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In this paper, the modeling of storage elements and a unified theory liberated of the I–V characteristics of a specific technology is developed. First, the definition of an ideal storage element with limited energy capacity is presented, then the semiideal storage properties are discussed. The addition of power conservative two-port network denoted POPI (Pout = Pin) is added in order to define a flexible storage element in terms of characteristics. The paper demonstrates the theory by examples of storage elements integrated in power electronics systems. The ideas and methodology presented in this work can be applied to power electronics applications as well as power systems, smart grids, and microgrids, where storage is an important factor. [ABSTRACT FROM AUTHOR]

Non-intrusive load monitoring is an algorithm or process that disaggregates the total power in a facility to identify consumption of individual appliances. In this paper, a new algorithm is proposed to classify events of appliance states based on modification of the cross-entropy (CE) method. The main contribution is a formulation and solution of the problem with the CE method as a constrained optimization problem. This new technique is called the modified CE method. The proposed algorithm is simple, as it operates in real time, using low rate sampling of the active power. In addition, there is no need to train the system or to use complex hardware. The algorithm is tested using the REDD and AMPds datasets and the results are compared to several state-of-the-art techniques. [ABSTRACT FROM AUTHOR]

The realization of capacitive converters based on a modular approach is presented and analyzed in this paper. The converters are based on topologies with identical capacitors. First, the switching network (SN) of a basic series–parallel topology is presented. The analysis reveals the assembly and growth rules for expanding the topology to any number of capacitors. Subsequently, the SN for the more versatile and complex general transposed series–parallel (GTSP) topology is presented. The topology is expanded by defining a basic cell comprising a capacitor and five peripheral switches. The expansion of this converter improves its performance by ameliorating accuracy and regulation in the dc/dc voltage ratio. The control schemes of these converters are also presented with emphasis on the GTSP topology, whose switches are not assigned in advance. The control scheme for achieving the desired voltage ratio is described. A five-capacitor converter with its control is built to illustrate the theory in open-loop mode, which provides experimental results that are in full agreement with the analytical predictions. [ABSTRACT FROM PUBLISHER]

Energy storage may improve power management in microgrids that include renewable energy sources. The storage devices match energy generation to consumption, facilitating a smooth and robust energy balance within the microgrid. This paper addresses the optimal control of the microgrid's energy storage devices. Stored energy is controlled to balance power generation of renewable sources to optimize overall power consumption at the microgrid point of common coupling. Recent works emphasize constraints imposed by the storage device itself, such as limited capacity and internal losses. However, these works assume flat, highly simplified network models, which overlook the physical connectivity. This work proposes an optimal power flow solution that considers the entire system: the storage device limits, voltages limits, currents limits, and power limits. The power network may be arbitrarily complex, and the proposed solver obtains a globally optimal solution. [ABSTRACT FROM PUBLISHER]