Investigation of the Classical Control Design Methodology to Improve the Performance of the Photovoltaic System on Grid

Abstract

Nowadays, several ways of electric generation have been investigated, one of the most promising is the photovoltaic system. They are renewable systems because they use the energy of the Sun as an input, and they are also an alternative to the types of sources more polluting like the combustible ones. This system produces electric energy in DC format, however, commonly several grids are AC grids, so it is necessary to transform DC to AC format, then it is necessary to use a device to convert DC/AC, i.e., namely voltage inverter, aiming to make the connection between the photovoltaic source for conventional grid. This device operates by using a set of semiconductors static key based on IGBT, which has a goal of shifting the DC voltage produced by the photovoltaic panel and transform in the sinusoidal output. Furthermore, the voltage inverter is used to connect the photovoltaic source with the grid. Then, several undesired problems appear like the loss of the setpoint and coordination between the grid and the protection system, and the instantaneous recloser and islanded operations of the inverter. Thus, in this work, it was proposed an analysis to improve the performance of the voltage inverter when applied on the photovoltaic system connected in the grid, so it was used the current mode control and Phased-Lock-Loop (PLL) to ensure the connection of the photovoltaic panels on the grid. Therefore, a classical design methodology was investigated to ensure the connection with grid and system stability. Finally, several tests are performed in the developed simulator aiming to show the possible uses of the classical control design methodologies to improve electric generation in photovoltaic systems.