Hi,

The L298 driving the BLDC motor is pulsing the three phases with

square-waves like a stepper motor.

An ESC uses a high frequency PWM signal, modulated to give an approximation of a 3 phase AC,

sinusoidal, signal.

Here is an example of an ESC output to a BLDC motor, the inductance of the motor windings helps to smooth out the PWM to give a sinusoid and smooth efficient running.

https://www.youtube.com/watch?v=Jdhgi5_kmvk

You can hear the difference, the L298 circuit sounds rattly compared to the ESC unit.

An ESC is a small version of a VSD that uses high frequency PWM to produce a variable sinusoidal AC current on 3 phases.

http://www.acdrivesguide.com/vsd-controltheory.htmlPWM frequencies can be as high as 16Khz, to produce a sinusoid AC of 50Hz or higher if overspeeding a 415Vac 3phase 50Hz motor.

Tom...