Direct torque control scheme for a five‐level multipoint clamped inverter fed induction motor drive using fractional‐order PI controller.

Summary: This paper proposes a fractional‐order PI controller‐based direct torque control (DTC) scheme for an induction motor (IM). The IM drive is fed with multipoint clamped (MPC) inverter to realize the five‐level operation. The DTC scheme is implemented with the help of stator‐flux coordinates. The DTC scheme estimates the reference stator voltages from the reference speed and torque commands and space vector modulator synthesizes the reference stator voltages to generate the switching states of the inverter. The paper begins by featuring the theoretical concepts related to five‐level MPC inverter and compares it with conventional multilevel inverters in terms of total number of components required, conduction and switching power loss. In this paper, space vector modulation (SVM) algorithm for the generation of switching pulses to the five‐level MPC inverter based on fractal structure has been proposed with optimal switching sequence which further reduces the switching power loss, total inverter system loss, and phase‐current harmonic distortion. The design procedure and tuning of PI controllers (using fractional‐order system) for the proposed DTC‐SVM scheme are also presented. The proposed drive system allows full‐load torque control with fast response and reduced torque ripple for wide range of speed variations. The proposed DTC‐SVM fed IM drive is implemented in the MATLAB/Simulink software. The simulation results are verified with experimentation. [ABSTRACT FROM AUTHOR]