| Abstract: | The magnetic modulation zero-flux current sensor, with its excellent characteristics, is widely used in both power supply and power consumption equipment. The rapid developments of the smart grid and big data lead to a remarkable increase in the demand for monitoring the working status of the sensor. To obtain the state feature information of the current sensor, this paper proposes a magnetic modulation analysis method based on the fact that the permeability of ferromagnetic materials varies with the strength of the magnetic field (or current). This method not only circumvents the shortcomings of magnetic modulation with trilinear analysis, but also is able to obtain clear relations among all parameters. Based on the fundamental principle of the zero-flux, the Fourier series is employed to analyze the frequency components carried by modulation and demodulation signals. By comparing the spectrum of modulation and demodulation signals with both zero and non-zero flux, the relevant frequency components indicating the working status of magnetic modulation are determined. According to the working principle of the zero-flux current sensor, a basic method is proposed to judge the working status of the magnetic-modulation-style zero-flux current sensor. The relation between the magnetic modulation feature information and the working status of the zero-flux current sensor is validated with real circuits, and the experimental results coincide with the inference. |
