A Real-Time Smart Sensor for High-Resolution Frequency Estimation in Power Systems

Power quality monitoring is a theme in vogue and accurate frequency measurement of the power line is a major issue. This problem is particularly relevant for power generating systems since the generated signal must comply with restrictive standards. The novelty of this work is the development of a smart sensor for real-time high-resolution frequency measurement in accordance with international standards for power quality monitoring. The proposed smart sensor utilizes commercially available current clamp, hall-effect sensor or resistor as primary sensor. The signal processing is carried out through the chirp z-transform. Simulations and experimental results show the efficiency of the proposed smart sensor

COMPARACIÓN DE LAS TÉCNICAS DE DETECCIÓN DE CRUCE POR CERO Y LA TRANSFORMADA Z-CHIRP PARA MEDIR FRECUENCIAS EN EL RANGO ULTRASÓNICO

ResumenEste trabajo presenta una comparativa entre 2 métodos para detectar y medir la frecuencia con una alta precisión en el rango ultrasónico. La aplicación propuesta para esta investigación es la medición de velocidad con ultrasonido mediante efecto el Doppler en actuadores lineales, esta se desarrollará en un trabajo posterior. Se generaron señales sintéticas con distintos niveles de ruido, simulando la señal entregada por un sensor ultrasónico. Para la detección de frecuencia se diseñó una metodología para comparar las técnicas de detección de cruce por cero y la Transformada-Z Chirp. La Transformada-Z Chirp, tiene mejores resultados ya que se tiene una buena aproximación de la frecuencia real, y el error no incrementa en señales con ruido, en cambio en la detección de cruce por cero el error incrementa mostrando unos picos indeseables. Una vez que la metodología se perfeccione, se implementará en un sistema embebido para el procesamiento en tiempo real.Palabras Claves: Alta resolución, detección de cruce por cero, efecto Doppler, estimación de frecuencia, transformada-Z Chirp, ultrasonido.COMPARISON BETWEEN ZERO-CROSSING DETECTION AND Z-CHIRP TRANSFORMED TECHNIQUES TO MEASURE FREQUENCIES IN THE ULTRASONIC RANGEAbstractThis work presents a comparison between 2 methods to detect and measure the frequency with a high precision in the ultrasonic range. The proposed application for this research is the measurement of velocity with ultrasound by Doppler effect in linear actuators, this will be developed in a later work. Synthetic signals were generated with different levels of noise, simulating the signal delivered by an ultrasonic sensor. For frequency detection, a methodology was designed to compare zero crossing detection techniques and the Chirp Z-Transform. The Chirp Z-Transform, has better results since it has a good approximation of the real frequency, and the error does not increase in signals with noise, instead in the detection of crossing by zero the error increases showing some undesirable peaks. Once the methodology is perfected, it will be implemented in an embedded system for real-time processing.Keywords: Chirp z-transform, Doppler effect, frequency estimation, high resolution, ultrasound, zero crossing detection