Real time implementation of DTC based on sliding mode speed controller of an induction motor

Abstract

This research work deals with the real time implementation on an Field Programmable Gate Array (FPGA) of the Direct Torque Control (DTC) of an Induction Motor (IM) utilizing a Sliding Mode controller (SMC) of the rotor speed. In several industrial applications, the speed is controlled by a Proportional Integral (PI) regulator, because of its simplicity. However, because of the model uncertainties of the motor, the stator resistance variation, and the variation of the load torque as an external disturbance, the PI controller becomes unable to guarantee the desired control performances. To overcome the PI insufficiency the SMC is proposed. SMC is featured by its capability to cope with the disturbances. Therefore, developing the SMC of speed presents the first contribution in this manuscript. The second contribution consists to implement the proposed approach referred as DTC-SMC using an FPGA due to its ability to execute this algorithm with high processing speed by adopting a parallel processing. The FPGA is proposed to overcome the DSPs and microcontrollers limitations, like the calculation delay due to its sequential processing. The DTC-SMC algorithm has been validated by simulation utilizing the Xilinx System Generator (XSG). The obtained results of simulation verify the proposed controller relative to the PI controller under load torque disturbances.