Research On Direct-Driven Wind Generation Inverter

Many governments take more and more attention on the wind energy generating systems because of its sustainability and cleanliness. Grid-connected inverter is the crucial part of the generation system. Based on the research results of these years, this paper proposes a design of 3MW direct-driven wind generation inverter, and takes much effort in the control algorithm research and Matlab simulation, some wonderful results are obtained. All this may provide the reference for practical application. The below is the main contents:(1) The operation principle and work patterns of the PWM rectifier are analyzed in this paper. With direct current control method, it could gain higher power factor, lower harmonic distortion of the line current and bi-direction transmission of energy when PWM rectifier is used.(2) The output of each inverter bridge of a grid-connected multiple structure inverter (MSI) is connected into power grid through transformer coupling and by this means the capacity of grid-connected inverter increases. In order to realize the high voltage output and overcome the influence of dead time on the system, the 11 square-wave-voltage superposed inverter was implemented using 6 common three-phase square inverters. A new novel SVPWM control method is proposed for the inverter. The whole system is controlled through combining 180°conduction and 120°conduction of SVPWM as well as using the inner current loop control and outer voltage loop control. The Matlab/Simulink result shows that the present method can eliminate the effect of dead time and improve the utilization ratio of power. The Matlab/Simulink result shows that the present method can eliminate the effect of dead time and improve the utilization ratio of power. The multiple superposed technology can improve the output voltage waveform, and increase the output voltage and power of inverter.(3) The fuzzy controllers are designed, based on fuzzy logic control theory, which can perfect control the wind generate system with no mathematic model. (4) Models of PMSG and dual PWM converter with their controllers are set by Matlab/simulink. In addition, experiments are made on the simulation platform of VSCF wind power generation system. The behavior of dual PWM converter is demonstrated by simulations and experiment and the control strategy is valid and correct.