The Design And Realization On The Generator Side Converter Control System Of Direct-driven Wind Power Generation

Large-power direct-driven wind turbine has become the main way of wind energy utilization nowadays with a promising future.In the control scheme of this generation system, the Direct-driven Permanent Magnet Synchronous Generator (PMSG) which can operate in the large range of wind speed does not need up-speed gear and excitation system.And the active power and reactive power of the generation system can be controlled freely. This thesis researches mainly on the large-power parallel back-to-back PWM converter and its control scheme of restraining circulating currents.At first, this thesis introduces the basic structure of direct-driven wind generation system,analyzes and compares the large-power conversion circuit topologies, the mathematic model of converter and PMSG is also founded,and gives comprehensive basic theories emphasized on the control scheme of 2 MW direct-driven wind generation conversion system.However, in accordance with its characteristic, conversion circuit which is called back-to-back PWM converter multistage paralleled structure exists the problem of circulating currents ,So the thesis brings up a new strategy of power control system of generator side converter including the control scheme of restraining circulating currents.This scheme can adjust the power factor,exchange the reactive power with grid ,and also realize the function of tracking the maximal power point of wind power.Then Sliding Mode Observer in the speed sensorless control sheme have been researched and tested in order to obtain the rotor speed and position of the PMSG over full frequency range,and it is adequately illustrated that Sliding Mode Observer with adaptive feedback gain can get excellent dynamic performance and robustness. The results of simulation under MATLAB/SIMULINK validate the validity of the converter control strategy.At last, control system of direct-driven wind turbine converter is designed based on DSP TMS320F2808 controller.This system chooses six phase permanent magnet synchronous machine as the generator,also generator and grid side converter are composed of parallel IGBT Power Modules controlled by dual DSP controller, parameters are communicated by CAN bus between DSP controllers.Moreover,the paper addresses the design of main converter system and control system based on the parallel PWM converter, and also details DSP control circuit such as IGBT drive and protect circuit, CAN communication interface circuit and optical fiber interface circuit. SVPWM method based on DSP is proposed besides the software flow charts of generator side converter control scheme.