TOP LED (Blue) blinks faster as turbine input voltage goes higher

130+ volts in blinks very fast and looks steady
88V  in is about 2 blink per second.
31V input is about 1 blink per second

MIDDLE LED (Bi-Color  Red/Green)

Bi-Color LED Red = Bulk,
Bi-Color LED  Green = Float
Both (Orange) = Absorb

BOTTOM LED
Error LED on = Current Limit OR HyperVoc

(Wind Curve operation in general)
Setting the wind turbine power curve in the Army Wind controller
(AWC) will best be done using a wind tunnel where the wind
speed presented to the blades of the turbine can be incremented
and steady while each point of the power curve is adjusted.

There are 16 data points on the curve that can be adjusted.

In the Y direction, the voltage at the turbine input.
In the X direction, the current at the battery output.

Voltage and current points can be adjusted in 1.0 volt and
1.0 amp increments.

Normally, in wind turbine jargan this would be power
and wind speed but using MPPT for wind, the voltage
at the turbine is raised when the output current to
the battery is raised.  This rising of turbine voltage
happens when the battery current rises.  How much
the turbine input voltage rises is determined by the
wind curve on the wind editor screen.

Since the battery voltage is basically constant, battery
current corresponds to power from the turbine (minus
any losses in the controller).

The turbine input voltage is proportional to wind speed.
When output power (battery current) goes up, this means
that the wind speed is going up and so the controller
changes its input voltage to allow the wind turbine to
spin faster, rather than holding the turbine speed down
as would happen if the turbine was connected directly
to the battery terminals.

How high the turbine input voltage rises for a given
battery current (X) depends on the corresponding input
voltage (Y) for that point on the wind curve in the graph.

In-between points on the curve, voltages and currents
are interpreted inside the controller so it transitions
smoothly between points.  It is, in general, recommended that
the points on the graph are not spread too widely...
i.e., try not to have one point at the low end of the curve
and the rest of the curves all bunched up at the top end of the
curve, or vice versa. This applies to both current and voltage
points of the power curve.

So when the battery gets full, (i.e. the battery voltage gets
to the absorb or float set point), higher wind speeds will
be superfluous and un-necessary for MPPT tracking and
the controller will raise the turbine input voltage to keep the
battery voltage from rising.  This is where the "clipper" comes
in to play.  The Clipper (either external or internal to the controller),
is there to keep the wind turbine from exceeding its RPM limits,
reduce turbine bearing wear and tear, to keep the turbine voltage
down and stop it from exceeding the controller's input voltage limits,
and to keep turbine noise down to a minimum.  The Clipper should
only come into play when wind speeds are high, batteries are
charged (in the absorb or float charge stage), or when the battery
output current limit of the controller is reached.  In these cases,
the input voltage of the controller (turbine voltage) must be
controlled by either "Clipping" the input voltage or manually
flipping a breaker to short and "brake" the turbine.  This is
electrical control of the turbine.  MPPT, Clippers and
electrical brakes are the three main methods of electrical
control.  Of course, there are also mechanical brakes for
some turbines.

(AW CLIPPER)

The Army Wind Controller's clipper, as it is today, works, but
does not presently dynamically track as it will in the next
version of this controller.  Also, we have found that the Clipper
circuit actually needs to be simplified, because at light loads,
this Clipper can make the turbine "clank" if it is barely trying to
keep the RPMs (turbine voltage) down below a certain value.
This will be fixed, but can possibly be hard on the turbine if
left with high wind speeds and lightly loaded electrically (battery
gets full).

The manual clipping voltage can be adjusted via the modbus
editor in the MNGP (remote control) shipped with the AW
controller.  This voltage should not be adjusted too high
so that the turbine RPMs can be safely limited, but also
so that it is not turning on at so low of a voltage that it
interfereres with the following of the MPPT power curve
it is trying to track.

