Research On Multiple Bidirectional DC-DC Transformation Technology In Energy Storage System

At present,the problems of environmental pollution and energy shortage are the main problems facing the world.In order to meet the development requirements of a low-carbon economy,bidirectional DC-DC converters are widely used in energy storage systems,electric vehicles,aerospace,etc.as a port that can carry out bidirectional energy flow.In this paper,the following research is conducted on the bidirectional conversion technology based on super capacitor energy storage system.For high-power occasions,the use of magnetic devices is greatly restricted,and isolated bidirectional DC-DC converters are difficult to apply.In this regard,this paper uses a non-isolated multiplexed bidirectional Buck/Boost converter as the main topology.First of all,this article explains the advantages of using multiple topologies to reduce inductor current ripple and reduce the voltage stress of the switch.Study and analyze the working principle of the two-way non-isolated bidirectional Buck / Boost converter.In order to enable the system to work in a higher power and larger current environment,the circuit's upper and lower arm switch tubes are complementarily turned on to achieve the circuit's soft switching function,reduce circuit losses.Secondly,the main parameters of the dual non-isolated bidirectional Buck/Boost converter are calculated and selected.When working on electronic components,the high temperature environment will have a serious impact on their reliability,stability,and working life.For the traditional thermal analysis can only observe the situation when the load is in steady state,so this paper uses ANYSYS finite element analysis software to observe the dynamic thermal analysis of IGBT and inductor.Finally,this paper proposes a new control method based on peak current control for the multiplexed circuit.The traditional voltage outer loop and multi-current inner loop control methods will cause uneven current in each phase.In view of this shortcoming,this article by adding a current sharing control loop between each phase current loop to ensure that each phase current achieves current sharing control.The corresponding simulation model is built under MATLAB/Simulink environment.The small signal model of the two-way non-isolated bidirectional Buck/Boost converter in Buck mode and Boost mode respectively,and the corresponding controller is established according to the small signal model to form a complete closed-loop control system.Through the simulation to verify the operation of the bidirectional DC converter,the constant current charge and discharge of the super capacitor can be realized.The super capacitor energy storage system can recover the excess energy of the load,and can also provide timely energy supply to the load.Control effect.