Unidirectional current detection device based on electromagnetic principle

Abstract

The invention provides a unidirectional current detection device based on an electromagnetic principle, which comprises a magnetic conductive frame, a permanent magnet, a magnetic conductive boss, a rotating shaft, reset springs and an execution mechanism, and is characterized in that the rotatable permanent magnet is arranged at a gap of the magnetic conductive frame, two ends of the permanent magnet are respectively connected with two sides of the gap through the reset springs, and under the action of the two reset springs, the magnetic conductive boss is driven to rotate; the permanent magnet and the magnetic conductive frame form a closed loop; the main circuit vertically passes through a loop formed by the permanent magnet and the magnetic conductive frame; the execution mechanism is driven by rotation of the rotating shaft and / or the permanent magnet. Current in a main circuit is utilized to induce a magnetic field in the magnetic conductive frame, the permanent magnet is driven to enable the notch of the magnetic conductive frame to be closed or opened, and the rotation action of the permanent magnet serves as driving force of the executing mechanism. The method can accurately and timely detect and identify the reverse fault current of the DC power distribution system, adopts a passive design, is not interfered by external signals, and is high in action reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of direct current power distribution, in particular to a unidirectional current detection device for a direct current power distribution system. BACKGROUND

[0002] At present, direct current power distribution networks are widely used in power supply systems. Compared with alternating current systems, direct current systems do not have natural zero points, and it is more difficult to break the direct current system. Therefore, a safe and reliable current detection device is needed to quickly cut off the short-circuit current when the loop fails, and to prevent misoperation of the current detection device when the main loop current is below the action current of the current detection device, thereby ensuring the safe and reliable operation of the direct current power supply system. For example, in a direct current traction power supply network, the power supply is a diode rectifier, which outputs unidirectional direct current when working normally, and generates reverse fault current when a fault occurs inside the rectifier.

[0003] The patent application with the application number CN202010516480.2 discloses a wide current band power transmission line self-powered current detection system and method, which includes a current detection device and a power taking device arranged on the power transmission line. The current detection device is used for primary side current detection, and the power taking device provides power for the current detection device. The detection system realizes accurate current detection in a large fluctuation range and real-time power supply of the active circuit module. The key parameter configuration of the compensation excitation current is combined with the information transmission of the inductive power taking device and the current detection device to make the taking energy magnetic core always work in the linear region. However, the current detection system has a complex structure and poor action reliability.

[0004] The patent application with the application number CN202310423751.3 discloses a current detection circuit and device. The current signal of the bus to be detected is finally converted into a second voltage signal through a detection resistor, a conversion module and a conversion resistor. The jump signal of the second voltage signal is detected by a difference detection module, and a corresponding third voltage signal is output based on the jump signal. The jump signal of the detection voltage is further used to detect the current. The current detection circuit realizes the detection of the current under the condition of low-voltage power supply such as integrated chip or on-chip integrated circuit, thereby expanding the application range of the current detection technology. However, the current detection system has a complex structure and poor action reliability.

[0005] At present, most current detection devices use the scheme of shunt + electric quantity transmitter, which has the disadvantages of poor reliability, low current detection accuracy and the need for external power supply. SUMMARY

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a unidirectional current detection device for DC power distribution systems. This device utilizes the current in the DC main circuit to induce a magnetic field in a magnetically conductive frame, driving a permanent magnet located at a gap in the frame to close or open the gap. The rotational motion of the permanent magnet during this process serves as the driving force for the actuator. This invention can accurately and promptly detect and identify reverse current in DC power distribution systems. Furthermore, it employs a passive design, requiring no external power supply, is unaffected by external signal interference, exhibits high reliability, can identify reverse fault currents, and possesses high current detection accuracy.

[0007] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0008] A unidirectional current detection device based on electromagnetic principles, characterized in that it includes a magnetic frame, a permanent magnet, a magnetic boss, a rotating shaft, a return spring, and an actuator. The magnetically conductive frame has a notch, and a magnetically conductive protrusion is provided at each end of the notch. The permanent magnet is located at the notch of the magnetically conductive frame, mounted on a rotating shaft, and can rotate around the axis of the rotating shaft. The two ends of the permanent magnet are connected to the magnetically conductive protrusions on both sides of the notch through return springs. Under the action of the two return springs, the permanent magnet and the magnetically conductive frame form a closed loop. The main circuit passes perpendicularly through the loop formed by the permanent magnet and the magnetically conductive frame. The actuator is driven by the rotation of a rotating shaft and / or a permanent magnet to disconnect the DC power distribution system circuit.

[0009] Furthermore, the actuator is a rotary pressure rod and a limit switch; the rotary pressure rod is fixedly installed on the rotating shaft, and the limit switch is mounted on the magnetic guide boss and located on the side of the rotary pressure rod. When the permanent magnet rotates, it can drive the rotary pressure rod to move the limit switch.

[0010] Furthermore, the magnetic guide protrusions at the notch of the magnetic guide frame have one side located at the upper left and the other side located at the lower right, with the two being staggered.

