The invention discloses a 
system and method for controlling an indirect torque of a single regulating loop of a three-phase 
induction motor and relates to the technical field of 
motor drive and alternated current speed regulation. The 
system is provided with an indirect 
torque controller, a 32-bit 
digital signal processor used as the core of the 
system and a corresponding 
peripheral circuit. The 
software of the system comprises a 
flux linkage observation and torque calculation unit, a steady slip calculation unit, a revolving speed sampling period integral unit, a torque 
regulator unit, a 
stator flux linkage vector amplitude and phase calculation unit and a space 
voltage vector calculating and outputting unit. Through the method provided by the invention, the space 
voltage vector of controlling the motor in the next period can be acquired by utilizing the efficient value formula of each-phase 
electromotive force of a motor 
stator (UE is equal to 4.44kfNF), namely the ratio of the 
voltage vector amplitude to the phase 
gain is maintained as a constant when the motion track of a 
stator flux linkage vector is a flux linkage circle. In the invention, only the torque single proportional-integral (PI) regulating loop is required, thus the 
system structure is simplified, the dynamic property of the system is enhanced, and the high-
performance control of the driving system of the three-phase 
induction motor is realized.