A Hall effect device is a magnetoelectric conversion device made of semiconductor material. When a control current IC is applied to the input terminal, and a magnetic field B passes through the magnetic sensing surface of the device, a Hall potential VH appears at the output terminal. The magnitude of the Hall potential VH is proportional to the product of the control current IC and the magnetic flux density B. Hall current sensors are made based on the Hall effect principle, applying Ampere's law, which states that a magnetic field proportional to the current is generated around a current-carrying conductor, and the Hall effect device measures this magnetic field. This makes non-contact current measurement possible.
Working principle of Hall current sensor
It is based on the magnetic balance Hall principle. According to the Hall effect principle, a current Ic is passed through the control current terminal of the Hall element, and a magnetic field with magnetic induction intensity B is applied in the normal direction of the Hall element plane. Then, a potential VH will be generated in the direction perpendicular to the current and the magnetic field (i.e., between the Hall output terminals), called the Hall potential. Its magnitude is proportional to the product of the control current Ic and the magnetic induction intensity B. That is, where: K is the Hall coefficient, which is determined by the material of the Hall element; Ic is the control current; B is the magnetic induction intensity; and VH is the Hall potential.
Hall effect current sensors are widely used in various fields, including frequency converters, inverters, power supplies, welding machines, substations, electroplating, CNC machine tools, microcomputer monitoring systems, power grid monitoring systems, and areas requiring isolated detection of high current and voltage, due to their numerous advantages such as high accuracy, good linearity, wide bandwidth, fast response, strong overload capacity, and no insertion loss. Hall effect sensors require a DC power supply to operate normally; therefore, their power consumption must be considered during product design.
Advantages of Hall current sensors
1. Non-contact detection
The advantages of non-contact measurement are evident in the retrofitting of imported equipment and the technical upgrading of old equipment; the current value can be measured without any modification to the electrical wiring of the original equipment.
2. High precision
The drawbacks of using a shunt are the lack of electrical isolation and the presence of insertion loss, which increases with the current and the overall size. Furthermore, it has been found that shunts exhibit unavoidable inductance when detecting high-frequency, high-current signals, failing to accurately transmit the measured current waveform, especially non-sinusoidal ones. Current sensors completely eliminate these drawbacks of shunts, while achieving the same accuracy and output voltage as shunts.
3. Easy to use
Take an LT100-C type current sensor, connect a 100mA analog meter or digital multimeter in series between the M terminal and the power supply zero terminal, connect the working power supply, and place the sensor on the wire circuit to accurately display the 0-100A current value of the main circuit.
4. Wide measurement range
It can measure current and voltage of any waveform, such as DC, AC, pulse, triangular waveform, etc., and can even faithfully reflect transient peak current and voltage signals.
5. Good dynamic performance
The response time is fast, less than 1µs; the response time of ordinary current transformers is 10-20ms.
6. High reliability and flexibility
With a long mean time between failures (MTBF) exceeding 510 hours, traditional detection elements are limited by factors such as specified frequency, waveform, and response lag, making them unsuitable for the development of high-power converter technology. This has led to the emergence of a new generation of Hall effect current and voltage sensors, as well as transmitters integrating current and voltage sensors with true-function AC/DC converters, which have become well-known and optimal detection modules. Furthermore, the development of electronic power devices towards higher frequencies, modularity, componentization, and intelligence simplifies device design, representing a fundamental and epoch-making transformation in the history of electronic power technology.
For Hall current sensors to be developed, the following are essential: First, improve sensitivity, stability under harsh conditions, reduce operating voltage, and minimize power consumption. Second, integrate and miniaturize the sensing elements and their processing circuits. Third, diversify functions; sensors with the same sensing mechanism can incorporate and integrate mature technologies from other branches of electronic technology to create new or composite functional products. Finally, facilitate networking; the information captured by the sensor should be easily interfaced with its upper and lower layers and transmitted via wired or wireless means to facilitate execution, storage, and processing.
Disclaimer: This article is a reprint. If it involves copyright issues, please contact us promptly for deletion (QQ: 2737591964). We apologize for any inconvenience.
