The battery speaks DC. The motor only listens to AC. Between them sits the inverter, chopping current thousands of times a second into three perfect waves. Take the controls.
Three coils, three currents, each a third of a turn apart. Their combined push is the rotating field from Stage 01. Speed up the waves and the motor must follow.
The motor control unit measures the rotor position thousands of times a second and times every pulse to land exactly where the push is needed.
A battery pushes current one way: DC. But the rotating field that drags the rotor around needs currents that rise and fall in sequence: AC. The inverter is the translator, and there is one for each eMotor.
The inverter cannot make a smooth wave directly: it can only switch the 800 V supply on and off. So it switches tens of thousands of times per second, varying the pulse widths so the average traces a perfect sine wave. That is pulse-width modulation, and you saw it under the toggle.
The rotor chases the rotating field, so wave frequency sets motor speed. Your accelerator pedal is really a frequency and current request to the MCU: the motor control unit that times every single pulse.