Design and implementation of a current controlled grid connected inverter for thermoelectric generator sources

This paper presents the digital implementation of a current controlled grid connected inverter for Thermoelectric Generator (TEG) sources. Considering the electrical characteristics of a TEG source, several important aspects that a designer has to consider in selecting the rating of power converters for the grid connected operation of TEG source are discussed. The closed loop control of a TEG fed grid connected voltage source inverter (VSI) requires line current control to regulate the power pumped into the grid. Considering the inverter, current sensor and line inductor models, a simplified method is espoused to determine the parameters of the digital current controller. An Altera Cyclone II FPGA board is used to implement the current control strategy in VSI fed with TEG power source. The proposed design approach is validated using simulations and experiments and verified with the time domain specifications.