A high current shunt

Abstract

The application discloses a large-current shunt, which comprises a base body and a sampling area arranged on the base body; an isolation area is arranged on the base body, and the isolation area divides the sampling area into a first sampling area and a second sampling area; the resistance values of the first sampling area and the second sampling area are greater than that of the sampling area; first sampling contacts are arranged on both sides of the first sampling area; second sampling contacts are arranged on both sides of the second sampling area; the first sampling contacts obtain first sampling signals, and the second sampling contacts obtain second sampling signals; the first sampling signals and the second sampling signals are added to obtain a large-voltage signal, and the large-voltage signal is used for current calculation; the original sampling area is divided into the first sampling area and the second sampling area through the arrangement of the isolation area, voltage signals of the first sampling area and the second sampling area are sampled respectively, a large-voltage signal is obtained, the large-voltage signal is used for current calculation, and more accurate measured current is obtained.

Description

Technical Field

[0001] This invention relates to the field of electronic instrumentation technology, and in particular to a high-current shunt. Background Technology

[0002] A shunt is used to measure direct current. It is made based on the principle that a voltage is generated across a resistor when a direct current passes through it. A shunt is essentially a resistor with a very small resistance. When a direct current flows through it, a voltage drop is generated, which is displayed on a DC ammeter. A DC ammeter is actually a voltmeter, and the ammeter and shunt are used together. Manganese-copper shunts are mainly used for voltage and current sampling in various instruments, especially in electronic energy meters. The voltage generated by the voltage drop across the manganese-copper resistive element of the shunt powers the energy meter for measurement and sampling.

[0003] When current flows through the shunt, a voltage is sampled across the manganin terminals to determine the current magnitude. For accurate measurements, the sampling voltage needs to be increased as much as possible, which requires increasing the resistance of the manganin. However, increasing the resistance leads to heat generation, affecting measurement accuracy.

[0004] For example, Chinese patent CN201810282319.6 discloses a manganese copper shunt and an electronic energy meter. It includes a sampling resistor, current sampling lines, and a pin insertion device. The sampling resistor includes a manganese copper sheet with a slot penetrating its center. A first connection point and a second connection point are respectively located on either side of the slot. The current sampling lines include a first sampling line and a second sampling line. The first end of the first sampling line is connected to the first connection point, and the first end of the second sampling line is connected to the second connection point. The projection of the spirally twisted first and second sampling lines onto the manganese copper sheet divides the slot into a first region and a second region. The pin insertion device includes a housing with a first pin insertion channel and a second pin insertion channel. The second end of the first sampling line passes through the first pin insertion channel, and the second end of the second sampling line passes through the second pin insertion channel. The area of ​​the third region formed between the first and second pin insertion channels is equal to the absolute value of the difference between the area of ​​the first region and the area of ​​the second region. During use, it is only necessary to control the third region to be parallel to the plane where the manganese copper sheet is located, so that the induced electromotive force generated by the first and second regions cancels out the induced electromotive force generated by the third region, thereby eliminating the interference caused by the alternating magnetic field. This application eliminates sampling errors by eliminating the interference caused by the alternating magnetic field, thereby improving the measurement accuracy from the side; however, the obtained sampling signal is still small, resulting in low accuracy of the calculated current. Summary of the Invention

[0005] This invention primarily addresses the problem of poor current measurement accuracy caused by the small voltage signal sampled by the shunt in existing technologies; it provides a high-current shunt that doubles the sampled signal while maintaining the same heat generation, thereby improving measurement accuracy.

[0006] The above-mentioned technical problems of the present invention are mainly solved by the following technical solution: a high-current shunt includes a substrate and a sampling area disposed on the substrate; an isolation area is disposed on the substrate, the isolation area dividing the sampling area into a first sampling area and a second sampling area; the resistance values ​​of the first sampling area and the second sampling area are greater than the resistance value of the sampling area; a first sampling contact is disposed on both sides of the first sampling area; a second sampling contact is disposed on both sides of the second sampling area; the first sampling contact acquires a first sampling signal, and the second sampling contact acquires a second sampling signal; the first sampling signal and the second sampling signal are added together to obtain a high-voltage signal, and the high-voltage signal is used for current calculation. By setting up an isolation zone, the original sampling area is divided into a first sampling area and a second sampling area. After current is split, it flows through the first and second sampling areas, keeping the voltages at both ends of the first and second sampling areas the same as those of the original sampling area. This ensures that the heat generated in the first and second sampling areas is the same as that in the original sampling area. After sampling the voltage signals of the first and second sampling areas respectively, a large voltage signal is obtained. The obtained large voltage signal is twice as high as the signal obtained when sampling the original sampling area alone. Using the large voltage signal for current calculation, a more accurate measured current is obtained.