[0011] The magnetic guide frame contains magnetic guide bosses within the notch, with one boss located at the upper left and the other at the lower right. When the permanent magnet is in a vertical position, it contacts the magnetic guide bosses on both sides and is held vertical by the elastic force of the return spring. When the permanent magnet rotates under electromagnetic force, it disengages from the magnetic guide bosses.

[0012] The rotating pressure rod is fixedly connected to the rotating shaft and can rotate with the rotating shaft. The limit switch is located on the side of the rotating pressure rod. When the rotating pressure rod rotates, the limit switch can be pressed down to activate the limit switch.

[0013] Furthermore, the notch is located on the upper or lower edge of the magnetically conductive frame, and the magnetic field direction of the permanent magnet is horizontal.

[0014] Furthermore, the direction of the magnetic field of the permanent magnet can be reversed.

[0015] Furthermore, the magnetically conductive frame is composed of multiple pieces of magnetically conductive material spliced ​​together.

[0016] Furthermore, the magnetically conductive frame is composed of multiple layers of magnetically conductive materials stacked horizontally.

[0017] Furthermore, the magnetic frame is composed of multiple layers of 0.5mm or 1mm magnetic sheets stacked together.

[0018] Furthermore, the rotating pressure bar is made of insulating material, preferably an epoxy resin bar.

[0019] Furthermore, the return spring is a compression spring.

[0020] A rotatable permanent magnet is installed at the notch of the magnetic frame of the current detection device. When a forward current flows through the main circuit, an electromagnetic attraction is generated between the magnetic protrusion and the permanent magnet, allowing the permanent magnet to be reliably held in its initial position, and the current detection device will not activate. When a reverse current flows through the main circuit, an electromagnetic repulsion is generated between the magnetic protrusion and the permanent magnet. Overcoming the force of the reset spring, the permanent magnet rotates, and an activation signal is emitted through the rotation of the rotating shaft, or an activation electrical signal is emitted externally through a limit switch installed in the current detection device. The unidirectional DC current detection device of this invention can identify normal operating current and fault current, achieving accurate and reliable protection for the DC power supply system.

[0021] This current detection device adopts a passive design, does not require an external power supply, is not affected by external signal interference, and has high operational reliability. Attached Figure Description

[0022] Figure 1 This is a state diagram of the unidirectional current detection device based on electromagnetic principles described in this invention under normal main circuit current conditions. The reference direction of the main circuit current is perpendicular to the paper and outwards.

[0023] Figure 2 This is a state diagram of the unidirectional current detection device based on electromagnetic principles described in this invention when the main circuit current is reversed. At this time, the reference direction of the main circuit current is perpendicular to the paper and inwards.

[0024] Figure 3 This is a schematic diagram of the action mechanism of an embodiment of the unidirectional current detection device based on electromagnetic principles described in this invention.

[0025] Figure 4This is a state diagram of the actuator of the unidirectional current detection device based on electromagnetic principles according to the present invention, under normal main circuit current conditions.

[0026] Figure 5 This is a state diagram of the actuator of the unidirectional current detection device based on electromagnetic principles according to the present invention, under the condition of reverse current in the main circuit.

[0027] Explanation of reference numerals in the attached diagram: 1. Magnetic guide frame, 2. Permanent magnet, 3. Magnetic guide boss, 4. Rotating shaft, 5. Return spring, 6. Rotating pressure rod, 7. Limit switch, 8. Main circuit. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0029] like Figure 1 As shown, the unidirectional current detection device based on electromagnetic principles of the present invention is characterized by comprising a magnetically conductive frame 1, a permanent magnet 2, a magnetically conductive boss 3, a rotating shaft 4, a return spring 5, a rotating pressure rod 6, and a limit switch 7. The magnetically conductive frame 1 has a notch, and a magnetically conductive boss 3 is provided at each end of the notch. One magnetically conductive boss 3 is located at the upper left; the other magnetically conductive boss 3 is located at the lower right, and the two are staggered. The notch is located on the upper or lower frame of the magnetically conductive frame 1; the magnetic field direction of the permanent magnet 2 is horizontal; the magnetic field direction of the permanent magnet 2 is reasonably interchanged left and right according to the position of the notch.

[0030] The permanent magnet 2 is located at the notch of the magnetic guide frame 1, mounted on a rotating shaft 4, and can rotate around the axis of the rotating shaft 4. Both ends of the permanent magnet 2 are connected to the magnetic guide protrusions 3 on both sides of the notch via return springs 5. Under the action of the two return springs 5, the permanent magnet 2 and the magnetic guide frame 1 form a closed loop; the main circuit 8 passes perpendicularly through the loop formed by the permanent magnet 2 and the magnetic guide frame 1. The actuator is driven by the rotation of the rotating shaft 4 and / or the permanent magnet 2 to disconnect the DC power distribution system circuit.

[0031] When a positive current flows through the main circuit 8, such as Figure 1 As shown, the direction of the main circuit current is perpendicular to the paper and outwards. A counterclockwise induced magnetic field is formed in the loop formed by the magnetic frame 1 and the permanent magnet 2. The direction of the induced magnetic field is the same as the direction of the magnetic field of the permanent magnet 2, so that the permanent magnet 2 and the magnetic protrusions 3 on the left and right sides generate an electromagnetic attraction, keeping the permanent magnet 2 in a vertical position and preventing the permanent magnet 2 from malfunctioning.

