Journal of Control, Automation and Electrical Systems https://doi.org/10.1007/s40313-017-0365-4 Harmonic Compensation Using a Series Hybrid Filter in a Centralized AC Microgrid Hélio Marcos André Antunes 1 · Sidelmo Magalhães Silva 1 · Danilo Iglesias Brandao 1 · Alysson Augusto Pereira Machado 1 · Braz de Jesus Cardoso Filho 1 Received: 31 August 2017 / Revised: 11 November 2017 / Accepted: 27 December 2017 © Brazilian Society for Automatics–SBA 2018 Abstract The current context of microgrids shows a considerable and unprecedented increase in distributed generation. A microgrid is defined as a network of electricity users composed of distributed generators, loads and storage elements able to operate as a single entity connected or isolated from the main grid. However, the microgrids have usually low short-circuit power capabilities due to the distributed generators composed of electronic converters, which makes the system very susceptible to power quality problems. This article presents an analysis of the series hybrid active filter connected to a centralized AC microgrid, under low power quality issue operation in islanded and grid-connected modes. The paper evaluates the series hybrid filter performance in harmonic compensation and resonance damping capability through simulation analysis. The results show that a series hybrid filter is capable of enhancing the microgrid power quality, requiring a low nominal capacity active filter. Keywords Harmonic filters · Hybrid filters · Microgrids · Passive filters · Power quality 1 Introduction The world has been experiencing a fast change in the pro- duction and use of electric power. The traditional electrical system operated transporting large amount of energy pro- duced by huge power plants located far from the consumer. However, with the introduction of distributed generation that scenario has been changing due to the use of energy renew- able sources and power production closer to end-users. The distributed generators (DGs) usually have nominal power between 1 kW and 10 MW (Malik 2013; Chen and Mili 2013; Medina et al. 2014). In this context, a new concept appears with the evolu- tion of the distributed generation named as microgrid (MG). According to (Lasseter 2001), a MG is a set of electrical microsources, loads and storage elements controlled as a dis- patchable unit (Mahmoud et al. 2014), in which the DGs are commonly based on renewable energy sources (Li and Neja- batkhah 2014). The storage systems are composed of battery B Hélio Marcos André Antunes helioantunes@ufmg.br 1 Graduate Program in Electrical Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil banks, air compressors and flywheel (Parhizi et al. 2015; Araújo et al. 2017). The development of power electronics converters based on voltage source inverters (VSIs) has enabled the inter- faces between sources of renewable generation to the grid and besides allows all operation modes of a MG. However, a MG is a weak electrical system with low short-circuit power and the expansion of nonlinear loads and DGs cause voltage and current distortion rates increasing at the point of com- mon coupling (PCC) of a MG (Balanuta et al. 2012; Bhende and Kalam 2013; do Nascimento Sepulchro et al. 2014). The main phenomena that affect a MG are voltage unbalance, har- monics, low power factor and frequency deviation (Natesan et al. 2014). Active filters (AFs), with series and shunt configurations, have been widely used in MGs for harmonic compensa- tion (Miveh et al. 2015). Traditional passive filters (PFs) applied to conventional electrical system can be a way to improve PQ, although they are not been well explored in MGs (Das 2004; do Nascimento Alves 2016). A very effective solution discussed in the literature for harmonic mit- igation can be obtained through a series connection between an active and a PF, forming a series hybrid filter (SHF). In this topology, the PF operates compensating reactive power and 123