The Effects of Negative Driving Torque in Servomotor Drivers

In many applications, a servomotor driver controls a motor to drive its load with either positive or negative driving torques. The negative driving torque is defined as torque applied to load in the reverse direction of the motor rotation. When the servomotor driver controls the motor to drive its load with negative driving torque, the effects of the negative driving torque may damage the servomotor driver. Thus, in this paper, we study the effects of negative driving torque in commercial servomotor drivers by using the numerical simulation that combines the simulation of the control system with that of the electronic circuit. The simulation results show that the negative driving torque is used for decelerating the motor and compensating the disturbance torque. When the negative driving torque is required, the servomotor driver generates regenerative current that flows from the motor back into the power supply and makes the power supply voltage rise