Siemens SINAMICS PERFECT HARMONY GH180 Function Manual page 182

Operating the Control
7.2 Frame of Reference
crosses back over to quadrant I, and assumes a positive value as the motor accelerates in this
direction. The signs of the signals of the applied torque and resultant speed are illustrated in the
figure above.
The injection frequency must always be opposing the direction of rotation and is only used in the
case of braking or negative energy flow. Therefore, it is zero in the motoring quadrants, I and III,
and is the inverse polarity of the electrical frequency in the braking quadrants, II and IV. See Table
Signal Polarities.
180
NXGPro+ Control Manual
Operating Manual, A5E50491925A