High-Precision Non-Contact Current Measurement Technology Using Magnetic Sensors

Abstract

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.