Re: [EE]:: Operation of water pumps from Wind Turbines

Wind Turbines are expensive and then there is the cost to erect them.

Batteries and inverters/DC converters are cheap these days and would be 
a small portion of the overall cost, and would allow much more 
operational flexibility and greater duty cycle.

Maybe you wouldn't need the inverter, but some control would be required.

Gord_W


On 2025-03-31 4:33 a.m., RussellMc wrote:
> TL;DR / Summary
>
> Comments on the following are invited - especially the practicality of
> using DC powered deep well water pumps to allow direct powering of water
> pumps by wind turbines across a wide range of wind speeds.
> Of significant uncertainty is the practicality of powering a 1-5 kW range
> DC powered pump from a highly variable wind source, and the ability to load
> the turbine close to maximally at all times to prevent damage.
>
> _____________________
>
> I'm interested in the operation of deep well water pumps powered by WT
> (wind turbines.)
> Direct alternator to pump action without batteries or inverter is desired.
> Pumps motors are typically in the 1 kW - 5 kW range.
> Smaller and larger may happen.
>
> In the target application pumps are in most cases powered by diesel fueled
> generators, but in some cases by AC mains power or solar panels.
> Solar with AC motors has the cost disadvantage of requiring batteries and
> inverters.
> Diesel operation is costly.
>
> When wind turbines are used the most usual method is to produce 3 phase AC,
> rectify it and store energy in a battery and then use an inverter to power
> the pump.
> This has the advantage of decoupling the pump operation from variations in
> WT output and wind energy variations. As required the pump may be operated
> at a relatively constant level in start / stop mode depending on mean wind
> energy availability.
>
> While grid scale WTs can be operated in constant speed mode and provide
> relatively stable AC frequency output, this is not practical with WTs of
> this size. Even if constant speed was viable, energy variations would occur.
> Non constant frequency operation makes operation of standard off-the-shelf
> motors problematic.
>
>
> Application environment:
>
> In this application it is intended that the WTs proper, and where practical
> also the alternators, will be constructed locally in countries where low
> income and possibly also high energy costs make this attractive.
> This replaces material costs with local labour but means that use of
> battery plus inverter systems adds substantially to the capital cost.
> Adequate knowledge and design resource exists in these areas, but more
> relevant input is alway welcome.
>
> DC system:
>
> I'm interested in the possibility of using DC pump motors. WT AC output
> would be rectified to DC and used to drive pumps directly or via an MPPT*
> system.
> This presents the DC motor with a variable voltage variable energy power
> source. Voltage and available energy need to be adequate to start the water
> pump from stall conditions and the pump must be able to provide the WT with
> a full load across its intended power design range.
> When the WT reaches maximum wind speed and power output furling systems
> prevent further increases in output. "Dump load" systems to add extras load
> at the top end are conceivable but undesirable if the energy is wasted.
> Depending on environment two or more pumps may be able to provide a staged
> load.
>
> ________________
>
> * MPPT = Maximum Power Point Tracking is a system which adapts a variable
> voltage level input source to a load (by adjusting the load seen at the
> source so that the energy source is optimally loaded (maximum power out) at
> all times.
> This can be thought of as an "electronic gearbox".
> A MPPT controller very usually contains an inverter
>
>
>
>      Russell