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Multilevel inverter plays a crucial role in industrial applications. The performance of cascaded multilevel inverter (CMLI) with reduced switch count is analyzed in this paper. If the switches have been increased the switching loss and THD will increase. The preferred topology is simulated for seven level and fifteen level by considering isolated DC source and PV. The reduced % THD is identified compare to other topologies. Four switches continuously working at fundamental switching frequency is considered as one of the advantage of the topology.

In recent years multilevel inverters have been extensively worn in high voltage and high power applications for their unique performance. Reliability of the power electronic equipment is very essential to make sure that inverter operation should be stable and it is most important to detect and locate the faults as speedily as possible. This paper deals with open switch-fault finding method in a multilevel inverter using wavelet transformation tool. A fault diagnosis procedure is proposed and executed using MATLAB.

Voltage source inverter (VSI) fed induction motors are widely used in variable speed applications. Space Vector Pulse Width Modulation (SVPWM) has become the successful techniques to construct three phase sine wave Voltage Source Inverter (VSI) parallel to control three-phase induction motor using v/f control. Because of the low maintenance and robustness induction motors have many applications in the industries. The speed control of induction motor is more important to achieve maximum torque and efficiency. VSI fed induction motor produces a pulsating torque due to the application of non sinusoidal voltages. Among the various modulation strategies Space Vector pulse width Modulation Technique is the efficient one because it has better spectral performance and output voltage is more closed to sinusoidal. Torque pulsation is strongly influenced by PWM technique used. This paper compares the torque ripples of convectional space vector PWM with hybrid PWM techniques. In hybrid PWM both continuous PWM and discontinuous PWM techniques are employed. The open loop V/f control of induction motor with hybrid PWM shows better reduction in torque ripples when compared with conventional space vector PWM technique. The simulated design is tested using MATLAB 7.8.

This paper presents an efficient and reliable evolutionary-programming-based algorithm for specific harmonic elimination (SHE) switching pattern. This method eliminates the considerable amount of lower order line current harmonics in pulse width modulation (PWM) inverter. Determination of pulse pattern for the elimination of some lower order harmonics of a PWM inverter necessitates solving a system of nonlinear transcendental equations. Evolutionary Programming is used to solve nonlinear transcendental function for PWM-SHE. In this proposed method 11th and 13th harmonics are eliminated using evolutionary programming. Simulation results using Matlab/Simulink are carried out to validate the solution.