This paper presents a new single-stage, nonisolated dc to dc boost converter with quadratic voltage gain for low and medium power applications. The attractive features of the topology are that it is having a simple structure with a single switch and its gain is twice that of a conventional quadratic boost converter (CQBC). The fact that it utilizes a single switch makes the practical implementation of the converter easy, as only one gate pulse is needed to control the switch. The other advantage of the proposed converter is that coupled inductor is not used in this topology. The coupled inductor is helpful in increasing the gain of the converters but at higher duty ratios the energy trapped in leakage inductance can increase the stress across the switch. The converter operates in continuous current mode (CCM) which makes it an attractive choice for renewable energy applications. The topology is compared with other existing topologies of quadratic gain converters. The efficiency of the proposed converter is determined by incorporating switching and conduction losses of various components through power loss data given in datasheet of MOSFET and diodes using PLECS which is a simulation software specially designed for carrying out the loss analysis of power electronics converters. A 100 W prototype of the proposed converter is developed in the lab. The experimental results closely agree with simulation and theoretical results.

The output voltage of a Multilevel Inverter (MLI) can be controlled using various low and high frequency modulation strategy. Apart from meeting the load voltage demand, the modulation strategy also tries to reduce the harmonics present in the output voltage waveform. In this paper, a novel modulation strategy, a Variable Structure Nearest Level Modulation (VSNLM) has been proposed with the objective to reduce the Total Harmonic Distortion (THD) thus giving better output voltage quality and smoother control. The development of the mathematical model and subsequent analysis has been carried out. Moreover, the proposed modulation scheme has been implemented on 7, 9, 11, and 13 level Cascaded H Bridge inverter and a generalized mathematical model of the proposed scheme has been developed. A comparison of the proposed strategy with the conventional NLC is presented in the paper. The results confirm the superior performance of proposed strategy in terms of THD. Experimental results have also been presented for validation.