Thermoelectric generator works under different working conditions, especially different temperature and load resistance. In order to improve its efficiency, the circuit was in place between thermoelectric generator and load resistance using a buck converter. Compared with the direct connection case the buck converter improves efficiency, especially with small load resistance. Power output and current ripple are the central focus for evaluating this buck converter. Regarding thermoelectric generator characteristic, PMW (pulse-width-modulation) mode is selected for regulating buck converter switch. The tool box selected for building simulation model of buck converter is Simscape in matlab/Simulink. To verify the model, differential equation mathematic model and state-space simulation model are built. To configure the parameters of the buck converter, all the possible data is collected by running simulation model with different sets of parameters. After configuration, the optimal parameters for the buck converter is obtained. A method of selecting optimal parameter set is introduced for the given requirement for the circuit performance.With a set of optimal circuit parameters such as capacitor and inductor values, a controller of PWM signal is to be designed for optimizing the circuit system efficiency, where the extreme seeking control was used. With the controller, it proves that even with different load resistance, the buck converter can delivered maximum power with optimized the duty cycle of PWM.
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