Inter University DSP Solutions Challange ‘99 Digital Signal Processing Solutions Date 04/22/00 HIGH PERFORMANCE DIRECT TORQUE CONTROL INDUCTION MOTOR DRIVE UTILISING TMS320C31 DIGITAL SIGNAL PROCESSOR

Recently, digital signal processors (DSP’s) are gaining more popularity in the area of ac motor control, in particular the induction motor drives. The fast number crunching capabilities of DSP’s which are traditionally meant for data processing tasks such as image processing and speech recognition, are being utilised to perform on-line calculation of the ac motor variables, such as electromagnetic torque, fluxes, mechanical speed, etc. This project presents the implementation of a high performance induction motor control technique known as direct torque control (DTC). In DTC drives, the de-coupling of the torque and flux components is accomplished by using hysteresis comparators which compares the actual and estimated values of the electromagnetic torque and stator flux. The torque and flux estimated values are calculated based on the sampled motor’s terminal variables, i.e. stator voltages and currents. Output of these comparators together with the stator flux orientation are used to select the appropriate voltage vectors of a three phase voltage source inverter. To ensure stability and high bandwidth operation, the sampling period must be made as small as possible which means that a fast calculation of stator flux and torque is required and this is achieved by utilising a DSP controller board, DS1102 from dSpace consisting of TMS320C31 at 60 MHz. To minimised the sampling period of the implemented drive system, a Xilinx FPGA (XC4005E) i