The internal clipper voltage can be adjusted by
Modbus Register   4204 in the MNGP Modbus Editor   

At the moment, it is adjusted for 60 volts DC input maximum.
which corresponds to a modbus register 4204 value of 700
(approximately)

    CLIP voltage adjustment register modbus 4204

  REGISTER
     VALUE        CLIP VOLTAGE

    250    = 137 V (131.6 V Fluke)
    300    = 128 V (123V Fluke)
    350    = 120 V
    400    = 110 V (106V Fluke)
    500    = 92 VDC
    600    = 74 V
    700    = 56 V

HOW TO CHANGE THE CLIP VOLTAGE
To gain access to the CLIP Register and to adjust it, to to the TWEAKS menu in the
MNGP Remote and press ENTER which will get you to the OFFSET voltage settings.

Press Soft-Right key  MORE which will put you into another setting menu.

From this menu, HOLD down the LEFT-ARROW

key and TAP the SOFT-RIGHT key TWICE (2 times)

You should now be in the MODBUS EDITOR which by
default starts off at modbus address 4182.

Press the UP ARROW key until address 4204  is showing.

Press the RIGHT ARROW key to highlight the value.

Adjust the value to one of those in the table above to choose
the maximum input clip voltage.

The value will immediately be available inside the wind controller.
To save this into the EEprom non-volatile memory of the wind
controller, HOLD the SOFT-LEFT key (SHIFT)  and tap the ENTER
button which will tell the wind controller to remember this value should
the power go off and back on again.

You may then press the STATUS button to return to the main status screen

If an external commercial modbus editor is used, this address of 4204
may show up as address 4205  which is common for typical modbus
software.  They add 1 to the physical address to make a logical address.

(If there are ANY questions, please check NOTE 3 at the bottom)

(GRAPH SHAPE)
The input (turbine) voltage and output (battery) current
graph must be monotonic.  i.e., The curve MUST have
a positive slope from left side to right side.  For this reason,
the controller will detect if the user tries to make a "dip" or
a "bump" in the curve and try to correct that error and allow
the rest of the curve to be entered. If an attempt is made to
adjust a voltage, Y axis point of the curve  above a voltage to
its right, the voltages to its right will automatically be "bumped up"
to make sure there is at least a 1.0 volt separation between points.
Similarly, as points to the left of the point being adjusted attempt
to be adjusted below those points, the points to the left will bump
down to keep a minimum of 1.0 volt separation between the
vertical points.

This correction should be the same for current, X axis points
on the graph, but at present, the battery current amp setpoints
on the graph will stop and not be able to be adjusted closer than
1.0 amp to the right or left of the adjusted points' neighbor.

(Adjustment of points on the Graph)

volts
In the wind graph editor, the soft-right key, (upper right) selects
whether you are adjusting voltage or current data points on the curve.
If the enunciator above the soft-right key says (VOLTS), then the Y axis
or input voltage points will be adjusted up or down when the UP or DOWN
keys are pressed.  Remember that the controller will adjust or "bump" the
neighboring Y voltage points up or down to keep a 1.0 volt separation
between them and to ensure there is always a positive upward sloping
curve from left to right.  You can hold the UP or DOWN keys so that
it repeats or just press one volt at a time. (Note 1)

amps
Pressing the Soft-Right key will change the editing from adjusting
input volts to adjusting battery (output) amps points on the curve.
Again, UP or DOWN keys will adjust the  graph point amps to the
right or to the left, increasing or decreasing that points' output
current amps that is associated with that points'  turbine input voltage.
If the amps at that point on the graph attempts to move beyond the point
to its right or left, the adjustment will stop there and the left or right
button will have to be pressed to move the amp point that is in the
way of the point you are trying to adjust. (Note 2)
At this point, any changes to the curve in the controller are active
but if the controller were to be turned off and back on again, they
would revert to the curve before the adjustments.  To save the
new curve to the controller's non-volatile memory (EEprom),
simpley press the ENTER button and it will be stored for power
up recall in the controller.

