Cogging torque is a critical dilemma in Permanent Magnet Brushless DC (PMBLDC) motors. In medium-low power PMBLDC motors, redundant vibrations and forbidding noises arise as a result of the harmonic magnetic forces created by cogging torque. This paper introduces a simple approach for minimizing cogging torque in PMBLDC motors by applying placement irregularities in rotor magnets. An angle shift in the rotor magnets in surface-mounted PMBLDC motors helps to attain magnet displacement. This displacement imparts an asymmetrical magnet structure to the rotor. Maintaining pole arc to pole pitch ratio (L/τ) of between 0.6 and 0.8, shifting angles from 1° to 8° were considered in order to analyze the effect of the angle shift on the rotor magnets. An analytical expression was also derived for finding the shifting angle with the minimum cogging torque in the PMBLDC motor by using the Virtual Work Method (VWM). The optimization of the shifting angle with minimum cogging torque was investigated using 3D Finite Element Analysis (FEA). A comparison of the simulation and analytical results of cogging torque was carried out. It was determined that the reduction of cogging torque in the analytical results showed good agreement with the FEA analysis.

Due to cutting-edge innovations in industry and academia, research is more centered around multilevel inverters (MLIs), which play a significant role in different high/medium voltage and high-power applications when contrasted with traditional inverters. Relative analysis of the reduced DC source count and switch inverter topologies highlight its significant benefits, which include control complexity, switch count, source count, reliability, efficiency, cost, voltage stress, total harmonic distortion (THD), and power quality. When switched-capacitor technology is deployed, it is seen that with the assistance of 14 switches, a 53 level result is accomplished, and the THD is just around 1.41%, which is kept up with as per the IEEE 519-2014 norms. Whenever cascaded MLI topology is employed, the inversion efficiency is more prominent, and is about 99.06%. Hence, this review focuses on a few of the late-evolved MLIs utilized, and the benefits and drawbacks for different topologies are examined. To assist with current modern research in this field and the decision of the proper inverter for various applications, a novel topology of an MLI can be planned later on. Different setups of MLIs have been exhaustively covered and reviewed.

Cogging torque is an unfavorable hindrance in Permanent Magnet Brushless DC (PMBLDC) motor. In medium-low power PMBLDC motors, the surplus oscillations and intolerable noise happen because of the harmonic magnetic forces created by cogging torque. This paper introduces a new approach for the diminution of cogging torque. This method is based on placement irregularities in rotor magnets, and for this a new combination of pole arc and pole pitch was considered. The reference model has a pole pitch of 90° and pole arc of 63°. The new pole pitch is attained by the application of shifting technique on the permanent magnet and for the new pole arc it was resized. An analytical expression using the Virtual Work Method (VWM) Method was derived for locating the pole pitch and pole arc with nominal cogging torque in the PMBLDC motor. The technique is explored using 3D Finite Element Analysis (FEA). The comparison of the simulation and analytical results of cogging torque is accomplished. It is figured out that the cogging torque minimization in the analytical results exhibited acceptable agreement with FEA analysis.

The necessity for DC−DC converters has been rapidly increasing due to the emergence of RES-based electrification. However, the converter designed so far exhibits the drawbacks of lower efficiency and non-compactness in size. Hence, to rectify this problem, the new topology of a flyback converter for PV application is proposed in this work. The proposed converter exhibits reduced ripple in input current and enhances the conversion efficiency. Finally, the efficiency of this proposed converter is verified using MATLAB. The results indicate that this projected topology can be suitable for high voltage DC applications.