VFD inverters and motor controllers

PAM modulation technique involves varying the DC link voltage amplitude to the motor in response to control signals, enabling robust speed and torque control. PAM inverters are suitable for applications where very high speed and ultra low losses of the motor are paramount, even at the slight increase of cost and size of the inverter.

FOC, also known as vector control, is a motor control technique that adjusts both the voltage and current supplied to the motor to achieve precise control of speed and torque. FOC inverters are commonly used for applications where high-performance control is required in addition to compact inverter size.

A six-step inverter configuration has the best trade-off to be used in usually low power, simple, reliable and cost effective applications, at the expense of efficiency. It typically consists of six switching devices that control the flow of current through the motor windings.