Research On Power Electronic Transformer With Hybrid Energy Storage

With the development of industry and national economy,the demand for energy is increasing,and electrical energy is one of the main energy sources.In order to meet the growing demand for electricity,the scale of the power system is also expanding.With the increase of power system structure and capacity,higher requirements have been placed on power transformers.Traditional transformers have been difficult to meet the requirements for power quality.Due to the advantages of small size and controllable power quality,power electronic transformers(PET)gradually replace traditional transformers into the power system,and have been widely used in AC and DC systems.This article first analyzes the working principle and commonly used topology of the power electronic transformer,focusing on the analysis of the transformer’s high-voltage rectification,intermediate isolation stage,and low-voltage inverter stage model,and the establishment of the three-stage H-bridge topology structure.Mathematical modeling.Secondly,it analyzes the three working modes of the hybrid energy storage system and the corresponding state changes of each energy storage unit,establishes a mathematical analysis model and an equivalent model for the important bidirectional DC/DC converter,and designs the power of the hybrid energy storage system Control Strategy.The power electronic transformer with hybrid energy storage system is analyzed and studied.Finally,a power electronic transformer model and a simulation test platform based on a hybrid energy storage system composed of a battery and a super capacitor were established,and a comparative test of simulation experiments was designed.The model was analyzed,and the hybrid energy storage system began when a voltage interruption occurred Discharge provides compensation.The voltage of the low-voltage DC bus has not dropped and has been stable at the target value of about 400 V.When the voltage drops,the hybrid energy storage system can maintain the sinusoidal characteristics of the output voltage,and the output distortion is small and maintained at about 311 V.It provides energy for the load normally and has obvious compensation effect.The simulation results show that the power electronic transformer with hybrid energy storage system has the compensation function after the voltage interruption and dip in the power grid.at about 311 V.It provides energy for the load normally and has obvious compensation effect.The compensation function of the power electronic transformer with hybrid energy storage system in the event of voltage interruption and dip in the power grid is verified.