Prashant Gorakhnath Patil et al IJSRE Volume 4 Issue 5 May 2016 Page 5407 Volume||4||Issue||05||May-2016||Pages-5407-5419||ISSN(e):2321-7545 Website: http://ijsae.in DOI: http://dx.doi.org/10.18535/ijsre/v4i05.18 Microgrid Power Quality Improvement by using Dual Output Four-Leg Inverter Authors Prashant Gorakhnath Patil 1 , Kalpesh M Mahajan 2 , Mohan T Patel 3 1 KCE Society's College of Engineering and Information Technology, Jalgaon 2 KCE Society's College of Engineering and Information Technology 3 K. K. Wagh Institute of Engineering Education & Research Email id: prashant7267@gmial.com ABSTRACT In this paper, a new system is proposed for connecting a microsource to a weak utility. The proposed system simultaneously conditions the quality of the power supplied to the microgrid loads. This system employs a recently introduced reduced switch count dual-output inverter in a so-called equal frequency mode which offers its best operation features such as maximum dc bus voltage utilization and minimum device ratings. Compared to the counterpart system, the proposed configuration enjoys an integrated structure and uses less number of semiconductor switches. Moreover, it retains the desirable features of the conventional system such as ability to compensate unbalanced/sagged utility and to supply three-phase unbalanced loads with balanced and ceaseless voltage. The proposed system is introduced and its carrier-based modulation scheme is elaborated. Subsequently, a detailed study on the maximum achievable modulation index under different working conditions is carried out. The report concludes with a discussion on control of the system and its controller design. The validity of operation of the proposed system is verified through simulation. Keywords—Distributed generation (DG), dual-output four leg inverter, microgrid. 1. INTRODUCTION Power quality is a term used to broadly encompass the entire scope of interaction among electrical suppliers, the environment, the system and the products. The widespread use of non-linear loads is leading to a variety of undesirable phenomena in the operation of power systems. The harmonic components in current and voltage waveforms are the most important among these. Conventionally passive filters have been used to eliminate line current harmonics. Current controlled voltage source inverters can be utilized with appropriate control strategy to perform active filter functionality. However, the extensive use of power electronics based equipment and non-linear loads at PCC generate harmonic currents, which may deteriorate the quality power. Recently various control strategies for grid connected inverters incorporating PQ solution. In an inverter operates as active inductor at a frequency to absorb the harmonic current. A similar approach in which a shunt active filter acts as active conductance to damp out the harmonics in distribution network is proposed. But the exact calculation of network inductance in real-time is difficult and may deteriorate the control performance. Generally current controlled voltage source inverters are used because of their faster response compared to voltage controlled voltage source inverters as it power is controlled by switching instant. And also in current controlled voltage source inverters active and reactive power is controlled independently.