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 8^th 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.