A study of constraints in the wind industry was conducted to guide the development process of the Uprise machine. The list is long, but here are the ones that effect energy capture are:
- Rotor RPM constraints
- Generator RPM constraints
- Power factor
- Parasitic losses
- Pitch stall impact on blade shape
- Blade area
Uprise innovations have eliminated all of these constraints
- The rotor is allowed to change RPM as the wind speed changes. This maintains the optimum tip speed ratio, which is known to optimize energy capture.
- The Uprise generator is driven at a constant RPM, which allows the use of a synchronous vs induction generator. The Uprise drive system eliminates the need for a fixed ratio gearbox. Voltage and frequency from a synchronous generator are maintained, eliminating the need for a transformer and an inverter.
- Conventional wind machines utilize induction generators, which produce lagging power factors, and require KVARS from the grid to excite the field coils. This decreases net output of the machine by 20-30%. As wind speed and rotor load drops, voltage drops, and excitation amperage increases, causing a lug on the rotor, which reduces low wind energy capture efficiency.
- Parasitic losses, namely line losses due to inefficiencies caused by the gearbox, transformer, inverter, and KVARS, amount to an additional 25-30% loss as compared to the Uprise drive system.
- Overloading of the blades, gearbox, and tower from wind gusts and high wind speed is a serious constraint. Conventional wind machines limit blade count and blade area to prevent overloading. As a result, low wind speed energy capture suffers. The Uprise machine incorporates 5 blades to improve low wind speed energy capture, as well as other benefits, such as low blade loading, lower noise levels, less toggling, and smoother operation. Unlike a conventional machine, an increase in rotor RPM on the Uprise machine is actually sought after. This is only one of the ways the Uprise machine increases energy capture. Ultimately, wind strength can overload the Uprise machine. In such a circumstance, the Uprise machine will automatically shut down and lay down to mitigate damage.
- Conventional blades are designed to prevent overloading and over speeding thru pitch stall. This is a constraint. Pitch stall is designed into the blade shape so that the blade can quickly rotate to “null” the load of a high-speed gust, and to prevent an increase in RPM. The downward slope of a conventional power output curve is the result of pitch stall. The Uprise machine is designed to manage wind gust energy capture, rather than blunt the power. The blades on the Uprise machine are not compromised by a pitch stall shape.
- Torque on a conventional wind machine increases dramatically at high wind speeds. This is due to the fact that load increases without an increase in RPM. The RPM of the Uprise machine increases with load, and as a result, torque and drive train loads are significantly lower, resulting in a lighter machine and longer life.