Juan M. Mauricio Villanueva

Wind speed measurement and uncertainty analysis using ultrasonic sensors with Kalman filtering

In this work, analyses of Kalman filtering for wind speed measurement using ultrasonic sensors is presented. A technique based on the Kalman filter procedure is developed for the determination of the wind speed. Data are gathered using the Discrete Extended Kalman Filter (DEKF) algorithm. The assessment of uncertainties on the wind speed measurement is analyzed. Practical design issues are considered and an application example is shown in order to illustrate the proposed procedure.

Wind Speed Measurement Data Fusion of Phase Difference and Time-of-Flight Techniques Using Ultrasonic Transducers

In this work, analyses of threshold detection and phase difference techniques for wind speed measurement using ultrasonic transducers are presented. The influence of uncertainties associated with additive noise and attenuation of the ultrasonic signal on the wind speed measurement uncertainty is analyzed. A data fusion procedure based on the Maximum Likelihood Estimation Algorithm is developed for the determination of the wind speed. Data are gathered using the threshold detection and phase difference technique. The data fusion procedure provides a lower measurement uncertainty than those obtained through the above techniques when taken separately. Practical design issues are considered and an application example is shown in order to illustrate the proposed procedure.

Ultrasonic time-of-flight estimation based on maximum likelihood data fusion using triangular distribution

In this paper, a data fusion proceeding was developed based on the Maximum Likelihood Estimation technique (MLE), considering the variables to be fused, having symmetric triangular probability distributions. This procedure was utilized to the wind speed measurement by means of indirect measure of the ultrasonic time-of-flight (ToF), fusing two independent measurements obtained by threshold detection and phase difference techniques. A computational model was built and simulations with different levels of additive noise and Wind velocities were carried out. The results were satisfactory, evidencing that this technique is quite promissory to instrumentation and measure applications.

Wind speed measurement based on ultrasonic sensors using Discrete Fourier Transform

In this paper is presented the procedure to wind speed measurement based on ultrasonic sensors. For this purpose the ultrasonic Time-of-Flight (ToF) was estimated using the DFT (Discrete Fourier Transform) technique. The analysis of the influence of multiplicative and additive noise of the medium into the DFT is carried out. Then, the uncertainties propagation for ToF and wind speed measurements is examined. Simulation results show that DFT technique provides a lower measurement uncertainty. The Probability Density Function is presented in order to compare the classical techniques like Threshold detection, Phase Difference and Maximum Likelihood Estimation with the DFT.

Evaluation of wavelet analysis performance in multiphase level measurement using ultrasonic sensors

This paper presents an evaluation of the performance of wavelet analysis in the filtering of ultrasonic echoes applied to the measurement of multiple levels of liquids in a single tank. A revision of previous references in the filtering of ultrasound signals used in this application is presented. A simulation model of ultrasonic sensors and the measurement system is developed, considering the attenuation of the mediums and the presence of additive noise. A single mother wavelet is used and the number of required levels of decomposition for signal detection is verified. Simulation results are presented with comparison of the measurement uncertainty achieved under different signal-to-noise ratios.

Wireless system for detecting high intensity current impulses applied to ground grids

Grounding system is an essential element for personal and electrical installations safety; for this reason, it is very important to evaluate the grid operational conditions. To draw a diagnosis of a ground grid it is necessary to determine its electrical characteristics both in industrial frequency and in surge conditions. The electrical characteristics are obtained from the injection of electrical current in the grid and its propagation effects are measured, i.e, several voltage signals are acquired at different points of the ground. The signal analysis is fundamental for the adequate evaluation of the grounding system operational conditions. This paper presents the development of a data acquisition system for assessment of grounding systems operational conditions when the grid is subjected to electrical current surges. The system is portable and capable to transfer data voltage signals acquired at different points of the ground employing a wireless network. The data acquisition system is based on a dsPIC 30F3011 microcontroller. The system has been tested and validated by using an impulse generator with an 11 kV capacitor charging. The system can be used to evaluate the degradation of the grounding grid and provide a predictive diagnosis.

Lead acid battery SoC estimation based on extended Kalman Filter method considering different temperature conditions

State of Charge (SoC) is the most important parameter to be estimated on a Battery Management System (BMS). Improper SoC management can cause faster battery degradation, reduce its operational lifetime and, on extreme cases of overcharge, it may lead to an explosion. In addition, batteries are complex electrochemical systems, and both the electrical components and chemical reactions vary significantly with changes in temperature. In this paper, it is presented the effect of the temperature on the Lead Acid battery SoC estimation. The data collection was performed varying the battery temperature, under a range of 10oC to 70oC. To determine the model parameters from the used battery, several data acquisition was performed. To obtain the SoC estimation it was implemented the Extended Kalman Filter that provide satisfactory results. The simulated results were obtained using the MATLAB environment. To verify the effectiveness and the performance of the implemented Kalman Filter it was applied the EKF for estimate the SoC of a Lead Acid battery described in the Introduction Section. It is important to realize that is a comparative study and the only evaluation comparison with the SoC estimation that we can do uses the Open Circuit Voltage (OCV).

Wind speed measurement based on time-of-flight estimation using Extended Kalman Filter

This paper presents the procedures for the wind speed measurement using ultrasonic transducers. The wind speed measurement is based on the time-of-flight (ToF) ultrasonic estimation that has been estimated using the Extended Kalman Filter (EKF) algorithm. For this purpose it was developed the dynamic system model in state space and was analyzed the convergence of the EKF algorithm. Simulation results are presented considering the presence of additive Gaussian noise.

Data Fusion Methods based on Fuzzy Theory for Wind Speed Measurement using Ultrasonic Transducers

In this work, a wind speed measurement model based on fuzzy data fusion of the time-of flight (ToF) information is presented. This information is obtained through threshold detection (TH) and phase difference (PD) techniques. Fuzzy membership functions are derived from ToF measurement values and represent measured values and their uncertainties. Two data fusion methods are presented based on the compatibility relationship between elements to be combined and using weights defined by the OWA (Order Weighted Average) operator. Uncertainty analysis the TH and PD techniques is carried out by determining the uncertainty associated to the ToF measurement. ToF data fusion values are determined considering several measured values using the TH and PD techniques.

Design considerations for ultrasonic signals acquisition

This paper presents some considerations about uncertainty and noise related to ultrasonic transducers in time of flight estimation for wind speed measurement with pulsed transmission mode. Experimental results show the noise distribution in a measurement setup using ultrasonic transducers and the relation between signal to noise ratio, uncertainties and number of cycles used in pulsed transmission by transceiver. From these results, the project considerations for ultrasonic signals acquisition can be defined, such as number of cycles and uncertainty evaluation.