Three-phase current sensor for new energy vehicles

Abstract

A three-phase current sensor for new energy vehicles comprises a shell and a circuit board, wherein the shell comprises a shell box and a shell cover, three copper busbar jacks are arranged in a concave cavity of the shell box, welding pins are arranged above the copper busbar jacks, a fisheye pin is arranged between two copper busbar jacks in the shell box, and the fisheye pin extends to the outside of the shell box, the circuit board is provided with a notch for installing a U-shaped block for shielding external magnetic field interference, the upper end of the U-shaped block is inserted into the notch and fixed with the shell box, the opening of the U-shaped block faces the left side of the shell box, the welding pin and the fisheye pin extend upward and are welded with the circuit board, three TMR chips are fixed at the lower end of the circuit board, three terminal blocks for grounding are welded and fixed at the lower end of the circuit board, each terminal block contacts the corresponding U-shaped block, three fixing nuts connected with the copper busbar are arranged on the outside of the shell box, a fixing part is arranged between each fixing nut, and a nut is arranged on the fixing part.

Description

Technical Field

[0001] The utility model relates to the technical field of sensors, and in particular to a three-phase current sensor for new energy vehicles. Background Art

[0002] The current detection of the three-phase copper busbar of the drive motor is an important function of the electronic control system. Its accuracy is related to the stability, reliability and driving comfort of the whole vehicle. At present, the use of Hall current sensors to test the three-phase current of the drive motor is the mainstream solution in the market. The current detection method of this solution has the characteristics of low loss, self-isolation and low cost. The Hall current sensor includes a magnetic core, a printed circuit board, a shell, and a Hall chip. The purpose of the magnetic core is to improve the accuracy of the current sensor by gathering the magnetic field. However, the Hall chip is highly sensitive to temperature. A large range of temperature changes will cause the output linearity of the Hall chip to deteriorate, resulting in a decrease in the accuracy of the Hall current sensor, and a large error between the measured current and the actual current. At present, the trend of high-voltage platforms for new energy vehicles is accelerating, and the current passing through the copper busbar is getting larger and larger, which leads to further increase in temperature. At present, the current sensor based on the Hall chip is increasingly difficult to meet the corresponding accuracy requirements. Summary of the invention

[0003] The purpose of the utility model is to provide a three-phase current sensor for new energy vehicles to address the shortcomings of the existing technology. This three-phase current sensor for new energy vehicles can improve the accuracy of large current detection of new energy vehicles and the consistency of measurement under high and low temperature conditions. It also has the characteristics of high small current resolution and strong anti-interference to stray magnetic fields.

[0004] The purpose of the utility model is achieved by adopting the following scheme: a three-phase current sensor for new energy vehicles, including a shell and a circuit board, the shell including a shell box and a shell cover, three copper bar jacks are arranged in the concave cavity of the shell box, welding pins are arranged above the copper bar jacks, a fisheye pin is arranged between two copper bar jacks in the shell box, the fisheye pin extends to the outside of the shell box, the circuit board is provided with a notch for installing a U-shaped block for shielding external magnetic field interference, the upper end of the U-shaped block is inserted into the notch and fixed with the shell box, the positioning plate and the limiting ribs arranged in the concave cavity of the shell box fix the U-shaped block, the opening of the U-shaped block faces the left side of the shell box, the welding pin and the fisheye pin face upward Extended and welded with the circuit board, the copper busbar jack passes through the gap between the U-shaped block and the circuit board, three TMR chips are fixed at the lower end of the circuit board, and each TMR chip is located between the openings of the U-shaped block. Three terminal blocks for grounding are welded and fixed at the lower end of the circuit board, and each terminal block contacts the corresponding U-shaped block to connect the U-shaped block with the circuit board, and three fixing nuts connected with the copper busbar are arranged on the outside of the shell box, a fixing part is arranged between each fixing nut, and a nut is arranged on the fixing part, the fisheye needle extends to one of the fixing parts and extends out of the shell box, and a through hole for the copper busbar to pass through is arranged on the shell cover, and the shell cover is fixed to the shell box after passing through the copper busbar jack.

[0005] The U-shaped block is made by stacking a plurality of silicon steel sheets.

[0006] The upper and lower end surfaces of the circuit board are perpendicular to the planes of the two end portions of the U-shaped block.

[0007] The wiring seat is a copper wiring seat, and the wiring seat is contacted and connected with the U-shaped block through a spring sheet.

[0008] The nut and the fisheye needle are an integral injection-molded structure, and a positioner is arranged in front of the fisheye needle.

[0009] The circuit board is provided with four notches for installing U-shaped blocks and through holes for soldering pins and fisheye pins to pass through.

[0010] A positioning column is arranged beside the welding needle.

