Investigation of Z source inverter topologies for photovoltaic systems

Abstract

This thesis deals with the design and development of new Z newline(impedance) source inverter topologies and its variants applicable for solar newlinephotovoltaic power systems are verified through simulation and experimental newlinevalidation. The design of proposed topologies of Z source inverters are based newlineon the comprehensive study of existing Z source inverters to suit for various newlineapplications. Many new topologies of Z source inverters are evolving and to newlinethe author s knowledge, the proposed topologies discussed in this thesis are newlinenot reported by others so far. While designing impedance network of Z source inverters, solar newlinephotovoltaic modules are treated as the input sources, so modelling, newlinesimulation and experimental verification of solar photovoltaic systems are newlinecarried out to obtain its performance characteristics. Photovoltaic (PV) newlinemodules connected in different array configurations are analyzed under newlinenormal/ partial shaded conditions and their performance are obtained in terms newlineof current voltage and power voltage characteristic curves, operating at newlinedifferent temperature and insolation conditions through simulation and the newlinesame is checked with suitable experimental set up to identify the best possible PV array configuration to be employed in the proposed Z source inverter newlinetopologies under investigation are discussed in Chapter 2. Chapter 3 deals with simulation and experimental investigations newlinecarried out to the existing inverter topologies in MATLAB/SIMULINK® and newlinehardware verifications of the conventional voltage source inverter (VSI), newlinediode assisted Cuk VSI and embedded Z source inverter are done through newlinescaled down laboratory prototype in Field Programmable Gate Array and newlinemicrocontroller environment. With these analysis and experiments under newlinedifferent pulse width modulation (PWM) switching schemes viz sinusoidal newlinePWM, space vector PWM and simple boost PWM, Z source inverter newlinetopologies are found to be promising to have better output voltage gain, newline