This paper presents a current controller that shapes, in the frequency domain, the input admittance of VSC converters connected to the grid. The controller is obtained by means of a H∞ synthesis procedure, which minimizes the difference between the application closed-loop input admittance and a modelreference defined by the designer. This formulation achieves good accuracy in both modulus and phase. The proposed methodology allows the fulfilment of other current control objectives, such as current tracking, by defining frequency regions where each objective is desired. Experimental results show the good response of the proposed controller, both in frequency and time domain.

Since the advent of the microgrid (MG) concept, almost two decades ago, the energy sector has evolved from a centralized operational approach to a distributed generation paradigm challenged by the increasing number of distributed energy resources (DERs) mainly based on renewable energy. This has encouraged new business models and management strategies looking for a balance between energy generation and consumption, and promoting an efficient utilization of energy resources within MGs and minimizing costs for the market participants. In this context, this paper introduces an efficient management strategy, which is aimed at obtaining a fair division of costs billed by the utilities, without relying on a centralized utility or MG aggregator, through the design of a local event-based energy market within the MG. This event-driven MG energy market operates with blockchain (BC) technology based on smart contracts for electricity transactions to both guarantee veracity and immutability of the data and automate the transactions. The event-based energy market approach focuses on two of the design limitations of BC, namely the amount of information to be stored and the computational burden, which are significantly reduced while maintaining a high level of performance. Furthermore, the prosumer data is obtained by using IEC 61850 standard-based commands within the BC framework. By doing so, the system is compatible with any device irrespective of the manufacturer implementing the IEC 61850 standard. The advantages of this management approach are considerable for: MG participants, in terms of financial benefits; the MG itself, as it can operate more independently from the main grid; and the grid since the MG becomes less unpredictable due to the internal energy exchanges. The proposed strategy is validated on an experimental setup employing low-cost devices.

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Abstract-This paper presents a novel active damping technique of current-controlled grid-connected power converters through LCL filters. Based on H∞ synthesis algorithms, a grid current controller is obtained so that the grid-connected power converted-based application admittance resembles a given frequency reference. By defining a low resistive admittance as the reference, considered application resonance is effectively damped, reducing grid current oscillations under grid voltage variations and avoiding their associated stability problems. Presented grid current controller senses only the PCC grid voltage and current, and is experimentally tested in both time and frequency domains. Additionally, the effectiveness of presented damping method is proved under different grid impedance scenarios.

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