In BMS application, accurate measurement of battery charge and discharge current is the most basic requirement. Because it is necessary to monitor and evaluate various states of the battery, such as SOC, SOH, etc., the sensor for DC current measurement needs to have the dual requirements of large range and ultra-high dynamic range.
In this case, the general hall open-loop hall, closed-loop principle can not meet the requirements. The current sensor based on the fluxgate principle launched by PAS technology has large dynamic measurement range, extremely low zero point and excellent temperature drift characteristics. It is very suitable for application in the field of battery charge and discharge.
In order to better adapt to the use of BMS integrators, fluxgate current sensors with RS-485 interface, Modbus RTU protocol and CANBUS interface are also introduced
Principle introduction:
Inject a low-frequency oscillation signal into a closed coil to make the magnetic core work in the state of alternating positive and negative saturation. The externally applied DC current will generate an additional magnetic field in the magnetic core. The magnetic field will offset the oscillation symmetrical waveform generated by the alternating positive and negative saturated magnetic core, so that the waveform is no longer symmetrical. Analyze it by MCU waveform, The magnitude and direction of DC current can be analyzed. Because the principle uses the magnetic characteristics of the magnetic core and the magnetic sensitive device is not a Hall component of semiconductor material, the sensor has more stable temperature characteristics than the hall principle. Moreover, because the magnetic sensitivity of the oscillation waveform is much higher than the hall principle, the current sensor using the fluxgate principle has high low current resolution, Thus, it has a higher dynamic range, that is, it can measure very small milliampere current and large hundred ampere kiloampere current.
