The study on the direct torque controlled induction motor based on low loss inverter with double-frequency for electric vehicles

This paper presents a new kind of direct torque control (DTC) system based on the inverter with double-frequency for the motor drives of electric vehicles (EVs). According to the theory of the converter with double-frequency, the topology of a new kind of inverter with double-frequency is derived, and the operation states of the new circuit are analyzed. This kind of inverter has good dynamic and steady-state performance as the high frequency inverter, and the efficiency is close to a single low frequency one. For the reduction of the torque ripple, improved switch table is employed in the DTC system. The observation of the flux linkage is achieved by the u - n model. The simulation results show that this system is effective for the control of the induction motor and the validity of the proposed new circuit is also verified.