Design Of Electronic Meter Based On Giant Magneto-resistive Sensor

With the rapid development of Smart Grid, the traditional meters will be replaced by Smart Meters, in order to better service the residents. Besides recording electricity consumption, Smart Meters have more abilities than traditional meter, as monitoring voltage, current and power, remote communication, payment convenience, etc. The new multi-users meters are popular with high-grade residential.This paper presents a design of electronic meter based on GMR sensor, the meter consists of voltage sampling module, current sampling module, power calculation module and electricity recording module. The voltage is measured by using common resistance voltage divider. Current is measured by GMR current sensor which is designed independently. FPGA is used to calculate power and energy, also controls to store energy used. LCD is used to display measurement result, including current,voltage, power and energy.The current sensor has been tested. Result shows that it can measure current range-1A to 1A, and the minimum changes of current it can exactly figure out is10 mA, which means the current sensor’s precision can reach 1%. Power calculation module is tested by simulation, because there is interference problem not saluted,which makes it unable to do physical tests.Finally, the problems in design are analyzed and solutions are given, at the same time, the work of this paper is summarized and prospected.