A novel symmetrical two-output three-level series resonant PSPWM inverter

This paper presents a two-output three-level inverter (a TOTL inverter) by using phase-shifted pulse-width modulation (PSPWM) to achieve the symmetrical output waveforms. A TOTL inverter is made of 3-legs of neutral point clamped inverter [1] which can provide two-output per one circuit. This is a concept to reduce a size and a number of components when it is compared with one output per one circuit. A TOTL inverter can be adjusted for output power by shifting PSPWM signals. In addition, all switches can operate under zero-voltage-switching condition (ZVS). This paper shows the analysis of operation modes, the simulation, and experimental results in order to prove the proposed concept. It is found that the proposed inverter can provide the rated power of 974 kW and 1140kW for each output, overall efficiency of 85.7% at switching frequency of 50 kHz.