Design of a grid connected inverter for a small wind turbine

Abstract

The depletion in the availability of fossil fuels and concern with regards to the pollution developed in the process of generation of energy, has lead to an increased interest in renewable energy. The contribution to advances in renewable energy technology has resulted in the reduction on the dependency on fossil fuels and aids in dealing with the ever increasing energy demand. One of the most promising renewable energy sources is wind power. This dissertation focuses on the control of a single-phase grid-connected inverter for a small scale wind turbine to regulate the power flow into the utility network. In addition to this, an LCL filter is also designed in order to connect the inverter to the utility supply to mitigate harmonics generated by the inverter switching. The control strategy mainly consists of: • The design of a controller for regulation of boost converter input current • The control of power flow from the generator side to the grid • Magnitude control and synchronisation of the inverter output current supplied to the grid Modelling and simulation of the aforementioned controllers was performed with Matlab-Simulink® software package to test the performance of the combined system prior to the practical implementation. Once an adequate performance was acquired, the control design was implemented into the STM32F407 microcontroller. The results obtained from the tests applied confirmed that the designed control algorithms were performing as intentioned and that the power supplied to the grid is in line with the imposed regulations.