Non-linear current detection based on magnetic modulation technology

With the increasing of power electronic devices, the leakage current caused by electrical equipment fault not only contains power frequency AC component, but also includes more and more DC and high frequency AC components, which means that the traditional leakage current sensor is not working anymore. For example, the DC component can easily drive the traditional current sensor into saturation state. As such, a simple leakage current sensor based on magnetic modulation technology is presented in this paper to detect the current from DC to several kilohertz with low power consumption. One typical application of the proposed sensor is the type B residual current device (RCD) complying with IEC60755, in which the residual current of sinusoidal AC, pulsating DC and smooth DC should be detected properly to protect person from electrical shock.