6 research outputs found
Terminal sliding mode control with sensor reduction of a permanent magnet synchronous generator supplying a pumping system with battery storage
No full textThis work is concerned with the study and development of a terminal sliding mode control process that employs an estimator of the wind speed and the mechanical rotation speed of the permanent magnet synchronous generator (PMSG). This results in a reduction in the overall cost of the wind power system, which comprises a PMSG, a Pulse Width Modulation (PWM) rectifier, a battery, a DC–DC converter, a PWM inverter and a centrifugal pump driven by an asynchronous squirrel-cage machine. The wind power system is validated in the MATLAB Simulink numerical simulation environment. Subsequently, the results obtained are compared with those of a conventional sliding-mode control (with a tachometric sensor and an anemometric sensor) in order to ascertain the efficacy of the proposed control method in terms of trajectory tracking, energy consumption and the reliability of the proposed estimation algorithm. The simulation results demonstrate that the proposed approach is both robust and reliable. However, it should be noted that the settling time of the estimated quantities is greater than that of the same quantities when measured with the compared approach (conventional sliding mode control)
A simple fuzzy logic based DC link energy management system for hybrid industrial power supply
No full textEnergy price hikes and the pollutant nature of fossil fuels have led energy producers to focus on the development of renewable energies. In the last few decades, the design of hybrid renewable energy systems presented itself as a difficult task because of its interference, uncertainty and especially unpredictable nature. However, scientific progress has enabled several solutions to be found to the problems associated with them. The aim of this article is to provide industries with satisfactory energy that respects the demand and supply balance with excellent energy quality, reduced losses and improved efficiency. To achieve these objectives, an energy management system based on fuzzy logic is proposed and applied to the hybrid photovoltaic hydroelectric system coupled to the DC link through electronic switches. The proposed method is based on the error in the output voltage at the AC link. On the basis of the error and its variations, 81 fuzzy rules are established and offer the advantage that they do not take in to account the mathematical model of the system. In addition, the proposed algorithm is seen at the DC link as a controlled current source which has the advantage of automatically compensating the power deficit required by the loads. Under the strong influence of non-linear loads, and in comparison with the Artificial Ant Colony (ACO) and Proportional Integral (PI) control techniques, simulation results in the Matlab/Simulink environment present satisfactory results for the proposed algorithm in terms of robustness to disturbances, good response and compensation speed, excellent energy balance and quality, with total harmonic distortion values well below the standards. Quantitatively, the proposed algorithm averagely improves the response speed of the system by 12.72%, the root-mean-square error by 31% and the total harmonic distortion by 30% as compared to the other two methods
A simplified approach to failure analysis of ball bearings combining Principal Component Analysis and Fast Fourier Transform.
No full textBall bearing monitoring employs time-frequency techniques to facilitate the early detection of faults; however, the presence of non-stationary or noisy signals can limit the effectiveness of these techniques, requiring advanced methods for reliable predictive maintenance. This study proposes a methodology for fault detection in complex systems,utilising Principal Component Analysis (PCA) to identify indicators with a higher probability of fault. Subsequent to this, the signal characteristics are decomposed using the Fast Fourier Transform (FFT). This technique is employed to identify the Hotelling component and the SPE (quadratic prediction error), with the objective of determining the state of health of the rolling bearings. This is achieved by extracting the frequencies and harmonics that characterise the fault. The Hotelling component considers elements in the main space with a higher energy representation for evaluation, while the SPE considers elements in the residual space. The results demonstrate a rapidly appreciable range of detection and dispersion of faulty signals. A comparative analysis of the KPCA-FFT and PCA-FFT results is performed. However, this study demonstrates that the combination of PCA-FFT with the Hotelling index test and SPE is more suitable for evaluating signals with defects
Numerical, electronic simulations and experimental analysis of a no-equilibrium point chaotic circuit with offset boosting and partial amplitude control
No full textContribution to the Development of a Smart Ultrasound Scanner: Design and Analysis of the High-Voltage Power Supply of the Transmitter
No full textA smart ultrasound scanner plays an important role in the transition to point-of-care imaging. DC–DC bipolar converters are essential in the generation of the ultrasound burst signal as they power the piezoelectric transducer. The conventional bipolar converter has minimal output gain and high-voltage stress, and the longer duty cycle on the semiconductors produces high conduction losses and reduces the efficiency of the system. The transmitter supply voltage is minimal, necessitating the use of high-gain bipolar converters. This proposed study is concerned with the development of an improved high-output voltage gain symmetric bipolar DC–DC converter topology which may be suitable for applications such as powering a smart ultrasound scanner transmitter. The proposed converter combines the conventional single-ended primary inductor converter (SEPIC) with a voltage multiplier cell (VMC) to improve voltage gain, transistor duty cycle, efficiency, and reliability. The present study describes the working principle of the proposed converter. The analysis of the voltage gain is carried out in continuous current mode (CCM) and discontinuous current mode (DCM), taking into account the nonidealities of the device. The simulation of the proposed system is carried out in the numerical environment Matlab/Simulink in order to verify its characteristics. A prototype model is realized and the experimental study presented validates the theoretical arguments and simulations. Due to the advantages of continuous input current, self-balancing bipolar outputs, and small component size, the proposed converter is a suitable choice for smart ultrasound transmitters
A Simple Lyapunov Function Based Control Strategy for Coordinated Transient Stability Enhancement of Power Systems
Full text linkTransient stability is still a serious impediment in power system operation due to their highly nonlinear nature. Over the last decades, a vast number of diverse nonlinear control algorithms for sub-controllers located at the generator subsystem and transmission lines have been developed to boost power system stability. However, for an effective and feasible operation of these power systems, coordination of these sub-controllers is very essential. In this paper, a simple direct Lyapunov based approach for coordinated control is proposed for global enhancement of power system stability. The proposed control scheme is achieved through the coordination of Lyapunov based decentralized steam valve, excitation and SSSC adaptive controllers. To test the efficacy of the proposed scheme, several comparisons in multi-machine fault scenarios with other design coordinated approaches are presented. Numerical simulations demonstrate the swiftness and efficacy of the proposed control scheme in boosting global stability
