Pulse-Width Modulation (PWM)
Pulse-width modulation (PWM) is a switching method that controls an inverter's average output voltage by changing how long its semiconductor switches remain on during each repeated cycle.
How it fits into motor control
The motor controller calculates desired phase voltages. PWM turns those commands into timed switch states, while the motor windings' inductance smooths much of the pulsed voltage into controlled current. Space-vector PWM is one common three-phase implementation, but it is not the only one.
PWM is not the same as field-oriented control: FOC calculates voltage targets, while PWM is one way the inverter realizes them. Higher switching frequency can reduce current ripple and shift acoustic components, but every transition adds switching loss. Modulation choice therefore affects efficiency, heat, noise, voltage utilization, and electromagnetic interference.
For the deeper relationship between current control and inverter switching, see Motor Control and Efficiency Maps.