【Daily Question 20090213】What is the role of torque enhancement during the parameter setting of an inverter?

To achieve excellent acceleration performance at the optimal V/F ratio!

It is used to compensate for the voltage drop caused by a decrease in motor speed; during V/F control, it enables the motor to obtain sufficient rotational force, thereby improving acceleration performance.

To achieve excellent acceleration performance at the optimal V/F ratio!

Also known as torque compensation, it is a method of increasing the f/V ratio in the low-frequency range in order to compensate for the reduction in torque at low speeds caused by the resistance of the motor stator windings. When set to automatic, the voltage during acceleration can be increased automatically to compensate for the starting torque, ensuring smooth motor acceleration. When manual compensation is used, a suitable curve can be selected through testing, based on the load characteristics, especially the starting characteristics of the load. For variable-torque loads, improper selection can result in excessively high output voltage at low speeds, leading to energy waste; it may also cause high current when the motor starts under load, preventing an increase in speed.

The torque function controls the motor slip, keeping the motor torque within the maximum set value; thus, even when the load torque suddenly increases or when the acceleration time is set too short, it prevents the inverter from tripping. When the acceleration time is set too short, the motor torque will not exceed the maximum set value either. A high driving torque is beneficial for starting, and it is appropriate to set it at 80–100%.

I don’t know much about it; I just heard that it is done to achieve excellent acceleration performance at the optimal V/F ratio.

In conventional V/F control, the voltage drop of the motor increases relatively as the motor speed decreases, which results in insufficient excitation and prevents the motor from obtaining adequate rotational force. To compensate for this deficiency, the inverter needs to increase the voltage in order to make up for the voltage drop caused by the decrease in motor speed. This function of the inverter is called “torque boost”. This feature increases the output voltage of the inverter, causing the motor’s output torque to increase in proportion to the square of the voltage, thereby improving the motor’s output torque. General-purpose frequency converters usually have a torque boost function, and the meaning of this function varies among different brands: for example, Fuji’s products define torque boost 1 and torque boost 2 ； The products of American company A-B define DC boosting, start-up boosting, operation boosting, and operation/acceleration boosting. In the torque enhancement function, there are various enhancement modes available for users to choose from. Products of different series from the same manufacturer have different default settings; if the setting of this parameter is not adjusted during system calibration, high starting torque of the load can lead to overcurrent tripping and thus failure to start the system.

Torque enhancement is intended to provide an appropriate increase in the output voltage when starting heavy loads, thereby increasing the starting torque. The general range is 0%-30%. It is generally set to automatic, but can also be adjusted manually. This post was last edited by chinahbzq on 2009-2-13 17:53]