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Boost 150mV to 1.5V

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Hi everyone.. Thank you so much for your feedback and suggestions. I'm appreciate it.

Actually, I'm doing my project based on the previous student who had design the MICRO - SAVONIUS VERTICAL AXIS WIND TURBINE (VAWT).
She do a research on the SAVONIUS WIND TURBINE PERFORMANCES ON WIND CONCENTRATOR.

And for my project, I wants to improve her project since her research studies’ design, there is no support in terms of power electronic part to enhance the power output. I decided to use a boost converter to increase the power output.

The attach file is my previous student's project.
 
The attach file is my previous student's project.

And in section 3.4 of that report we have the following vital piece of information:

upload_2016-3-26_11-31-24.png


So, is the "motor" a permanent magnet DC motor, or is it a brushless DC motor?
It makes a big difference.
One will work well if driven at a suitable speed, the other one will not produce much at all.

JimB
 
In this thread it has been variously implied that DC motors will operate as generators. Other contributors have stated the converse. Which is true? I have a feeling it is the later. I seem to remember that the reason is due to commutation timing, especially with high speed motors which are not designed for reverse operation. In essence, the armature coil needs to be fed a current prior to reaching the respective stator pole so it has time to build up a magnetic field. For generator operation the opposite commutation timing is required but, thinking out loud, maybe reversing the armature rotation may do the job and improve the efficiency of a DC motor used as a generator.

If you remove the commutation electronics, say from a PC brushless fan motor, they make fairly good n phase alternators. In fact, maybe you could just use a PC fan for NI's application, but perhaps JonSea might get upset about the aerodynamics. :)

spec
 
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There is just one point about some of the posts on this thread: the OP has asked for suggestions to convert a low voltage into a higher voltage to illuminate a bulb. The error of requiring more power out than in aside, the OP has not asked for the turbine or generator to be re-designed, however desirable that may be.

As for answers to the request, there have been a couple of useful suggestions, including energy harvesting techniques. It seems to me that if NI's objective is to indicate when the fan is turning, a moving coil meter would do the job simply with no other mods. The other approach would be to do a DC to DC conversion and drive a high efficiency red LED. There is just enough power to do the job.

spec
 
I decided to use a boost converter to increase the power output.
Hello NI,

Can I just explain one thing: a boost converter cannot boost power. This may sound pedantic but it is fundamentally important: a boost converter only boosts voltage and, at the same time, reduces the amount of available output current in the process. Furthermore, the boost converter wastes power in the process and typically this loss would be in the range 10% to 30% depending on many factors.

Take an example.
You wish to convert a power source of 1.5V (typical AA battery voltage) to 5V to power some 74 series logic chips.
The 1.5V supply might have a maximum current of 100mA. Thus:

Input power = 1.5V * 100mA= 150mW
Assume a boost converter efficiency of 80%, thus the output power would be 0.8 * 150mW= 120mW.
As you want an output voltage of 5V, the maximum output current would be 120mA/5 =24mA.

Incidentally, the missing 20% of power would be dissipated by the boost converter as heat.

spec
 
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...
Incidentally, the missing 20% of power would be dissipated by the boost converter as heat...
How can someone get to the second or third year of an electrical engineering course without understanding this?????
 
Hi NI,

I have just read the attached report and very interesting and informative it is. I now know what a Savonius wind turbine looks like.

But, like JimB, I find section 3.4 erroneous. Quite simply, it is not to the same standard as the rest of the report:

3.4 DC Motor

'DC motor is a device that can convert mechanical energy to electrical energy. Mechanical energy
comes from the rotation of the rotor which is connected to the shaft of the DC motor and the
electricity produced will be connected to the load from the output terminal as shown in Figure 3.3.
Furthermore, in order to produce high reliability and high efficiency of small wind turbine, the
preferred choice of motor is the brushless DC motor as shown in Figure 3.4.'

To be technically correct, the opening sentence should read:

'A DC motor is an electro mechanical device that converts DC electrical energy into mechanical energy. Under certain circumstances a motor can be used for the reverse function.'

But a motor is not applicable to this application, so the opening sentance of section 3.4 should read:

'A DC generator is an electro mechanical device that converts mechanical energy into DC electrical energy. In some circumstances a DC motor can be used as a DC generator'

Then there is JimB's point about DC brushless motors being unsuitable for use as DC generators.

I know it is probably not in your remit, but you really should bring these points to the attention of your tutor because they throw the credibility of the whole report into question.

