Power Supply 230Vac/12Vdc and 24Vdc/3kW

[Svele]

Hi, I have a problem to build power supply - starter for cars and trucks and my idea is to build SMPS starter,some kind a cheap version like electronic transformers for halogen lamps but for much more power like 2 or 3 kW.Is anyone is willing to send me a schematic for this purpose?Here is schematic of simple halogen lamp electronic transformer:

 

[MicrosiM]

In order to get some support, I would like to know more information's, specifications, also 2 ~3KW supply wont be cheap in all cases!

 

[Svele]

In the attached image You will see the circuit that I want to start with...My idea is to put some strong transistors like BU508 (few in parallell with balancing resistors 0,1 ohms for equalizing the currents through transistors) and one or two in darlington connection with BU to get current gain through BU's, and I think that for current of 15A through transistors I should put about 10uF/400Vdc non electrolitic caps in both sides instead of 0,22uF/400Vdc (I will put 3x3,3uF/275Vac in parallell in every half of circuitry).But I still do not know what core to put for power of 2,5 kW for example.Should I increase the working frequency which is now something above 22kHz, and how to do that?I have cores of Ae of 4.5cm2, I think that is enough for that power.And finally how to calculate windings for that tranformer?