95
modifications
Modifications
→Generator choice
''Pour la traduction française, voyez '''[[Micro-éolienne à axe horizontal imprimée en 3D|ici]]'''.
[[Fichier:micro_eolienne_rotor1.jpg|Micro-éolienne|300px|right]]
The assembly of the different parts is simple:
* blades are assembled with threaded rods and M3 nuts. L'assemblages des différentes parties se fait simplement:* les pales s'assemblent avec des tiges filetées et des écrous de M3. Les clavettes utilisées pour guider l'assemblage sont de forme parallélépipédique de Keys used to guide the assembly have a parallelipiped shape with a 4mm de côtéside. (voir dessins techniques pour la longueur des tiges filetées et la longueur des clavettes see technical drawings for all lengths (dépend du it depends on the set de pale choisiof blades choosen)).* Tous les autres boulons utilisés sont de type All others bolts and nuts used in our design are M5 (les différentes longueur sont disponibles dans les dessins techniqueslengths are available on technical drawings)
==Tests==
===Test bench===
The schematic of our test bench can be found hereinbelow. The generator output is triphased, we passed in DC with a rectifier. A boost converter is then placed followed by a resistive charge. This boost allows to vary the charge seen by the windturbine. So we can fix any rotational speed at any imposed wind speed. We know in real time the rotational speed of our windturbine thanks to the encoder connected to the generator. Based on the real time rotational speed, we regulate the boost duty cycle with a Proportional Integral control.
[[Fichier:Regulation_bis.png|Regulation|400px|center]]
===Results at the ''von Karman Institute''===
The different results obtained at the Von Karman Institute can be analysed. They represent the evolution of the power coefficient ( percentage of the wind power converted in mechanical power) function of the tip speed ratio ( ratio between the speed at the end of the blades and the wind speed). The tip speed ratio of design was 3. We can see on our graphs that the power coefficient maximum is obtained for a tip speed ratio near the designed one. The power coefficient reaches 0.4 for the first set of blades and 0.38 for the second one. These values equal or exceed the values of others small wind turbines with which we compared our prototype.
[[Fichier:vki1.png|Micro-éolienne|400px|center]]
[[Fichier:vki2.png|Micro-éolienne|400px|center]]
==Replicability==
=== Generator choice === Normally, any DC generator can be used if the design of the nacelle is adapted. It has to be kept in mind that the nominal rotational speed of the set of blades and his nominal torque must remain lower than those of the generator. Indeed, if the rotational speed exceed its maximum value, it may cause dommages to the generator. If the torque exceed the maximum one, it will be impossible to brake the wind turbine and will cause the destrution of the generator. The designed rotational speed is fixed by the tip speed ratio for the nominal wind speed. The maximum torque is given by the matlab program for any type of set of blades. === Blades design === Thanks to our matlab program (available in file section), it is possible for everyone to create his own set of blades. Several parameters can be modified and put in arguments: profile type, radius of the blades, designed wind speed and designed wind speed ratio. === Regulation === == Files ===
[[Fichier:thesis.pdf|pdf du mémoire]]
[[Catégoriehttps:Projets]//makilab.org/sites/default/files/microwindturbine_CAD_Igot_Snyers.zip CAO files]