Research On Power And Load Control Technology Of Grid-connected Horizontal Axis Marine Current Turbine

The excessive consumption of traditional energy has led to the problems such as environmental pollution and energy shortage,the development and utilization of renewable energy have gradually become a research hotspot.The marine current energy is rich in reserves and it has huge energy with broad application prospects.With the trend of large-scale and industrialization,the paper takes the grid-connected marine current turbine as the research object,and studies its maximum power point tracking control,grid-connected control and load control strategies to improve resource utilization and extend the service life.The contents of each chapter are as follows:The first chapter introduces the background of the research and expounds the research status about marine current turbine,maximum power point tracking control and load control of transmission chain at domestic and abroad,finally puts forward the significance and contents of research.In the second chapter,compares the different electrical schemes of the grid-connected converter,then chooses the back-to-back PWM converter.Analyzes the control principle in different operating areas,and expounds the control objectives of this paper.Then analyzes the power control principles,summarizes and compares the common control methods of maximum power tracking.The third chapter mainly studies the power control strategy of grid-connected marine current power generation system,and applies the fuzzy control in the control system to improve the adaptability.Focusing at the deficiency of existing mountain climbing algorithm,the algorithm of maximum power tracking control of climbing mountain with fuzzy variable step is proposed.The mathematic model of three-phase voltage-source PWM converter is established and SVPWM modulation technique is studied.Through the analysis of the mathematical model of the permanent magnet synchronous generator,the control strategy with speed and current double-loop control is adopted.Based on the mathematical model of three-phase PWM inverter,adopts the voltage and current double-loop control based on grid voltage orientation.The fourth chapter mainly demonstrates the simulation analysis,furthermore,compares the simulation results with the experimental data of the power generation system.PMSG speed control model is established to verify the correctness of the proposed speed control strategy by Matlab software.Taken the measured flow rate as input,the simulation results are compared with the experimental data,which verifies the feasibility and correctness of the proposed control strategy.In view of the problem that the weak damping of the transmission chain is easy to damage the key components under high current velocity,the damping control method based on full power converter is proposed and the simulation is carried out by Matlab software.The chapter six summarizes the research work of the subject and puts forward the further research direction.