All-digital vector demodulation method of magnetic modulator

Abstract

The invention discloses an all-digital vector demodulation method of a magnetic modulator. The all-digital vector demodulation method of the magnetic modulator comprises the steps of: introducing first current of known magnitude into the magnetic modulator; converting analog signals generated on the excitation winding and the detection winding of the magnetic modulator into digital signals, so that excitation signals and detection signals are obtained; constructing secondary harmonic reference signals, removing the direct-current component of the detection signals so as to obtain signals to be detected, and performing correlation operation on the secondary harmonic reference signals and the signals to be detected, so that the signal output amplitude is obtained; introducing current to be detected into the magnetic modulator, and repeating the above steps to obtain the signal output amplitude of the current to be detected; and obtaining the amplitude of the current to be detected according to the amplitude of the signal output amplitude for two times and the frequency of the excitation signals for two times. According to the all-digital vector demodulation method of the magnetic modulator in the invention, the measurement resolution is increased by utilization of the secondary harmonic amplitude and phase of the signals of the detection winding; noise interference due to demodulation is weakened through the all-digital method; and furthermore, the error introduced by the measurement sensitivity change due to excitation power frequency change can be weakened through a proportional coefficient self-calibration method.

Description

technical field [0001] The invention belongs to the field of electrical technology, and more specifically relates to an all-digital vector demodulation method of a magnetic modulator. Background technique [0002] The magnetic modulator is a high-precision current sensor based on the principle of magnetic modulation. It is mainly composed of four parts: iron core, excitation winding, detection winding and demodulation circuit. The working principle of the magnetic modulator is that the iron core is deeply saturated by exciting the winding. When there is no current, that is, when there is no bias magnetic field inside the iron core, the internal magnetic flux of the iron core only contains odd harmonic components; when there is current When it is connected, that is, when a bias magnetic field appears inside the iron core, an even-order harmonic component proportional to the DC current to be measured appears in the magnetic flux inside the iron core. [0003] The detection wi...

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Problems solved by technology

[0005] Aiming at the defects of the prior art, the purpose of the present invention is to provide an all-digital vector demodulation method of a magnetic modulator, which aims to solve the problem that the existing magnetic modulator demodulation method will introduce errors and reduce the measurement resolution

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