Current transformer and current transformer system
By combining a magnetic core and a DC sensing resistor into a current transformer system, the problems of insufficient applicability of current sensing devices in fast protection and miniaturized modular power supplies in the prior art are solved, and fast response and low cost current sensing are achieved.
Patent Information
- Application Number
- CN202422860377.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-11-22
AI Technical Summary
Existing current sensing devices have delayed response or cannot detect DC signals in fast protection applications, and cannot meet the application requirements of miniaturized modular power supplies or power controllers.
Design a current transformer and current transformer system that combines a magnetic core, magnetic core frame pins, transformer input winding, and transformer coil. By combining the transformer input winding with a DC sensing resistor, it is possible to simultaneously detect DC and AC currents or pulse currents, and expand the current testing range without changing the transformer size.
It achieves fast-response current sensing, can directly drive actuators, avoid circuit damage, and meets the design requirements of miniaturization and low cost. It is suitable for modular power supplies or power controllers.
Smart Images
Figure CN223551788U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of current transformer technology, and in particular to a current transformer and a current transformer system. Background Technology
[0002] Currently, the main types of devices for detecting current are as follows:
[0003] 1. Resistive Current Measurement: Resistive current sensing is a direct method for measuring current, simple and with good linearity. However, resistors consume energy, so the resistance value is generally small. The obtained signal needs to be amplified, compared with a reference, or processed before being applied to the actuator. The process of current detection reaching the actuator has a delay of tens of microseconds to hundreds of milliseconds depending on the processing circuit. For applications requiring rapid protection, such as high-current short-circuit protection, circuit damage often occurs during this delay. Especially in cases where the line is short-circuited first and then connected, the protection delay is even longer, making it difficult to meet the requirements of rapid protection.
[0004] 2. Magnetic induction type:
[0005] o Current transformer: It measures current through the principle of electromagnetic induction and is suitable for high current measurement.
[0006] Current transformers require AC or pulse signals to flow through them; they cannot detect DC signals. Currently, there is a modified DC current transformer, but it requires additional internal circuitry, resulting in a complex structure and large size, which does not meet the requirements for miniaturized modular power supplies or power controllers. Furthermore, the size of the transformer increases proportionally with the increase in current.
[0007] o. Rogowski coil: Utilizes changes in magnetic field to measure current, suitable for high-frequency current measurement.
[0008] A Rogowski coil (air-core coil) requires a current loop to pass through the coil and also requires an AC signal or pulse signal; otherwise, an effective electromotive force cannot be generated, and it cannot be detected for DC signals.
[0009] Hall effect devices:
[0010] It has advantages such as high accuracy, fast response speed, non-contact measurement, linear characteristics, and strong anti-interference ability. However, its disadvantages include: low sensitivity, significant temperature drift, high sensitivity to magnetic field amplitude and direction, high cost, and large size, which cannot meet the application requirements of miniaturized modular power supplies or power controllers.
[0011] 3. Transistor type:
[0012] o RDS(ON): Drain-to-source on-resistance, suitable for direct measurement. The on-resistance is integrated inside the MOSFET, eliminating the need for an additional resistor. However, this method shares the same advantages and disadvantages as resistive measurements.
[0013] 4. Other methods: such as thermoelectric methods, which are suitable for high-frequency and low-frequency current measurement and are performed using thermocouples.
[0014] Thermoelectric method: Suitable for high-frequency and low-frequency current measurement with a wide range, but requires calibration to ensure accuracy. It is also unsuitable for use as a component in circuits. In reality, there are no instances of this thermistor being used as a component within circuits for extended periods.
[0015] Therefore, we propose a current transformer and a current transformer system. Utility Model Content
[0016] In view of the shortcomings of the prior art, this utility model provides a current transformer and a current transformer system to solve the technical problems in the prior art.
[0017] To achieve the above objectives, this utility model provides the following technical solution:
[0018] A current transformer and a current transformer system are disclosed, comprising a current transformer and the current transformer system thereof. The current transformer includes a magnetic core, magnetic core bobbin pins, a transformer input winding, and a transformer coil. The magnetic core is sleeved on the magnetic core bobbin pins, the transformer coil is wrapped around the magnetic core bobbin pins, and the transformer input winding is wrapped around the transformer coil.
[0019] A current inductance system includes a current inductance component (CTS). The CTS has pins connected to an external pulse signal output terminal and pins connected to an external pulse signal input terminal. A variable resistor RS is connected to the pulse signal input terminal. The CTS also has pins connected to an external DC signal output terminal.
[0020] As a preferred technical solution of this utility model, the mutual inductance component includes an iron core and a one-sided winding and a secondary winding.
[0021] As a preferred embodiment of this utility model, the input winding of the current transformer is in contact with the inner wall of the magnetic core.
[0022] As a preferred technical solution of this utility model, the input winding of the current transformer is attached to the surface of the DC sensing resistor.
[0023] This utility model provides a current transformer and a current transformer system, which have the following features:
[0024] Beneficial effects:
[0025] (1) It can detect DC current and AC current or pulse current at the same time; it can react quickly to large pulse current, and the signal can be directly applied to the actuator to make it act and quickly protect the circuit.
[0026] (2) Small size: The device is designed based on the size of the miniaturized current transformer used in the current module power supply or power controller.
[0027] (3) With the current transformer volume unchanged, the test capability is improved, which can be applied to larger current applications and provide the required signal.
