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Synchronization of single-phase inverters is a challenging task due to the difficulty of deriving a rotating voltage frame, in the absence of adequate information from the other two phases. Moreover, modern standards, such as the fault ride-through (FRT) directives, require inverter-based distributed generators (IBDGs) to respond as fast as possible to grid disturbances; thus, it is necessary to rely on accurate and fast synchronization algorithms. The scope of this paper is to propose a new synchronization technique, which satisfies three important requirements: a) fast dynamic response, b) adequate double frequency rejection, c) low computational complexity. Our synchronization technique is a flexible method relying on variable-length transfer delay, which calculates network frequency by analyzing voltage angle differentials. To enhance this differentiation process and address potential discontinuities, we introduce Heaviside-based functions. Both simulations conducted in MATLAB/Simulink and experimental trials demonstrate that our proposed synchronization method outperforms the most widely adopted existing techniques in terms of dynamic response and computational efficiency. Due to its excellent dynamic performance, the proposed method can offer a stable FRT capability, with fast detection of the voltage dips and seamless resynchronization following fault clearance, all while preventing DC-link overvoltage issues.

This work introduces a compensation scheme that uses a genetic algorithm to mitigate the 2nd voltage harmonic component of hybrid microgrids. The foremost advantage of the proposed scheme, is its capability to effectively compensate the 2nd harmonic component regardless of the feeder impedance, the location of the equipment and without any need for real-time communications. A graphical representation of the genetic algorithm parameters is also presented, being a handily tool for designing it for any microgrid application and the mathematical analysis of hybrid microgrids under the prospect of harmonic compensation is given. Simulations and experimental tests verify the effectiveness of the proposed method, indicating that its efficiency is maintained at about 90%, while the efficiency of the other methods falls below 35% when the impedance of the connection line increases at $1+\,\,\text{j}0.16\,\,\Omega _{\mathrm {(\text{@}100 Hz)}}$ . Finally, a comparative analysis is also performed between the proposed method and existing ones.

This paper presents a transmitter side control scheme for a series-series compensated wireless power transfer (SS-WPT) system for electric vehicle (EV) charging applications. The proposed control scheme matches the reflected load impedance, by controlling accordingly the front-end dc-dc converter (FEC) of the SS-WPT system. The proposed control scheme drives the FEC, through an optimizer which takes into account the misalignment but also the operational conditions of the system to achieve high efficiency throughout the entire charging process - regardless the EV type, the misalignment conditions or the on-board charger. The novelty of the proposed optimizer lies upon its universal characteristic, which makes it compatible to various SS-WPT topologies. As such, the proposed charging concept is a universal solution, which optimizes the system efficiency regardless the receiver side on-board charger topology (single-stage or double-stage), technical characteristics or control scheme that implements the charging profile. Finally, for the necessary communication between the transmitter and the receiver sides, the Internet of Things (IoT) is employed, offering a low-cost and flexible solution that overcomes compatibility problems between wireless antennas. Simulation and experimental results validate the feasibility of the proposed control scheme, highlighting the efficacy of the proposed wireless charging process.

To increase the reliability of aerospace electronics and reduce their overall power consumption, we investigated the possibility of incorporating active thermoelectric cooling (TEC) solutions. The harsh avionic environment demands sophisticated active control schemes that enable the achievement of high coefficient of performance. The positive effect of active PWM control has been validated both in simulation and on a working laboratory prototype that allowed us to clarify the pros and cons of the incorporation of TEC techniques in avionics applications. This paper has been performed under the framework of CLEAN SKY-THERMICOOL project.

Standalone photovoltaic systems is a key technology for the increase of renewable energy sources share in electricity production worldwide. The power quality of those systems plays a fundamental role in avoiding volatile power supply. This calls for a concrete design in order to meet power quality specifications. In this context, a methodology has been developed in a previous work, in order to set the values of the parameters that optimize the power quality indices of the system. In this paper, an extensive sensitivity analysis is performed regarding the influence of the optimized parameters variation on the power quality indices. Throughout the outcomes of the sensitivity analysis a more insightful view of the system performance under the deviations of system parameters is revealed, which in combination with the aforementioned optimal design strategy becomes an essential tool that ensures high power quality level. The theoretical outcomes are validated by experimental results, highlighting the effectiveness of the proposed design strategy.