Design Of Pitch Angle Drive System In 3MW Wind Turbine

Pitch angle drive system is one of the most important parts in wind power, that fixed pitch wind turbine will be replaced by pitch angle wind turbine because of reliability and fast responsibility of pitch angle drive system. A kind of pitch control drive system was designed on the background of 3MW wind power, which consisted of circuit and software. Simulation model of pitch angle driver was built, and the simulation was made with PID controller and Fuzzy-PID controller. Finally, a method to improve reliability of pitch angle driver, which was based on VCE of IGBT grey prediction, was proposed.Control requirement was represent by analyzing structure of pitch angle drive system and characteristic of pitch control moment. Circuit of pitch control drive system, which consisted of main circuit, detecting circuit, DSP periphery circuit, serial communication circuit, and battery monitor circuit, etc, type of electronic device and means to calculate parameter of circuit were given, pitch control drive system software, which consisted of main program, PWM program, double closed loop program, and serial communication program, etc.In order to confirm rationality of the pitch control drive system design, simulation models of pitch control moment and pitch drive system were built. Sample time of regulator, sample time of double closed loop program, parameter of circuit, were tested and verified using PID and Fuzzy-PID as position regulator.At last, in order to improve the reliability of pitch driver in wind power generation, IGBT fault prediction, which was based on VCE when IGBT gate was on, using algorithm of innovation grey prediction was proposed. The method can predict VCE of IGBT in future by constructing GM(1,1) grey prediction model of VCE, using old data of VCE, once the value of VCE is bigger than threshold value, system alarms, turns three blades to 0 degree and stops the turbine. Equal dimension metabolism arithmetic changes data which are used in constructing grey model on time to makes sure that the grey model is fresh enough to generate accurate result. Gray prediction of variation step length was put forward; a formula which describes step length was supplied, too. VCE detecting circuit, with high anti-interference capability, high reaction speed, high reliability and simple frame, is designed. The result of experiment shows that equal dimension metabolism arithmetic can predict VCE of IGBT effectively; it is doable in improving reliability of pitch driver.