[0007] Preferably, the sampling area is a manganin resistor. Using manganin as the resistor for sampling provides better stability and accuracy.

[0008] Preferably, the isolation region is an elongated through-hole that penetrates the substrate. This process is simple and effectively separates the manganese-copper resistors.

[0009] Preferably, the first sampling region and the second sampling region are connected in parallel, and the resistance of the first sampling region and the second sampling region are the same. Connecting the first sampling region and the second sampling region in parallel results in two identical voltage signals, thereby improving the sampling signal.

[0010] Preferably, the first sampling contact includes a first positive terminal on one side of the first sampling area and a first negative terminal on the other side of the first sampling area. The terminals are used to connect the wires, preventing wire breakage.

[0011] Preferably, the second sampling contact includes a second positive terminal on one side of the second sampling area and a second negative terminal on the other side of the second sampling area. The terminals are used for wire connection to prevent wire breakage.

[0012] Preferably, the first sampling contact further includes a reference terminal located on the side of the first positive terminal. The reference terminal diverts the meter's operating current, preventing it from affecting the measurement current and improving measurement accuracy.

[0013] Preferably, the substrate has two circular through holes along the current flow direction for fixing. Fixing the entire shunt through these circular through holes provides a more secure installation.

[0014] The beneficial effects of the present invention are: (1) By setting an isolation area, the original sampling area is divided into a first sampling area and a second sampling area. After the current is shunt, it flows through the first sampling area and the second sampling area, keeping the voltage at both ends of the first sampling area and the second sampling area the same as that of the original sampling area. This makes the heat generation of the first sampling area and the second sampling area the same as that of the original sampling area. After sampling the voltage signal of the first sampling area and the second sampling area respectively, a large voltage signal is obtained. The obtained large voltage signal is twice as high as the signal when the original sampling area is sampled alone. The large voltage signal is used to calculate the current and obtain a more accurate measurement current. (2) The sampling area is divided by using a long strip-shaped through hole. The process is simple and will not affect the original shunt substrate, which is convenient for production. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the shunt in an embodiment of the present invention.

[0016] In the figure: 1. Base; 2. Circular through hole; 3. Fixing groove; 4. First manganin resistor; 5. Second manganin resistor; 6. Reference terminal; 7. First negative terminal; 8. First positive terminal; 9. Second negative terminal; 10. Second positive terminal; 11. Isolation zone. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the invention.

[0018] Example: A high-current shunt includes a substrate 1 and a sampling area disposed on the substrate. Compared to traditional manganese copper shunts that only have one manganese copper resistor on the substrate for current sampling, this invention has an isolation area 11 on the substrate. The isolation area divides the sampling area into a first sampling area and a second sampling area. The first and second sampling areas are formed by dividing the cross-sectional area of ​​the original complete manganese copper resistor in half, creating a first manganese copper resistor 4 and a second manganese copper resistor 5 with the same cross-sectional area. According to the resistance calculation formula R = ρL / S, where ρ is resistivity, L is the length of the conductor, and S is the cross-sectional area of ​​the conductor, the resistance of the divided first and second manganese copper resistors is doubled compared to the original complete manganese copper resistor. Figure 1 As shown, the current flows from right to left, and after being shunt, it flows through the first and second manganese copper resistors, maintaining the same voltage drop across both resistors. Therefore, the heat generated by the first and second resistors is the same as that generated by the original manganese copper resistors. The resulting large voltage signal, obtained by adding the detection signals, is twice the size of the original signal. To improve current measurement, the invention provides first sampling contacts on both sides of the first sampling area and second sampling contacts on both sides of the second sampling area. The first sampling contacts acquire the first sampling signal, and the second sampling contacts acquire the second sampling signal. A wire connects the first and second sampling contacts, transmitting the sampling signals to the metering chip. The metering chip adds the first and second sampling signals to obtain the large voltage signal, which is then used for current calculation, resulting in more accurate current measurement.

[0019] The isolation zone set in this invention is an elongated through-hole that penetrates the substrate. The elongated shape can be elliptical, rectangular, or any through-hole that can divide a complete manganese copper resistor into two manganese copper resistors of the same size through the cross section.

[0020] After being separated by the isolation zone, the first and second manganese copper resistors have equal resistance values ​​and are connected in parallel when connected to the measurement circuit, thus achieving current shunting and equal detection voltage.