You will also notice the soft-left key functions as "MEM" or Memory
recall and saving.  This enters the MNGP's 9 internal user memories
for future use.  Also, MNGP memory locations accessed above number
9 are for recalling factory saved default curves for certain turbines
that are more often used by customers.   The MEM area of MNGP
wind memories are only saved or recalled from within the MNGP,
(remotes) internal non-volatile memories.  However, as soon as
an internal memory of the MNGP is recalled, it is immediately sent
to the controller and is then the active power curve.
Usually, you will be adjusting a curve within the controller from the
main wind graph curve editor screen, press ENTER to save it into
the controller's EEprom memory and then hit the MEM soft-left
key and save it also in one of the MNGPs one of nine (1 of 9)
memories for future reference.  If you think you may have a better
operating power curve than before you started editing, then you
can save it in, say, MEM number 1.  Then, after adjusting power
curves more, you think you "might" have a better curve but are
not sure, press MEM and save your latest curve in MEM 2.

To recall MEM number 1, simply press the MEM soft key and
hit the DOWN button to select MEM number 1 and then press the
soft-right RECALL key and your last curve will be recalled and
placed into the controllers memory and will be active.
Press MEM (soft-left), UP to memory 2, RECALL (soft-right)
and MEM 2's curve is active again.

(Finding the cut-in voltage)
The first important thing to remember is that if the turbine voltage
at a particular wind speed is NOT HIGHER than the battery voltage, then
it will NOT be able to put power or energy into the battery.  The input
voltage MUST be somewhat higher than the battery voltage.
For example, if you have two batteries that are both 25.0 volts each and
connect them in parallel, there will be NO current from one to the other.
If one battery is 25.0 volts and the other battery is 25.1 volts and you
connect them in parallel, they will then be the same voltage BUT energy
will flow from the battery with open circuit voltage (Voc) of 25.1 volts
into the battery that was 25.0 Voc.   With a small wind turbine, with
(typically) higher series resistance than a battery, the voltage difference
should be even higher than the case with the batteries for any significant
energy to flow and charge the lower voltage battery.   So, the voltage
that should be used for wind turbine cut in will depend on its size (power)
and/or resistance.  If the nominal battery voltage is 24 volts and the
nominal turbine voltage is say, 72 volts, then the cut-in voltage is going
to be much higher than a turbine with nominal voltage of 24 volts.

Remember that step 01 (0 amps) is where the controller will turn on at.
Step 01 volts (cut-in) should be at least somewhat above battery voltage.
Battery voltage can vary from low when disharged to higher when fully
charged.  If the turbine is a higher nominal voltage than the battery voltage,
the step 01 voltage will usually be set higher than the fully charged battery
voltage.

If the turbine is the same nominal voltage as the battery, then step 01
might be set higher than the highest expected battery voltage OR it might
be set somewhere below fully charged voltage but definitely above battery
voltage that is considered discharged.  For example, a 24V battery and
24V turbine might want its cut-in voltage to be around 25 to 27 volts if the
turbine's series resistance is low enough that it can start charging at that
low of voltage so you don't lose out on lower wind speeds.  Otherwise,
at low wind speeds, the idle power of the controller may be wasted and
unnecessary for the controller to be on and running at such low input
voltage. But if the batteries are above discharged voltage then it doesn't
matter so much that the controller is running.  Also, too low of cut-in
voltage will annoy some with the controllers clicking on and off at low
winds unnecessarily.

(Finding a curve with a Wind Tunnel)
If you are lucky enough to just happen to have a wind tunnel handy,
finding a power curve for a particular turbine should be fairly
straightforward after the cut-in speed of the turbine is found.

An easier first way to find the power curve  (PREFERRED METHOD)

It may be much faster to find the power curve including the cut-in
voltage and wind speed by using a top down approach rather than the
bottom up method.  i.e. Start with a higher voltage and wind speed and
then work down in wind speed and voltage, gathering voltage and battery
current data points along the way.  The last thing that will be found
will be the cut in speed and voltage which may be hard to find otherwise
when the nominal turbine voltage is higher than the battery voltage.

The controller modes that allows this is manual method is the hydro MPPT mode
running in Manual MPP V sub-mode to set a starting point voltage OR, even
better, the U-Set Voc % mode (original % set to ~100 %).

