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Maximum Power Point Trackers (MPPTs) are power electronic conditioners used in photovoltaic (PV) system to ensure that PV structures feed maximum power for the given ambient temperature and sun's irradiation. When the PV panels are shaded by a fraction due to any environment hindrances then, conventional MPPT trackers may fail in tracking the appropriate peak power as there will be multi power peaks. In this work, a shuffled frog leap algorithm (SFLA) is proposed and it successfully identifies the global maximum power point among other local maxima. The SFLA MPPT is compared with a wellentrenched conventional perturb and observe (P&O) MPPT algorithm and a global search particle swarm optimisation (PSO) MPPT. The simulation results reveal that the proposed algorithm is highly advantageous than P&O, as it tracks nearly 30% more power for a given shading pattern. The credible nature of the proposed SFLA is ensured when it outplays PSO MPPT in convergence. The whole system is realised in MATLAB/Simulink environment.

This study proposes a novel topology for reducing commutation torque ripple in a brushless DC motor (BLDCM) drive system using a three-level neutral-point-clamped (NPC) inverter combined with single-ended primary-inductor converter (SEPIC) converters. In the BLDCM, current ripples arise because of the influence of stator winding inductance, which generates torque ripples. The torque ripple that is generated in the commutation period prevents the use of BLDCM in high-precision servo drive systems. In this study, two-stage converters are proposed to reduce the torque ripple. The first stage consists of two SEPIC converters to obtain the desired commutation voltage according to motor speed. A dc-link voltage selection circuit is combined with the SEPIC converters to apply the optimised voltage during the commutation interval. To reduce the torque ripple further, a three-level NPC inverter is used to apply a half dc-link voltage across the motor winding and this effectively reduces the torque ripple. Experimental results show that the proposed topology is able to reduce commutation torque ripple significantly under both low-speed and high-speed operation.

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A new single-phase H-bridge multilevel inverter (MLI) topology constructed using auxiliary reverse-connected voltage sources along with a hybrid pulse width modulation (PWM) strategy is proposed, to extract a variable frequency variable amplitude output voltage. The principle eschews an astute philosophy to employ PWM approach only for a particular Hbridge that serves to produce the desired level while the remaining add-on modules function with the theory of fundamental switching. It involves the use of reduced number of switching devices for a specific number of output voltage levels in comparison with conventional MLIs. The design of the hybrid PWM suitable to power the appropriate switches add strength to its formulation in the sense it requires only either addition or subtraction to generate the square wave modulated pulses for the power devices in the other units other than that responsible for offering the preferred level of output voltage. The MATLAB R2010b-based simulated performance adequately validated through experimental results foresee the emergence of a new variety of MLIs and forge a different dimension for inverter interfaces in power control applications.