NLC and SFO Control Technique Based Multilevel Inverter fed 3-φ Induction Motor Drive

In this work, hybrid control technique based 3$-\varphi$ induction motor drive fed from a cascaded multilevel inverter is presented. In the past decades regular two level inverters are, however these are having output voltage with harmonic content. To improve the solar photovoltaic system power quality and voltage rating, the multilevel inverters are employed along with several lower voltage dc sources is employed. In multilevel inverters power conversion is by synthesizing a staircase voltage waveform. The presented inverter configuration is derived from a module of addition and subtraction of sources. It helps to reduce the number of components - number of sources, switching drive, capacitors, diodes and majorly power switches. In this work, performance analysis and operating modes of 3$-\varphi$ cascaded hybrid control technique based multilevel inverter for both symmetrical and asymmetrical topologies are explained. Further, the nearest level control (NLC) and switching frequency optimal (SFO) control techniques are employed in this work. To operate the power switches in this topology the switching signals are generated by using hybrid SFO-NLC technique. The enhanced features of this topology with the perspectives of power quality and optimized switching count are presented. The inverter fed drive system with proposed control technique is simulated by MATLAB/Simulink for the verification of the performance of the technique under both steady state and dynamic conditions.