A current transformer coil same-name end detection circuit

Abstract

The present invention relates to the technical field of transformer coil same-name end detection, and specifically to a current transformer coil same-name end detection circuit, which is used to detect the same-name end of the current transformer coil. The detection circuit includes a single-chip microcomputer for detecting the current transformer coil, a detection end and a detection end arranged on the single-chip microcomputer and used to connect the head and tail ends of the secondary side of the current transformer coil, an alternating current end and an alternating current end arranged on the single-chip microcomputer and used to output alternating current, a same-phase proportional amplifier circuit connected to the detection end, a power supply circuit, a display and surrounding supporting circuits respectively connected to the single-chip microcomputer, and the output end of the same-phase proportional amplifier circuit is connected to the detection end, and the input end is connected to one end of the secondary side of the current transformer coil. The present invention can detect the same-name end of the current transformer coil, has high detection efficiency, low cost, and greatly improves the convenience and safety of the current transformer when in use.

Description

Technical Field

[0001] The invention relates to the technical field of transformer coil same-name end detection, and in particular to a current transformer coil same-name end detection circuit. Background Art

[0002] Transformers can convert high voltage into low voltage and high current into low current, so as to realize the standardization and miniaturization of measuring instruments, protection equipment and automatic control equipment. At the same time, transformers can also be used to isolate high voltage systems to ensure the safety of people and equipment.

[0003] When using existing mutual inductors, the polarity of the secondary side of the mutual inductor is often reversed, which leads to errors in the relay protection circuit and inaccurate measurement data of the metering circuit during subsequent use, and even endangers personal safety. Therefore, the mutual inductor coil needs to be detected after winding. The existing detection method of the same name end is relatively cumbersome, and has low detection efficiency, complex equipment structure and high cost. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a current transformer coil same-name end detection circuit, which can detect the same-name ends of the current transformer coil, has high detection efficiency and low cost, and greatly improves the convenience and safety of the current transformer when used.

[0005] The technical solution adopted by the present invention is to provide a current transformer coil same-name terminal detection circuit for detecting the same-name terminals of the current transformer coil, the detection circuit comprises a single-chip microcomputer for detecting the current transformer coil, a detection terminal and a detection terminal arranged on the single-chip microcomputer and used to connect the head and tail ends of the secondary side of the current transformer coil, an alternating current terminal and an alternating current terminal arranged on the single-chip microcomputer and used to output alternating current, an in-phase proportional amplifier circuit connected to the detection terminal, a power supply circuit respectively connected to the single-chip microcomputer, a display and surrounding supporting circuits, the output terminal of the in-phase proportional amplifier circuit is connected to the detection terminal, and the input terminal is connected to one end of the secondary side of the current transformer coil; On this basis, during detection, the primary side of the current transformer coil is connected in series between one end of the AC power and the other end of the AC power, or after connecting a cable between one end of the AC power and the other end of the AC power, the current transformer coil is put on the cable, and then the head and tail ends of the secondary side of the current transformer coil are respectively connected to the input end of the in-phase proportional amplifier circuit and the detection ends. The electrical signal induced by the secondary side of the current transformer coil is amplified by the in-phase proportional amplifier circuit and then transmitted to the single-chip microcomputer through the detection end. The single-chip microcomputer judges the electrical signal input at the detection end, and the judgment result is displayed on the display.

[0006] The in-phase proportional amplification circuit includes an operational amplifier, a current limiting resistor 1, a current limiting resistor 2, a current limiting resistor 3, a current limiting resistor 4, a current limiting resistor 5 and a rectifier capacitor. The current limiting resistor 1 and the current limiting resistor 2 are connected in series between the inverting input terminal and the signal output terminal of the operational amplifier. The inverting input terminal of the operational amplifier is grounded after passing through the current limiting resistor 3. The non-phase input terminal of the operational amplifier is connected in parallel with the current limiting resistor 4 and the rectifier capacitor. The current limiting resistor 4 is grounded. The current limiting resistor 5 is arranged between the signal output terminal of the operational amplifier and the single-chip microcomputer. One end of the head and tail ends of the secondary side of the current transformer coil is connected to the input end of the rectifier capacitor.

[0007] The first current limiting resistor is a variable resistor.

[0008] The single chip microcomputer model is STM32F103.

[0009] The process of the single chip microcomputer determining the electrical signal input at one end of the detection is specifically as follows: When the electrical signal inputted at one end of the detection is a positive signal, it is determined that the secondary side of the current transformer coil is connected to the same end as the primary side output current end of the current transformer coil at the detection end, and the other end of the secondary side of the current transformer coil is the same end as the primary side input current end of the current transformer coil; When the electrical signal input at one end of the detection is not a positive signal, it is determined that the secondary side of the current transformer coil is connected to the same end as the primary side input current end of the current transformer coil at one end of the detection, and the other end of the secondary side of the current transformer coil is the same end as the primary side output current end of the current transformer coil.

