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Your search keyword '"Franquelo, Leopoldo G."' showing total 321 results
Start Over Author "Franquelo, Leopoldo G." Publication Type Periodicals
321 results on '"Franquelo, Leopoldo G."'

6. Generalized Feed-Forward Sampling Method for Multilevel Cascaded H-Bridge Converters

Author

Alcaide, Abraham M., Poblete, Pablo, Vazquez, Sergio, Aguilera, Ricardo P., Leon, Jose I., Kouro, Samir, and Franquelo, Leopoldo G.

Abstract

Multilevel cascaded H-bridge (CHB) converters are usually operated applying a phase-shifted pulsewidth modulation (PS-PWM) method. In this modulation strategy, it is important to define the sampling instants in order to obtain a superior harmonic performance in the CHB output waveforms. Previous approaches to define the PS-PWM method consider a shorter sampling time, becoming even smaller when the number of cells of the CHB is large. In addition, unbalanced operational conditions in the CHB aggravate this issue also degrading the CHB harmonic performance. In this article, both challenges (small sampling time and unbalanced operational conditions) are faced. A feed-forward compensation technique is proposed to face with the unbalanced operating conditions and enlarging the available computational time for control schemes keeping the good CHB harmonic performance. Experimental results demonstrate the superior performance of the proposed strategy.

Published
2024
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10. Common DC-Link Capacitor Harmonic Current Minimization for Cascaded Converters by Optimized Phase-Shift Modulation

Author

Zhou, Xuanyi, primary, Choy, Wei Juin, additional, Alcaide, Abraham M., additional, Wang, Shuo, additional, Guenter, Sandro, additional, Leon, Jose I., additional, Monopoli, Vito Giuseppe, additional, Franquelo, Leopoldo G., additional, Liserre, Marco, additional, Galea, Michael, additional, Gerada, Chris, additional, and Buticchi, Giampaolo, additional

Published
2023
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11. Extremely Low Frequency PS-PWM Based Technique for Cascaded H-Bridge Converters With Grid Voltage Compensation Capability

Author

Alcaide, Abraham M., Monopoli, Vito Giuseppe, Rendine, Giuseppe, Bruno, Lara, Leon, Jose I., Liserre, Marco, and Franquelo, Leopoldo G.

Abstract

Cascaded H-bridge (CHB) converters are good candidates for many industrial applications. Among the modulation techniques that can be applied to CHB converters, the phase-shifted pulse width modulation (PWM) method (PS-PWM) provides very good harmonic quality being the most popular modulation technique at the expense of presenting high switching losses. On the contrary block switching technique as well as selective harmonic elimination/mitigation techniques provides lower switching frequency and losses with a lower harmonic quality. Additionally, with these techniques the converter operation becomes stiff. In this work a modification of PS-PWM based on an extremely low frequency carrier is proposed with the objective of achieving both low switching losses and an acceptable harmonic quality, simultaneously. The main advantage of the proposed solution is the capability of adjusting the phase-shift angle among the carriers to compensate for harmonic grid voltage disturbance. Several experimental results have been reported to demonstrate the good performance of the proposed modulation technique.

Published
2024
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12. An Improved Indirect Pulsewidth Modulation Technique for Modular Multilevel Converters

Author

Yin, Jiapeng, Dai, NingYi, Vazquez, Sergio, Marquez, Abraham, Leon, Jose I., Perez, Marcelo A., and Franquelo, Leopoldo G.

Abstract

For a modular multilevel converter (MMC) operating in the medium-voltage range, carrier-based pulsewidth modulation (PWM) methods are good options for modulating the converter, as harmonic contents of the phase voltage/current can be centered around the carrier frequency and/or its multiples. However, in the relevant literature, arm voltage references are mostly normalized by the submodule (SM) capacitor voltage reference, leading to the so-called direct modulation, while the indirect modulation considering the capacitor voltage ripples receives much less attention. This article investigates the indirect modulation of MMCs, focusing on a specific PWM method where only two SMs per phase operate in PWM mode in each control period. It is found that the direct PWM (DiPWM) generates phase voltages/currents that contain high-amplitude low-order harmonics, while the indirect PWM (IndiPWM) presents well-suppressed low-order harmonics but significant distortions around the carrier frequency. The cause of the above problem of the IndiPWM is revealed theoretically through Fourier analysis, and a solution with simple implementation is developed by rearranging the switching pulses of the PWM-mode SMs. Both simulations and experiments are carried out. The results show that the proposed method combines the advantages of both DiPWM and IndiPWM, achieving low harmonic distortions simultaneously in the low frequency and around the carrier frequency.

Published
2024
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13. Computationally Efficient Sphere Decoding Algorithm Based on Artificial Neural Networks for Long-Horizon FCS-MPC

Author

Zafra, Eduardo, Granado, Joaquin, Lecuyer, Vicente Baena, Vazquez, Sergio, Alcaide, Abraham M., Leon, Jose I., and Franquelo, Leopoldo G.