[0011] The fixing nut and the nut are copper nuts, and the fisheye needle and the welding needle are both made of copper material.

[0012] The advantages of the utility model are: 1. The three-phase current sensor for new energy vehicles uses TMR chips instead of Hall chips as the sensing unit. Due to the high sensitivity and good temperature stability of the TMR chip, the sensor can achieve high-precision detection of large currents in the motor controller of new energy vehicles, avoiding the problem of low testing accuracy of the Hall current sensor under high current and high temperature conditions.

[0013] 2. U-shaped silicon steel sheet The U-shaped block not only shields the interference of the external magnetic field on the chip, but also gathers the magnetic field generated by large current. At the same time, the U-shaped block is composed of multiple silicon steel sheets stacked together, which can increase the resistance of the U-shaped block, reduce the influence of eddy current, and improve the performance of the U-shaped block.

[0014] 3. When current is passed through the U-shaped block, eddy currents will be generated. The greater the current and the higher the frequency, the greater the eddy currents will be. Eddy currents will generate magnetic fields and generate heat, causing the sensor temperature to rise, affecting the sensor accuracy. The copper terminal block grounds the U-shaped block, which can reduce the eddy currents generated by alternating current and improve measurement accuracy.

[0015] 4. The metal objects other than the U-shaped block, such as the fixing nut and the fisheye needle, used in the present invention are all made of non-magnetic copper, which can further reduce external magnetic field interference and improve the sensitivity of the sensor.

[0016] The utility model can improve the accuracy of large current detection of new energy vehicles and the consistency of measurement under high and low temperature conditions. It also has the characteristics of high small current resolution and strong resistance to stray magnetic fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the utility model.

[0018] Figure 2 It is a schematic diagram of the disassembly of each component of the utility model.

[0019] Figure 3 This is a schematic diagram of the structure of the housing and chip assembly of the utility model.

[0020] Figure 4 It is a schematic diagram of the external structure of the utility model.

[0021] Figure 5 This is a schematic diagram of the wiring socket structure in the utility model. DETAILED DESCRIPTION

[0022] like Figures 1 to 5As shown, a three-phase current sensor for new energy vehicles includes a housing 1 and a circuit board 11. The circuit board 11 is provided with four notches 11a for installing U-shaped blocks 12 and through holes 11b for passing soldering pins 9 and fisheye pins 4. The housing 1 includes a housing box 1-1 and a housing cover 1-2. Three copper bar sockets 14 are provided in the concave cavity 1-4 of the housing box 1-1. Soldering pins 9 are provided above the copper bar sockets 14. Fisheye pins 4 are provided between two copper bar sockets 14 of the housing box 1-1. The fisheye pins 4 extend to the outside of the housing box 1-1. The circuit board 11 is provided with a notch 11a for installing a U-shaped block 12 for shielding external magnetic field interference. The upper end of the U-shaped block 12 is inserted into the notch 11a and fixed to the housing box 1-1. The upper and lower end surfaces of the circuit board 11 are perpendicular to the planes of the two ends of the U-shaped block 12. The positioning plate 8 and the limiting rib 1a set in the concave cavity of the housing box 1-1 fix the U-shaped block 12, and the opening of the U-shaped block 12 faces the left side of the housing box 1-1. The U-shaped block 12 is made of multiple silicon steel sheets stacked together. The U-shaped block 12 formed by stacking multiple silicon steel sheets can reduce the eddy current generated by alternating current and improve the performance of the sensor. The welding needle 9 and the fisheye needle 4 extend upward to weld with the circuit board 11. A positioning column 7 is set next to the welding needle 9, and the positioning column 7 positions the circuit board 11. The copper busbar jack 14 passes through the gap between the U-shaped block 12 and the circuit board 11. Three TMR chips 13 are fixed at the lower end of the circuit board 11. Each TMR chip 13 is located between the openings of the U-shaped block. Three grounding terminals 10 are welded and fixed at the lower end of the circuit board 11. Each terminal 10 contacts the corresponding U-shaped block 12 to connect the U-shaped block 12 to the circuit board 11. The terminal 10 is a copper terminal. The terminal 10 is tightly contacted and connected with the U-shaped block 12 through a spring 10a. The terminal 10 can reduce the influence of the eddy current generated by the alternating current on the sensor. Three fixing nuts 2 connected to the copper busbar are arranged on the outer side of the housing box 1-1. A fixing part 1-3 is arranged between each fixing nut 2. A nut 5 is arranged on the fixing part 1-3. The fisheye needle 4 extends to one of the fixing parts 1-3 and extends out of the housing box 1-1. A through hole 6 for the copper busbar to pass through is arranged on the housing cover 1-2. The housing cover 1-2 is fixed to the housing box 1-1 after passing through the copper busbar jack 14. The nut 5 and the fisheye needle 4 are an integral injection molding structure, a positioner 3 is arranged in front of the fisheye needle 4, and the positioner 3 positions the copper bar. The fixing nut 2 and the nut 5 are copper nuts, and the fisheye needle 4 and the welding needle 9 are made of copper material. The components made of copper material can further block the interference of the external magnetic field.

