The fastest way is to hire somebody who's done it before.
Alternatively, there are university courses and books that can help you. This is not a weekend project, even if you're already a power electronics engineer...
You can start by using pre-assembled modules for the power electronics and for the DSP boards. This will allow you to concentrate on the software. The IEEE as many paper relating to the control strategies. You could also license sections of software from various OEM. Check on the Internet you will find some module suppliers like Powerex. Some of these modules come equipped with gate driver's and power supplies. All you need to do is plug in your DSP board...
Even with the above, expect two or three years of development before having something that looks like product. Then, another two or three years of product maturation where you will get the application bugs out.
If you're in a hurry, buy a small company that has already done most of the work but is running out of money for commercialization.
Good luck, this is a very competitive market.
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Experienced is earned, common sense is taught, both are rare essentials of life.
I don't know how Big this needs to be but you can purchase off the shelf electric motors that are variable speed that are used on washing machines and blower motors on furnaces.
If you need specific models that I know of just ask I am not near tech manuals.