Hi Madbunny,
The pwm is no where directly related to drive a BLDC motor. Many people confuse with this because mostly all ESCs (Electronic Speed Controller) takes a pwm input to drive BLDC.
So first get some hints regarding bldc
Actually BLDC motor is not just like a normal brushed DC motor which runs simply by connecting a power supply.
BLDC motors need to change phase in order to run, simply different coil has to be excited in a cyclic manner.
Actually normal motors also need to change phase, but this work is automatically done using the mechanical brushed setup.
But for BLDC u have to control this, how fast you are changing the phase will be the speed if the motor.
If is just connect power supply to any two of it's wire, it will just produce a turn with heavy torque and remain in the same position, then you have to change the power supply in another combination of the wires. Then the other two. Hence finally it will produce one complete rotation.
So finally it's not mandatory to use pwm for its control.
It's all about shifting phases.
Be careful while using them, they are high power. Their current can reach to several amperes. Don't connect any propellers while testing.
Also coils are not rotors in bldc, they are actually the magnets, hence the exterior rotates.
All the best!!!!