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WHITE PAPER

Ultracapacitors Improve Reliability for Wind Turbine Pitch Systems

By Adri an S c hneu w l y Maxwell Technologies, SA – Rosse ns, Switzerland

Introd uction

Today’s advanced wind turbines are three- bladed, variable speed turbines. The rotor blades are adjusted and controlled via three independent electro-mec h anical propul si on uni ts for t h e pi tch s y st ems. On a pi tch con t rol l ed wi nd t u rbi n e the turbine's electronic controll er checks the po wer output of th e tu rbin e sev e ral t i m e s per second. When the power outp ut becomes too hi gh , i t sends an o r der to the bl ade pitch mecha n ism, which immedi ately turns the rotor blades sligh t ly ou t of th e w i n d . C o nversely, the blades are turned back into the wind whe n ever the wind drops again. Thus aerodynam i c efficiency and red u ce d loads on the drive train is assured, prov idin g redu ced maint e n a n c e and lon g er t u rbin e lif e. T o en h a n c e the lev e l of safety, ne w e r wi nd t u r b i n e technol o gy uses t h e wi nd not onl y to prod uce wi nd energy but also for its own safety. The co nver ters feature aerodynam i c braki n g b y individual pitch control. The rotor at tai n s the f u l l braki n g eff e ct wi th a 9 degree off position of all three blades. E v en i f a bl ade pi tch uni t fai l s , the other two rotor blades fi ni sh off t h e braki n g pr ocess safel y . To e nha nc e the l e vel of safet y ea ch of t h e autonomous pitch systems is equipped with a n em ergenc y power supply to i mmedi ately ens u re t h e reli able fu ncti oni n g of the fast blade pitch s y s t em in the event of a total power failure or for maintenance purposes.
Three bl ade d wi nd turb i n es Indep e ndent el ectro-mech ani c al pi tch propul si on u n i t s Maxw el l T e ch nol o gi es, I n c. Maxw el l T e ch nol o gi es S A 9244 Bal b oa Ave nue, San Di ego, CA 92123 CH1728 R o s s e ns U n i t e d S t at es S w i t ze r l an d Phone: +1- 8 5 8 - 503- 3300 Phone: +41 ( ) 26 411 85 00 F a x: +1- 858- 5 03- 3301 F a x: +41 ( ) 2 6 411 8 5 05 © Maxwell T e chnolog i es, I n c. | www. maxwell.co m | info@ m axwell.co m |