How to wire current sensor - Application of motor controller - [Weikewei]
How to wire the current sensor in the application of motor controllers in the electric vehicle industry? Due to fundamental differences in the design and use of motor controllers, low-speed vehicles typically use motor controllers to detect three-phase currents. B52 can be used, but there are certain differences in technical parameters and installation methods. B51 is widely used in low-speed vehicles and electric buses, mainly manifested in the following aspects. This type of sensor has a high cost-effectiveness and is a commonly used material in the market, but its overall reliability is not as good as other series. In addition, B51 and B52 are currently the application methods for household electric vehicles. The main reason is that the two series of current sensors have simple structures and do not require PCB processing circuits. All detection and processing are completely centralized in the Hall chip. The reliability of the chip is very high. We need a PCB to fix the Hall element and a magnetic ring to sense the magnetic field.
The above is a brief introduction to the use of current sensors in household electric vehicles.
1. Comparison and Structure of Current Sensors
According to the decomposition diagram above, although B51 is more widely used in the market than other products, there are approximately 20 electronic components on the PCB circuit. Each additional component will reduce the overall reliability of the current sensor. Relatively speaking, the B51 circuit is very simple, consisting only of Hall chips and magnetic cores. The structure is extremely simple and the reliability is greatly improved. In addition, after testing, it was found that the magnetic core and chip will only fail simultaneously when the high temperature reaches 125 ° C. However, if the temperature reaches 125 ℃, it is estimated that other components within the vehicle controller have partially malfunctioned, so the failure rate of this current sensor is very low.
Attention: Comparison between closed-loop current sensor, open-loop current sensor, and electric vehicle current sensor
2. When selecting and using current sensors, the following issues should be noted
Answer: It is necessary to pay attention to whether the size of the holes through the sensor can ensure that the wires can pass through. If measuring cables, it is necessary to pay attention to the maintenance of the product and whether the sensor is easy to disassemble after the cable head is completed. It is best to use copper bars, which are beautiful and easy to maintain and install;
B. Pay attention to whether the spatial structure meets the requirements;
C. When wiring, please pay attention to the exposed conductive parts of the terminal block to prevent ESD impact. Engineers with professional construction experience are required to perform wiring operations on the product. All connection wires for power supply, input, and output must be connected correctly and cannot be placed in the wrong position or reversed, otherwise it may damage the product.
D. The installation and use environment of the product should be free of conductive dust and corrosiveness
E. Pay attention to the wiring method, so that the tested conductor fills the sensor hole as much as possible. If it cannot be reached, please place the tested conductor in the middle and fix it, which can reduce the position error caused by shaking.
The above are the wiring suggestions and usage precautions provided by Weikewei's electrical engineers. If there are more topics in the future, Weikewei's professionals will have more in-depth communication and sharing with everyone.