AC Drives Provide Precise Control Critical to Next-Generation Test Stands

Direct Torque Control (DTC) is widely used as a method for controlling AC motors in many demanding applications. It is a unique method for controlling AC motors. In pulse-width modulation (PWM) drives, the output frequency and voltage are the primary control reference signals for the power switches, rather than the desired torque in/of the motor shaft. For those who are not familiar with inverter technology, the DTC principle can be illustrated most accurately via this mechanical analogy: the continuous calculation of the best angle at which to rotate a shaft, with a given arm length and the forces available. These electrical “force vectors” are generated with the help of semiconductor switches called Integrated Gate Bipolar Transistors (IGBT).