Angel Navarro-Rodriguez

This paper presents a rolling horizon-based energy exchange in a building-to-building (B2B) grid using a game theory method. The system combines the predictive capability of long-short-term memory (LSTM) based machine learning forecasting with game theory-based energy exchange decisions, enabling informed energy exchange decisions between participating buildings. A customized LSTM model is implemented to improve forecasting, utilizing adaptable hyperparameters, lookback windows, and a 24-hour forecast horizon to accommodate individual building photovoltaic (PV) generation and load energy profiles. The system formulates the energy exchange between the buildings in a non-cooperative Stackelberg game. The proposed model is analyzed, and a comparison is carried out for a game theory-based model without a forecast, with an LSTM-based forecast, and with a perfect forecast, considering four buildings with PV generation and load profile measurements from Barcelona, Spain. The proposed model with an LSTM-based and perfect forecast has a percentage cost saving of 2.67 % to 28.63 % and 3.33 % to 58.82 %, respectively. The sensitivity of the proposed model to energy storage capacity change and utility grid price variations is also studied. The proposed model demonstrates scalability by efficiently optimizing energy exchange with a higher number of buildings with optimal execution times, showcasing its ability to handle larger, more complex networks while maintaining reasonable computational performance.

En un trabajo anterior, los autores presentaron la herramienta SIMBIKE ELECTRIC, la cual permitía estimar las prestaciones globales, el consumo energético y los flujos de calor generados por los componentes eléctricos de una moto de competición eléctrica rodando en un circuito de velocidad. Esta herramienta utilizaba modelos muy simplificados tanto de la parte eléctrica y térmica como de la dinámica vehicular y estaba destinada a analizar de manera aproximada distintas configuraciones de geometría y puesta a punto básica de la motocicleta con el objetivo de optimizar su diseño y su uso. Durante la validación experimental de la herramienta se apreciaron una serie de aspectos susceptibles de mejora como son el modelo de piloto utilizado, la trazada realizada, la existencia de peralte lateral en algunas curvas o la bajada de ciertas prestaciones conforme desciende el voltaje de la batería. En base a lo anterior, se ha desarrollado una nueva versión de la herramienta SIMBIKE ELECTRIC que incorpora cambios en la discretización de la trazada en sectores, incorporando distintos tipos de curvas, en la dinámica vehicular y el modelo de piloto a utilizar en los sectores tipo curva y en el modelo eléctrico para conseguir un ajuste mejor a los resultados experimentales. Esta nueva versión se ha validado comparando los resultados de la simulación con los obtenidos por la motocicleta eléctrica del equipo de la Universidad de Oviedo en las pruebas dinámicas de la competición Motostudent Electric en el circuito de Motorland Aragón.

In this paper, a new method for the delay compensation when using an aggregation of virtual synchronous generators is proposed. Lack of inertia in power converters can potentially provoke stability issues that can be mitigated by the use of virtual inertia techniques. Among those, the Virtual Synchronous Generator (VSG) concept has received strong impulse in the last years. This paper is focused on the idea of using the distributed VSG concept in a renewable power plant, in which a single Synchronous Central Angle Controller (SCAC) is used for the power control exchange at the Point of Connection (PoC), while distribution control units are employed for the local inverter control. This idea, already discussed in the literature, is in here extended to consider the implementation on industrial string-level commercial power converters, recalling the importance of accessible measurements and communication delays. In order to validate the proposal, firstly communication delays are measured and modelled. Following, simulations with different SCAC operating modes are conducted, and finally experimental results validation of different operation modes with commercial converters are presented.

This article proposes a new control strategy for power electronic converters interfacing two dc networks. The proposed control, based on a modification of the dc virtual generator concept, has grid-forming capability in both sides of the converter simultaneously without intermediate energy storage device. Departing from the dc virtual generator control concept, capable of controlling voltage in one of the converter sides while withdrawing the power from the other side, an adaptation is done to make it reversible. A priority weight is assigned to each side voltage control. A weight calculation method, proportional to the voltage deviation from its rated value, is proposed. This weight calculation strategy makes the control system to contribute to the side most in need (using voltage deviation with respect to rated value as an indicator of the neediness). The interlinking converter with the proposed weighted strategy is capable of stable work in grid-forming mode at both sides simultaneously, just requiring a grid-feeding converter with $P/V$ droop to be connected in either side. No control architecture was found in the literature with this capability for dc–dc interlinking converters. The theoretical discussion has been supported with small-signal analysis and hardware-in-the-loop validation.

This paper proposes a novel droop technique for AC microgrids with no frequency deviation in steady-state. This droop implementation replaces the conventional $P/f+Q/V$ and $P/V+Q/f$ for inductive and resistive lines respectively by a $S/V_{dq}$ complex-valued droop in which the coupling terms that appear when the line is not purely inductive/resistive are considered. The proposed droop departs from the conventional approach by considering the $dq$ -decomposition instead of calculating $P$ and $Q$ expressions derived from the voltage polar equation, which requires sine and cosine terms. This allows to create a droop combining both voltage components versus $P$ and $Q$ , without requiring small-signal simplification of the trigonometric functions (\boldmath $\sin {\delta }\approx \delta$ and \boldmath $\cos {\delta }\approx 1$ ) and taking into account the coupling terms. In that way, the designed droop is valid for any $R/X$ ratio. The discussion is supported with small-signal analysis and hardware-in-the-loop validation.

This article analyzes the dynamic behavior of the voltage control loop based on proportional-integral regulators, commonly used for grid-forming converters in 3-phase AC and DC Microgrids and applications that involve a DC-link voltage control. The article proposes a simple and accurate generalized analysis useful both for the system characterization and design. Two different control schemes, based on linear (Direct Voltage Control, DVC) and quadratic voltage feedback (Quadratic Voltage Control, QVC), are analytically studied, simulated and experimentally tested, demonstrating a superior performance of the QVC under the presence of constant power loads. The operation limits, the system stability and the disturbance rejection capability are analyzed considering the effect of control and plant parameters and the effect of the different types of disturbances and the operating point, taking into account the non-linearities of the system. The analysis is mainly focused on the effect of constant power loads given their negative impact on the system performance. The study provides a generic procedure for the analysis and design of proportional-integral voltage controllers, including the selection of the system capacitance for meeting specific dynamic specifications while considering system characteristics as the load level, the stability margins and the maximum voltage deviation under disturbances.

This paper proposes an online grid impedance estimation method for AC Grids under the presence of grid-tied converters. A novel modelling approach in the α,β,0 reference frame is proposed, including the relationship with the instantaneous power theory. The proposed modelling framework considers both balanced and unbalanced conditions and operation in the four quadrants. For the impedance identification, a Pulsed Signal Injection (PSI) approach together with a Recursive Least Square (RLS) algorithm is used. The proposed modelling and identification method is thoroughly evaluated by simulation and experimental results. The work presents a contribution for the optimization of the distribution grid operation with high-dynamic impedance changes due to the integration of distributed resources.