Search for: All records

In this work, a synchronous model for grid-connected and islanded microgrids is presented. The grid-connected model is based on the premise that the reference frame is synchronized with the AC bus. The quadrature component of the AC bus voltage can be cancelled, which allows to express output power as a linear equation for nominal values in the AC bus amplitude voltage. The model for the islanded microgrid is developed by integrating all the inverter dynamics using a state-space model for the load currents. This model is presented in a comprehensive way such that it could be scalable to any number of inverter-based generators using inductor–capacitor–inductor (LCL) output filters. The use of these models allows designers to assess microgrid stability and robustness using modern control methods such as eigenvalue analysis and singular value diagrams. Both models were tested and validated in an experimental setup to demonstrate their accuracy in describing microgrid dynamics. In addition, three scenarios are presented: non-controlled model, Linear-Quadratic Integrator (LQI) power control, and Power-Voltage (PQ/Vdq) droop–boost controller. Experimental results demonstrate the effectiveness of the control strategies and the accuracy of the models to describe microgrid dynamics. 

Microgrids, especially renewable-based, represent an opportunity to increase sustainability and resiliency in places prone to natural disasters. The aftermath of hurricane María accelerated the discussion in Puerto Rico about supporting microgrids as an energy policy and strategy to build a different power grid. This paper presents an overview of microgrid literature relevant to Puerto Rico and it is used to identify best practices. The paper also describes a recommended process for feasibility studies needed to develop a community microgrids based on distributed energy resources (DER). An example applying this process to an actual community wraps up the paper 

This paper presents a formal methodology for the analysis and design for discrete time proportional-resonant classic (PR) controllers applied to a single-phase DC/AC converter using Sisotool/Matlab tool. This tool allowed integrating and visualizes the classical control theory requirements (overshoot, settling time, etc.) with the design of Proportional Resonant (PR) controllers. Simulations results demonstrate the effectiveness of the methodology presented for the design of PR controllers. 

This paper presents a voltage control design algorithm for a three-phase voltage source converter (VSC) connected to a linear load using a passive LCL filter. The controller is based on an optimal regulator, combined with the integral of the voltage error, which is called LQI that achieves null tracking of the error. The main objective of this paper is to present an algorithm to design a voltage controller through frequency analysis of the singular values of the system, the weight of the states involved in the system, the movement of the closed poles and their respective step response to evaluate performance and robustness against load changes. The simulation results show a satisfactory operation of the voltage controller with fast recovery after a resistive load change 

This document presents the develop and implementation of a low-cost research platform based on a microcontroller. The platform was validated through implementation of a resonant controller in αβ-frame for Inverter-Based Generators. Also, this work proposes a comparative analysis between a dSPACE 1006 and the embedded systems for control applications in inverter-based generators (IBGs). For the development of the research platform, a microcontroller from the Texas Instruments TMS320F28379D C2000 line was used. Our analysis revealed that control behavior for IBG applications through a low-cost platform based on a microcontroller is similar to that of a dSPACE. 

In this paper, a microgrid scenario composed by a PV generator, a battery system and residential loads in a power Hardware-in-the-Loop (HIL) platform is developed and tested. The electrical structure of the system, the component software modelling and hardware implementation are described. This paper proposes an EMS for microgrid power balance and execution of Time of Use (TOU) and load shedding Demand Response (DR) functions. Experimental results of each component of the scenario are shown.