0

I'm working on an electrical power generation project , where the prime mover's shaft rotation speed is variable (for example a wind turbine). We have an initial guess at the optimal speed and torque available at a nominal operating point. What computational steps are required to determine:

  • (a) shaft input power, given an estimate of torque at various speeds
  • (b) the efficiency and optimal speed/torque for maximum mechanical power extraction to the shaft
  • (c) the voltage coefficient of the shaft driven electrical generator given a desired DC or AC bus voltage
  • (d) an estimate of the electrical power generated and efficiency at the optimal operating point
  • (e) an estimate of how efficiency and electrical power output would drop either side of optimal.

Originally posed as: Im doing a certain project of power generation from rotating shaft that is not uniform (rotations). I just know the shaft rotations that can be produced. What would be the next calculations to predict the generated power value ?

BobT
  • 624
  • 3
  • 8
Prasad Ujalambe
  • 1
  • 1

2 Answers2

1

As usual, you need to understand your system. What generator do you use? Do you have any gear? What load is on your generator?

Basically, you will get all the power you have on input, minus the losses. The losses include friction, heat on the generator, and other parts. Probably for each point on the speed chart the losses will differ, which means you may be able to optimize.

For example, if you are charging a battery with your generator, you can use a circuit to adjust charging current to the rotor speed. Another loss would be the power of the circuit including any speed sensor, but it may pay off by reducing other inefficiencies.

Anyway, there is a lot to do to really understand this system.

0

The speed (RPM) at any instant will determine the voltage and for AC also the frequency. The current drawn by the load will determine the torque required. You can design a voltage converter that will convert whatever voltage it receives to the voltage that you want. The available output current will be governed by conservation of energy. Mechanical power in (torque X speed) is equal to electrical power out plus losses: (voltage x current x efficiency x (power factor for AC).

With variable input power available, the system is pretty much limited to generating energy for storage or for immediate sale to the grid. Variable energy is not very useful for immediate use for most loads. It would be useful for pumping water for irrigation or storage.