Microcontroller Based Multilevel Inverter for Photovoltaic System

This paper proposes the hardware design and implementation of a microcontroller based single-phase five-level cascaded Hbridge multilevel inverter for photovoltaic system. The inverter is capable of producing five levels of output-voltage levels (2V dc , V dc , 0, -V dc , and -2V dc ) from the dc supply voltage. Selective harmonic elimination pulse width modulation (SHEPWM) technique was employed to improve the output waveform quality. Digital optimized switching angles algorithm was implemented in a low cost processor ATMega 8535 to generate switching signal. The proposed system was verified through a small-scale laboratory prototype was built and tested. Its results indicated the proposed method's effectiveness and the application feasibility of the fundamental frequency switching.