Note:...   I found that I had to first have the controller run for a moment
in wind track mode and then I could come down to U-Set mode.
Remember that in either mode, if lower than 15 or so watts output for
90 seconds, the controller will shut off because of low power.
For it to come back on again,  the input voltage must do one of two things...
Either rise at least two volts above the previous open circuit voltage, OR
fall below the cut-in voltage (step 01) on the wind tracking graph curve
for a moment.   This is to reduce unnecessary turning off-on-on-off when
at particular input voltage would be too low to operate more than 15 watts
of output power.

After the controller turns on, the input (turbine) voltage and thus its electrical
load can be adjusted from the main status screen of the MNGP Remote
using the Soft-Left key (lower input V) and Soft-Right keys (raise input V).

1) (initial starting point)
Let's assume that the turbine will make useful power at 25 MPH.

Set the wind speed to 25 MPH at the turbine and note the wind speed.
Turn the controllers' mode to ON.   The relay in the controller shoud click.

If using the U-Set mode, when the controller turns on at 100 % input
voltage, the turbine will be unloaded because the voltages are equal.

2) (reducing voltage)
Press the Soft-Left key to lower the turbine input voltage and watch the
output (battery) current rise on the display.  (and watts too if wanted)

Because of inertia, you must bring the voltage down slowly and/or wait a
moment after it stops dropping until the kinetic energy stored in the rotating
blades dies down and you get a real (stable) output current reading.

Lower the voltage until the output power and current eventually stops
increasing and actually starts to drop.

Press the Soft-Right key to raise the input voltage again to verify the
maximum power point input voltage corresponding output current.

Again, because of inertia, when raising the input voltage, the output power
and current may drop some until the turbine speeds up to match the wind
speed.

This point can be one of the points entered on the graph.

3) (next point)
Lower the wind speed  to say, 20 MPH and repeat step 2 above to
find the next lower maximum power point voltage, current and power.

4) (repeat)
Keep repeating step 2 and 3 until the output drops to 1 amp output
current.   The input voltage corresponding to an output battery current
of 1 amp will be placed at wind power curve step 02.

5) (finally, cut-in)
At this point, cut-in voltage and wind speed is just below the values we just
found in step 4, above.  It may take a bit of emperical adjustments to get it
right, but should be very similar to finding the 1 amp output setting in step
4 above.

Alternately lower the wind speed slightly and then the input voltage slightly
to find the input voltage that corresponds to 0 amps as best as possible.

This last turbine voltage will be put into wind power graph
step 01   (0 amps output)

Beware that some turbines may find these low power steps eating into
the normal battery voltages.  In this case, you may want the re-think
the 0 amp step just a bit....  The first power curve graph step must
be lower than the second graphic step though.  The 1 amp step turbine
voltage may want to be changed to  2 amps or higher maximum power
point turbine voltage if the cut in voltage would be too far below the
highest battery voltage to keep the 0 amp step voltage reasonable.

6) (more to do, but the hard part is done)
Lastly, starting at 30 MPH, which is 5 MPH above the 25 MPH we started
at in step 2 above, raise the input voltage until you find its maximum
output current and power operating voltage and note this.

Keep repeating this every 5 MPH or so until either maximum output
current limit, turbine RPM or maximum rated input voltage of the controller
is reached.

OTHER RECOMMENDATIONS
Gathering more data points is always better than gathering too few data
points and remember that if you have extra power curve graph points
left over, you can place an extra point inbetween 2 other points, usually.

It is usually best to no spread the data points too far apart so that they
are bunched up to one end of the power curve graph.  More evenly is
better, but at spots along the curve where it is steeper may be better
to use more data points to make the steep curve smoother.
Either way, the controller will interpolate between data points along
the curve.

(If there are ANY questions, please check NOTE 3 at the bottom)

(Building the curve using the wind curve graphic display editor)

It is highly suggested to use the manual voltage adjustment method
shown above.

The controller will turn on and start to operate as soon as the wind
speed brings the free-wheeling turbine voltage up to the wind graph's
left most step, (step 01), which will be at an output current of
0.0 amps, (watts = 0)

Bottoms Up
The method of finding the proper power curve using the graphic editor
should be started by working your way from the bottom up.  i.e., Start
at low wind speed, (step 01) and work up to highest wind speed and
the last step (step 16).

