Reliability Improvement of the Cascaded H-Bridge Multilevel Inverter for Induction Motor Drive Applications

Abstract

To increase the reliability of electrical drives system FOC-IM which is supplied by the cascaded H bridge multilevel inverters in faulty
conditions, this paper uses new detecting method based on the differences between output voltage and control signal of each H bridge, and
proposes new improved SVM algorithm for cascaded H bridge multilevel inverters when the open-circuit problem occurs. By analyzing the
effect of the faulty H bridge, the switching states that creating standard voltage vectors are chosen precisely to achieve following objectives: Output voltage is maximum, three phases are balanced, and the common mode voltage is optimized. This algorithm can be applied to
H bridge inverters at any level. Besides, the affect of the open-circuit issues is evaluated with and without proposed algorithm, based on the
simulation results of electrical drives system FOC-IM model supplied by 11-level cascaded H-Bridge Inverters on MATLAB – Simulink.