wind with smbs0

[A. J. Tarnas]

Has anyone got power from a wind turbine playing nicely with an smbs0?

My use case is that I live off-grid and use solar for power. I'm in the Mojave desert, it's quite sunny. But when it's cloudy, and at night, it's often windy, and having 50-200W coming in during those times would be great. Currently I depend on about 500W of solar during daylight.

I know wind turbines are relatively expensive, short-lived, and hard to manage compared to solar. But the wind blows at night.

https://www.youtube.com/watch?v=QSfWnIscDTM

(I don't really want this, but leaving it here for reference:)

https://mwands.com/dual-wind-turbine-charge-controller

[Dacian Todea]

If you check the statistics it will be mostly windy during the day and not at night. Also when it is windy in majority of the cases will also be sunny.

This short of diversion load should work up to a certain speed but for high wind speeds that is not enough protection and your wind turbine may get damaged. Just this winter a few weeks ago I had close to 120km/h gusts and that will have damaged a wind turbine if not in electromagnetic break.

The SBMS0 will need to control that and some small modification may be needed so that when EXT IOx set as type 1 is open circuit the wind turbine stops charging the battery and defaults on diversion. But as just mentioned the wind turbine will get damaged in high wind speeds.

[Robert Tagscherer]

Hi

I am actively trying to develop some hardware to control a wond turbine. Mine is only 300 W but braking is still important for high wind gusts. It is possible to actively brake the turbine, even if that may consume power. If you could provide me some details about your situation I can try to scale the design accordingly.

[Kohala Jim]

Robert & A.J. -

I too have plans to integrate a 500W micro turbine using the newer diversion capable DSSR20's.
It's going to take some additional sensing and control logic, however, I think it will be worthwhile for me.
I'll be living uphill from theHawi Wind Farm, and we get steady trade winds due to the topography of Mauna Kea and the Maui channel.

I'm a couple months away from moving before I can even think about getting this setup, so I won't have much to contribute in the short term.
I'd like to compare notes and see where you guys land...

[Dacian Todea]

Robert,

The way the electromagnetic braking is done on small wind turbines is by shorting the wind turbine output (assuming 3 phase wind turbines here).

You can not just directly break while the wind turbine is spinning as that will damage the turbine maybe even the blades so the wind controller I have uses PWM to first slow down the turbine and then fully break. SO PWM duty cycle changes over a few seconds before is fully ON shorted.

Jim,

The DSSR20 can not be used for Wind turbines. You will need a separate wind turbine controller.

[Kohala Jim]

We've had this turbine conversation before...

In my post I explicitly mention a dedicated controller, and I'm planning on a pair of diverting DSSR20's that are PWM'd to load shed if/when the battery is recharged.

All that initial diversion occurs on the rectified DC side, and I'll also have inline AC series loads for heavy winds and an ultimate pair of brake switches.
The control strategy is similar to that employed by John Daniel and his turbine installations.
I'm hopeful I can make it work as it patterns a successful method.

[Dacian Todea]

Jim,

I do not remember the exact discussion but DSSR20 can not be PWM'd (it will not respond faster than 2x ON/OFF per second).

The DEXT16 has a small delay between disconnecting from battery and connecting to diversion and that may be enough for voltage to exceed the DSSR20 input limit.

Solar PV is so very different from Wind turbine.   With solar you know voltage will never exceed the open circuit voltage as solar panel is like a diode or huge TVS thus it ensures voltage is limited. Then similar for current as it is a constant current limited source with the amount of current limited by the amount of light getting to the panel. Since the sun is the highest power light source around and that has a fairly fixed max limit you know what the max current from a panel will be.

With Wind turbine the voltage is proportional with the RPM of the turbine and the current is limited by the internal winding resistance and load resistance.

But Wind turbines are destined for moderate winds 9 to 12m/s depending on model so the spec power is for those wind speeds and not much above that around 14 or 15m/s the wind turbine controller should try to break the wind turbine and on the smaller wind turbines usually that is done trough electromagnetic break but that means the wind controller needs to be specifically designed for that Wind Turbine that will be used else one or both will be damaged.

Double the wind speed and power will be 8x higher and that is just a huge difference and double the rated wind speed is not much.

