Hybrid cascaded nine level inverter using dspace controller for standalone photovoltaic applications

Abstract

This paper discusses about the hybrid cascaded nine level inverters for photovoltaic applications. Cascaded multi-level inverter is made up of series connected half bridge inverters and the output voltage of cascaded MLI is the sum of all inverter output voltages. Cascaded MLI produce staircase output voltage waveform having less harmonics, high output voltage, lower acoustic noise, as compared to the conventional voltage source and current source inverters. Cascaded MLI produce almost sinusoidal output voltage waveform from several DC sources, which may be obtained from a solar cell, fuel cell, batteries and ultra-capacitors. The cascaded H-bridge MLI produce an AC output voltage waveform from separate DC sources. MATLAB simulation is done to verify the harmonic performance of the seven levels and nine level converters. Then the nine-level inverter is implemented in hardware and the firing pulses for the nine-level inverter is generated from the Dspace 1104 controller.