Common-mode voltage of hybrid multilevel high voltage inverter and its cancellation technology

Common-mode voltage must be taken into account when inverters are designed and used because it will influence the system reliability. Consequently, the common-mode voltage of hybrid asymmetrical multilevel inverter was analyzed with deferent PWM modulation methods. Based on analysis of the different influences on the common-mode voltage of high and low voltage cells, a partial elimination technology to eliminate common-mode voltage was proposed. The new modulation method can eliminate the high frequency and low voltage part of common-mode voltage. Meanwhile, simulations and tests are carried out to verify the feasibility and validity.