Data Acquisition For a Grid Connected PV System And Study Of Z-Source Inverter

Abstract

In the proposed work, we develop a Data acquisition system (DAS) for a grid connected PV system that comprises number of PV array connected to a Z-source inverter for integration to the grid. Data acquisition system (DAS) is an important component of design of a Renewable power system. It is needed for collection of several data in order to develop a reliable and stable operation and to determine system performance. Data acquisition system also plays a prominent role to maintain records of generation in order to develop a historical report which gives idea about generation over a period of time. To develop an automation system which is essential these days so that system gets shutdown whenever there is fault in the system needs again estimation of parameter so it is very important to develop a system which not only collects data but also stores data and processes it. The proposed framework comprises of an arrangement of sensors for measuring electrical parameters such as voltage, current and its profile such as harmonics at different section such as PV output, inverter output etc. The gathered information are first adapted utilizing exactness electronic circuits and after that interfaced to a PC utilizing an information obtaining card. The code on LabVIEW is utilized to further process, show and store the gathered information in the PC environment. Z-source inverter has been introduce. Its unique features has been outlined which makes it unique in terms of not only in reduction of system size but also to boost output voltage its features extend to reduced number of switches thus reduced system complexity and nevertheless a single stage operation is observed.
Z-source inverter need a shoot-through mode for boosting output voltage so it’s mandatory to use modified PWM with shoot-through so different kind of technique is also being outlined. This helps us choose what kind of technique will be appropriate for what kind of application.
Implementation of space vector pulse width modulation (SVPWM) both in MATLAB and LabView has been implemented NI cRIO-9075 has been chosen for data acquisition and to develop PWM for inverter. cRIO has embedded Spartan-6 FPGA chip inbuilt which has sampling frequency of 400Mhz sampling at this frequency is far more sufficient to perform task in real time. cRIO-9075 also has 256MB of in built memory which offers enhanced system performance by allowing to save the program on the memory itself when the program is compiled. This PWM vii signal is fed to VSI inverter and again the output is traced back into the system using cRIO module hence all the data is being acquired and a human user interface (HMI) layout is developed.