High-precision non-contact current measurement technology using magnetic sensors

In recent years, magnetic sensors have been applied not only to pure magnetic field detection but also to various fields. Current measurement using a shunt resistor is a common method, but high accuracy measurement is impossible due to self-heating drift and loss of micro resistance. In the current measurement using a current sensor, the insertion loss that the sensor gives to the circuit is extremely small, and high-precision measurement is possible. Therefore, a current sensor is essential device for development of a high efficiency power conversion system such as a power conditioner and an inverter. We have continued to develop high-precision and wideband current sensors using various detection methods for over 40 years. This paper introduces detection methods and features of various current sensors. In addition, key considerations when choosing a current sensor and precautions for high-precision measurement are described. © 2017 The Institute of Electrical Engineers of Japan.