Application of sophisticated look-up tables with 12-sectors for vector control of induction motor drive

Abstract

The control of Induction motor drives constitutes a vast subject and with the advent of latest technologies like vector control, direct torque control etc., these drives have been playing a vital role in the industries for variable speed applications. The control strategies of induction motor drives are more complex than DC drive control strategy. This is because in AC drives variable frequency, variation of machine parameters occurs. The various control strategies for the inverter fed induction motor have provided good steady state but poor dynamic response. To overcome the problem of undesired ripples in current, torque and flux during steady state in FOC, a new method is employed in this paper that generates the stator current more accurately by applying the active voltage vector or zero voltage vectors using switching table within a sampling interval. Based on the output of controllers and position of stator current, an optimum look-up table is constructed. This approach gives faster torque response like in vector control methods and it also reduces ripples as in DTC method. To validate the proposed method numerical simulations have been carried out and compared with the existing algorithms. The simulation results confirm the effectiveness of the proposed method.

Key Words? Induction Motor Drive, Look-up table, Vector Control