Also, because of this, you are being given an almost impossible task which bears no resemblance to the main object of the exercise, which is to assess the feasibility of wind turbines for Malaysia. By the way, I lived in Kuala Lumpur for a while, and apart from the monsoon season, it was practically windless.

spec
 
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The wind speed in Malaysia seems to be almost zero. In my part of Canada there are many huge lakes that have very strong winds blowing across them. Boats use fan propellers and vertical spinning things driving generators to charge their batteries. The windmills spin like crazy and produce at least ten thousand times the power of this project. The windmills are about the same size as the one in this project.
 

Attachments

  • compact windmill generator.png
    compact windmill generator.png
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You know what?
In places where it is always cloudy and raining they do not use solar panels to produce electricity.
In the desert where there are no rivers they do not use water-wheels to drive generators to make electricity.
In Malaysia where there is almost no wind they do projects with windmill generators?
 
A boost converter is like the big gear driving the little gear.
A buck converter is like the little gear driving the big gear.
Either way; one horse power in and about one HP out. (slight loss)
**broken link removed**
Gears don't make power. They change its form. (weak and fast or slow and strong)
You can't get more power from your car by adding a gear.
Some people don't understand gears. So probably a bad example.
 
This thread actually illustrates a common problem. Both the original poster and almost everyone who has replied fell into this trap - starting with a solution before the problem is understood and defined.
32 years of conditioning. The one thing we got in the most trouble for was questioning the customer's specs.
I have seen a lot worse Mike :wideyed:
spec
When I was a senior at Cal State University in EE, the computer science guys literally did not know how to turn on an oscilloscope.

Sadly, in today's age of SPICE modeling everything, I suspect most EE seniors don't know how to turn on an oscilloscope....
 
When I was a senior at Cal State University in EE, the computer science guys literally did not know how to turn on an oscilloscope.

Sadly, in today's age of SPICE modeling everything, I suspect most EE seniors don't know how to turn on an oscilloscope....
:banghead:

The biggest shock I had was a highly respected and long time analogue designer, complete with pipe and patches on his jacket elbows (sure signs of intellectual gravity and integrity in the UK at the time). I did a design review on his stuff for a particular system. He was trying to sum two analogue voltages by joining them with two resistors and feeding the junction into the non inverting input of a parallel feedback opamp. He also thought it was OK when the flaw was pointed out. Then he didn't know about long tailed pairs either.

Another engineer was asked to design a 10Mhz Xtal oscillator. He kept complaining that he could not get the circuit to work. He had copied a low frequency Xtal oscillator circuit from a 4000 CMOS data book. Also the leads on the Xtal were around 5 inches long.

Another engineer built a switch mode buck PSU with the first capacitor he found laying around the lab. He kept complaining that the data sheet for the chip he was using was a lie, because he could only get 55% efficiency. When I told him that he needed a low ESR capacitor and that the equivalent circuit of a capacitor is quite complex he would not accept it and more or less called me an idiot. :wideyed:

spec
 
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32 years of conditioning. The one thing we got in the most trouble for was questioning the customer's specs.
Same here- in fact it was verboten.

The number of times that a simple change to the customer's specification could have saved a fortune and improved the design. One minor example was a video interface which was specified at 2.83V RMS and was immediately attenuated to 1V RMS at the receiving end. In another case we even designed a card to provide a resolver output when the resolver input on the receiving end had been deleted months before.

spec
 
You know what?
In places where it is always cloudy and raining they do not use solar panels to produce electricity.
In the desert where there are no rivers they do not use water-wheels to drive generators to make electricity.
In Malaysia where there is almost no wind they do projects with windmill generators?

Hydroelectric originated power AG. Lot of.
 
By the way, I lived in Kuala Lumpur for a while, and apart from the monsoon season, it was practically windless.

Around six months a year, right?
 
Around six months a year, right?
Perhaps I should have said monsoon rather than monsoon season. As far as I can remember it rained heavily for around a week on and off and that was it. It was the same in Singapore.

In front of our flat in KL there was this huge 10 feet deep drain and as it only ever had a trickle of water in the bottom I thought it was overkill big time, until the monsoon came that is. The drain turned from a trickle to a raging torrent and filled right up.

I didn't know much about Malaysia's climate it seems: http://www.eoearth.org/view/article/151260/ It is interesting that peninsular and eastern Malaysia have different climates.

spec
 
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