3.2.3. FC 301 vs. FC 302 Control PrincipleThe FC 301 is a general-purpose adjustable frequency drive for variable speed applications. Thecontrol principle is based on voltage vector control (VVC plus ).The FC 301 can handle asynchronous motors only.The current sensing principle in the FC 301 is based on current measurement in the DC link ormotor phase. The ground fault protection on the motor side is solved by a desaturation circuit inthe IGBTs connected to the control board.Short circuit behavior in the FC 301 depends on the current transducer with positive DC link, andthe desaturation protection with feedback from the 3 lower IGBTs and the brake.The FC 302 is a high-performance adjustable frequency drive for demanding applications. Theadjustable frequency drive can handle various kinds of motor control principles such as U/f specialmotor mode, VVCplus or flux vector motor control.The FC 302 is able to handle permanent magnet synchronous motors (brushless servo motors),as well as normal squirrel-cage asynchronous motors.Short circuit behavior on the FC 302 depends on the 3 current transducers in the motor phases,and the desaturation protection with feedback from the brake.3. Introduction to FC 300 FC 300 Design Guide22 MG.33.B9.22 - VLT® is a registered Danfoss trademark.3