Abstract

Successful application of finite control set model predictive control strategies with long prediction horizon depends on the careful design of the optimization algorithm. The conventional method involves transforming the problem to an equivalent box-constrained integer least-squares formulation that can be solved with branch-and-bound techniques, such as the sphere decoding algorithm (SDA). In this work, it is proposed to define an artificial neural network (ANN) to replace the SDA, avoiding its inherent computational variability. Similarly to practical applications of the SDA, the ANN finds an approximate solution of the underlying optimization problem. In contrast, the main benefit of the proposed approach is that it can be implemented in a low-cost microprocessing platform, greatly improving the performance in terms of resources in comparison with other advanced techniques proposed in the literature.

Published
2024
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14. Prediction Window Selection in FCS-MPC for Two-Level VSI Applications

Author

Zafra, Eduardo, Vazquez, Sergio, Dragicevic, Tomislav, Alcaide, Abraham M., Leon, Jose I., and Franquelo, Leopoldo G.

Abstract

Semiconductors in power converters are operated in switched-mode. For a given sampling frequency, a digital controller computes the next actuation according to several objectives. Typically one desires to regulate current or voltage values with minimal error and harmonic distortion. Higher switching frequency of the semiconductor is helpful as the granularity of the problem is improved and the harmonic spectrum is shifted toward high-order harmonics that are easier to filter with passive elements. However, the switching losses increase. Finite control set model predictive control (FCS-MPC) is proven to be an excellent control method with a great ability to maximize harmonic quality in terms of the switching frequency, particularly when the controller is configured to consider long prediction horizons. Nonetheless, in order to avoid computational overruns, the prediction horizon and the sampling frequency cannot be indefinitely increased. In this article, the tradeoff between these two parameters is studied, providing guidelines on FCS-MPC tuning for different configurations.

Published
2024
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22. Lifetime Extension Approach Based on the Levenberg–Marquardt Neural Network and Power Routing of DC–DC Converters

Author

Zhang, Jiusi, Tian, Jilun, Alcaide, Abraham M., Leon, Jose I., Vazquez, Sergio, Franquelo, Leopoldo G., Luo, Hao, and Yin, Shen

Abstract

The power conversion system based on the modular connection has widespread applications in various power electronic systems. To accurately estimate the state of health without recognizing the systematic mathematical model and to extend the lifetime, this article proposes a lifetime extension approach based on the Levenberg–Marquardt back propagation neural network (LM-BPNN) and power routing of interleaved dc–dc boost conversion systems. The LM-BPNN model is constructed based on the voltage, current, and temperature data generated by the system. On the basis of the trained LM-BPNN, the real-time cumulated damage estimation of each power cell in the conversion system can be accomplished. Applying the power routing concept, the dc–dc boost conversion system allocates different power to the cells according to the cumulated damage of each cell, thereby delaying the failure of cells with higher cumulated damage. Numerical simulation results show that the proposed lifetime extension approach can extend the overall system lifetime. Furthermore, an experimental setup of the interleaved dc–dc boost conversion is constructed to verify the proposed approach, which is of great significance for predictive maintenance in the industrial system.

Published
2023
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32. A Single DC-Link Multilevel 42-Sided Polygonal Voltage Space Vector Generation With Lower Order Harmonic Suppression Using Switched-Capacitor Filter.

Author

Dewani, Rahul, Gopakumar, K., Loganathan, Umanand, Franquelo, Leopoldo G., and Rajashekara, Kaushik

Subjects
VECTOR spaces, HARMONIC distortion (Physics), INDUCTION motors, VOLTAGE, REACTIVE power, MOTOR drives (Electric motors)
Abstract

In this work, a multilevel 42-sided polygonal space vector structure for suppression of lower order harmonics for open-end induction motor (OEIM) drive applications is proposed. The proposed power circuit topology consists of two inverters feeding an OEIM from either side. The main inverter fed with a single dc-link providing active power for motoring operation is switched at low switching frequency. The secondary inverter fed with a capacitive supply is switched at high frequency to suppress lower order harmonics upto 39th order, up to the base speed of operation allowing maximum utilization of the dc-link. The advantages of lower order harmonic suppression in motor phase voltage, for polygonal space vector structures, are combined with multilevel inverter topology. This offers various advantages like multilevel operation with low inverter switching for the main power delivery inverter and harmonic suppression throughout the modulation range. The low switching frequency primary inverter generates harmonics of the order $6*k \pm 1$ , where $k = 1, 2, 3,{\ldots }$. The harmonics are suppressed by the capacitor-fed secondary inverter, which supplies only reactive power for suppression of lower order harmonics in motor phase voltage. Use of a single dc-link facilitates four-quadrant operation of the inverter. The proposed scheme is validated for steady-state and dynamic performance by experimental results. [ABSTRACT FROM AUTHOR]

Published
2022
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