Yazar "Guerrero, Josep M." seçeneğine göre listele

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    Analysis of Multilayered Power Module Packaging Behavior Under Random Vibrations
    (Ieee-Inst Electrical Electronics Engineers Inc, 2020) Liang, Di; Wu, Qiong; Ghaderi, Davood; Guerrero, Josep M.
    Solder joints are the critical components of the printed circuit boards (PCBs) in the moving electronic systems, such as satellites and automotive industries that are most vulnerable to accidental vibrations. Therefore, the reliability of these boards since they are designed to be used for long-time applications is important. Since the laboratory tests are time-consuming and require well-equipped and costly measurement devices, reliability tests are preferred to perform through the analytical methods. In this article, an analytical model based on the multilayer plate theory is presented for the random vibration analysis, and the results are obtained for the different vibration frequencies, including the natural vibration frequency. For the proposed model, the state of the PCB layer and the amount of the stress in the solder joints are investigated separately, and the normal and shear stresses are obtained through the combined sinusoidal-exponential equation. Results by the finite-element method (FEM) analysis show that the cracks form at the edge of the interconnection points of the board, and the solder and void formation and crack propagation appear in the corners of the PCB in frequencies closed to the natural vibration frequency. Reliability increases by the reduced solder height.
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    An improved automated PQD classification method for distributed generators with hybrid SVM-based approach using un-decimated wavelet transform
    (Elsevier, 2021) Yılmaz, Alper; Kucuker, Ahmet; Bayrak, Gökay; Ertekin, Davut; Shafie-Khah, Miadreza; Guerrero, Josep M.
    Artificial intelligence (AI) approaches are usually coupled with the wavelet transform (WT) for feature extraction to classify the power quality disturbances (PQDs). Therefore, selecting a useful WT-based signal processing approach is required for a reliable classification, especially in real-time applications. In this study, a new hybrid, un-decimated wavelet-transform (UWT)-based feature extraction method using a support vector machine (SVM) with a "' a trous" algorithm is proposed to classify PQDs in distributed generators (DGs). The proposed method was performed in a real-time application of a DG system to classify PQDs. The derived features were tested on five different machine learning (ML) models by determining the most appropriate classification technique for the proposed UWT-based feature extraction method. An experimental DG system is constituted in the laboratory using a LabVIEW environment, and the proposed method is tested under different grid conditions. Besides, other well-known and studied conventional ML methods were also tested under 25 dB, 30 dB, and 40 dB noise and compared to the developed method. The experimental and simulation results show that the features extracted with the proposed UWT-based method provide much more successful results in classification than the existing wavelet methods in the literature. Furthermore, the proposed method's noise sensitivity performance is much better than other conventional wavelet algorithms, especially in real-time applications.
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    Sliding mode controller-based switched-capacitor-based high DC gain and low voltage stress DC-DC boost converter for photovoltaic applications
    (Elsevier Sci Ltd, 2021) Qi, Qun; Ghaderi, Davood; Guerrero, Josep M.
    High-gain DC-DC power boost converters blocks have been converted to the main transitional topologies for the PV applications to enhance the level of the generated voltages of these panels for grid applications. The single switched and transformer-less converters due to their higher efficiency, and cheaper and light-weighted features are the first selection for these converters design. This study presents a transformer-less DC-DC power boost converter with a switched-capacitor structure with a sliding mode controller (SMC) to increase the DC voltage gain and decrease the voltage stress on the power switch. This advantage is doing based on the preamplifier block by using an extra inductor at the input side. Also, the switched-capacitor block easily decreases the voltage stresses on the main power switch and other diodes. Presenting high voltages under the small duty cycles is one of the most important features of the proposed converter that allows longer off-time duration for power switch for Continuous Current Mode (CCM) operations. This leads to lower amounts of the dynamic losses for the power switch and higher efficiency. On the other hand, the control process of the proposed converter under the different input voltages and output powers and loads due to using only one power switch is simpler compared with multi switched topologies. All calculations for obtaining the gain, currents follow through the components, voltage ripples through the capacitors, and efficiency is presented. The hardware prototype with 300 W power is tested and the results confirm the theoretical calculations.