Five-level diode-clamped inverter-fed induction motor drive system

Multi-level inverters give a clear solution to bring the advantages of speed controlled induction motor drive. A nine-level hysteresis based direct torque control was proposed to provide accurate mapping of the torque errors and to prove five-level inverter diode-clamped multi-level inverter (DCMLI) superior performance compared to two-level inverter. The practical design of control system was given in detail. The proposed control strategy guaranteed excellent dynamic and steady state characteristics. The simulation results using MATLAB/SIMULINK show its superior performance in terms of torque and flux ripples decreasing and source current harmonics minimisation. The experimental implementation of the five-level DCMLI fed induction motor in open loop mode validated its theoretical analysis in the proposed strategy.