The post explains how to make a simple windmill generator circuit which can be used for charging batteries, or for operating any desired electrical equipment, all through day and night, free of cost.
Solar Panel vs Windmill
One of the biggest drawback of solar panel electricity is that it's available only during the day time and that too only when the sky is clear. Furthermore, the sun light being at its peak only during midday and not throughout the day makes its harnessing very inefficient.Contrary to this a windmill generator which depends on wind power appears to be much efficient because wind is available all through the day and does not rely on seasonal changes.
However a windmill generator may work with greatest efficiency only if it's installed or positioned on specific regions such as on higher altitudes, near sea or river shores etc.
For a homemade windmill generator to be most efficient one must position it on the roof top of the house in order to get the highest possible wind speed efficiency, the higher the better.
It's said that over 100 meters from ground wind speeds are the maximum and it's active all through the year non-stop, so that proves, higher the altitude better the wind efficiency.
Designing a Windmill Generator
A simple windmill generator circuit concept presented here can be built by any hobbyist for charging small batteries at home, completely free of cost and with negligible efforts.
Bigger models of the same can be tried for achieving greater power outputs which may be used for powering small houses.
Principle of Operation
The principle of operation is based on a traditional motor generator concept where a permanent magnet type motor's spindle is integrated with a turbine or propeller mechanism for the required harnessing of wind power.
As may be seen in the above diagram, the employed propeller or the turbine structure looks different. Here a twisted "S" shaped propeller system is used which has a distinct advantage over the traditional airplane type of propeller.
In this design the turbine rotation does not rely on the wind directions rather responds equally well and efficiently regardless from which side the wind may be flowing, this allow the system to get rid of a complex rudder mechanism, which are normally used in conventional windmills in order to keep the propeller self adjusting its front position in line with the wind flow.
In the shown concept the motor connected with the turbine keeps rotating with maximum efficiency no matter from which side or corner the wind may be appearing, which allows the windmill to be extremely effective and active all through the year.
Integrating an Electronic voltage Regulator
The electricity generated by the rotation of the motor coil in response to the torque from the turbine can be used for charging a battery or may be for driving an LEd lamp or any desired electrical load as per the user preference.
However, since the wind speeds could be fluctuating and never constant, it may be imperative to include some kind of stabilizer circuit across the output of the motor.
Using a Buck Boost Converter
We can solve the issue by adding a boost or a buck converter circuit as per the specs of the connected load.
But if your motor voltage specs is slightly higher than the load and if there's ample wind, you may exclude the involved boost circuit and directly connect the windmill output with the load after the bridge rectifier.
In the diagram we can seen a boost converter being employed after rectifying the windmill electricity through a bridge rectifier network.
The following image explains the details of the involved circuits, which are also not so complex and may be built using most of the ordinary components.
Circuit Diagram Setup
The above image shows a simple boost converter circuit with a feedback error amplifier regulator stage. The output from the windmill is suitably rectified by the associated bridge rectifier network and fed to the IC 555 based boost rectifier circuit.
Assuming the average windmill motor output to be around 12V, the boost circuit can be expected to boost this voltage to upto 60V+, however T2 stage in the circuit is designed to restrict this voltage to a specified stabilized output.
The zener diode at the base of T2 decides the regulation level and can be selected as per the required load restrictions specs.
The diagram shows a laptop battery being attached for charging from a windmill generator, other types of batteries may also be charged using the same circuit, simply by adjusting the value of the T2 zener diode.
Alternatively the number of turns of the boost inductor can also be altered and tweaked for acquiring other voltage ranges, depending upon the individual application specs.
The following video shows a small windmill set up in which a boost converter can be seen attached with a motor, and converting low power output from the motor to illuminate a 1 watt LED.
Here the motor is rotated manually with fingers, so the results are not so good. If the set up is attached with a turbine then the outcome can be much more enhanced.
Another Video Clip which shows a small motor with an attached gear box generating sufficient energy to illuminate a 1 watt LED brightly. This motor could be configured with propellers and used in high wind conditions for charging a Li-Ion battery or any preferred battery:
Using LTC1042 IC
The latest IC LTC1042, a 12V DC permanent magnet motor, as well as a low-cost power FET may be used to build a basic wind-powered battery charger. The voltage output is equivalent to the RPM of the DC motor, which is utilized as a generator. The LTC1042 controls the voltage output and complete the following necessary tasks:
- The control circuit is operational and the NiCad battery is charged by means of the LM334 current source whenever the windmill generator voltage output is lower than 13.8V. The lead-acid battery in this situation isn't getting any current.
- The 12V lead acid battery begins charging at a rate of around 1A/hour as soon as the generator voltage output gets between 13.8V and 15.1V. (restricted by the power FET).
- If the generator voltage increases over 15.1V (due to high wind speed or a completely charged 12V battery), a fixed 36 ohm 5 W load gets switched by the extreme right side MOSFET, restricting the generator RPM and preventing any possible damage.
- Where wind energy is abundant, for example in aboard yachts or remote radio repeater locations, this charger can be utilized as a remote source of energy. In contrast to the solar panels, this device may be used in inclement weather and at also during night.