An improved anti-differential configuration based hall-effect current sensor

Abstract

A new, simple and low cost current measurement system based on the anti-differential arrangement of the Hall-Effect based sensors is presented in this paper. The output of the existing anti-differential Hall-Effect current sensor is highly sensitive to the distance between the conductor and the Hall Effect sensors. This distance is a function of the thickness of the insulation and it vary from wire to wire. Non-uniformity of the insulation is also a factor. Another issue of anti-differential system is that the conductor should be kept exactly at the middle of the two Hall sensors. These factors are always prone to introduce errors in the output, and in some cases it can be of unacceptable error range. The proposed scheme is a modified version of the anti-differential configuration. The scheme is modified such that the output is not dependent on the distance between the conductor and the Hall Effect sensors, also the conductor need not be exactly at the middle of the sensors. This approach enables easy manufacturing and installation of the system and avoids the errors due to the above listed factors that otherwise affect the output. Finite Element Method (FEM) studies have been conducted to evaluate the functionality of the proposed method. A prototype of the proposed scheme has been developed and tested in the laboratory, in detail. The prototype developed has all the positive points mentioned above, in addition, it is compact, and retains all the benefits of the coreless Hall-Effect based current sensors. The proposed current sensing scheme will have number of applications in power system, machine monitoring, metering, etc.