Modified Diode Clamped Inverter-Based Single Phase Induction Motor Closed-Loop V/f Control

In this paper, a nine-level inverter fed single-phase induction motor with closed-loop scalar control is proposed. A modified diode-clamped inverter is used to produce the nine-level voltage to the motor. The inverter's topology is controlled with phase disposition pulse width modulation, it utilizes an H-bridge and four-switch multilevel DC-DC converter. This topology proposes fewer components than a conventional Diode Clamped Inverter (DCI). A varying load torque is applied to the motor to study the system behavior under constant V/f control. The system is proven to maintain reference speed, and the V/f ratio is observed throughout the operation and kept constant realizing a region of constant power (voltage saturation). The simulated output voltage of the proposed system has a Total Harmonic Distortion (THD) of 3.11 %. The simulation results are obtained through MATLAB/Simulink.