Torque limitation

Operating the motor with torque levels above the nominal torque is permitted within clearly defined limits. If the limits are exceeded, the drive generates a diagnostic message. The power output stage is switched off and the motor coasts down.

To enable the inverter to be operated in a fault-free manner, even at maximum load, the maximum motor torque is reduced automatically.

 

Derating is based on the following measured variables:

• Motor temperature
• Inverter power supply (IGBT) temperature
• Inverter cold plate temperature
• Overload as per inverter current integral
• Overload as per motor current integral
• Undervoltage or overvoltage in the HV circuit

 

 

Derating calculates a limit for the torque current. To ensure that this limit is not exceeded, the torque limits are influenced. Only the positive or negative torque limit that is currently active during operation is influenced.

No error messages are issued when the voltage limits are exceeded. However, torque cannot be taken from the motor that would cause the limits to be exceeded further.

If power is being reduced, this is signaled via X140 BO3 and via the CAN bus with CAN variable 'AMK_bDerating' .

 

Configuring torque limitation:

Temperature Motor	Temperature measured by KTY in the motor winding, connected to terminal X12 at the inverter
	ID32798 'User list 1' ID32798 - 11 Motor temperature at which full torque is available ID32798 - 12 Motor temperature at which no torque is available
Temperature Inverter power supply (IGBT)	Temperature measured (IGBT) by temperature model
	ID32798 'User list 1' ID32798 - 8 Power supply temperature at which full torque is available ID32798 - 9 Power supply temperature at which no torque is available
Temperature Inverter cold plate	Temperature measured by KTY on cold plate
	ID32798 'User list 1' ID32798 - 5 Inverter temperature at which full torque is available ID32798 - 6 Inverter temperature at which no torque is available
Overload as per inverter current integral	Always active, cannot be deactivated
	ID32999 'Overload limit inverter' Threshold of the inverter current integral from which derating starts and a message is issued
Overload as per motor current integral 1)	Activate the I²t monitoring of the servo motor in ID32773 'Service bits', bit 14
	ID114 'Overload limit motor' Threshold of the motor current integral from which derating starts and a message is issued.
	Relevant motor parameters ID109 'Motor peak current' ID34096 'Standstill current motor' ID34168 'Time maximum current motor'
Undervoltage or overvoltage in the HV circuit	ID32798 'User list 1' ID32798 - 3 Maximum battery voltage (end-of-charge voltage) ID32798 - 4 Minimum battery voltage (deep discharge) ID32798 - 7 Start of reduction for end-of-charge voltage ID32798 - 10 Start of reduction for deep discharge protection

 

Configuration information: Siehe 'FSE parameters'.