Renewable energy is imperative. While no renewable source is the answer
for all of our energy needs, wind energy has its attributes. Unlike the sun, wind is everywhere all
the time. Wind power has become
reasonably cost effective compared to other renewable forms. However, wind is not as cost effective
as it should be. The
variability of wind causes severe constraints on the design of wind
machines, which reduces its effective capture of available wind energy.
The goal of Uprise Energy is to improve wind gust energy capture thru the use and application of four innovations.
- Wind prediction
- Variable speed transmission
- Constant speed generator
- Sophisticated programming of loads and RPM
It is important to understand the reasons for the above mentioned constraints in order to appreciate the solutions.
The variability of wind is manifested in two manners. Wind velocity and wind direction.
Wind velocity creates benefits and problems. The power in wind increases dramatically as wind velocities increase. For example, 20 MPH wind has 8 times the power of 10 MPH wind, and 30 MPH wind has 27 times the power of 10 MPH wind. This example illustrates the importance of capturing the energy of higher velocity wind. The problem is that wind is not steady.
There is universal agreement that a wind turbine blade will perform optimally at a given relationship to the wind speed. Therefore, as wind velocities vary from 10 MPH to 30 MPH, such as in a gust, the blades and rotor RPM must vary (triple) in direct relationship to the wind speed, or suffer inefficiencies.
Unfortunately, conventional wind turbines do not react quickly to the variability of wind velocities, and therefore do not capture much of the gust energy.
Wind does not always blow in the same direction. The efficiency of a wind machine depends on the rotor to face the wind squarely, not on an angle. Again, turning the rotor to face the wind takes time, and the power of a wind gust may be lost.
The blade RPM response problem is further exacerbated by another constraint in the industry, generator RPM.
The grid is the problem. The world’s power grid is either 50 or 60 HZ alternating current (AC). In order to generate electricity and deliver power into the AC grid, exact frequency must be adhered to.
A typical conventional large wind machine must deliver AC power to the grid at a steady voltage and frequency. With variable wind velocities, the rotor rpm will vary, and the voltage and frequencies will fluctuate, which requires use of expensive and inefficient transformers and inverters to purify the power to be grid acceptable. In order to eliminate expensive, heavy, and failure prone gearboxes, generators are custom purpose built at great costs. Even so, the industry uses permanent magnet induction generators as a poor substitute for a superior AC synchronous generator, simply because they cannot maintain constant RPM and frequency.
The negative consequences for the use of the gearbox, transformer, inverter, and custom induction generator are higher costs, weight, parasitic losses, and poor power factor for which the power company discounts the value of the supplied power.
Power factor of less than 1.0 (unity) is a result of an imbalance of capacitive vs inductive loads. When a generator is running slower than or faster than grid frequency, a leading or lagging power factor occurs. The power company will discount KW production for power factors less than 1.0.
All of these negative consequences are mitigated with the Uprise Energy system.
In order to prevent severe voltage and frequency fluctuations, wind turbine designers constrain rotor RPM. This is accomplished thru the use of brakes and pitch stall. Essentially, they purposefully avoid wind gust energy thru dumping wind energy to prevent overspeeding.
All of these constraints and limitations can be mitigated.
Uprise Energy, thru years of experience, has developed an understanding of these constraints, and has developed an innovative and sophisticated system to exploit wind gust variability.
While Uprise Energy has developed a number of additional features to improve wind turbine output, the scope of this project is to focus on a system that can be applied to any machine, small, medium, or large, new or retrofit.
The system allows any wind machine:
- To allow the blades to spin at their optimum RPM to maintain a correct ratio to the wind speed
- To drive an AC synchronous generator at grid voltage and frequency without the need for transformers and inverters
- To predict wind direction, speed, and duration thru the use of laser anemometers
- To adjust the system load thru programmable excitation of the AC generator.
The benefits of this system are interesting.
- An existing machine can increase its annual output
- A smaller machine can replace a larger machine at a lower cost
- Shipping costs, erection costs will be less
- Total elimination of transformers, static inverters, gearboxes, and weight
- Lower operation and maintenance costs
- Lower parasitic losses
- Technically simpler machine
- Programmable to optimize each machine and its behavior in each wind environment
- Programmable for seasonal conditions
- Power down features
- Lower mast loads
- Off the shelf components
- Lower cost generator
The Uprise system blends an intelligent mixture of conventional equipment with state of the art programming to prepare any wind machine for the wind conditions, optimizing wind energy capture.