DC/DC Converter

Gentlemen,

I am starting the design of a DC/DC converter used as a Wind turbine battery-charging system.

The DC wind turbine output voltage will be connected to the input of the Controller. The output of the controller will be connected to a lead-acid 24 Volts battery bank, 1440 Ah capacity.

The basic data of the wind turbine output are:

At low Low speed: 35 volts 1 amp At High speed : 156 Volts 13 amps

What kind of DC/DC Step-down topology (Buck, Push-Pull) is the most suitable:

- Buck classic

- Buck synchronous

- Several Buck in parallel

- Multiphase Buck

- Push Pull topology

How can I deal with the very large input voltage, because I found no PWM controller. The closest I found is the LINEAR LTC 3703 that can work up to 100 Volts.

Is there any PWM controller else ?

Thanks four your help A.

From a certain power up, the DC/DC is done as sync rectified transformer converter. Possibly even as multiphase.

Rene

I'll say! This is a 35 to 156V range, or a nearly 5x voltage range and 35W to 2kW, which is a 60x power range. These are not easy parameters for a simple buck converter, or whatever. I wonder if any of the commercial wind-generator converters work effectively and efficiently over this full range. What's more, one cannot regulate output voltage, current or power, per se, because these should all be variable, as a complex function of wind speed. If one attempts to regulate any one of these, the generator could be loaded to the point of stall and a poor wind-power collection would result.

Apparently the generator is a permanent magnet DC motor with the torque proportional to the current and the revs proportional to the voltage. It requires a maximum-power-tracker to have revolutions and torque maximized, repectively the product of it. The only parameter is apparently the DC voltage burden giving the revolutions. Yes, a more advanced design would have the attack angle of the blades variable. Running that optimally would possibly be beyond a simple controller though. A weak point of the current design is the point of the batteries being full.

Rene