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A model predictive control (MPC) strategy based on optimal switching sequence concepts is presented for direct power control of grid-connected three-level neutral-point clamped converters. The proposed control strategy explicitly considers the modulator in its formulation along with the model of the system. Through two well-formulated optimal control problems, the proposed strategy is shown to optimally achieve control of the average trajectory of the active and reactive powers as well as the dc-link capacitor voltages without using weighting factors to tradeoff both control targets. Experimental results demonstrate this strategy produces improved steady-state performance with a well-defined output voltage spectrum and fixed-switching frequency while maintaining the inherent fast dynamic responses of MPC strategies. [ABSTRACT FROM AUTHOR]

In this paper, a novel reaching law for discrete-time sliding-mode control is proposed. The reaching law is established based on an exponential term that dynamically adapts to the variation of the switching function. The difference function is also employed to redefine the change rate as the second-order difference of the disturbance. Unlike existing works, the proposed reaching law is able to guarantee smaller width of the quasi-sliding-mode domain (QSMD) while decreasing the reaching time in the same time. The ultimate magnitude of the QSMD in proposed method is of the order O(T3). Moreover, the reaching steps for the system to converge to the sliding surface are obtained and the system dynamics in and out the QSMD are theoretically analyzed. Both numerical simulations and experimental investigations on a piezoelectric actuator are employed to validate the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]

There is a clear trend to increase the use of electrical systems in aircrafts, leading to a growing demand for electrical power in the aircraft. This increasing power consumption has resulted in increasing dc voltage levels, to reduce energy losses and the size of wiring, as a result of the reduced current levels. However, traditional protections such as circuit breakers are not adequate for the protection of the new systems in high dc voltage, and consequently, it is necessary to introduce new technologies in the field of protection devices. One of these is the solid-state power controller (SSPC), which combines the functions of connecting loads to the bus bars and protecting electrical installations against overload and short circuits. On the other hand, within these electrical systems, the connection of certain loads, such as highly capacitive ones (dc–dc, inverters, etc.), implies the need to develop new control strategies to improve the connection process by SSPCs. This paper presents and analyzes a new advanced control strategy that optimizes the performance during the connection of highly capacitive loads using SSPCs. [ABSTRACT FROM PUBLISHER]