Research On Single-phase Grid-connected System Based On Semiconductor Thermoelectric Power Generation

Presently,with the development of social economy,various needs for energy going diversification.Semiconductor Thermoelectric Generation(TEG)as a new way of Generation is getting more and more attention from the whole society.TEG array is composed of multiple temperature sensors and act as a DC source,the temperature difference between up side and down side has a significant impact on performance in output voltage and power.So,the power conversion and control technology become the key to reliable use of TEG system.This article has a deep research on Maximum Power Point Tracking(MPPT)and two-stage of single-phase grid-connected converter.First of all,according to the analysis of TEG mathematical model,the generation characteristics of semiconductor thermoelectric material are revealed clearly.Several traditional MPPT algorithm are analyzed detailedly.For the shortcoming of those traditional algorithm,the improved algorithm is proposed.The proposed algorithm divide the Power-Voltage(P-V)curve into three sections.In each section,it will automatically adjust step size to promote tracking speed.In addition,a regional limited method is also proposed in this paper.the simulation system has been set up and demonstrated that the proposed MPPT algorithm brings a substantial increase for dynamic convergence process,reduces the oscillation amplitude on the maximum power point,and makes a quick adaption to the change of temperature.Secondly,the system of two-stage single-phase full bridge grid-connected inverter has been researched.The Interleaved Boost Circuit has been chose to reduce the input current ripple.The low current ripple can reduce the effect on DC working points for the converter,at the same time,low input current ripple can bring a smaller input filter capacitor which will reduce the power loss and promote the efficiency.The single-phase full bridge circuit has been accepted as post-stage DC/AC circuit and the current voltage double closed-loop has been accepted as the controlling method.Finally,the simulation model of single-phase grid-connected converter based on TEG has been set up in MATLAB/SIMULINK.The simulation results show that the efficiency of inverter is more than 92% and the grid harmonic is 3.75% which conformed to the requirements of grid-connected.What's more,a temperature controlled experiment system of TEG has been designed detailedly.Based on the experiment system the main circuit is designed with MOSFET and the control system is designed with DSP2812.A 250 W converter has been made out and some experiment are proceeded.The results show that the TEG grid-connected system realize the grid-connected power generation and MPPT well.