Browsing by Keyword "Optimization algorithms"
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Item Circulating Current Control for Modular Multilevel Converters with (N+1) Selective Harmonic Elimination - PWM(2020-08) Perez-Basante, Angel; Ceballos, Salvador; Konstantinou, Georgios; Pou, J.; Sanchez-Ruiz, Alain; Lopez, Iraide; Martinez de Alegria, Inigo; POWER ELECTRONICS AND SYSTEM EQUIPMENTModular multilevel converters (MMCs) require control of the circulating current, i_circ, to improve their operation and efficiency. This is particularly important when low switching frequency modulation techniques, such as selective harmonic elimination (SHE-PWM) are applied. This work provides a novel method to control the circulating current along with (N+1) SHE-PWM. Unlike the case of (2N+1) SHE-PWM, explicit redundant levels are not available and, therefore, different modulation indexes, m_1 and m_2, are employed in the upper and lower arms to obtain the desired modulation index m_a. Unlike previous (N+1) circulating current methods, the distances between m_a, m_1 and m_2 remain constant to not disturb the phase output voltage, with an interchange of m_1 and m_2 between the arms used to follow the desired i_circ. The control adjusts the dc component of the circulating current and the energy stored in the SMs to their references, while maintaining the energy balance between the upper and lower arms. Simulation tests and experimental results, obtained from a single-phase laboratory prototype MMC, validate the proposed control technique.Item PIACERE: Programming trustworthy Infrastructure As Code in a Secure Framework(CEUR-WS, 2021-03) Alonso, Juncal; Joubert, Christophe; Orue-Echevarria, Leire; Pradella, Matteo; Vladušič, DanielInfrastructure-as-Code (IaC), enables the automation of several deployment, configuration and management tasks. IaC has a lot of potential in cloud computing as it results in a significant saving of time when an application needs to be redeployed on a different set of resources, even running on different infrastructures. Unfortunately, IaC still suffers from some important issues, such as the large variety of competing tools or the strong orientation toward the cloud, leaving aside e.g. the edge. Also, trustworthiness and security aspects of are often left for the end of the cycle, where errors and vulnerabilities are often too late or too expensive to correct. We present here the PIACERE project, which provides tools, methods and techniques for the Infrastructure-as-Code approach. The project will make the creation of IaC more accessible to designers, developers and operators, increasing the quality, security, trustworthiness and evolvability of infrastructural code while ensuring its business continuity by providing self-healing mechanisms anticipation of failures and violations.