switching between power supplies

Thread Starter

WSUBG

Joined Jun 12, 2021
30
Hi,
I have wind turbine with 4 miniature generators. I am using two generators in series to power and Arduino I want to be able to switch between two and four generators in series as power sources for the Arduino without loosing power. This is because at low speed it takes all four generators to keep things alive. But at high speed the voltage is too large for buck-bust converter to handle. I can employ a Zener diode as voltage regulator but then I would be loosing in the efficiency. The voltage of each generator is monitored by Arduino. Cannot use a battery. Any help is appreciated.
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LowQCab

Joined Nov 6, 2012
1,914
OOOhh, now you tell us that it's a Classroom Competition ...............

If we help You, then You learn nothing,
and that's cheating.

"" I can employ a Zener diode as voltage regulator but then I would be loosing in the efficiency. ""

Loosing "Efficiency" is precisely what You want to do.

If You DON'T loose efficiency, then where is all that "extra-Power" going to go ?????

Connect all the 3-Phase-Bridges in series.
(using standard Bridge-Rectifiers is already wasting a full ~40% of the available Power as HEAT)

Then install a ~12-Volt-Zener across the Output of all 4 series-connected Bridges.
The Zener will regulate the Torque-Load placed on the Propeller,
and therefore regulate it's RPM,
and therefore keep everything extremely stable, right at the Zener-Voltage,
regardless of the Wind-Speed.

The largest increase in actual "Efficiency" would require
Active-Switched-FET Bridge-Rectifiers on the Outputs of all 4 Generators,
along with Large Filter-Capacitors to smooth-out the Ripple-Voltage.
( 8 very small Super-Capacitors would act just like a Battery ).

If You want to win the Competition,
the Active-Bridge-Rectifiers are the "Secret-Sauce" that will smoke all other competitors.

All the extra Processors are just a waste of Power.
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Last edited:

AnalogKid

Joined Aug 1, 2013
9,933
at low speed it takes all four generators to keep things alive.
For a DC/DC converter with a rrelatively constant load, the input current required increases as the input voltage decreases. In your system at low wind speeds, is the problem with two generators that they do not make enough current , or that the series output voltage is to low?

ak
 

LowQCab

Joined Nov 6, 2012
1,914
Also, determine how many degrees the Generators have between "Cog-Bumps",
( that's when each Magnet is directly lined-up with a corresponding Winding-Pole ),
divide the number of degrees by 4, N/4=X,
rotate each Generator-Housing on the shaft so that they are "X-number of degrees" apart,
this will insure that the Cogging effect is minimized, allowing the Shaft to turn much more smoothly,
and spreading-out the Voltage-Ripple from each Generator so that they don't all Cog at the same time,
and the over-all Voltage-Ripple will be minimized, even without a Bulk-Storage-Capacitor.
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