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Ensuring service continuity in safety critical applications is crucial. In some of these applications, multilevel converters play a vital role. In this regard, this research work presents a self-healing fault-tolerant control approach to ensure the resiliency of a neutral-point clamped converter when a semiconductor component encounters an open circuit fault. The defective semiconductor can be a power switch or a clamping diode. By applying the proposed real-time fault-tolerance control, the rated output voltage and output current are restored during post-fault operation. Furthermore, the total harmonic distortion value of the output voltage during application of the real time self-healing control does not increase when compared with that during healthy operation. Since the realization of the proposed control strategy does not require any bidirectional switch, a fast transition between the healthy and fault-tolerant operation is accomplished. Moreover, the proposed structure can ensure service continuity in case of a fault event in the anti-parallel diodes, something which has been overlooked in previously conducted research works. [ABSTRACT FROM AUTHOR]

Therefore, Konstantinou et al. [[4]] intended to design a TEG system that produced the maximum power possible using the exhaust gases of a maritime internal combustion engine. Waste heat present in exhaust gas produced from various industrial processes or internal combustion engines in transport are a reservoir of untapped energy. According to Sousa et al. [[2]], to maximize the exploitation of the TEG, the operation should take place at a uniform temperature near the temperature limit of the TEG. [Extracted from the article]

Energy harvesting has become a promising and alternative solution to conventional energy generation patterns to overcome the problem of supplying autonomous electrical systems. More particularly, thermal energy harvesting technologies have drawn a major interest in both research and industry. Thermoelectric Generators (TEGs) can be used in two different operating conditions, under constant temperature gradient or constant heat flow. The commonly used TEG electrical model, based on a voltage source in series with an electrical resistance, shows its limitations especially under constant heat flow conditions. Here, the analytical electrical modeling, taking into consideration the internal and contact thermal resistances of a TEG under constant temperature gradient and constant heat flow conditions, is first given. To give further insight into the electrical behavior of a TEG module in different operating conditions, we propose a new and original way of emulating the above analytical expressions with usual electronics components (voltage source, resistors, diode), whose values are determined with the TEG's parameters. Note that such a TEG emulation is particularly suited when designing the electronic circuitry commonly associated to the TEG, to realize both Maximum Power Point Tracking and output voltage regulation. First, the proposed equivalent electrical circuits are validated through simulation with a SPICE environment in static operating conditions using only one value of either temperature gradient or heat flow. Then, they are also analyzed in dynamic operating conditions where both temperature gradient and heat flow are considered as time-varying functions. [ABSTRACT FROM AUTHOR]

In this paper, a comparative analysis has been presented of two equivalent circuits of non-isolated buck/buck-boost converters under synchronous control, used in a stand-alone Photovoltaic-battery-load system. The first circuit consists of two cascaded buck and buck-boost classical converters with two controllable switches. The buck converter is used to extract the maximum power of the Photovoltaic source, and the buck-boost converter is applied for the output voltage level control. The second circuit consists of a proposed converter with a single controllable switch. In both cases, the switching frequency is used to track the maximum power point and the duty ratio controls the output voltage level. Selected simulation results and experimental tests confirm that the two conversion circuits have identical behavior under synchronous control. This study shows that the single switch converter has a lower size and cost, but it is limited in the possible control strategy. [ABSTRACT FROM AUTHOR]

Numerous advantages offered by Photovoltaic (PV) generation systems coupled with the increasing power demands for clean energy put PV systems in the front of many research works. For stand-alone applications powered with PV systems, the reliability of the power conversion stage is essential to ensure the continuous supply of energy. Therefore, in the case of any failure occurring in the power conversion stage, it is mandatory to provide remedial actions to guarantee the service continuity of the produced electrical power. This paper analyses the service continuity of a two-stage buck/buck-boost converter with energy storage, driven with synchronous control. The initial two-stage converter is made fault-tolerant and robust to failures of its two switches by adding only one additional switch associated with two diodes. In this study, only open-circuit switch faults are considered. The proposed fault-tolerant circuit and the initial one have the same electrical behavior when synchronous control is used. The applied synchronous control in both healthy conditions and post-fault operation ensures the same functionalities without degrading the system’s performances. The proposed two-stage synchronously-controlled circuit is validated through simulation in the cases of open circuit faults on the two switches of the initial converter. The obtained results show the feasibility of the proposed functional redundancy and the continuity of operation at full power after switch fault diagnosis. [ABSTRACT FROM AUTHOR]