Design Of Digital Buck/Boost Bi-directional DC-DC Converter

With the rapid development of the social economy,the electronic information industry has penetrated into all walks of life in the national economy.As a basic technology in the electronic information industry,Power electronic technology plays an increasingly important role.As one of the research hotspots in the field of power electronics technology,the Bi-directional DC-DC converters are more economical and easier to control than traditional unidirectional DC-DC converters in the case of they achieve the same function.It has good application value in micro grid energy storage system,DC uninterruptible power supply system,power electronic transformer,aerospace power supply system,etc.The bi-directional DC-DC converter applied in the microgrid energy storage system as the research object in this paper,firstly write a brief description of the research background and research status of the bi-directional DC-DC converter,various of topological structures and working principles of the bi-directional DC-DC converter are analyzed,finally the bidirectional Buck/Boost converter topology are selected to design and study.According to the circuit design requirements to calculate the circuit parameters and designs the peripheral hardware circuit.In order to controlling the power flow and make the converter circuit meet the charging and discharging requirements of the lithium battery in the energy storage system,the state space averaging method is used to model the small signal of the bi-directional DC-DC converter,and compensates the loop.The Matlab software is used to simulate and analyze the designed control circuit and verified the stability of the system.Secondly,the DSP TMS320F28335 is used to control the converter,choose the appropriate sampling frequency and sampling method to program the software,respectively programs the ADC,PWM and SCI modules,then discretize the parameters of the control loop to make digital control of the circuit,so that it can meet the demand for the circuit when the lithium battery is charged.In this paper,an experimental circuit based on TMS320F28335 control is developed,and the design scheme is experimentally verified.The rationality of theoretical analysis,loop simulation and digital control strategy is verified through the analysis of the experimental data,which provides a research basis for further design and control of efficient digital bidirectional DC chopper circuit.