Research Of Thermoelectric Generation System Based On Short Circuit Current Method MPPT Control

With the expansion of energy demand,the damage of traditional fossil energy to the ecological environment is intensifying,and it is urgent to find a clean alternative energy source.The thermoelectric generator as a new energy power generator directly converts thermal energy into electrical energy.The heat energy can be solar energy,geothermal energy,ocean temperature difference,industrial waste heat,etc.The power generation process of thermoelectric generator has no vibration,noise,and pollution discharge,thus thermoelectric generator will have broad application prospects.This paper mainly studied the short-circuit current maximum power point tracking method of semiconductor thermoelectric generator,the bidirectional DC/DC converter and micro-inverter of thermoelectric power converter.Firstly,by analyzing the equivalent model of the semiconductor thermoelectric generator and the external electrical characteristics,and combining the circuit diagram of each working mode of Boost circuit,a method to calculate the short-circuit current of the thermoelectric generator using Boost inductance current is proposed.The inductor current value is effectively controlled at half of the short-circuit current of the thermoelectric generator by the PI controller to achieve maximum power point tracking.In addition,the MPPT control algorithm using inductive current to estimate short circuit current is improved by introducing a series switch branch of the input capacitor,thus improving the overall efficiency of the system.Different from the traditional MPPT control strategy of thermoelectric power generation,this method only needs to collect the inductance current value,and a single control cycle can complete the accurate positioning of the maximum power point,which has no influence on the normal operation of the converter,and no oscillation and static error after steady-state operation.Secondly,in order to build a thermoelectric power converter system,a bidirectional Buck/Boost circuit was selected to stabilize the DC bus voltage,manage the charging and discharging the storage battery.The flyback micro-inverter was selected to provide AC power to the load.Finally,the simulation model and experimental prototype of the short-circuit current MPPT converter,bidirectional Buck/Boost converter and flyback micro-inverter are built to verify the correctness of the system.The simulation and experimental results show that the proposed short-circuit current MPPT strategy can accurately track the maximum power point of the thermoelectric generator.The bidirectional DC/DC can stabilize the DC bus voltage,and the flyback micro-inverter can provide stable AC power for load.The GUI can display the working status of each part of the system in real time.The simulation and experimental results show that the short-circuit current method MPPT control strategy proposed in this paper can accurately calculate the short-circuit current of the thermoelectric generator and control the converter to work at the maximum power point.