Fast-response direct-current current transformer based on multi-sensor fusion

A fast-response direct-current transformer (DCCT) based on multi-sensor fusion, comprising:

• a magnetic modulator (1), a current correction module, an excitation transformer (3), an alternating current detection and filtering circuit (4), a phase-sensitive demodulation and filtering system (5), a PI controller (6), and a power amplifier (7),
• wherein an excitation voltage input terminal of the magnetic modulator (1) is connected to an output terminal of the excitation transformer (3), a feed-back input terminal is connected to an output terminal of the power amplifier (7) and is configured to excite a magnetic core of the magnetic modulator (1) through an excitation voltage, a balance determination signal is outputted by a first signal output terminal to the phase-sensitive demodulation and filtering system (5), and an alternating current induced voltage signal is outputted by a second signal output terminal to the alternating current detection and filtering circuit (4),
• wherein the current correction module is configured to measure a primary current and obtain a feed-forward signal, output a false balance state configured to control a magnetic core to quickly exit or avoid entering magnetic saturation after amplifying the feed-forward signal and a PI control signal, and keep output of the magnetic modulator stable,
• wherein an input terminal of the excitation transformer (3) is configured to be connected to a power frequency alternating current, a first output terminal is connected to the excitation voltage input terminal of the magnetic modulator (1), and a second output terminal is connected to a second input terminal of the phase-sensitive demodulation and filtering system (5) and is configured to provide a periodic excitation voltage for the magnetic modulator (1) and provide the phase-sensitive demodulation and filtering system (5) with a required square wave signal,
• wherein an input terminal of the alternating current detection and filtering circuit (4) is connected to the second signal output terminal of the magnetic modulator (1) and is configured to perform detecting and filtering on the alternating current induced voltage signal outputted by the magnetic modulator (1),
• wherein a first input terminal of the phase-sensitive demodulation and filtering system (5) is connected to a first output terminal of the magnetic modulator (1), and the second input terminal is connected to a third output terminal of the excitation transformer (3) and is configured to perform phase-sensitive demodulation processing on the balance determination signal and output a balance adjustment signal,
• wherein a first input terminal of the PI controller (6) is connected to an output terminal of the alternating current detection and filtering circuit (4), and a second input terminal is connected to an output terminal of the phase-sensitive demodulation and filtering system (5) and is configured to perform proportional integral control on the filtered alternating current induced voltage signal and the balance adjustment signal and output the stable PI control signal,
• wherein an input terminal of the power amplifier (7) is connected to an output terminal of the current correction module and is configured to output the feed-back signal after performing power amplifying and filtering processing on the feed-forward signal and the PI control signal.