The invention belongs to the technical field of current detection and especially relates to a novel high precision and low noise DC high current detecting device and method. The detecting device comprises an E-E fluxgate measuring head 1, a RL multi-vibrator 3, an inverter 4 , a feedback compensation circuit, a current coil winding 115 under test, and a precision operation amplifier potential acquisition circuit; by means of the E-E fluxgate measuring head and magnetic circuit design, noise is eliminated to simplify a demodulator circuit; high accuracy detection of large DC current is carriedout by measuring a noiseless DC feedback signal generated by feedback compensation; the invention has the advantages of easy-to-get and stable and reliable square wave excitation, skillfully eliminating noise in iron core through magnetic circuit structure without considering symmetry of noise amplitude, and eliminating errors caused by asymmetry of excitation current, greatly simplifying circuit,ensuring and improving measurement accuracy, and achieving low power consumption, low cost and high accuracy.

Novel high precision and low noise DC high current detecting device and method

The invention discloses a magnetic sensor for magnetotelluric detection. The magnetic sensor comprises a magnetic core, combined induction coils, control circuits, combined feedback coils and a selector switch module. The magnetic core is used for receiving excitation current generated by the control circuits, and thereby generating magnetic flows. The combined induction coils are used for inducing and receiving magnetic field signals and transmitting the magnetic field signals to the control circuits. The control circuits are used for processing and outputting the magnetic field signals, generating excitation current and transmitting the same to the magnetic core, and generating feedback current and transmitting the same to the combined feedback coils. The combined feedback coils are usedfor converting the circuit feedback current into magnetic fields. The selector switch module is used for switching and selecting combination and connection relations among the combined induction coils, the combined feedback coils and the control circuits. The magnetic sensor has the advantages that the problems of single function and small frequency band range of a traditional magnetic sensor aresolved, usage range of the magnetic sensor is expanded greatly, and measurement accuracy of magnetic sensor is increased.

Magnetic sensor for magnetotelluric detection

The embodiment of the invention provides a noise detection device and noise detection method of an orthogonally fundamental-mode flux gate sensor. The device comprises a probe, a probe replacement circuit and a signal processing circuit, wherein the probe replacement circuit is a response circuit built according to a probe principle, a probe is used for being matched with the signal processing circuit for noise detection and evaluation of total noise of the sensor, the total noise of the sensor comprises probe self noise and signal processing circuit self noise, and the probe replacement circuit is used for being matched with the signal processing circuit for noise detection and evaluation of signal processing circuit self noise. In the device and the method, provided by the embodiment ofthe invention, the probe replacement circuit is arranged and matched with the signal processing circuit for noise detection, the signal processing circuit self noise is acquired, the probe self noiseis further obtained according to the total noise of the sensor, noise separation detection of the probe and the signal processing circuit is achieved, data support is provided for achieving targeted sensor noise optimization design, and the sensor noise optimization design effect is favorably improved.

Noise detection device and noise detection method of orthogonally fundamental-mode flux gate sensor

Disclosed are a passive wireless magnetic field characteristic sensing tag and sensing system and a passive wireless magnetic field characteristic sensing system-based magnetic field quantity acquisition method. Specifically, a passive resonant magnetic field sensor is used for integration in a board-level passive electronic tag, and an RFID technology-based magnetic field sensing system is built in cooperation with a reader-writer and a host computer to implement the highly precise and highly intelligent monitoring of the magnetic field quantity. By means of the design of the passive resonant magnetic field sensing tag that is compatible with single and dual sensor acquisition modes, the acquisition modes may be switched according to the control of the reader-writer, which solves the problems in which existing RFID technology-based small-scale magnetic field sensing systems have a single operation mode, the space for secondary development is small, and accuracy and sensitivity cannot be ensured. The solution of the present invention may monitor both a constant magnetic field and an alternating magnetic field, and is particularly suitable for magnetic field monitoring of power transmission devices in large power transmission centers.

Passive wireless magnetic field characteristic sensing tag and sensing system

The invention relates to a common-mode noise inhibition device and method of a time difference type flux gate sensor. A detection circuit I and a reference circuit II are included, a resistor in the detection circuit I is replaced with a time difference type flux gate probe, and a digital signal collection circuit and a collection result thereof are obtained; and subtraction is carried out on the obtained collection result, and common-mode noise is removed from two paths of signals. Compared with a present signal processing circuit of the time difference type flux gate sensor, it is not required to change the structure of the signal processing circuit or flux gate probe, or use a complex algorithm, and common-mode noises of the time difference type flux gate sensor can be inhibited rapidly by only ensuring that the two circuits can realize synchronous real-time measurement. Noise, introduced by excitation current, of the time difference type flux gate sensor can be inhibited effectively, and the strict requirement for an excitation current signal generator can be reduced.

Common-mode noise inhibition device and method of time difference type flux gate sensor

The invention relates to a broadband composite magnetic sensor. An inductive magnetic sensor primary probe and an inductive magnetic sensor secondary probe are installed at two ends. A fluxgate sensor probe is installed at the middle position of an inductive sensor hollow magnetic core. The inductive magnetic sensor primary probe, the inductive magnetic sensor secondary probe and the fluxgate sensor probe are fixed in a shell and are connected to a conditioning circuit through multi-core shielding cables. The broadband composite magnetic sensor has a high frequency working mode and a low frequency working mode, the fluxgate sensor probe is fixed to a composite magnetic sensor structure at the middle position of the inductive magnetic sensor primary probe and the inductive magnetic sensor secondary probe. Compared with a traditional single fluxgate sensor, the broadband composite magnetic sensor has the advantages that the sensitivity of a fluxgate sensor is improved, disadvantages that the high frequency noise of the single fluxgate sensor is high, the low frequency noise of a single inductive magnetic sensor is high, and a static magnetic field can not be measured are overcome, and the measurement of a wideband and low noise magnetic field is realized.

Li Jingjie

Papers

Common-mode noise inhibition device and method of time difference type flux gate sensor

Broadband composite magnetic sensor