12m/s is 43km/h (27mph) and double that speed is easily possible as is just 86km/h (54mph) and that will increase the mechanical power 8x that is 4000W for a 500W rated wind turbine.

[Kohala Jim]

We've had a number of turbine exchanges, and you deal with dozens of different individuals day-in-day-out... I don't expect you to recall all these details
First, there's no DEXT16 in play, so there shouldn't be any limitation to PWM frequency or period other than the internal resistive effects of gate transition across the FET junctions? (yes/no)

Second, using an external controller gives me tons of latitude in methods of load control... I understand the potential for transients if the PMA is left unloaded.
Correct me if I'm wrong here too, but it's my understanding that the diversion ready DSSR20 can have both load and diversion channels activated at the same time? (yes/no)

The strategy employed by Olympic Power Controls (John Daniel) on turbine management is to load both the battery bank and the PMA with modulated diversion loads.

I should be able to employ this same strategy along with a controllable full disconnect from the battery bank with divertible DSSR 20's and the right diversion resistive loads (at least that's my belief).

All this belief in controller method is in context of "non-catastrophic" wind conditions in which case I'll also have inline AC diversion and full-stop braking switches as yet another layer of protection.
I'm willing to experiment and attempt to make something operable, and indeed, the DSSR20's may not pan out in the end.

[Dacian Todea]

Jim,

The PWM limitation is not related to DEXT16.  There is a special IC circuit both on the Battery charge path and on the diversion that limits haw fast you can switch ON/OFF.  This circuit was needed for multiple reasons. One was to be able to shut down in case battery voltage was to low or there was a short circuit on the battery output side as the ideal diode mosfets will be damaged if this circuit was not there to stop the output to battery when voltage dropped below 9V or so and there is also a delay of 250ms before attempting to re-enable so that mosfets have time to cool down else they will get damaged. Same circuit is also used fro remote ON/OFF so you can not do more than 2 to 3 ON/OFF cycles per second more than sufficient for the type of application DSSR20 was designed for. Also this delay is needed in case there is a noisy signal on the remote ON/OFF input signal so that there is no rapid ON/OFF oscillation resulting in excessive heat on the mosfets.  

Yes both battery charging and diversion can be activated at the same time.

The DSSR20 looks like a simple circuit but it took some effort to design and make it fairly robust.

[Kohala Jim]

Good to know about the modulation and switching design of the DSSR20, thank you Dacian.
For the finer modulation controls I think I want, I'll need to employ some alternate load switching SSR's on the diversion side of the DSSR20's.

I also understand your position Dacian on PV vs. PMA power sources, however, I'm wanting to try and build this diversion control and I'm not as concerned about cost or time... it's more about the end result for me.
Midnite Solar makes a programmable diversion controller I've seen deployed on many turbine installs, and that's my fallback should I fail or get impatient.

To A.J. and Robert, hoping to compare notes on diversion controller designs...

[A. J. Tarnas]

I'm not an electronics person by any means, so my only way to do something like this would be to copy someone else who's documented their affordable build very carefully and clearly. If no one gets wind to play nicely with SBMS0, then I wouldn't be the one to invent the solution!

> If you check the statistics it will be mostly windy during the day and not at night. Also when it is windy in majority of the cases will also be sunny.

This is not true for my location or power needs, Dacian. But I may end up using rotational wind power strictly for pressurizing tanks, pumping water, and other mechanical/rotary applications, where high winds do not create an electrical issue. High efficiency is not what I need, if cost can be low.

[Dacian Todea]

Wind energy especially for small installations is much more expensive than solar.  In very large grid scale applications Wind can still compete with solar just because of the scale of those wind turbines but even there it barely makes sense.

There are no wind controllers designed for Lithium as far as I'm aware. If there was such a thing then SBMS0 will have no problem controlling that.  A wind controller should have a remote ON/OFF signal that will break the wind turbine when battery is full. DSSR20 are only designed for PV panels or other constant current sources that are OK being left open circuit.

I had a small 300W wind turbine a few years ago (it is still there) but only used that for the first year or so then I disconnected the turbine and used the cables to add more PV panels as Wind turbine was fairly useless even if is fairly windy at my location it was just not windy when I needed that the most so it was fairly useless.