Abstract:
To solve the problems of non-constant switching frequency and big torque ripple in traditional direct torque control(DTC), considering the characteristics of space vector decoupling of the six-phase motor, a novel backstepping SVM-DTC of six-phase induction motor based on rotor flux closed-loop was proposed. Firstly, the mathematical model of motors was built, and the new virtual voltage balance vector was used to determine the space voltage vector pulse width modulation (SVPWM), in order to reduce the motor stator harmonic current. Furthermore, the backstepping principle was applied that aspeed backstepping controller was used to replace a PI controller in traditional DTC. A torque and flux backstepping controller was designed to gain stator voltage. Finally, the system was verified by simulation in Matlab/Simulink. At the same time, the modified DTC was compared based on PI control, and the result shows that the proposed strategy has rapid response, low torque ripple, a few adjusted parameters, and the stator current waveform is improved and make inverters have constant switching frequency.