A Solar PV Based Multistage Grid Tie Inverter

Abstract

The inherent advantage of fuel less and maintenance free energy production from solar photovoltaic makes it a very important source of energy. For harnessing power from the solar photovoltaic (PV) cell/array and to supply it to the utility grid, dc to ac inverters is needed. The conventional line commutated dc-to-ac inverter has square shaped line current which contains higher order harmonics whereas PWM based inverters employing IGBT/ MOSFET are less reliable and has low power handling capability. Moreover, a dc-to-dc converter is generally employed along with the inverter circuit to operate the solar PV array at maximum power point. It adds to the cost, which increases with the size of the system. This paper describes a multistage series converter topology for solar PV based grid tie inverter with low harmonic in line current and inbuilt maximum power point tracking (MPPT) features. The developed prototype has been experimentally tested and verified.

Keywords: Multistage converter, Grid tie inverter, Maximum power point tracker (MPPT), Total harmonic distortion, photovoltaic system.