A carrier-transposed modulation technique for multilevel inverters

Multilevel inverters are commonly modulated by using multicarrier pulse width modulation techniques such as phase-shifted multicarrier modulation and level-shifted multicarrier modulation. However, level-shifted multicarrier modulation technique produces the best harmonic performance than the phase-shifted multicarrier modulation technique. But it is having apparent disadvantages of unequal device switching frequency and unequal device conduction periods. This is not desired in high power applications. This paper presents a new modulation technique, a carrier-transposed multicarrier modulation for multilevel inverters that combines the advantages of equal device switching frequency and even power distribution from phase-shifted multicarrier modulation technique and best harmonic performance from level-shifted multi-carrier modulation technique respectively.