[0010] The beneficial effect of the present invention is that it provides a current transformer coil same-name end detection circuit, which can quickly detect the same-name ends of the current transformer coil, has simple operation, high detection accuracy, low cost, and greatly improves the convenience and safety of the transformer use. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a circuit schematic diagram of the present invention; In the attached figure, U1 is a single chip microcomputer, U2 is an operational amplifier, R1 is a current limiting resistor one, R2 is a current limiting resistor two, R3 is a current limiting resistor three, R4 is a current limiting resistor four, R5 is a current limiting resistor five, and C1 is a rectifier capacitor. DETAILED DESCRIPTION

[0012] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0013] like Figure 1 As shown, the present invention provides a current transformer coil same-name terminal detection circuit, which is used to detect the same-name terminals of the current transformer coil. The detection circuit includes a single-chip microcomputer U1 for detecting the current transformer coil, a detection terminal in+ and a detection terminal in- which are arranged on the single-chip microcomputer U1 and are used to connect the head and tail ends of the secondary side of the current transformer coil, an alternating current terminal out+ and an alternating current terminal out- which are arranged on the single-chip microcomputer U1 and are used to output alternating current, a common-phase proportional amplifier circuit connected to the detection terminal in+, a power supply circuit respectively connected to the single-chip microcomputer U1, a display and surrounding supporting circuits, wherein the output terminal of the common-phase proportional amplifier circuit is connected to the detection terminal in+, and the input terminal is connected to the current transformer. One end of the secondary side of the coil is connected; on this basis, during detection, the primary side of the current transformer coil is connected in series between one end out+ of the AC power and the second end out- of the AC power, or after connecting a cable between one end out+ of the AC power and the second end out- of the AC power, the current transformer coil is put on the cable, and then the head and tail ends of the secondary side of the current transformer coil are respectively connected to the input end of the in-phase proportional amplifier circuit and the detection terminal in-. The electrical signal induced by the secondary side of the current transformer coil is amplified by the in-phase proportional amplifier circuit and then transmitted to the single-chip microcomputer U1 through the detection terminal in+. The single-chip microcomputer U1 determines the electrical signal input at the detection terminal in+, and the determination result is displayed on the display.

[0014] The single-chip computer U1 can generate alternating current through a built-in inverter. The alternating current is transmitted from one end out+ of the alternating current to the other end out- of the alternating current as the signal source sensed by the current transformer. The detection end in+ and the detection end in- of the single-chip computer U1 serve as the access ends of the secondary side head and tail ends of the current transformer coil. The in-phase proportional amplifier circuit can amplify the electrical signal in-phase proportionally. The output signal and the input signal have the same phase, so that the input signal received by the single-chip computer U1 is more stable and the judgment is more accurate.

[0015] The detection operation process specifically includes connecting the primary coil head and tail ends of the current transformer in series between the AC power terminal out+ and the AC power terminal out- according to the current direction, connecting the secondary coil head and tail ends of the current transformer to the input end of the in-phase proportional amplifier circuit and the detection terminal in-, and the AC power of the microcontroller U1 passes through the AC power terminal out+, the primary coil of the current transformer, and the AC power terminal out- in turn. The secondary coil of the current transformer induces an electrical signal, which is amplified by the in-phase proportional amplifier circuit. The microcontroller U1 receives the amplified electrical signal with the help of the detection terminal in+, and the microcontroller U1 performs in-phase terminal judgment through the electrical signal, and the judgment result is displayed on the display.

[0016] The through-type current transformer has only one secondary coil. When testing, first connect the AC end out+ and the AC end out- through a cable, and then put the through-type current transformer on the cable. The rest is the same as above.

[0017] like Figure 1 As shown, the in-phase proportional amplifier circuit includes an operational amplifier U2, a current limiting resistor R1, a current limiting resistor R2, a current limiting resistor R3, a current limiting resistor R4, a current limiting resistor R5 and a rectifier capacitor C1. The current limiting resistor R1 and the current limiting resistor R2 are connected in series between the inverting input terminal and the signal output terminal of the operational amplifier U2. The inverting input terminal of the operational amplifier U2 is grounded after passing through the current limiting resistor R3. The non-phase input terminal of the operational amplifier U2 is connected in parallel with the current limiting resistor R4 and the rectifier capacitor C1. The current limiting resistor R4 is grounded. The current limiting resistor R5 is arranged between the signal output terminal of the operational amplifier U2 and the single-chip computer U1. One end of the head and tail ends of the secondary side of the current transformer coil is connected to the input end of the rectifier capacitor C1.

[0018] The in-phase proportional amplifier circuit inputs the input signal from the in-phase input terminal of the operational amplifier U2, and the output signal has the same phase as the input signal. C1 and R4 form a differential circuit to form a sharp pulse signal, which is amplified by the secondary signal amplifier circuit. The microcontroller U1 determines the same-name terminal through the received amplified electrical signal. It has a simple structure, low cost, high determination accuracy, and easy operation.

[0019] like Figure 1 As shown, the current limiting resistor R1 is a variable resistor.

