Single-phase High-frequency Grid Inverter System Research And Design

Because of lack of energy, using electricity reasonable and effective is advocatedby the world. Inverter is a kind of electric energy conversion device, it can convert dc(direct current) into various forms of alternating current(ac) for all kinds of electricequipment to use. And it can also sent energy back to the grid in order to save energy.With the working frequency transformer and analog circuit, the traditional invertersystem is generally bigger and the efficiency is lower. Thanks to the control systemwhich is composed by analog circuit, the control method is single and changed difficult,its response speed is slower. At the same time the cost is on the high side.In view of the above problems, based on the high frequency inverter system as theresearch object, the scheme uses high frequency pulse signal, the working frequency ofthe inverter system improved, the higher the reliability of the inverter system and morequickly dynamic response. The main research contents are as follows:1. Analyses the advantages and disadvantages of kinds of high frequency invertertopology, then determines the whole bridge type high frequency inverter topology andcontrol scheme and its feasibility is verified by the simulation modeling.2. Researches the current tracking control technology in grid-connected controltechnology and achieve the synchronization by means of current double closed-loopcontrol technology.3. Designes the main circuit of the inverter system and control module andcalculate the parameters of the important related components; describe the digital PIcontrol, the generation of SPWM wave and the digital phase-locked loop which is thekey part involved in detail, the corresponding part of the software flow chart is given inthe last.4. Debugs and testes the design of high frequency inverter system is. Through testand analysis the key part of the waveform and data, the design is able to complete theinversion process and its result conforms the relevant power quality standardrequirement.The thesis first researches the main circuit topology structure of high-frequency inverter and descripts its working principle and control scheme in detail. Then, thesisdiscusses the grid-connected with high-frequency link, compares several grid currenttracking control scheme and states current double closed loop control. Finally, throughdesigning each module, complete the construction of the experimental platform. Therelated technologies in the thesis have been verified by measuring the waveforms of keypoints in the experiment effectively.