The function of the current transducer is generally sampling, that is, the current value in the circuit under test is converted into a voltage value by electromagnetic induction or resistance, and then converted into a digital signal by a special analog-to-digital converter for analysis and processing, and the core controller can be The detected signal adjusts the conduction level of the FET, thereby changing the current value in the controlled circuit.
Working principle
The current transducer is based on the two basic principles of Hall magnetic balance principle (closed loop) and Hall direct measurement (open loop).
1. The principle of the open-loop current transducer: Hall Open Loop Current Sensor For Welding Machine the magnetic flux generated by the primary current IP is concentrated in the magnetic circuit by the high-quality magnetic core, the Hall element is fixed in a small air gap, and the magnetic flux is linearly detected, and the Hall device After the output Hall voltage is processed by a special circuit, the secondary side outputs a follow-up output voltage consistent with the primary side waveform, and this voltage can accurately reflect the change of the primary current.
0-10V Closed Loop Hall Effect AC Current Transducer
2. The magnetic balance type current transducer is also called a compensation type transducer, that is, the magnetic field generated by the main circuit measured current Ip at the collecting magnetic ring is compensated by a secondary coil, and the magnetic field generated by the current is compensated, so that the Hall device is in the detection zero. The working state of the magnetic flux.
The specific working process of the magnetic balance current transducer is: when a current flows through the main circuit, the magnetic field generated on the wire is concentrated by the collecting ring and sensed on the Hall device, and the generated signal output is used to drive the corresponding power tube and Turn it on to obtain a compensation current Is. This current then generates a magnetic field through a multi-turn winding that is exactly opposite to the magnetic field produced by the current being measured, thereby compensating for the original magnetic field and gradually reducing the output of the Hall device. When the magnetic field generated by multiplying Ip and the number of turns is equal, Is no longer increases. At this time, the Hall device acts to indicate zero flux, which can be balanced by Is. Any change in the measured current will destroy this balance. Once the magnetic field is out of balance, the Hall device has a signal output. Immediately after power amplification, a corresponding current flows through the secondary winding to compensate for the unbalanced magnetic field. From the imbalance of the magnetic field to the rebalancing, the time required is theoretically less than 1 μs, which is a process of dynamic equilibrium.