[0032] When reverse current flows through the main circuit 8, such as Figure 2As shown, the main circuit current direction is perpendicular to the paper and inwards. The clockwise induced magnetic field formed in the loop composed of the magnetic frame 1 and the permanent magnet 2 is opposite to the magnetic field direction of the permanent magnet 2, causing electromagnetic repulsion between the permanent magnet 2 and the magnetic protrusions 3 on both sides. When the reverse current is less than the rated current, the electromagnetic repulsion between the permanent magnet 2 and the magnetic protrusions 3 on both sides is less than the spring traction force provided by the return spring 5, keeping the permanent magnet 2 in a vertical position and preventing malfunction. When the reverse current is greater than the rated current, the electromagnetic repulsion between the permanent magnet 2 and the magnetic protrusions 3 on both sides is greater than the spring counter-traction force provided by the return spring 5, causing the permanent magnet 2 to start rotating, thereby driving the actuator to start operating.

[0033] like Figure 3 , Figure 4 The diagram shows a specific embodiment of the actuator, which includes a rotary pressure rod 6 and a limit switch 7. The rotary pressure rod 6 is fixedly mounted on a rotating shaft 4, and the limit switch 7 is mounted on a magnetic guide boss 3 and located on the side of the rotary pressure rod 6. Figure 5 As shown, when the permanent magnet 2 rotates, it can drive the rotating pressure rod 6 to rotate, which can move or press down the limit switch 7, causing the limit switch 7 to operate.

[0034] Furthermore, the magnetic frame 1 can be composed of multiple pieces of magnetically conductive material spliced ​​together, or of multiple layers of magnetically conductive material horizontally stacked, for example, using 0.5mm or 1mm magnetically conductive sheets horizontally stacked, which facilitates processing and manufacturing. The rotating pressure rod 6 can be made of insulating materials such as epoxy resin rods. The return spring 5 can be a spring-like spring such as a compression spring.

[0035] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A unidirectional current detection device based on electromagnetic principles, characterized in that, Includes a magnetic guide frame (1), a permanent magnet (2), a magnetic guide boss (3), a rotating shaft (4), a return spring (5), a rotating pressure rod (6), and a limit switch (7); The magnetic frame (1) has a notch, and a magnetic protrusion (3) is provided at each end of the notch. The permanent magnet (2) is located at the notch of the magnetic frame (1), mounted on a rotating shaft (4), and can rotate around the axis of the rotating shaft (4). The two ends of the permanent magnet (2) are connected to the magnetic protrusions (3) on both sides of the notch by a return spring (5). Under the action of the two return springs (5), the permanent magnet (2) and the magnetic frame (1) form a closed loop. The main circuit (8) passes vertically through the loop formed by the permanent magnet (2) and the magnetic frame (1). The actuator is driven by the rotation of a rotating shaft (4) and / or a permanent magnet (2) to disconnect the DC power distribution system circuit.

2. The unidirectional current detection device based on electromagnetic principles according to claim 1, characterized in that, The actuator is a rotary pressure rod (6) and a limit switch (7). The rotary pressure rod (6) is fixedly installed on the rotating shaft (4), and the limit switch (7) is installed on the magnetic guide boss (3) and located on the side of the rotary pressure rod (6). When the permanent magnet (2) rotates, it can drive the rotary pressure rod (6) to move the limit switch (7).

3. The unidirectional current detection device based on electromagnetic principles according to claim 1, characterized in that, The magnetic guide protrusion (3) at the notch of the magnetic guide frame (1) has one magnetic guide protrusion (3) on the upper left and the other magnetic guide protrusion (3) on the lower right, and the two are staggered.

4. The unidirectional current detection device based on electromagnetic principles according to claim 1, characterized in that, The notch is located on the upper or lower edge of the magnetic frame (1); the magnetic field direction of the permanent magnet (2) is horizontal.

5. The unidirectional current detection device based on electromagnetic principles according to claim 1, characterized in that, The magnetic field direction of the permanent magnet (2) can be reversed.

6. The unidirectional current detection device based on electromagnetic principles according to claim 1, characterized in that, The magnetic frame (1) is made of multiple pieces of magnetic material spliced ​​together.

7. The unidirectional current detection device based on electromagnetic principles according to claim 1, characterized in that, The magnetic frame (1) is made of multiple layers of magnetically conductive materials stacked horizontally.

8. The unidirectional current detection device based on electromagnetic principles according to claim 7, characterized in that, The magnetic frame (1) is made of multiple layers of magnetic sheets of 0.5mm or 1mm.

9. The unidirectional current detection device based on electromagnetic principles according to claim 1, characterized in that, The rotating pressure bar (6) is made of insulating material, preferably epoxy resin.

10. The unidirectional current detection device based on electromagnetic principles according to claim 1, characterized in that, The return spring (5) is a compression spring.

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