Simulation of Grid Connected Three-Level Neutral-Point-Clamped qZS Inverter using PSCAD

Abstract This paper is focused on a single-phase three-level neutral-point-clamped quasi-z-source inverter when it is operating being connected to the electrical grid. A control strategy for injecting current synchronized in phase with the voltage at the point of common coupling has been proposed and studied. It is achieved by means of controlling the output voltage between branches adjusting the output current by using a d-q frame and the analysis of the output filter. The control strategy generates the reference to be used in the modulation technique and it has been validated with and without shoot-through switching states. A method to calculate the minimum value of the shoot-through duty cycle is also explained in order to assure the proper control of the injected current when the input voltage is less than peak value of the grid voltage. It is an important feature because 3L-NPC qZSI due to its possibility of boosting input voltage in a single stage would operate better than a traditional inverter, for instance in photovoltaic applications when the value of irradiance is decreased. The presented results have been obtained using PSCAD/EMTDC as a simulation tool.

[1]  D. Vinnikov,et al.  FPGA control of the neutral point clamped quasi-Z-source inverter , 2012, 2012 13th Biennial Baltic Electronics Conference.

[2]  Dmitri Vinnikov,et al.  Analytical and Experimental Investigation of Neutral Point Clamped Quasi-Impedance-Source Inverter , 2011 .

[3]  Baoming Ge,et al.  Quasi-Z source inverter with battery based PV power generation system , 2011, 2011 International Conference on Electrical Machines and Systems.

[4]  Janis Zakis,et al.  Study of Simple MPPT Converter Topologies for Grid Integration of Photovoltaic Systems , 2011 .

[5]  김흥근,et al.  Capacitor Voltage Control for MPPT Range Expansion and Efficiency Improvement of Grid-connected Quasi Z-Source Inverter , 2010 .

[6]  F. Blaabjerg,et al.  Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching , 2006, IEEE Transactions on Industry Applications.

[7]  Dmitri Vinnikov,et al.  Quasi-Z-Source-Based Isolated DC/DC Converters for Distributed Power Generation , 2011, IEEE Transactions on Industrial Electronics.

[8]  F. Blaabjerg,et al.  Three-Level Z-Source Inverters Using a Single LC Impedance Network , 2007, IEEE Transactions on Power Electronics.

[9]  D. Vinnikov,et al.  CCM operation analysis of the single-phase three-level quasi-Z-source inverter , 2012, 2012 15th International Power Electronics and Motion Control Conference (EPE/PEMC).

[10]  Shuai Jiang,et al.  Low-Cost Semi-Z-source Inverter for Single-Phase Photovoltaic Systems , 2011, IEEE Transactions on Power Electronics.

[11]  Jianfeng Liu,et al.  Sliding-mode control of quasi-Z-source inverter with battery for renewable energy system , 2011, 2011 IEEE Energy Conversion Congress and Exposition.

[12]  F.Z. Peng,et al.  Four quasi-Z-Source inverters , 2008, 2008 IEEE Power Electronics Specialists Conference.

[13]  T. W. Chun,et al.  Power control for a PV generation system using a single-phase grid-connected quasi Z-source inverter , 2011, 8th International Conference on Power Electronics - ECCE Asia.

[14]  Yuan Li,et al.  Quasi-Z-Source Inverter for Photovoltaic Power Generation Systems , 2009, 2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition.

[15]  Pravin P. Kalubarme.  Quasi-z-source inverter for photovoltaic power generation systems , 2014 .

[16]  Enrique Romero-Cadaval,et al.  Simulation Study of Different Modulation Techniques for Three-Level Quasi-Z-Source Inverter , 2012 .