This research deals with the efficiency comparison between AC and DC distribution networks that can provide electricity to rural and urban areas from the point of view of grid energy losses and greenhouse gas emissions impact. Configurations for medium- and low-voltage networks are analyzed via optimal power flow analysis by adding voltage regulation and devices capabilities sources in the mathematical formulation. Renewable energy resources such as wind and photovoltaic are considered using typical daily generation curves. Batteries are formulated with a linear representation taking into account operative bounds suggested by manufacturers. Numerical results in two electrical networks with 0.24 kV and 12.66 kV (with radial and meshed configurations) are performed with constant power loads at all the nodes. These simulations confirm that power distribution with DC technology is more efficient regarding energy losses, voltage profiles and greenhouse emissions than its AC counterpart. All the numerical results are tested in the General Algebraic Modeling System widely known as GAMS.

In this paper, a control strategy for an isolated DCDC dual active bridge converter to adapt different voltage levels in a DC microgrid is proposed. The control strategy allows regulating the output voltage while maintaining in zero the mean value of the current in the high frequency transformer. The system is represented with a linearized version of its generalized average model and the controller is designed using classical techniques. The performance of the proposal is validated with simulations and experimental results.

A new controller for a grid connected inverter with an LCL filter is proposed in this paper. The system is described by its complex representation and the controller is designed using the complex root locus method. The complex representation allows a considerable reduction in the order of the system, simplifying the design task and making it possible to use of advanced techniques such as the complex root locus. The new complex controller adds an extra degree of freedom that makes it possible to move the poles of the systems, and improve stability and speed of response compared to the conventional controls. The paper include a detailed discussion of the effect of the gains of the controller on the root locus. The proposal is validated with simulation and experimental results.

This paper addresses the optimal dispatch problem for battery energy storage systems (BESSs) in direct current (DC) mode for an operational period of 24 h. The problem is represented by a nonlinear programming (NLP) model that was formulated using an exponential voltage-dependent load model, which is the main contribution of this paper. An artificial neural network was employed for the short-term prediction of available renewable energy from wind and photovoltaic sources. The NLP model was solved by using the general algebraic modeling system (GAMS) to implement a 30-node test feeder composed of four renewable generators and three batteries. Simulation results demonstrate that the cost reduction for a daily operation is drastically affected by the operating conditions of the BESS, as well as the type of load model used.

An interconnection and damping assignment (IDA) controller is proposed for regulating the output voltage and frequency of a three-phase DC–AC converter, independently of the supplied load. A modified IDA strategy is used to design the controller, in order to obtain a proper tracking of the reference variables. Moreover, the closed-loop stability is ensured through a proper choice of the desired energy function. Different from classical approaches, such as conventional PI control in dq coordinates, the proposed controller provides a better dynamic response while it allows performing a joint design of the voltage and current control loops. Besides, the proposed modified IDA design allows a more precise output voltage control when supplying nonlinear loads, when compared with the classical IDA design. Simulations and experimental results are presented for validating the proposal.