If the low speed steps start too far off and turbine voltage (cut-in) too low,
the turbine may stall and the higher speeds and steps may not come
into play. If low speed voltage is too high, those low steps may be
occupying steps that should be reserved for the higher wind speed voltages.

First Steps
The first 2 (two) points, step 01 and step 02 are going to be the most
important to start adjusting with.  At first, the absolute values of these 2
points will not need to be accurate.  Finding the cut-in and second
step may be the toughest part of building the power curve.

The voltage for Step 01 (0 amps)  should be set for a turbine voltage
that is just slightly lower than a voltage that it will supply power at.
That's why it is 0 amps....   0.0 amps *times*  Y volts = 0 watts

1)
Unload the turbine, electrically, by turning the controller mode to off so
you can still view the unloaded voltage on the controller's display.

2)
Slowly raise the wind speed until the unloaded DC voltage into the
controller becomes higher than the battery voltage by at least a few
volts.  If the turbine is the same nominal voltage as the battery, this
voltage may be a good cut in voltage to start at.  Maybe.  It just
depends on the turbine and its resistance and/or size.

Now, it may be that although the turbine is generating voltage that is
higher than the battery voltage, that it may stall if connected at
this voltage...  Especially if the turbine is rated at a higher nominal
voltage than battery voltage.

If it can connect at this voltage and smoothly ascends to step 02
with increasing wind speed, then you have found the cut-in voltage.

3)
This method is unfinished.   Please use the manual mode, above, for now if at all possible.
Otherwise call me on the phone 425-876-7402  (cell)  or  360-403-7207 ext. 21 (work)
bob@midnitesolar.com

OVERSPEED

(How fast is TOO fast ?)
You might want to try and  determine at what wind speed the
turbine becomes electrically uncontrollable.  After this speed is
known when the turbine is used in real wind, you will of know
when to mechanically brake or lower the turbine so it doesn't
self destruct.

Bringing up the wind tunnel speed in steps,  let the turbine free-wheel
then using a Clipper, try to lower its RPM by lowering the Clipper
voltage.  The wind speed at which its RPM won't come down is too fast.

Some turbine designs (usually ones with high inductance), may actually
spin faster when loaded abruptly, like with a shorting brake switch or
a Clipper that is not brought down slowly.  In a controlled environment
like with a wind tunnel, you can try to brake the turbine with a shorting
switch at high or semi-high speed wind without permanently hurting the
turbine because the wind can be turned off quickly.  If the turbine
cannot be stopped to a crawl with a shorting switch or by slowly
reducing the Clipper voltage, it may be too fast and may want to
think about lowering the turbine before the wind speed gets this high.

Axial Flux turbine designs with little steel or iron in the magnetic path
normally have lower inductance and can be controlled at higher wind
speeds than turbine designs with iron laminations that increase
the inductance....  That is, if the magnetic gap isn't so wide that it
hinders electrical output and also electrical control by loading it down.

With the turbine shorted, bring up the wind tunnel speed.  The wind speed
at which the turbine breaks free from the shorted stall is too fast.

Remember that a shorted turbine (in wind) will NOT stop completely.  It can only
slow to a crawl, maybe one revolution per seond. The mechanism behind the
slowness (Lenz's Law) means that the turbine MUST turn at least very
slowly.

The turbine must be able to be controlled or slowed down below some
specified wind speed, otherwise at wind speeds above this, if it continues
to spin fast into a short or large load, the windings can burn up.

(Note 1)
Some times this correction from within the controller will look like it is trying to fight your adjustments
and not be as smooth as it should be. This anomoly will be made smoother eventually, but for now,
if it happens, just press the button again.

(Note 2)
Battery output amps will eventually be able to "bump" to the left or to the right of the neighboring
points, but for now, the other points must be manually moved out of the way.

(Note 3)
If there are ANY questions, call me, bob gudgel's phone 425-876-7402 (cell)
or  360-403-7207 ext. 21 (work)   or Ryan at ext. 151
bob@midnitesolar.com   ryan@midnitesolar.com