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anne
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Posted 5 Months, 1 Week ago #1
Hi..please help me to solve my problem.

In order to run in variable speed, we can use the variable frequency control where the synchronous speed is changing suitable to the load torque. To do this, we can use the concept of scalar control where the ratio between voltage and the frequency is kept constant as long as the frequency is not higher than the base speed. My question is, can I use the V/f constant ratio even though the frequency is higher than the base speed for wind turbine application? I feel so confuse with this because for wind turbine generation, we need generator speeds operate higher than the base speed. Please help me if anyone can give me a comment or feedback. Many thanks for your help.
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hobbist
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Posted 5 Months, 1 Week ago #2
ONE WAY IS TO DECREASE PROP ANGLE TO MIN.OR INCREASE LOAD.

TO ANSWER YOUR QUESTION ARE UAEING A STANDARD GENERATOR OR IS IT ALT.

THE BEAUTY OF AND ALT IS IT WORKS BETTER AT LOW RPM.SO WHAT IS IT.
anne
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Posted 5 Months, 1 Week ago #3
Thanks for reply.

I use standard generator with 4 poles. When wind speed increases from cut-in wind speed to rated wind speed (let say 4 to 10 m/s), the rotation of the generator will be increased as well. So, it's meant during the changing of wind speed from one wind speed to another, torque of the aerodynamic also increasing. To operate in adjustable speed, we need to increase the generator (rotor) speed so that the generator torque can be aligned with the aerodynamic torque. This can be achieved by changing the synchronous speed so that the torque can be matched when frequency(rotor speed) is increasing at another speed. At high wind speed, let say 10m/s, the generator speed will over the base speed where the synchronous speed will also be higher than the base speed. But, from text book, if we use V/f constant ratio concept, we need to fix the voltage if the frequency is greater than the base speed. this make me confuse thanks for any feedback.
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hobbist
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Posted 5 Months, 1 Week ago #4
UNFORTUNELY THIS IS A DRAW BACK OF A STANDARD 4POLE GENERATOR. iN THE 1930S JACOB WIND 4 POLE GENERATOR USED A GEAR BOX 2:1 RATIO.SPEED WAS CONTROLED BY LIMITATION OF GEAR BOX DRAG.ALSO INCORPATED A BREAK DRUM SHOES FLING OUT ACCORDING TO SPRING TENSION MUCH LIKE A BRAKE DRUM.

MY HOME MADE WIND GENERATOR USED A 24 VOLT TRUCK ALT.
I CONTROL THE SPEED WITH 3OO OHM RESISTOR (OVEN HEATING ELEMENT FROM ELECTRIC STOVE)THIS KEPT OUTPUT CONSTANT) ACROSS BATTERY OUT PUT TO GRND.ALT CASE.BATTERY OUTPUT FEEDS 4 SIX VOLT BATTERIES.THEN CONVERT TO 110VOLT 3000WATTS AC POWER CONVERTORS.PROP IS DIRECT DRIVE.REMEMBER ALT WILL OUTPUT DOWN TO 500 RPMs.then feed voltage (24v)to alt field circuit this lets the alt maintane output constant with min hardware or software.THE TERMINAL R USED A 24V LIGHT BULB ACROSS A 10OHM RESISTOR THIS CONTROL REGULATOR
WHEN 24 V APPEARS ON BOTH SIDES OF LAMP AND RESISTOR.you add a switch you can turn on and off alt.some days i turn off system to prevent batteries damage excessive ware and tear on unit.
THEN LAMP GOES OUT MAINTAIN PRE SET ON REGULATOR.
REMEMBER LOWER BATTERIES VOLT HIGHER THE AMPS LONGER THE OUT PUT.MY BATTERIES LAST 24 TO 48 HOURS UNDER CONSTANT USE.GENERATORS ARE THE THING OF THE PAST THEIR OBSOULETE.TAKES TO MANY RPMs OVER 2OOO two much heavy hardware BEFORE IT STARTS having any output.YOUR ARE MAKING A MOUNTAIN OUT OF A MOLE HILL THEIR NO REAL FIXES FOR GENERATOR DRAW BACKS are machanical and windings not enough poles for low speed output. DESIGN FLAWS.alt has 13 to 26 poles 12 truns three times to make 3 phases.each delta termanial connections has 48 volts ac x3.
MY SYSTEM IS 13YRS OLD WITH OUT CIRCUIT FAILURE.REPLACED BATTERIES TWICE AN ADD MORE I KNOW I HAVE 48 BATs 6v deep charge marine boat BATTERIES.STORAGE HAS BEEN INCREASED
OPERATES LONGER KNOW UP TO 3 OR 4 DAYS STORAGE.
Last Edit: 2009/10/15 14:50 By hobbist. Reason: spelling and paragraft editing.
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