Embedded Power and Energy Measurement System Based on an Analog Multiplier

This paper deals with the development of an analog electronic wattmeter based on a high-accuracy electronic four-quadrant multiplier and appropriate amplifying and averaging circuits. The proposed instrument presents a simple design and is constructed using commercially available components. Its main advantage is that it can be integrated with the signal conditioning circuit, obtaining low cost, high resolution, and reduced dimensions. It can measure in circuits with very low power factors and nonsinusoidal waveforms. The implemented prototype is a portable laboratory instrument, integrated with a digital system capable of processing the signals, and displaying the main parameters of both electric power and energy. It has been designed to easily integrate the main blocks in that either industrial or civil equipment requiring the power measurement for monitoring or control purposes. A Fluke 6100A power standard is used to calibrate the wattmeter over a wide range of current magnitudes and widths and at power factors down to 0.02; several results are reported and discussed.