Fc 301 Vs. Fc 302 Control Principle - Danfoss VLT AutomationDrive FC 301 Design Manual

Basic Operating Principles

3.6.2 FC 301 vs. FC 302 Control Principle

FC 301 is a general purpose frequency converter for variable speed applications. The control principle is based on Voltage
+
Vector Control (VVC ).
FC 301 can handle both asynchronous and PM motors.
The current sensing principle in FC 301 is based on current measurement in the DC-link or motor phase. The ground fault
protection on the motor side is solved by a de-saturation circuit in the IGBTs connected to the control board.
Short-circuit behaviour on FC 301 depends on the current transducer in the positive DC-link and the desaturation protection
with feedback from the 3 lower IGBT's and the brake.
L1 91
L2 92
L3 93
Illustration 3.4 Control Principle FC 301
FC 302 is a high performance frequency converter for demanding applications. The frequency converter can handle various
kinds of motor control principles such as U/f special motor mode, VVC
FC 302 is able to handle Permanent Magnet Synchronous Motors (Brushless servo motors) as well as normal squirrel cage
asynchronous motors.
Short circuit behaviour on FC 302 depends on the 3 current transducers in the motor phases and the desaturation
protection with feedback from the brake.
L1 91
L2 92
L3 93
Illustration 3.5 Control Principle FC 302
®
VLT AutomationDrive FC 301/FC 302 Design Guide, 0.25-75 kW
Load sharing +
89(+)
R inr Inrush
88(-)
Load sharing -
Load sharing +
89(+)
R inr
88(-)
Load sharing -
P 14-50 R Filter
MG33BF02 - Rev. 2013-12-20
De-saturation protection
+
or Flux Vector motor control.
LC Filter +
(5A)
Inrush
LC Filter -
(5A)
R+ Brake
82 Resistor
R-
81
U 96
V 97
M
W 98
Drive
Control
Board
R+ Brake
Resistor
82
R-
81
U 96
V 97
M
W 98
19
3 3