A Memory-Efficient True-RMS Estimator in a Limited-Resources Hardware

Abstract

More and more human activities are increasingly dependent on the power quality energy they are supplied. In particular, those loads that have an electronic switching mode power supply (SMPS) and microcontrollers or microprocessors are very susceptible to de-energization of the AC line as voltage monitoring takes place on the DC end and may not have enough time to cope with a voltage event involving energy loss. There have been many proposals that analyze power quality or current consumption, even those using limited resources hardware or the classic formulas of discrete root mean square (RMS). In this proposal, an approximation to the problem by means of an RMS value estimator that uses as a base a microcontroller of basic range and low economic cost and algorithms of calculation of very low computational cost that elude complex arithmetic operation to controllers, such as powers or roots, is presented. The results of the experiments to which the proposal was subjected show its ability to provide an estimation of the RMS value of voltage with sufficient precision or an event alarm in less time than the options analyzed. The validation tests and functional comparison of the prototype which were carried out support its viability.

Design and Implementation of Real Time RMS Measurement System based on Wavelet Transform Using adsPIC-type Microcontroller

“…The proposed method for the calculation of the RMS values based on equation 10is compared with the analytical approach which consists of the application of the definition given by equation (8).…”

“…In order to evaluate the proposed approach accuracy, MATLAB has been used to compare the results of this method with analytical approach, which consists of the application of the definition given by the equation (8). Initially, digital current and voltage signals have been generated to be used as input signals in the proposed method of calculation.…”

“…The wavelet transform has received great importance in the last years on the power system analysis because the multi-resolution analysis presents proprieties good for the transient signal analysis. Continuous been used in non-stationary signals analysis, and several recent papers have proposed the use of Wavelets for power system parameters calculation [2][3][4][5][6][7][8][9][10][11]. For example, E. Y. Hamid et al [6] proposed an approach based on wavelet packet transform (WPT) for RMS values of voltage and power measurements.…”

“…The analytical expressions were derived and using a Graphical User Interface (GUI) designed and experimental works the validity of analytical expressions was demonstrated. In [8] an RMS voltage estimator that eludes the inherent uncertainty of complex arithmetic operations related to the discretized RMS algorithm has been presented. The authors proposed an approximation to the problem by means of an RMS value estimator that uses as a base a microcontroller of basic range and low economic cost and algorithms of calculation of very low computational cost that elude complex arithmetic operation to controllers, such as powers or roots.…”

Special Issue “Analysis for Power Quality Monitoring”

“…The contribution by Flores-Arias et al, "A Memory-Efficient True-RMS Estimator in a Limited-Resources Hardware" [5], presents an RMS voltage estimator that eludes the inherent uncertainty of complex arithmetic operations related to the discretized RMS algorithm on an ATmega328p microcontroller. Its capability as a sag/swell detector was exhibited on substation signals.…”