RMS Estimator Built Using Limited Resources Hardware

Researchers from University of Córdoba developed a root mean square (RMS) value estimator using limited resources hardware

Electric power is considered ‘reliable’ when the electric supply is available and dependable and ‘clean’ when the AC current and voltage waveforms that are supplied essentially fit a sinusoidal wave shape at a frequency of 50 Hz or 60 Hz depending on countries where users live. Dirty power, steady-state under voltages (brownouts) and over voltages can lead to electrical and mechanical equipment damage. Now, a team of researchers from University of Córdoba focused on automatic detection of de-energizing dip, brownout, or outage events related to the AC voltage at the supply inlet. The team also determined the viability of a proposal of an RMS estimator.

The estimator was built with the help of limited resources hardware. The reliability and accuracy of the RMS estimator was validated to demonstrate that even limited resources microcontrollers that are not intended for arithmetic functions can perform and to attain an estimation that can offer an RMS phasor module value that can be used in a voltage control loop or in a de-energizing alarm system. The RMS estimator avoids the inherent uncertainty of complex arithmetic operations that are associated with discretized RMS algorithm. The limited resources hardware and high-efficiency program decreases the system requirements and prevents data memory overflow.

Therefore, the phasor module estimator restricts its response time to offer a valid estimation. Moreover, the estimator can be implemented in simple microcontrollers, which do not have high-performance arithmetic units or specific resources for digital signal processing. The team compared the performance of the estimator to a low-cost embedded system based on an ATmega328p microcontroller—one of the most basic phasor module estimator by the company Microchip to verify its ability to operate as either a sag/swell detector, a true RMS meter in a protective alarm or idling system, or at a not too demanding voltage loop of a regulator. The research was published in the journal MDPI Energies on May 5, 2019.

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About the Author: Furgus Degrout