Research On Control System Of MW-level Permanent Magnet Direct-driven Wind Power Generation

Permanent magnet direct-driven wind turbine is considered to be a research focus for its high energy conversion efficiency and a high reliability and flexibility in grid power control, etc. In this paper , the object is directed-driven wind generation system of 1.5MW and then the 1.5MW Direct-driven turbine inverter's control were studied.This paper Analyzes the advantages and disadvantages of a variety of wind power generation system and several typical converter circuits to determine the main converter circuit topology.The structure of main circuit is to use"uncontrollable rectifier+double chopper+SVPWM converter"in converter system. In this paper ,the models of the various parts of the permanent magnet direct-driven wind power system are derived,such as aerodynamic model, wind turbine and permanent magnet synchronous motor model, uncontrollable rectifier and double chopper circuit model and SVPWM Inverter model,etc. The working principles of the various parts are analyzed. The paper has syudied the control strategy of the direct-drive permanent magnet synchronous wind power generation system. Using the grid voltage-oriented vector control technology, this paper has builded the grid side converter of current inner loop, double loop PI voltage outer loop control system, derived the control strategy of independent decoupled active and reactive power by using the rotor active current and reactive current. The paper analyzes the technology of space vector pulse width modulation (SVPWM) and its implementation, builds the SVPWM model.The paper designs the MPPT control algorithm of the double rate of change to complete the maximum power point tracking quickly. This paper establishes simulation model of wind turbine according to power curve fitting foe the need of simulation.Finally, based on MATLAB/Simulink, direct-drive permanent magnet synchronous wind power generation system is established,including overall system simulation model , machine-side converter simulation model and grid-side converter simulation model. The grid-side converter control strategy,MPPT control strategy and SVPWM generation module were simulated.The simulation results adequately confirm the validity and feasibility of the strategy which is presented in this paper.The innovation of this paper is that it designs the MPPT control algorithm of the double rate of change to achieve the rapid control of speed.This algorithm can deduce the wind turbine output power fluctuations, complete the maximum power point tracking quickly.