In variable-frequency drives of AC motor, it needs to control the relevant variables to ensure three-phase equilibrium of the sinusoidal input current in order to keep the electromagnetic torque of AC motor constant. Judging from the dynamic mathematical model of the induction motor in ABC coordinate system, it’s a strong-coupling multi-variable system, which is hard to control. This paper presents the dynamic mathematical model of the induction motor in MT coordinate system. When the direction of the rotor...