A NPC step-up inverter for thermo-electric generators

Among single stage, single phase, inverter configurations the Neutral Point Clamped topology is advantaged by its quiet rail switching mechanism, producing negligible common mode currents. However, it requires a double input voltage if compared with a classic full bridge inverter. A modified Neutral Point Clamped, three level, single phase, inverter topology is presented in this paper intended for Thermoelectric Generation Systems applications. The proposed topology owns an inner voltage boosting capability, thus, it can be supplied with an input DC voltage equivalent to that of a conventional H bridge inverter, or even lower. Moreover, it is able to compensate voltage drops caused by variations of the thermoelectric generator operating temperature. Finally, no extra high frequency switching devices are introduced to implement the voltage boosting function.