The principle of fluxgate current sensor
Fluxgate current sensor
The fluxgate current sensor uses a high-permeability magnetic core to generate a fluxgate signal under the excitation of an internal alternating power supply. After signal sampling, filtering, and amplification, it outputs a current signal that is proportional to the primary current.
Three-ring fluxgate current sensor
Winding 1 is a DC zero flux detector. Winding 2, together with the inverter and the DC bias detection resistor, forms an excitation flux compensation circuit. Winding 3 forms the detection winding of the magnetic integrator and also serves as an AC zero flux detector. A secondary compensation current flows through the secondary winding to cancel the magnetic field generated by the measured current on the primary side, thereby achieving accurate measurement.
The principle of Hall current sensors
Open-loop Hall current sensor
The magnetic flux generated by the primary current is concentrated in the magnetic core and detected by the Hall element at the air gap where the Hall element is located, and a voltage signal is output. After being processed by the amplification circuit, a standard voltage signal is output at the sensor output terminal. This voltage signal accurately reflects the change of the primary current.
Closed-loop Hall current sensor
The magnetic flux generated by the primary current is concentrated in the magnetic core and detected by the Hall element at the air gap, which outputs a voltage signal. This signal is amplified and generates a secondary current, causing the magnetic flux generated by the secondary coil to be opposite in direction and equal in magnitude to the primary magnetic flux. The secondary current accurately and proportionally reflects the change in the primary current.
The principle of fluxgate and Hall voltage sensor
Fluxgate voltage sensor
The fluxgate voltage sensor utilizes the alternating saturation characteristics of a high-permeability magnetic core under alternating magnetic field excitation to quickly modulate the current signal generated by the primary side voltage to the secondary coil through the equal ampere-turn principle, so that the output current of the secondary coil can accurately follow the changes in the primary side voltage signal.
Closed-loop Hall voltage sensor
The primary voltage is converted into a primary current through the load resistor, and the resulting magnetic flux balances the magnetic flux generated by the current amplified by the Hall voltage through the secondary coil. The secondary current accurately reflects the change in the primary voltage.