[0021] The first sampling contact includes a first positive terminal 8 located on one side of the first sampling area and a first negative terminal 7 located on the other side of the first sampling area. The second sampling contact includes a second positive terminal 10 located on one side of the second sampling area and a second negative terminal 9 located on the other side of the second sampling area. The first positive terminal, the first negative terminal, the second positive terminal, and the second negative terminal are all bent metal sheets, one end of which is fixedly installed on the substrate, and the other end is fixedly connected to the wire, through which the sampling signal is transmitted to the metering chip.

[0022] The first sampling contact also includes a reference terminal 6 located on the side of the first positive terminal. The reason for setting up the reference terminal is that when the power supply current of the meter and the sampling current pass through the positive terminal, a voltage drop will be generated. This voltage drop will be superimposed on the sampling signal, affecting the detection accuracy. At the same time, the voltage drop of the terminal will also change with temperature, thus easily generating a large measurement error. By setting up the reference terminal, the sampling circuit is distinguished from the power supply circuit of the meter, preventing the power supply current of the meter from generating a voltage drop on the sampling terminal, reducing errors, and improving measurement accuracy.

[0023] The substrate has two circular through holes 2 for fixing along the direction of current flow, and multiple fixing grooves 3 for snap-fit ​​fixing on the upper and lower sides. The substrate is fixed and installed through the circular through holes and fixing grooves.

[0024] This invention divides the original sampling area into a first sampling area and a second sampling area by setting an isolation zone. After current is split, it flows through the first and second sampling areas, keeping the voltage at both ends of the first and second sampling areas the same as that of the original sampling area. This ensures that the heat generated in the first and second sampling areas is the same as that in the original sampling area. After sampling the voltage signal of the first and second sampling areas respectively, a large voltage signal is obtained. The obtained large voltage signal is twice as high as the signal obtained when the original sampling area is sampled alone. Using the large voltage signal for current calculation, a more accurate measured current is obtained.

[0025] For example, in a traditional manganese copper shunt, the manganese copper resistance is R, the current flowing through it is I, and the detected voltage signal is U. The metering chip calculates the current using the voltage signal U and the known manganese copper resistance value R. Because the voltage signal U is very small, errors are prone to occur. This invention, however, divides the manganese copper resistor into two parallel manganese copper resistors with a resistance of 2R. The voltage signals from these two resistors are sampled separately, and their sums yield a voltage signal of 2U. Based on the power calculation P = U... 2 / R, the heat generated by the two split manganese copper resistors is the same as the original heat generated, but the obtained sampling signal is doubled. Using 2U for current measurement calculation can obtain a more accurate measurement value.

[0026] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A high-current shunt, characterized in that, include: The substrate and the sampling area set on the substrate; An isolation zone is provided on the substrate, which divides the sampling area into a first sampling area and a second sampling area. The resistance values ​​of the first and second sampling areas are greater than the resistance value of the sampling area. First sampling contacts are provided on both sides of the first sampling area; Second sampling contacts are provided on both sides of the second sampling area; The first sampling contact acquires a first sampling signal, and the second sampling contact acquires a second sampling signal; The first and second sampled signals are added together to obtain a large voltage signal, which is then used for current calculation. The isolation zone is a long, narrow through-hole that penetrates the substrate; The first sampling contact includes a first positive terminal on one side of the first sampling area and a first negative terminal on the other side of the first sampling area. The second sampling contact includes a second positive terminal located on one side of the second sampling area and a second negative terminal located on the other side of the second sampling area.

2. A high-current shunt according to claim 1, characterized in that, The sampling area is a manganese copper resistor.

3. A high-current shunt according to claim 1, characterized in that, The isolation area is a long, narrow through-hole that penetrates the substrate. The shape of the through-hole can be elliptical, rectangular, or any shape that can divide the complete sampling area into a first sampling area and a second sampling area of ​​the same size through a cross-section.

4. A high-current shunt according to claim 2, characterized in that, The first sampling area and the second sampling area are connected in parallel, and the resistance of the first sampling area and the second sampling area are the same.

5. A high-current shunt according to claim 1, 2, or 3, characterized in that, The first positive terminal, the first negative terminal, the second positive terminal, and the second negative terminal are all bent metal sheets. One end is fixedly installed on the base, and the other end is fixedly connected to the wire, which transmits the sampling signal to the metering chip.

6. A high-current shunt according to claim 5, characterized in that, The first sampling contact also includes a reference terminal disposed on the side of the first positive terminal.

7. A high-current shunt according to claim 1, characterized in that, The substrate has two circular through holes along the direction of current flow for fixing.

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