ISSN (Print) : 2320 – 3765 ISSN (Online) : 2278 – 8875 International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering (An ISO 3297: 2007 Certified Organization) Vol. 4, Issue 11, November 2015 Copyright to IJAREEIE DOI:10.15662/IJAREEIE.2015.0411049 8844 AC-DC Hybrid Microgrid with Harmonic Elimination Krishnanunni S 1 , Daru Anna Thomas 2 PG Student [Power System], Dept. of EEE, SAINTGITS Engineering College, Kottayam, Kerala, India 1 Assistant Professor, Dept. of EEE, SAINTGITS Engineering College, Kottayam, Kerala, India 2 ABSTRACT: Hybrid ac/dc microgrids have been planned for the better interconnection of different distributed generation systems (DG) to the power grid, and exploiting the prominent features of both ac and dc microgrids. Connecting these microgrids requires an interlinking ac/dc converter (IC) with a proper power management and control strategy. During the islanding operation of the hybrid ac/dc microgrid, the IC is intended to take the role of supplier to one microgrid and at the same time acts as a load to the other microgrid and the power management system should be able to share the power demand between the existing ac and dc sources in both microgrids. The paper proposes a decentralized power sharing method in order to eliminate the need for any communication between DGs or microgrids.The interlinking converter uses PI controller in dq reference frame which along with the coordinated control logic, controls the power flow. But when a non linear load was connected to the system it was found that the current waveform was having high harmonic content. Also in certain load conditions when the power in the hybrid grid becomes too low it is not feasible to connect the non linear load. Hence an active filter has also been designed and incorporated in the system so as to make the system more reliable. Hysteresis control in dq reference frame is used for this. The performance of the proposed power control strategy is validated for different operating conditions with and without the active shunt filter is validatedin the PSCAD/EMTDC software environment. KEYWORDS: AC-DC Hybrid Microgrid; Distributed Generation; decentralized power sharing; Interlinking Converter; PI controller. I. INTRODUCTION Due to increasing deployment of DGs in power systems, managing the power of different DGs and the grid has raised a major concern. In this field, microgrids have become a widely accepted concept for the superior connection of DGs in power networks. Corresponding to the conventional power systems, ac microgrids have been established foremost and a variety of surveys have been reported particularly on the subject of power sharing of parallel-connected sources. Since the majority of renewable energy sources generate dc power or need a dc link for grid connection and as a result of increasing modern dc loads, dc microgrids have recently emerged for their benefits in terms of efficiency, cost and system that can eliminate the dc-ac or ac-dc power conversion stages and their accompanied energy losses. However, since the majority of the power grids are presently ac type, ac microgrids are still dominant and purely dc microgrids are not expected to emerge exclusively in power grids. Therefore, dc microgrids are prone to be developed in ac types even though in subordinate. Consequently, linking ac microgrids with dc microgrids and employing the profits of the both microgrids, has become interesting in recent studies. The idea is to merge the ac and dc microgrids through a bidirectional ac/dc converter and establishing a hybrid ac/dc microgrid in which ac or dc type energy sources and loads can flexibly integrate into the microgrids and power can smoothly flow between the two microgrids. The main idea is to use the locally generated energy and reducing the power draw from the grid. A coordinate control scheme is developed in order to manage the whole system in different operating conditions. A microgrid is a controllable component of the smart grid defined as a part of distribution network capable of supplying its own local load even in the case of disconnection from the upstream network. Microgrids incorporate large amount of renewable and non-renewable distributed generation (DG) that are connected to the system either directly or by power electronics (PE) interface. The need for microgrids is so significant for many reasons but the most important issue is to the need to move to renewable sources of energy with very less carbon emission. Technical concerns over dynamics of microgrids especially in autonomous (island) mode necessitate revision of current paradigms in control of energy systems. [1] [2]