BL-DC Motor Speed Controller

Hi,
I want to make a speed controller for 48v 250w bl-dc motor , ı searched on the internet for information but there isn't much thing to go on. Can anyone tell me at least where i should start from?

This covers the basics:
https://ww1.microchip.com/downloads/en/appnotes/00857b.pdf

Quite a few PIC devices have three phase (or more) PWM outputs, with extra features like dead time and fault inputs on the higher end devices.

I personally like the dsPIC33EP256MC502, but there are many other devices in different series that can do similar things.
Some library software here:
https://www.microchip.com/design-centers/motor-control-and-drive/motor-control-library

The material is actually everywhere. You probably just don't know where to look. In addition to what rjenkinsgb posted, your best resources are the different app notes from microcontroller manufacturers that explain how to use their microcontrollers to drive brushless motors. Like Freescale/Motorola, Texas Instruments, NXP, and ST (and of course Microchip).

an ebike motor controler springs to mind,cheap as chips too!

The PicMicro development board is a good source, PICDEM MC LV has the software and schematics for download.
Max.