In this paper, the implementation of 3-phase seven level cascaded H-bridge inverter is discussed with Arduino microcontroller and harmonic analysis is performed using Fourier series. The multilevel inverters (MLI) give several benefits as reduced switching voltage stresses and the capability to operate in higher level voltage applications. A new and simple architecture Arduino Mega 2560 microcontroller is employed to produce the control signals for the seven level cascaded H-bridge MLI switches. The computer simulation is carried out in PSIM environment and prototype experimental model is developed with TLP 250 driver ICs and power MOSFET switches to validate the simulation results. The THDs present in different voltage level inverters are mathematically analysed using Fourier series. © 2017, Editura Universitatii din Oradea. All rights reserved.