Experimental Hybrid AC/DC-Microgrid Prototype for Laboratory Research Enrique Espina 1,2 , Claudio Burgos-Mellado 3 , Juan S. G ´ omez 1 , Jacqueline Llanos 4,1 , Erwin Rute 1 , Alex Navas F. 1 , Manuel Mart´ ınez-G´ omez 1 , Roberto C´ ardenas 1 , and Doris S´ aez 1 1 University of Chile, Santiago, Chile. 2 University of Santiago, Santiago, Chile. 3 PEMC, University of Nottingham, Nottingham, UK. 4 Universidad de las Fuerzas Armadas ESPE, Sangolqui, Ecuador. 1 Email: eespina@uchile.cl Acknowledgments This work was supported by CONICYT-PCHA/Doctorado Nacional/2017-21171858, 2019-21190961, 2019-21191757, by SENESCYT-CZ03-000368-2018, in part by FONDECYT 1180879 & FONDECYT 1170683, in part by SERC-Chile ANID/FONDAP/15110019, in part by FONDEQUIP EQM130158, and in part by AC3E Basal Project FB0008. Keywords ≪Hybrid microgrid≫, ≪AC/DC microgrid≫, ≪Experimental prototype≫, ≪Laboratory research≫, ≪Testbed microgrid≫. Abstract This paper describes a flexible testbed of a hybrid AC/DC microgrid developed for research purposes. The experimental setup is composed of 3 AC and 6 DC distributed generator units which are emulated by using three-legs inverters and settable output filters. The microgrid architecture allows to validate control schemes upstream of the modulation stage of each inverter, by using real-time targets and Mat- lab/Simulink interface. Two independent real-time communication networks can be used. The first one is based on optical fibre technology, whereas the second one is an Ethercat communication network. Both of them are used for instrumentation purposes and to implement the primary control level of the micro- grid. To implement secondary control schemes into the microgrid (or higher control levels), an additional optical fibre-based network is used, allowing to emulate scenarios with or without communication issues such as latency, data-losses and topology changes. The built microgrid can be splitted into AC-side (3 and/or 4 wires), DC-side and interlinking-side, where both the AC and the DC side can be operated inde- pendently, according to the required electrical topology. In this testbed, several control schemes, such as proportional-integral, proportional-resonant or predictive controllers, have been investigated. Realised experimental tests include load changes, plug-and-play and communication issues scenarios. Introduction The concept of microgrid (MG) refers to a flexible and modular power generation and distribution sys- tem, i.e. distributed generators (DGs) are located near local loads completing an autonomous electrical system, which can operate in either ‘grid-connected’ or ‘islanded’ mode [1]. This concept is especially useful when combined with converter-based DG technologies, including Battery Energy Storage Systems (BESS), and the stochasticity of Low-Voltage (LV) conventional distribution networks. MGs have three main architectures depending on their voltage nature, which are: (i) AC, (ii) DC and (iii) hybrid AC/DC. The latter combines the benefits of both MGs through bi-directional interlinking converters (IC). Fur- thermore, hybrid MGs enhance reliability (as power can be transferred bidirectionally through the IC) while reducing power conversion stages and losses (by up to 30%) [2]. For these reasons, hybrid MGs have become a focus to conduct research at a laboratory level.