| With the reduce of the fossil energy,the development of renewable energy is being paid more and more attention gradually.However,the technology of tidal current energy to generate electricity has not developed well up to now.There is abundant tidal current energy in China and an increasing demand for electricity in sea islands.Meanwhile,with Chinese government’s promotion of national strategic aim of building an ocean power,the study of the power system based on the sea island microgrid including tidal current turbines has a huge application prospect and value.Firstly,this paper introduces the domestic and overseas research status of current tidal turbines and the microgrid power system.The concept of the microgrid,the typical construction and the feature of the microgrid are described.Secondly,the paper studies the features of tidal current and the basic principle of electricity generation and has designed the key parts of the tidal current generator.The model of the tidal current generator system has been established,including the turbine model,the generator model,the frequency scaling circuit,the rectifier and the inverter.Then,the whole program of the micro-grid connected with tidal current turbines has been designed.Thirdly,the sea island microgrid including the tidal current turbines has been established.Nowadays,the most common structure of microgrid is the hybrid AC-DC structure.The solar power system,the super capacitor energy storage system and the battery energy storage system are connected to the DC microgrid.The wind energy generation system,the diesel generation system and two tidal current turbines are connected to the AC microgrid.Fourthly,in consideration of the microgrid stability,different conditions of the micro-grid operation have been simulated,which are charge and discharge of the energy storage system,one or two tidal current turbines connected to the microgrid,all the electricity power resources connected to the microgrid,changes of the environment load and changes of the electrical load.The operation of different parts of the micro-grid is shown in oscilloscopes according to the voltage,current,active power and reactive power.Especially,the influences on the tidal current generation system are studied under different situations.Finally,the operation conditions of the microgrid have been studied when the single-phase voltage drops to different degrees,especially in effect to the tidal current turbines.In addition,a model based on dynamic vector has been established to improve the quality of the power generated by the tidal current as well as the stability of the microgrid. |
