Design and control of fully parallel embedded Z-source inverters based flexible photovoltaic systems for grid power quality improvement under distorted condition

This paper presents the design and control of fully parallel embedded Z-source (FPEZ-source) inverter in flexible photovoltaic (FPV) systems. FPEZ-source inverters are one of the Embedded Z-source (EZ-source) inverter topologies with two isolated dc sources embedded with each inductor of X-shaped network in series, so two PV panels can be used in this structure and PV input current flows smoothly during the whole switching period unlike the traditional Z-source inverters without any extra LC filter. Inductor and capacitor of X-shaped impedance network is designed in a way that the ripple of capacitor voltage and inductor current could be put in a desired value. Moreover the corrected p-q control theory and simple MPPT method are used as reference current generator for FPV system that injects maximum available power of PV array and compensates load harmonics, reactive power and imbalance. Finally simulation is performed by PSCAD/EMTDC software, and results are presented to demonstrate effectiveness of proposed concept.

[1]  Fang Zheng Peng.  Z-source inverter , 2002 .

[2]  F. Blaabjerg,et al.  Four-leg parallel Z-source inverter based DG systems to enhance the grid performance under unbalanced conditions , 2007, 2007 European Conference on Power Electronics and Applications.

[3]  S. Danyali,et al.  PV power system based MPPT Z-source inverter to supply a sensorless BLDC motor , 2010, 2010 1st Power Electronic & Drive Systems & Technologies Conference (PEDSTC).

[4]  Xing Zhang,et al.  Study of Z-Source Inverter for Grid-Connected PV Systems , 2006 .

[5]  S. H. Hosseini,et al.  Modified p-q theory applied to flexible photovoltaic systems at the 3-phase 4-wire distribution grids , 2012, 2012 Proceedings of 17th Conference on Electrical Power Distribution.

[6]  Malabika Basu,et al.  Understanding the operation of a Z-source inverter for photovoltaic application with a design example , 2011 .

[7]  Sumedha Rajakaruna,et al.  Steady-State Analysis and Designing Impedance Network of Z-Source Inverters , 2010, IEEE Transactions on Industrial Electronics.

[8]  David Infield,et al.  Modeling and control of Z-source grid-connected PV system with APF function , 2009, 2009 44th International Universities Power Engineering Conference (UPEC).

[9]  E.F. El-Saadany,et al.  Flexible distributed generation: (FDG) , 2002, IEEE Power Engineering Society Summer Meeting,.

[10]  Frede Blaabjerg,et al.  Asymmetrical and symmetrical embedded Z-source inverters , 2011 .

[11]  F. Blaabjerg,et al.  Operational analysis and comparative evaluation of embedded Z-Source inverters , 2008, 2008 IEEE Power Electronics Specialists Conference.

[12]  F. Gao.  Embedded EZ-Source Inverters , 2009 .

[13]  F. Blaabjerg,et al.  Z-Source-Inverter-Based Flexible Distributed Generation System Solution for Grid Power Quality Improvement , 2009, IEEE Transactions on Energy Conversion.

[14]  Shahrokh Farhangi,et al.  Comparison of z-source and boost-buck inverter topologies as a single phase transformer-less photovoltaic grid-connected power conditioner , 2006 .

[15]  Bin Wu,et al.  Space Vector Modulation for High Power Five Level Current Source Inverters , 2006 .

[16]  J. R. Vazquez,et al.  Mapping matrices against vectorial frame in the instantaneous reactive power compensation , 2007 .

[17]  Gyeong-Hun Kim,et al.  A study on the performance analysis of the grid-connected PV AF system , 2007, 2007 International Conference on Electrical Machines and Systems (ICEMS).

[18]  F.Z. Peng,et al.  $Z$-Source Inverter for Residential Photovoltaic Systems , 2006, IEEE Transactions on Power Electronics.