Current sensor working principle, Current sensor Buy
In modern electrical systems, current sensors, as a key electronic component, undertake the important task of accurately measuring current. Whether in the field of industrial automation, power systems, or in new energy vehicles and other emerging industries, current sensors play an indispensable role. Today, MobikeChip will provide you with an in-depth analysis of the working principle of the current sensor.
Electromagnetic Induction Current Sensors: Classical Application Based on the Law of Electromagnetic Induction
(A) Basis of operation
Electromagnetic induction current sensors work on the basis of Faraday's law of electromagnetic induction. When a current passes through a conductor, a magnetic field is generated around it. Electromagnetic induction current sensors indirectly measure the current by detecting changes in this magnetic field. A common type of induction current sensor is the current transformer, which consists of a primary winding and a secondary winding, and is usually wound on an iron core.
(B) current measurement process
In practice, the measured current passes through the primary winding, generating an alternating magnetic field. This field passes through the core and extends to the area where the secondary winding is located. Since the secondary winding is in a varying magnetic field, according to the law of electromagnetic induction, an induced electromotive force is generated in the secondary winding. The magnitude of the induced electromotive force is proportional to the magnitude of the current in the primary winding. By measuring the induced electromotive force or induced current in the secondary winding, and then according to the turns ratio of the primary and secondary windings, the size of the measured current in the primary winding can be calculated. For example, in a turns ratio of 100:1 current transformer, if the secondary winding induces a current of 1A, then the measured current in the primary winding is 100 A. This type of current sensor is widely used in power systems for current measurement and protection, and is able to accurately monitor high voltage transmission lines in the large current.
The Hall effect type current sensor: the use of Hall effect to achieve accurate measurement
(A) Hall effect principle
Hall effect current sensor utilizes the physical phenomenon of the Hall effect. When the current perpendicular to the external magnetic field through the semiconductor material, in the semiconductor perpendicular to the magnetic field and the current direction of the potential difference between the two end surfaces will appear, this potential difference is called Hall voltage. The magnitude of the Hall voltage is related to the current through the semiconductor, the strength of the magnetic field and the characteristics of the semiconductor material.
(B) Sensor structure and measurement method
Hall effect current sensor usually consists of a Hall element and a magnetic core. The measured current passes through the magnetic core, generating a magnetic field around the core. The Hall element is placed in the air gap of the magnetic core to detect the magnetic field strength. When a current passes through, the magnetic field acts on the Hall element and generates a Hall voltage. By measuring the magnitude of the Hall voltage and going through the corresponding signal processing circuit, the magnitude of the current being measured can be obtained. This type of current sensor has the advantages of fast response speed, high accuracy, good linearity, etc. It is widely used in industrial automation equipment, battery management system of electric vehicles, etc. It is able to accurately measure DC and AC currents.
Fluxgate current sensors: current measurement based on magnetic saturation characteristics
(A) Fundamentals of the fluxgate principle
Fluxgate current sensors work based on the magnetic saturation characteristics of soft magnetic materials. Soft magnetic materials are easily magnetized under the action of the magnetic field, when the magnetic field strength reaches a certain value, the material will enter the magnetic saturation state, at this time its permeability will change. Fluxgate current sensors usually consist of an excitation winding and a detection winding, wound on a core made of soft magnetic material with high permeability.
(B) Current detection process
The excitation winding is energized with an alternating current, which alternates between positive and negative saturation states of the magnetic core. When the measured current passes through the core, an additional magnetic field is generated, which affects the magnetic saturation characteristics of the core and thus changes the induced electromotive force in the detection winding. By detecting the change in the induced electromotive force in the detection winding and through complex signal processing algorithms, the magnitude of the measured current can be accurately measured. Fluxgate current sensors have very high accuracy and sensitivity, suitable for current measurement precision requirements are very high occasions, such as aerospace, precision instruments and other fields.
The Roche coil current sensor: no iron core current measurement program
(A) Roche coil principle
Roche coil current sensor is a hollow coil sensor based on the principle of electromagnetic induction. It consists of a uniformly wound hollow coil without an iron core. When the measured current passes through the Roche coil, an alternating magnetic field is generated around it, and this field induces an electric potential in the Roche coil.
(B) Measurement characteristics and applications
The electric potential induced by the Roche coil is proportional to the rate of change of the measured current. By integrating the induced electromotive force and other signal processing, the size of the measured current can be obtained. Roche coil current sensor has the advantages of wide measurement band, good linearity, no magnetic saturation, etc. It is especially suitable for measuring high frequency, high current and rapidly changing current signals. In the field of power electronics, such as frequency converters, inverters and other equipment current monitoring, Roche coil current sensors are widely used.
At MobikeChip, we are committed to providing you with professional knowledge of electronic components and high quality current sensor products. Understanding the working principle of current sensors will help you accurately select and apply the right current sensors in different electrical systems. If you have any questions about the selection and use of current sensors, please feel free to visit MobikeChip website, our professional team will be happy to serve you.
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