Solar energy is among the renewable energies that are gaining popularity for electrical power generation. Solar energy is converted into direct electricity (DC) using photovoltaic (PV) panels. Since most of the standard electrical appliances operate in alternating current (AC) mode, the DC electricity must be converted into AC form. An inverter is used to perform such function. Conventional PWM-controlled inverter is switched at tens of kilo-hertz range, and this will lead to high switching losses and reduced efficiency in the system. In contrast, a multilevel inverter can be switched at a much lower frequency and will produce lower switching losses and hence, higher efficiency. Among the multilevel inverter topologies, cascaded H-bridge multilevel inverter is gaining popularity for high power PV applications because the modular structure enables higher voltage operations using standard low-voltage semiconductors This project focuses on the modeling, simulation and hardware prototyping of a elevenlevel cascaded H-bridge multilevel inverter. The simulation model of a eleven-level cascaded H-bridge multilevel inverter is modeled using PSIM software. However, the switching angles of the eleven-level cascaded H-bridge multilevel inverter must be properly selected so that a staircase AC output voltage waveform which is to a near sinusoidal waveform can be obtained. Therefore, four switching angle arrangement techniques are evaluated in the simulation. Simulation result show that one of the switching angle arrangement techniques is able to produce an output voltage waveform with harmonic contents as low as 7.56%. To validate the simulation result, a hardware prototype of the eleven-level cascaded H-bridge multilevel inverter was constructed and tested. The experimental result shows that the harmonic contents of the inverter is 7.56%, which corroborates with the simulation results.
