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Experimental Investigation on Single-Phase Multilevel Inverter for Generating 21-Level Output Voltage Using Four H-Bridge Units

In this paper, an experimental investigation has been carried out on single-phase multilevel inverter to obtain 21-level output voltage using cascaded four H-bridge units. The proposed system consists of four cascaded H-bridge MOSFET-based voltage source inverters, a microcontroller-based Arduino module, four separate input dc sources and isolating circuit. The gate drive signals for MOSFETs of the four H-bridge inverters are generated by using ATmega 2560 microcontroller-based Arduino board. The microcontroller has been used to reduce the complexity of generating gate drive signals for higher levels of inverter output voltage. Different-level output voltages have been obtained from experimental works. It is found that the proposed system requires less number of power switching devices and total harmonic distortion is reduced with increasing number of levels at the output voltage of the multilevel inverter.