Any ideas for an embedded renewable/energy project?

In comp.arch.embedded,
Warren <ve3wwg@gmail.com> wrote:
> Stef expounded in news:b1298$4c73dd0d$54f63171$5945@abuse.newsxs.nl:
>
>> In comp.arch.embedded,
>> Warren <ve3wwg@gmail.com> wrote:
>>> Alex expounded in news:4d220f9d-0536-46e5-8265-e2e28b2fba50
>>> @v41g2000yqv.googlegroups.com:
>>>
>>>> Does anyone have any ideas for an embedded renewable/energy related
>>>> project? I want to do something at home so I can put it on my resume
>>>> and try to enter this field, after a LONG hiatus. Type away with
>>>> what you got. I thought it would be good for me to include these
>>>> aspects: - wireless communications
>>>> - data gets sent to a website
>>>> - SMS messaging
>>>> Yea, stuff like that. If you've had any ideas relating to renewable-
>>>> energy related embedded projects, please share them. Thankyou!
>>>
>>> One idea I've had, would be to use a MCU to control the
>>> input to an automotive alternator, used in a wind generator. 
>>> When the wind dies down below a threshold, you want to cut the 
>>> rotor input power, since you're not going to get anything back.
>>> When it picks up, apply some input power to help it "generate".
>>>
>>> Beyond the threshold test, the MCU could adjust input power levels to
>>> the rotor to maximize the output generation. If the wind is weak,
>>> then you need to supply less of a field. But to get more out of a
>>> strong wind, you could add more rotor input power.
>>>
>> To avoid this hassle, wind turbines often use permanent magnet rotors.
>> :-) It's also more power efficient (no exictation) and less wear (no
>> brushes) Car alternators can be modified to permanent magnet.
>
> The MCU makes it a non-hassle ;-)  The downside is the
> brushes naturally, but the upside is that you can
> vary power output with the strength of the wind.  IIRC,
> you can get up to 60 Amps from a little alternator, perhaps
> more with some models, though probably not continously.
>
> The trick is to monitor the rpm and not to exceed
> maximum continous ratings. If you increase the field,
> does output continue to increase (while maintaining rpm),
> or does it tend towards stalling? If it tends to stall,
> you back off the field and acheive a compromise for
> maximum generated power.
>
> Putting a permanent magnet in, just destroys all the fun!

No, no, it just starts the fun! (law of preservation of hassle :-)

Using a permanent magnet means you have no control over the
alternator output. So now you should add a controller that regulates
the power take off to maintain optimum power point and does not
destroy your battery!

Oh, and don't forget to add a braking mechanism, otherwise your
turbine will spin out of control on strong winds and light loads
(battery full for example).


-- 
Stef    (remove caps, dashes and .invalid from e-mail address to reply by mail)

My pants just went to high school in the Carlsbad Caverns!!!

Stef expounded in news:5e09b$4c767894$54f63171$3844@abuse.newsxs.nl:

> In comp.arch.embedded,
> Warren <ve3wwg@gmail.com> wrote:
>> D Yuniskis expounded in news:i53bvq$sbs$1@speranza.aioe.org:
>>
>>> Warren wrote:
>>>> Alex expounded in news:4d220f9d-0536-46e5-8265-e2e28b2fba50
>>>> @v41g2000yqv.googlegroups.com:
>>>> 
>>>>> Does anyone have any ideas for an embedded renewable/energy related
>>>>> project? ..
>>>> 
>>>> One idea I've had, would be to use a MCU to control the
>>>> input to an automotive alternator, used in a wind generator. 
>>>> When the wind dies down below a threshold, you want to cut the 
>>>> rotor input power, since you're not going to get anything back.
>>>> When it picks up, apply some input power to help it "generate".
>>> 
>>> I wonder if you could watch the field in the windings to
>>> detect RPM (without having to add a tacho).  
>>
>> Even though the alternator rectifies the current, it is
>> not pure DC. So the charging current will look like a
>> series of bumps. Feed that into a opamp circuit and 
>> shape that into something a MCU can count.
>>
>> This is the "whine" component of the alternator.  At 
>> least this is how I would attack it, as it requires
>> no addional parts for monitoring (rpm).
> 
> Most alternators hav a 'W' contact. This is connected to the AC
> side of the rectifier, giving you a higer amplitude rpm signal.

"W" for "whine". ;-)

Warren