High efficiency, low harmonic distortion switching type power amplifier using multilevel inverter

This paper proposes a novel ideas of 10 kW 200 kHz power amplifier using the switching technology of Multilevel inverter by compensating dead time. Its amplifier is composed of multiplexing 3 level inverter with interphase reactors. It has 81 switching patterns for 9 level of output voltage and two switching control modes in this proposed multilevel inverter. By employing this control method, the switching frequency can be reduced by about 1/8 of 200 kHz carrier frequency and the circulating current can be reduce within 1 ampere. The efficiency of this system is 95.6% at 4 kW and the THD is under 2% at 5 kHz output frequency with open loop control. Further, by applying the dead time compensation, and the carrier frequency is made to increasing at 400 kHz and realized 200 kHz frequency characteristic. This paper also presents the methods to improve frequency characteristics and distortion for arbitrary output waveforms of the system