Research On Key Technology And Device Development Of T-type Three-level Converter For Energy Storage

In recent years,with the rapid development of material living standards and industrial information fields,countries have increasingly demanded traditional energy sources.However,the traditional energy reserves in the world are limited.Under the background,the development and utilization of new energy sources has become the research focus.Especially in the field of distributed energy storage,it has become a research hotspot.The distributed energy storage system can be combined with the new energy system to realize the on-grid utilization of new energy.The research on energy storage system is significance.In this paper,On the basis of related research on energy storage system,the related technology of bidirectional DC / AC converter is mainly studied.A two-stage energy storage system is designed in this paper,which include bidirectional DC / DC converter and bidirectional DC / AC converter.The bidirectional DC /DC converter realizes the rise and fall of the DC voltage,and the bidirectional DC / AC converter realizes the conversion between the direct current and the alternating current.Buck-Boost three-phase staggered parallel topology is used in the DC / DC converter selects,which can effectively reduce the current ripple and the voltage and current stress of the device.The topology and basic working principle of the converter are analyzed and studied.The PI control strategy is used to achieve stable buck-boost function.T-type three-level topology is used in DC / AC converter.The paper analyzes the basic principle of T-type three-level bidirectional converter to realize energy conversion,and adopts a new ip-iq detection method to carry out current Detection,detailed analysis and study of the three-level converter SVPWM control strategy,and combined with a new ip-iq detection method to control the converter,the steps are simple,but also it is better to realize the function of the converter to control the bidirectional flow of energy.And build a simulation model,the simulation of the designed control method is verified,and the effectiveness of the method isproved.Secondly,the problem of sudden voltage change in the process of energy storage system switching between on-grid and off-grid is analyzed and studied.The pre-synchronous control strategy are used to control the energy storage system on-grid and off-grid switching.In this way,the smooth transition of the energy storage system on-grid and off-grid can be realized,and the impact caused by the on-grid and off-grid switching can be reduced.Finally,based on the above theoretical research,a T-type three-level bidirectional converter device is designed.The circuit design mainly includes the main circuit structure of the converter,power supply module design,acquisition circuit design,switch quantity acquisition and output circuit design,PWM output circuit,IGBT drive circuit design.The main system software work flow chart of the bidirectional converter is given,including the main program,interrupt program,instruction current operation subroutine,PWM operation subroutine and on-grid and off-grid mode switching procedures.An experimental prototype of a T-type three-level bidirectional converter was built.