[0020] The resistor R1 is used as the feedback resistor of the operational amplifier. By changing the resistance value of the current limiting resistor R1, the amplification factor and gain of the operational amplifier U2 can be adjusted to achieve signal amplification and attenuation to adapt to different current transformer coils under test and improve the versatility of the device.

[0021] like Figure 1 As shown, the single chip microcomputer U1 is of model STM32F103.

[0022] The single-chip microcomputer U1 adopts any one of the STM32F103 series, which has low cost and integrates multiple peripheral functions such as timer, CAN, ADC, SPI, I2C, USB, UART, etc., meeting the use requirements of the present invention.

[0023] like Figure 1As shown, the process of the single-chip computer U1 judging the electrical signal input at the detection end in+ is specifically that, when the electrical signal input at the detection end in+ is a positive signal, it is determined that the secondary side of the current transformer coil is connected to the same-name end of the primary-side output current end of the current transformer coil of the detection end in+, and the other end of the secondary side of the current transformer coil is the same-name end of the primary-side input current end of the current transformer coil; when the electrical signal input at the detection end in+ is not a positive signal, it is determined that the secondary side of the current transformer coil is connected to the same-name end of the primary-side input current end of the current transformer coil of the detection end in+, and the other end of the secondary side of the current transformer coil is the same-name end of the primary-side output current end of the current transformer coil.

[0024] The determination method has the advantages of being simple and fast. Taking whether it is a positive signal as the determination condition, the same-name terminal on the secondary side of the current transformer coil can be determined quickly and accurately, further reducing costs and making detection simpler.

Claims

1. A current transformer coil same-name end detection circuit, used for detecting the same-name ends of current transformer coils, characterized in that: The detection circuit comprises a single chip computer (U1) for detecting a current transformer coil, a detection end (in+) and a detection end (in-) arranged on the single chip computer (U1) and used to connect the head and tail ends of the secondary side of the current transformer coil, an alternating current end (out+) and an alternating current end (out-) arranged on the single chip computer (U1) and used to output alternating current, a common-phase proportional amplifier circuit connected to the detection end (in+), a power supply circuit, a display and surrounding supporting circuits respectively connected to the single chip computer (U1), wherein the output end of the common-phase proportional amplifier circuit is connected to the detection end (in+), and the input end is connected to one end of the secondary side of the current transformer coil; On this basis, during detection, the primary side of the current transformer coil is connected in series between one end (out+) and the second end (out-) of the AC power, or after connecting a cable between one end (out+) and the second end (out-) of the AC power, the current transformer coil is put on the cable, and then the head and tail ends of the secondary side of the current transformer coil are respectively connected to the input end of the in-phase proportional amplifier circuit and the detection terminal (in-). The electrical signal induced by the secondary side of the current transformer coil is amplified by the in-phase proportional amplifier circuit and then transmitted to the single-chip computer (U1) through the detection terminal (in+). The single-chip computer (U1) determines the electrical signal input to the detection terminal (in+), and the determination result is displayed on the display.

2. A current transformer coil same-name end detection circuit according to claim 1, characterized in that: The in-phase proportional amplification circuit comprises an operational amplifier (U2), a current limiting resistor 1 (R1), a current limiting resistor 2 (R2), a current limiting resistor 3 (R3), a current limiting resistor 4 (R4), a current limiting resistor 5 (R5) and a rectifier capacitor (C1); the current limiting resistor 1 (R1) and the current limiting resistor 2 (R2) are connected in series between the inverting input terminal and the signal output terminal of the operational amplifier (U2); the inverting input terminal of the operational amplifier (U2) is grounded after passing through the current limiting resistor 3 (R3); the non-inverting input terminal of the operational amplifier (U2) is connected in parallel with the current limiting resistor 4 (R4) and the rectifier capacitor (C1); the current limiting resistor 4 (R4) is grounded; the current limiting resistor 5 (R5) is arranged between the signal output terminal of the operational amplifier (U2) and the single-chip computer (U1); and one end of the head and tail ends of the secondary side of the current transformer coil is connected to the input end of the rectifier capacitor (C1).

3. A current transformer coil same-name end detection circuit according to claim 2, characterized in that: The current limiting resistor 1 (R1) is a variable resistor.

4. A current transformer coil same-name end detection circuit according to claim 1, characterized in that: The model of the single chip microcomputer (U1) is STM32F103.

5. A current transformer coil same-name end detection circuit according to claim 1, characterized in that: The process of the single chip microcomputer (U1) determining the electrical signal inputted from the detection end (in+) is specifically as follows: When the electrical signal inputted at one detection end (in+) is a positive signal, it is determined that the secondary side of the current transformer coil is connected to the same end of the primary output current end of the current transformer coil connected to the detection end (in+), and the other end of the secondary side of the current transformer coil is the same end of the primary input current end of the current transformer coil; When the electrical signal input at one detection end (in+) is not a positive signal, it is determined that the secondary side of the current transformer coil is connected to the same end of the primary input current end of the current transformer coil at the detection end (in+), and the other end of the secondary side of the current transformer coil is the same end of the primary output current end of the current transformer coil.

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