An AC/DC sensing method based on adaptive magnetic modulation technology with double feedback properties

In this paper, An AC/DC (alternating current, direct current) current sensing method is proposed to detect the current from DC to several kilohertz (kHz) with wide sensing range and low power consumption. A novel adaptive magnetic modulation technology with double feedback properties is applied to modulate the current. And a simplified demodulation method, involving an 8th order low pass Butterworth filter is designed to measure the current. One typical application of this method is the detection of residual current for type B RCD (residual current device) complying with IEC60947-2, in which the residual current of sinusoidal AC, pulsating DC and smooth DC should be detected to protect person and machine. The type B RCD with the current sensing method characterizes wide current sensing range, low power consumption and high current measurement accuracy.