Research On Variable Pitch Control System Of AC Asynchronous Motor

The China have made a lot of achievements in the field of wind power.But there is a big technical gap with the international level in the pitch system.This paper has carry out research and experiment on the pitch system.On the basis of the research theory,there are carry out some experimental analysis of important components to ensure the safe and reliable operation of the components in the pitch system.First of all,this paper analyses the principle of pitch and describes the advantage of the pitch compared to the fixed pitch.And this paper has design six kinds of pitch system work mode: forced manual mode,manual mode,test mode,teach mode,emergency mode and auto mode.Then this paper explains the design of the proportional feedforward control in the program control.Finally,there are some tests of the Beckhoff PLC controller by EMC,and observe the working ability of Beckhoff PLC in electromagnetic interference.Secondly,the DC/DC determines whether the control system can operate normally.Under the condition of electrical performance.There are somevibration tests and wet heat tests.It is used to test the work situation in bad environment.As a backup power supply,the supercapacitor has unparalleled importance and superiority:charging faster.The supercapacitor charger is studied to ensure the use of the power supply and to analyze the fluctuation of the power grid and to test the charger.Then,in the selection of the motor part,and after comparing the performance of 3main types of motor,selection of the AC servo motor.It has the advantages of simple structure,high reliability,convenient maintenance and so on.Due to the particularity of the pitch,in practical,the encoder for the three loop control of current loop,speed loop and position loop are the multi circle absolute value and incremental encoder.Then this paper introduces the hardware design,software design,communication design,diagnosis and protection of the servo system.Finally,the pitch system needs toattention some problems: low temperature,lightning protection,fire and so on.These places that need to be paid attention to.