A positive and negative sequence current measuring device and method based on an electric energy metering platform

Abstract

At present, the current positive and negative sequence extraction methods are all based on high-performance analog-to-digital converters and need high-performance microprocessors. Or the negative sequence current measurement circuit is constructed using an analog operational amplifier, and the phase shifting method is used to achieve the measurement purpose. The above methods need to be implemented by chips with high computing power. They even need to build an additional positive sequence current measurement circuit, which makes the circuit more complex and cost-effective. This paper proposes a positive and negative sequence current measuring device and method based on the electric energy metering platform. Through the external phase, the current access device is to be measured using the power measurement value formed by the voltage channel, current channel, and multi-function measurement channel corresponding to the single-phase metering chip of the measurement unit, the included angle of phase current can be calculated, thus realizing the calculation of positive and negative sequence current. It avoids using high-performance analog-to-digital converters, effective value, frequency tracking, phase measurement, and other complex algorithms, reduces the computational requirements for MCU master chip, and reduces the development difficulty and cost.