Development of a Transient Magnetic Field Sensor Based on Digital Integration and Frequency Equalization

Abstract

Transient magnetic field sensors are used in various electromagnetic environment measurement scenarios. In this paper, a novel magnetic field sensor based on a digital integrator was developed. The antenna was a small B-DOT loop. It was designed optimally for the simulation. The magnetic field signal was digitally integrated with the improved Al-Alaoui algorithm, resulting in less integration error. To compensate for the bandwidth loss of the optical fiber system, we specially designed an FIR (finite impulse response) filter for frequency compensation. The circuit was described, and the transimpedance amplifier was specially designed to ensure the low noise characteristic of the receiver. The sensitivity of the sensor was calibrated at 68.2 A·m−1/mV, the dynamic range was 50 dB (1–300 kA/m), the linear correlation coefficient was 0.96, and the bandwidth was greater than 100 MHz. It was tested and verified under the action of an A-type lightning current. The sensor exhibited high-precision performance and flat amplitude-frequency characteristics. Therefore, it is suitable for lightning positioning, partial discharge testing, electromagnetic compatibility management, and other applications.

Design of Self-Integrating Transient Surface Current Density Sensor Integrated Fiber Transmission Link

“…In order to ensure impedance matching, both terminal loads of the inner core are 50 Ω. In the practice of measuring the intensity for the magnetic component of an electromagnetic field, it has been proved that SSL has an advantage versus the unshielded loop antenna, because it can effectively suppress the interference of the electric field without differential balun [16]. In this design, SSL is made of semi-rigid coaxial cable (SR086-50) with characteristic impedance of 50 Ω.…”

“…The measurement of the surface current density is essentially the measurement of the magnetic field signal. There are many ways to sense magnetic fields; in [16], a transient magnetic field sensor based on a digital integrator was developed. The antenna was a small B-dot loop, but it is not suitable for the measurement of the surface current density due to the large size of the detector.…”

Identification and Compensation for D-Dot Measurement System in Transient Electromagnetic Pulse Measurement

“…In this situation, integration computation is a standard method for post-processing the sensor’s output signal, which is implemented by the design of analog hardware (such as a passive integrator) or signal recovery software (such as a digital integration algorithm). Even though there is evidence of some hardware improvements, such as in [ 18 , 19 , 20 ], the developed EMP measurement still distorts the input pulse signal to various degrees when circuit design details such as impedance matching, parasitic parameters, and other aspects are absent. As a result, the dynamic performance of the test system with a hardware integrator often needs to be further enhanced.…”