Harnessing Wind Energy: The Power of AC in Wind Turbines
Updated: Sep 12
The term AC from an electronics standpoint does not mean air conditioning. Instead, alternating current or AC describes the flow of charge that changes direction periodically. As a result, the voltage level also reverses along with the current. This differs from direct current or DC since DC only flows in one direction. #AlternatingCurrent #DirectCurrent
Let’s take a look at a simple electric motor model, the motor is connected to a battery. When the switch is closed, the current starts to flow, and the coil becomes an electromagnet. In this case, the current is flowing anticlockwise at the top of the coil. This makes the top a north pole. This north pole is attracted to the south pole on the left. So, the top of the coil turns towards the left. Notice that the bottom of the coil is a south pole and is attracted to the magnet on the right.
Once the coil gets to the upright position, there is no turning force on it because the electromagnet of the coil is lined up with the permanent magnets. If the current in the coil were constant, the coil would stop in this position. However, to keep it spinning, the commutator breaks contact in this position. So, the current stops for an instant. The momentum of the coil keeps it going and the contacts are reconnected.
Figure 1: AC motor schematic diagram.
Putting it all together
A wind turbine turns wind energy into electricity using the aerodynamic force from the rotor blades, which work like an airplane wing or helicopter rotor blade. When wind flows across the blade, the air pressure on one side of the blade decreases. The difference in air pressure across the two sides of the blade creates both lift and drag. The force of the lift is stronger than the drag, and this causes the rotor to spin, thus generating electricity.
Figure 2: Wind turbine schematic.