[0023] After the chip assembly is installed in the shell 1-1, glue is poured into the shell 1-1 to fix the chip assembly to ensure the stability of the three-phase current sensor structure. After the chip assembly is fixed, the shell cover 1-2 and the shell 1-1 are assembled to improve the sealing of the entire three-phase current sensor.

[0024] The U-shaped block 12 in the three-phase current sensor for new energy vehicles can be made of different soft magnetic materials according to the usage, and the TMR chip can also be replaced with other chips according to the usage.

[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A three-phase current sensor for a new energy vehicle, comprising a housing (1) and a circuit board (11), characterized in that: The housing (1) comprises a housing box (1-1) and a housing cover (1-2); three copper busbar jacks (14) are arranged in a concave cavity (1-4) of the housing box (1-1); welding pins (9) are arranged above the copper busbar jacks (14); a fisheye pin (4) is arranged between two copper busbar jacks (14) of the housing box (1-1); the fisheye pin (4) extends to the outside of the housing box (1-1); and the circuit board (11) is provided with a device for installing and shielding external magnetic field interference. The U-shaped block (12) is provided with a notch (11a), the upper end of the U-shaped block (12) is inserted into the notch (11a) and then fixed to the housing box (1-1), the positioning plate (8) and the limiting rib (1a) arranged in the concave cavity of the housing box (1-1) fix the U-shaped block (12), the opening of the U-shaped block (12) faces the left side of the housing box (1-1), the soldering pin (9) and the fisheye pin (4) extend upward and are soldered to the circuit board (11), and the copper busbar socket (14) is provided with a notch (11a) and a notch (11a) of the U-shaped block (12), the upper end of the U-shaped block (12) is inserted into the notch (11a) and then fixed to the housing box (1-1), the positioning plate (8) and the limiting rib (1a) arranged in the concave cavity of the housing box (1-1) fix the U-shaped block (12), the opening of the U-shaped block (12) faces the left side of the housing box (1-1), the soldering pin (9) and the fisheye pin (4) extend upward and are soldered to the circuit board (11), and the copper busbar socket (14 ) passes through the gap between the U-shaped block (12) and the circuit board (11); three TMR chips (13) are fixed at the lower end of the circuit board (11); each TMR chip (13) is located between the openings of the U-shaped block; three wiring seats (10) for grounding are welded and fixed at the lower end of the circuit board (11); each wiring seat (10) contacts the corresponding U-shaped block (12) to connect the U-shaped block (12) and the circuit board (11); three fixing nuts (2) connected to the copper busbar are arranged on the outer side of the housing box (1-1); a fixing portion (1-3) is arranged between each fixing nut (2); a nut (5) is arranged on the fixing portion (1-3); the fisheye needle (4) extends to one of the fixing portions (1-3) and extends out of the housing box (1-1); a through hole (6) for the copper busbar to pass through is arranged on the housing cover (1-2); the housing cover (1-2) passes through the copper busbar jack (14) and is fixed to the housing box (1-1).

2. The three-phase current sensor for new energy vehicles according to claim 1 is characterized in that: The U-shaped block (12) is made by stacking a plurality of silicon steel sheets.

3. The three-phase current sensor for new energy vehicles according to claim 1 is characterized in that: The upper and lower end surfaces of the circuit board (11) are perpendicular to the planes of the two end portions of the U-shaped block (12).

4. The three-phase current sensor for new energy vehicles according to claim 1 is characterized in that: The wiring seat (10) is a copper wiring seat, and the wiring seat (10) is contact-connected with the U-shaped block (12) via a spring sheet (10a).

5. The three-phase current sensor for new energy vehicles according to claim 1 is characterized in that: The nut (5) and the fisheye needle (4) are an integral injection-molded structure, and a positioner (3) is arranged in front of the fisheye needle (4).

6. The three-phase current sensor for new energy vehicles according to claim 1, characterized in that: The circuit board (11) is provided with four notches (11a) for mounting U-shaped blocks (12) and through holes (11b) for soldering pins (9) and fisheye pins (4) to pass through.

7. The three-phase current sensor for new energy vehicles according to claim 1, characterized in that: A positioning column (7) is arranged next to the welding needle (9).

8. The three-phase current sensor for new energy vehicles according to claim 1, characterized in that: The fixing nut (2) and the nut (5) are copper nuts, and the fisheye needle (4) and the welding needle (9) are both made of copper material.

Images