A Fluxgate Current Sensor With an Amphitheater Busbar

Abstract

Large DC and AC electric currents are often measured by open-loop sensors without a magnetic yoke. A widely-used configuration uses a differential magnetic sensor inserted into a hole in a flat busbar. The use of a differential sensor offers the advantage of partial suppression of fields coming from external currents. Hall sensors and AMR sensors are currently used in this application. In this paper, we present a current sensor of this type that uses novel integrated fluxgate sensors which offer a greater range than magnetoresistors and better stability than Hall sensors. The frequency response of this type of current sensor is limited due to the eddy currents in the solid busbar. We present a novel amphitheater geometry of the hole in the busbar of the sensor which reduces the frequency dependence from 15% error at 1 kHz to 9%.

Rectangular Array Current Transducer with Integrated Microfluxgate Sensors

“…The equation for calculating the weights for each sensor and the total current is shown in (5), (6), respectively. = (5) = = 1 1 + 2 2 + 3 3 +⋯+ 16 16 16 (6) IV. CHARACTERISTICS OF THE YOKELESS TRANSDUCER AND LEM SENSOR A.…”

“…The other problem is frequency dependence due to non-uniform current distribution caused by eddy currents in the solid bar. In [5] and [6] a busbar with an amphitheater hole and wedge bar respectively is shown, these methods significantly reduce frequency dependence. A similar busbar sensor with a range of 300 A is described in [7].…”

Testing and application of an integrated fluxgate sensor DRV425

“…Several interesting applications of the DRV425 integrated fluxgate were presented by its manufacturer (Texas Instruments) and other authors [5][6][7][8]. USB interfaced probe with the DRV425 sensor was built to make the development of new applications easier, faster and more effective.…”

“…Typical fluxgates are bulky, very expensive and power consuming devices [1]. Newly developed miniaturized and integrated fluxgate sensor DRV425 [2][3][4] opens new area of possibilities in the application of fluxgates [5][6][7][8]. The dimensions of the sensor are 4 × 4 × 0.8 mm and power consumption is < 30 mW (if operated continuously).…”

A Busbar Current Sensor With Frequency Compensation

“…The busbar sensor with a hole has the advantage over a sensor on the surface that the frequency dependence is lower. With a cylindrical hole, the frequency error is 14%, while for amphitheater geometry, the error was reduced to 9% [10]. Problems with amphitheater geometry were the large sensitivity to a geometrical mismatch, and increased manufacturing complexity.…”