Average Current Control with Internal Model Control and Real-time Frequency Decoupling for Hybrid Energy Storage Systems in Microgrids

Among hybrid energy storage systems(HESSs),battery-ultracapacitor systems in active topology use DC/DC power converters for their operations.HESSs are part of the solutions designed to improve the operation of power systems in different applications.In the residential microgrid applications,a multilevel control system is required to manage the available energy and interactions among the microgrid components.For this purpose,a rule-based power management system is designed,whose operation is validated in the simulation,and the performances of different controllers are compared to select the best strategy for the DC/DC converters.The average current control with internal model control and real-time frequency decoupling is proposed as the most suitable controller according to the contemplated performance parameters,allowing voltage regulation values close to 1%.The results are validated using real-time hardware-in-the-loop(HIL).These systems can be easily adjusted for other applications such as electric vehicles.

Optimal microgrid planning for enhancing ancillary service provision

Microgrids have presented themselves as an effective concept to guarantee a reliable,efficient and sustainable electricity delivery during the current transition era from passive to active distribution networks.Moreover,microgrids could offer effective ancillary services(AS)to the power utility,although this will not be possible before the traditional planning and operation methodologies are updated.Hence,a probabilistic multi-objective microgrid planning(POMMP)methodology is proposed in this paper to contemplate the large number of variables,multiple objectives,and different constraints and uncertainties involved in the microgrid planning.The planning methodology is based on the optimal size and location of energy distributed resources with the goal of minimizing the mismatch power in islanded mode,while the residual power for AS provision and the investment and operation costs of the microgrid in grid-connected mode are maximized and minimized,respectively.For that purpose,probabilistic models and a true multi-objective optimization problem are implemented in the methodology.The methodology is tested in an adapted PG&E 69-bus distribution system and the non-dominated sorting genetic algorithmⅡ(NSGA-Ⅱ)optimization method and an analytic hierarchy process for decision-making are used to solve the optimization problem.

Sizing and Siting of Battery Energy Storage Systems:A Colombian Case

This paper presents a mixed-integer linear programming(MILP)formulation for sizing and siting of battery energy storage systems(BESSs).The problem formulation seeks to minimize both operation costs and BESS investment.The proposed model includes restrictions of the conventional securityconstrained unit commitment problem,a piece-wise linear approximation to model power losses,and a linear model of hydro generation units.The proposed model is tested in a 6-bus test system and a 15-bus system representing the Colombian power system.For the two studied systems,simulation results show that the reduction of operation costs due to the installation of BESSs compensates the investments,under some of the considered technical cost cases.Additionally,results show that adequate sizing and siting of BESSs reduce renewable energy curtailment in the Colombian power system with high penetration of fluctuating renewable generation.