I think you need to drop back and make some aerodynamic calculations on the turbine. Given the stated airflow, how much power can you theoretically get from the turbine?
You absolutely can not exceed this power output, but in reality, it's worse than that.
You need to consider the efficiency of converting this mechanical energy to electrical energy. This is where you evaluate permanent-magnet motors verses a purpose-built generator verses an alternator. The output power from this conversion will be less than the mechanical power generated by the turbine. This is called efficiency and it CAN NOT exceed a factor of 1.
Only after this point can you consider the conversion of electrical energy to a useful form. Again, you need to consider the efficiency of this step, and again, the efficiency WILL BE LESS THAN 100%. There are losses in each conversion, and it's not possible to get more power out than power in. All you can do is maximize the efficiency at each step of the conversion process.
I think I just outlined your project for you...at least what it needs to be even if it's not what you want it to be.