that The auto-voltage regulator body (1) is provided with two output connection terminals (14, 15) respectively connected to the two ends of the low-voltage, high-current secondary coil (7), constituting secondary connection terminals.