Hall current sensor based on the magnetic balance Hall principle, according to the Hall effect principle, from the control current end of the Hall element into the current Ic, and in the Hall element plane normal direction to apply magnetic induction intensity of B magnetic field, then perpendicular to the current and magnetic field direction (that is, between the Hall output end), will produce a potential VH, called Hall potential. Its magnitude is proportional to the control current I.

       1, the basic principle of Hall current sensor

       Hall device is a kind of magneto-electric conversion device made of semiconductor material. If a control current IC is passed through the input, when a magnetic field B passes through the magnetic surface of the device, the Hall potential VH appears at the output.

       The magnitude of the Hall potential VH is proportional to the product of the control current IC and the magnetic flux density B, i.e. VH=KHICBsinΘ

       Hall current sensor is made according to the Hall effect principle, the ampere law is applied, that is, a magnetic field is generated around the current carrying conductor, and the Hall device is used to measure this magnetic field. Therefore, the non-contact measurement of current is possible.

       2, the detection principle of Hall current sensor

       Because the magnetic circuit has a good linear relationship with the output of Hall device, the output voltage signal U0 of Hall device can indirectly reflect the size of the measured current I1, that is, I1∝B1∝U0

       We calibrate U0 to be equal to 50mV or 100mV when the measured current I1 is rated. This creates a Hall direct detection (no amplification) current sensor.

       3. Compensation principle of Hall current sensor

       There is a measured current I1 in the main loop of the primary side, which will generate a magnetic flux Φ1, and the magnetic flux Φ2 generated by the current I2 passing through the secondary side compensation coil will be compensated to maintain a magnetic balance state, and the Hall device will always be in the role of detecting zero magnetic flux. So it is called Hall magnetic compensation current sensor. This advanced principle mode is better than the direct detection principle mode, the outstanding advantages are fast response time and high measurement accuracy, especially suitable for small current detection.

       Know: Φ1=Φ2, I1N1=I2N2, I2=NI/N2·I1

       When the compensating current I2 flows through the measuring resistance RM, it is converted into a voltage at both ends of RM. Used as a sensor to measure voltage U0: U0=I2RM

       According to the Hall magnetic compensation principle, the current sensor with rated input range from ~ series is made.

       Because the magnetic compensation current sensor must wind tens of thousands of turns of compensation coil on the magnetic ring, the cost increases. Secondly, the working current consumption also increases correspondingly; However, it has the advantages of high precision and fast response, which are incomparable to direct detection.