Analog implementation of a rear-end DC-AC inverter for realization of a solar system

Abstract

Solar converter topologies are power electronic circuits implemented to recondition the Direct Current (DC) power harnessed from the Photovoltaic (PV) arrays for different uses. In this thesis, the converter changes the power from the PV arrays into an Alternating Current (AC) source that is matching to the utility grid, so that this power generated can be pumped into the grid. Several topologies are possible for this application but this project looks into the performance of a 2-stage converter consisting of a DC-DC Boost Converter cascading a DC-AC Voltage Source Inverter (VSI) via a DC link. The study of the performance will be focusing on the hardware implementation of the converter, thus, most of the work done is designing and building the hardware.

The Boost Converter also includes a Maximum Power Point Tracker (MPPT) control circuit to harness the maximum available DC power from the PV array. The Inverter is controlled by a synchronization control circuit to produce an AC output that is matching to the grid AC voltage so that it can be connected onto the grid.

The MPPT control is based on the Perturb & Observe algorithm while the synchronization is achieved using the Phase Locked Loop (PLL) technique. Most of the power converters built are implemented using DSP-based digital control in the projects done by previous batches of graduating students, thus, this project seeks to attempt analog control to investigate the feasibility of doing so.