Reasonable frequency converter torque boost function setting

The torque boost function is a parameter that is often used when the frequency converter is at a low frequency. The so-called torque boost is to increase the additional DC component to increase the motor torque and increase the output voltage of the inverter to increase the carrying capacity when the current torque cannot be satisfied. General frequency converter can reach about 0%-20%.

Because of the traditional V/F control method, the output torque and frequency of the inverter are proportional. Generally in the case of low frequencies, the torque boost function is actually a way to increase the internal voltage of the inverter in the case of a low frequency, which is to increase the output torque by increasing the current. When using this function, the torque boost function can't be blindly adjusted too much, too much will report over-current protection.

When working in the low frequency range, the excitation voltage of the motor is reduced and underexcitation occurs. The automatic torque boost function of the inverter compensates the under-excitation of the motor and enhances the torque (U/f characteristics enhancement) when the motor runs at low speed.

The torque boost is mainly applied below the cut-off frequency (P05.02). The boosted V/F curve is shown in the following figure. The torque boost can improve the low-frequency torque characteristics of V/F.

The amount of torque should be properly selected according to the load size, and the load can be increased to increase the lift. However, the lift value should not be set too large. When the torque is increased too much, the motor will be over-excitation, the inverter output current will increase, and the motor will increase in heat. The efficiency is reduced.

When the torque boost is set to 0.0%, the inverter is automatically torque boosted.

Torque boost cut-off point: Below this frequency point, the torque boost is effective. If this set frequency is exceeded, the torque boost will be invalid.