Research On High Performance Bidirectional Buck-Boost DC/DC Converter

As one of the key components of fuel cell vehicles,the bidirectional DC / DC converter plays an important role in the energy conversion of the power system,and plays an important role in the energy distribution and management of the entire vehicle.Therefore,the research on bidirectional DC / DC converter is of great significance in the field of fuel cell vehicles.Based on the actual needs of the fuel cell vehicle super capacitor charge and discharge energy management system,this paper selects a bidirectional DC / DC converter as the energy management unit of the super capacitor,and analyzes and studies the control circuit of the converter.This paper mainly does the following jobs:(1)According to the overall design requirements,the parameters of the bidirectional DC / DC converter are formulated,and through a comparative analysis of several basic isolated and non-isolated converter topologies,it can be concluded that the bidirectional Buck / Boost converter has overall power The advantages are small number of devices,small electrical stress,high energy transfer efficiency and easy control.Therefore,the bidirectional Buck / Boost converter is more suitable for the application of the technical scene of this subject.This paper selects the main circuit topology of the bidirectional Buck/ Boost converter,and introduces the current control method,and analyzes and designs the principle of the converter.(2)The hardware circuit and control module of the bidirectional DC / DC converter are designed.Firstly,the selection of energy storage inductor,filter capacitor and switching device is carried out to analyze the loss of switching device and inductor and other components in the converter circuit.Meanwhile,the circuit of energy storage inductor,input and output capacitor and related parameters of components are designed.Designed the bidirectional DC / DC converter,introduced the control method of the DC / DC converter,adopted the double closed-loop current-mode control as the control strategy of the bidirectional DC / DC converter,and based on the dual-loop control,using PI control,To improve the self-adaptive ability of the nonlinear system,the controller of the bidirectional DC / DC converter is designed.The control circuit of the bidirectional DC /DC converter is designed,which mainly includes MOSFET drive circuit,signal acquisition circuit,system power module,signal conditioning circuit,temperature detection circuit,etc.According to the vehicle-mounted communication method,this design adopts CAN protocol communication method to analyze and design the main controller interface circuit and CAN communication interface circuit.(3)Complete prototype and experimental research of bidirectional DC / DC converter.A prototype of 1600 W was designed.First,the two functional modes(current / voltage mode)of the bidirectional DC / DC converter were tested and tested to verify the functional index parameters of the converter;secondly,the voltage of the bidirectional DC/ DC converter Test and experiment with performance indicators such as current adjustment time,error,efficiency,etc.to verify the performance indicators of the converter.According to the above experimental tests and analysis,this bidirectional DC / DC converter meets the design parameter requirements,has the characteristics of adjustable output voltage / current,high control accuracy,fast response speed,high efficiency,etc.It meets the performance requirements of practical applications and meets expectations Design goals.