A global integral terminal sliding mode control based on a novel reaching law for a proton exchange membrane fuel cell system

Proton exchange membrane fuel cells are devices with huge potential for renewable and clean industries due to their high efficiency and low emissions. Since the proton exchange membrane fuel cell employed in this research supplied a low output voltage, it was encouraged to use a boost converter with a designed non-linear controller to provide a suitable end-user voltage. In this paper, we proposed a novel control framework based on sliding mode control, which is a global integral sliding mode control linked with a quick reaching law that has been implemented in a commercial fuel cell system Heliocentris FC50 through a dSpace 1102 control board. We compared the strategy with a conventional sliding mode controller and an integral terminal sliding mode controller where we addressed a Lyapunov stability proof has for each structure. We contrasted the experimental outcomes where we proved the superiority of the proposed novel design in terms of robustness, convergence speed. Additionally, as the sliding mode controllers are well known by the energy consumption caused by the chattering effect, we analysed every framework in these terms. Finally, it was found that the proposed structure offered an enhancement in the energy consumption issues. Moreover, the applicability of the proposed control scheme has been demonstrated through the real time implementation over a commercial fuel cell.The authors wish to express their gratitude to the Basque Govern-ment, through the project EKOHEGAZ (ELKARTEK KK-2021/00092) , to the Diputacion Foral de alava (DFA) , through the project CONA-VANTER, and to the UPV/EHU, through the project GIU20/063, for supporting this work. The authors wish to express their gratitude to the Basque Govern-ment, through the project EKOHEGAZ (ELKARTEK KK-2021/00092) , to the Diputacion Foral de alava (DFA) , through the project CONA-VANTER, and to the UPV/EHU, through the project GIU20/063, for supporting this work

Robust fault tolerant control of induction motor system

Research into fault tolerant control (FTC, a set of techniques that are developed to increase plant availability and reduce the risk of safety hazards) for induction motors is motivated by practical concerns including the need for enhanced reliability, improved maintenance operations and reduced cost. Its aim is to prevent that simple faults develop into serious failure. Although, the subject of induction motor control is well known, the main topics in the literature are concerned with scalar and vector control and structural stability. However, induction machines experience various fault scenarios and to meet the above requirements FTC strategies based on existing or more advanced control methods become desirable. Some earlier studies on FTC have addressed particular problems of 3-phase sensor current/voltage FTC, torque FTC, etc. However, the development of these methods lacks a more general understanding of the overall problem of FTC for an induction motor based on a true fault classification of possible fault types.In order to develop a more general approach to FTC for induction motors, i.e. not just designing specific control approaches for individual induction motor fault scenarios, this thesis has carried out a systematic research on induction motor systems considering the various faults that can typically be present, having either “additive” fault or “multiplicative” effects on the system dynamics, according to whether the faults are sensor or actuator (additive fault) types or component or motor faults (multiplicative fault) types.To achieve the required objectives, an active approach to FTC is used, making use of fault estimation (FE, an approach that determine the magnitude of a fault signal online) and fault compensation. This approach of FTC/FE considers an integration of the electrical and mechanical dynamics, initially using adaptive and/or sliding mode observers, Linear Parameter Varying (LPV, in which nonlinear systems are locally decomposed into several linear systems scheduled by varying parameters) and then using back-stepping control combined with observer/estimation methods for handling certain forms of nonlinearity.In conclusion, the thesis proposed an integrated research of induction motor FTC/FE with the consideration of different types of faults and different types of uncertainties, and validated the approaches through simulations and experiments