Model 3.1 is officially running 24/7! The unexpected blackout last week interrupted the beginning of testing 24-hour autonomous operations. The final challenge in beginning official 24-hour operations was the successful verification of engineer Mark Chang’s Variable Speed Algorithm (VSA), which truncates energy output as wind speeds reach rated power—the maximum amount a generator can provide.

How does this work? When generated energy approaches the maximum safe capacity, the Wind Harvester’s VSA forces the generator to throttle the Tip Speed Ratio. 

What is the Tip Speed Ratio? One challenge present for all turbines is maintaining an optimal tip speed ratio (TSR), the ratio of the blade speed to the incoming wind speed. This metric depends on the number of blades, the blade’s airfoil, the type of turbine, and more. Optimal TSR is difficult to maintain because wind speeds at 10-20 meters above the ground are much more volatile than they are higher up. Thus, Model 3.1 is also subject to extreme changes in wind speed; recently, our team measured a 34 mph increase in under two seconds! Our customized VSA is instrumental in handling this. 

What happened after the blackout? Following up on our last blog, the turbine proved it could appropriately handle a sudden loss of power after an accident knocked out the local grid last week. However, we also found that we should add some improvements to its procedures, which are now being implemented. Our team of engineers has since simulated an additional power failure to test these changes. We made changes to the control code that will provide redundancy in the fault detection and ensure proper shutdown in the event of power failures, partial power failures, overspeed, and other conditions. 

We are proud of our engineering team’s ability to produce a turbine and the necessary controls to ensure it can withstand all manners of challenges, including loss of power and even the most aggressive gusts of wind.

Test the waters disclaimer page here