[0028] (4) To achieve the goal of small size and low cost, and to solve the contradiction between size, cost and speed that cannot be overcome in the current design. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of the front structure of the current transformer in this utility model;
[0030] Figure 2 This is a schematic diagram of the back structure of the current transformer in this utility model;
[0031] Figure 3 This is a side sectional view of the current transformer in this utility model;
[0032] Figure 4 This is the circuit diagram of the current transformer in this utility model;
[0033] Figure 5 This is a partial circuit diagram of the circuit transformer in this utility model.
[0034] In the diagram: 1. Magnetic core skeleton pin, 2. Magnetic core, 3. Current transformer input winding, 4. Current transformer coil, 5. DC detection resistor. Detailed Implementation
[0035] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0036] Therefore, a feature pointed out in this specification is used to describe one feature of one embodiment of the present invention, and does not imply that every embodiment of the present invention must have the described feature. Furthermore, it should be noted that this specification describes many features. Although certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.
[0037] The principle and structure of this utility model will be described in detail below with reference to the accompanying drawings and embodiments:
[0038] refer to Figure 1-5 A current transformer and a current transformer system, comprising a current transformer and the current transformer system thereof, wherein the current transformer comprises a magnetic core 2, a magnetic core frame pin 1, a transformer input winding 3 and a transformer coil 4, the magnetic core 2 being sleeved on the magnetic core frame pin 1, the transformer coil 4 being wrapped around the magnetic core frame pin 1, and the transformer input winding 3 being wrapped around the transformer coil 4;
[0039] The current transformer system includes a current transformer component (CTS). Pins 3 and 4 of the current transformer component CTS are connected to external pulse signal output terminals, and pins 1 and 2 of the current transformer component CTS are connected to external pulse signal input terminals. A variable resistor RS is connected to the pulse signal input terminals, and pins 1 and 2 of the current transformer component CTS are also connected to external DC signal output terminals.
[0040] The mutual inductance component includes an iron core, a one-sided winding, and a secondary winding.
[0041] Among them, the input winding 3 of the current transformer is attached to the inner wall of the magnetic core 2.
[0042] The input winding 3 of the current transformer is attached to the surface of the DC sensing resistor 5 (RS).
[0043] Specifically, the current transformer and the non-inductive DC resistor are combined into a single sampling device: when the loop current is DC, the DC resistor is used to detect the DC current, and most of the current flows through the DC resistor, while the remaining small portion of the current flows through the current transformer, ensuring that the transformer will not saturate; when the pulse current exceeds the set requirement, the transformer operates, and the generated signal directly acts on the operating components, which can directly trigger the circuit protection.
[0044] Furthermore, the impedance ratio of the transformer primary winding RP and the current sensing resistor RS should be appropriate: it should be ensured that the maximum current detected before system protection does not saturate the transformer. For example, if the maximum current detected by the transformer is 10A and the maximum current in the system is 100A, then ZRP:ZRS = 9:1. For a given transformer, only an appropriate sampling resistor needs to be matched.
[0045] Furthermore, in cases where DC detection current may cause transformer saturation, a small air gap can be appropriately added to the transformer core to enhance its anti-saturation capability.
[0046] Furthermore, the detected DC signal is corrected to obtain the correct value. For example, if the detected signal is 9V and ZRP:ZRS = 9:1, then the signal should be amplified by 10:9 to achieve the true DC signal of 10V.
[0047] The advantages of this invention are as follows:
[0048] (1) Any existing current transformer can expand its AC current or pulse current testing range by matching an appropriate current sensing resistor according to the impedance of its primary winding, without changing the size of the transformer core. This greatly reduces costs and the space requirements of the components in the product design.
[0049] (2) The presence of the current transformer can detect the rapidly changing current in a timely manner and provide the signal level for direct drive of the actuator, so that the line protection action is timely and rapid, and the circuit is not damaged. The presence of the DC resistor overcomes the disadvantage that the current transformer cannot test the DC current. The combination of the two creates a new application form: it can be integrated into a single device or the above purpose can be achieved by connecting wires.
[0050] (3) This invention can be directly soldered to the printed circuit board without changing the original planar structure of the circuit board, bringing convenience to design upgrades.
[0051] (4) The present invention has outstanding advantages in situations where it is necessary to quickly trigger the protection circuit to avoid line failure caused by the delay of the processing circuit, but also to accurately measure the current.
[0052] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.
Claims
1. A current transformer and a current transformer system, comprising a current transformer and a current transformer system, characterized in that, The current transformer includes a magnetic core (2), a magnetic core bobbin pin (1), a transformer input winding (3), and a transformer coil (4). The magnetic core (2) is sleeved on the magnetic core bobbin pin (1), the transformer coil (4) is wrapped around the magnetic core bobbin pin (1), and the transformer input winding (3) is wrapped around the transformer coil (4). A current inductance system includes a current inductance component (CTS). Pins 3 and 4 of the current inductance component CTS are connected to external pulse signal output terminals, and pins 1 and 2 of the current inductance component CTS are connected to external pulse signal input terminals. A variable resistor RS is connected to the pulse signal input terminals, and pins 1 and 2 of the current inductance component CTS are also connected to external DC signal output terminals.
2. A current transformer and current transformer system according to claim 1, characterized in that, The mutual inductance assembly includes an iron core, a one-sided winding, and a secondary winding.
3. A current transformer and current transformer system according to claim 1, characterized in that, The input winding (3) of the transformer is in contact with the inner wall of the magnetic core (2).
4. A current transformer and current transformer system according to claim 1, characterized in that, The input winding (3) of the current transformer is attached to the surface of the DC sensing resistor (5).