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This paper presents a comparison between NPC (neutral point clamped) and H-cascaded multilevel inverters by considering the increas or decrease of harmonics in the output line to line voltages, phase voltages and common mode voltage. Multilevel voltage source converters are getting increased importance for applications in the medium and high voltage range. A conventional two-level PWM (pulse width modulated) inverter generates high frequency common mode voltage with high dv/dt. In the same way, commonly used multilevel inverter modulation schemes generate common mode voltage. Common mode voltage may cause motor shaft voltages, bearing currents and EMI (electromagnetic interference). Common mode voltage depends not only on switching method but also on earth mass. The use of earth mass on a proper place in the circuit can reduce the common mode voltage. Sinusoidal (sine-triangle) PWM scheme is being used for this purpose and simulation results are being presented in this paper by using software “Simplorer ” and “Post Processor Day”. Keyword