Improved Maximum Power Point Tracking Of Direct-drive Permanent Magnet Synchronous Wind Power Generation System Based On Power Feed-forward

Wind energy,as a clean and efficient renewable energy sources,widely distributed,has a huge storage capacity and availability,thus gradually been widespread concern.After hundreds of years' development,wind power is becoming the most mature technology,the most developed commercial scale conditions and prospects for the development of power generation.In this paper,on the basis of a lot of previous research results,carried out for the maximum wind power point tracking(MPPT)study.Above all,the mathematical model of direct-drive permanent magnet synchronous(D-PMSG)wind turbine systems with the full-power 2-PWM converter are developed,including the wind turbine,generator,drive chain,converter and other sections.Control technology is the key technology of wind power,the paper describes the generator and converter control technology,at the same time,gives a detail introduction of the sinusoidal pulse width modulation(SPWM)technology,Finally,based on the control technology,gives a comprehensive control strategy of the system.The next,around MPPT control algorithm,detailed analysis the control principle of the broader application of optimal tip speed ratio algorithms and power curve algorithms,as well as their advantages and disadvantages.At the same time,a simulation model of MPPT systems based on rotor speed feedback and power feedback are established in the simulate software PSCAD/EMTDC.Simulation results show that,when the step change in wind speed,the control method based on the rotor speed feedback has a faster response speed,but there is a big power shock;the control method based on the power feedback can achieve a smooth transition,but the response time is longer.Afterwards,as the conventional MPPT control algorithm step change in wind speed,either speed control or power control is difficult taking into account the speed of response and dynamic stability of the system.In this paper,an improved MPPT control algorithm of D-PMSG system was given based on power feed forward,the control algorithm is introduced before the power was fed to obtain a corresponding additional rotor speed,the additional speed is superimposed onto the traditional optimum rotor speed as the new reference system rotor speed,so as to realize MPPT control system.Meanwhile,the paper establishes the simulation model,by comparing it to the traditional control method,on the one hand the improved control algorithm can improve the system's response speed while the step change in wind speed,on the other hand can effectively alleviate power shock caused by the step change in wind speed.Finally,to further ease the shock power,the text use sliding mode controller,select the rotor speed error as the controller's input,q-axis current as the output of the controller,meanwhile,use the saturation function instead of sign function to design sliding mode controller of this article,and then establish the simulation model.The simulation results show that the controller design correctness,while the newly introduced sliding mode controller may further weaken the system's power shock.