No abstract

No abstract

No abstract

The objective of the present work is to obtain a three level ac output, which is obtained by a 3-phase, 3-level multi level inverter. An inverter receives dc supply for its input and produces ac output. Here the dc input to the multilevel inverter is obtained by a single-phase un-controlled full wave rectifier. 230 V, 50 Hz single-phase ac supply is directly taken from supply mains, stepped down to 48 V by a step down transformer and is rectified by the rectifier circuit. Using a simple L-C filter at the rectifier output terminals the obtained dc supply can be made ripple free. The rectifier circuit consists of 4 number diodes and in each half cycle a pair of diodes conduct and pulsated dc obtained and finally rectified to obtain a pure dc. The obtained dc from the rectifier is directly fed to the multi level inverter. The switching sequence of switches used in the multilevel inverter inverts the dc input and a 3-phase, 3-level ac output is obtained. Simulation of the firing pulse generation circuit and multilevel inverter was done using MATLAB 7.5 and Simulink.

No abstract

No abstract

In this paper, a new type of capacitor clamped coupled inductor bidirectional DC–DC converter is proposed, which offers high voltage gain with smooth starting current transients, as well as reduced stresses on the capacitor. Steady state operation, mathematical modelling, and state space modelling for the proposed converter are presented in detail. A simplified single voltage clamped circuit is developed to mitigate the voltage spikes caused due to the coupled inductor by recovering the leakage energy effectively. Moreover, the clamping capacitor helps in reducing the ripples in output voltage, which in effect significantly reduces the stress on the switch and offers less ripple content at the load terminals. Simulation of the proposed converter is carried out using Simulink/MATLAB for the conversion of 24V DC to 200V DC. For this conversion, simulation results have proven that there is reduction of 13.64% of capacitor voltage stresses. Further, under line varying conditions, converter responses have proven that there is a 119% and 25.25% reduction in input current and output voltage transients, respectively. Similarly, 25.25% and 76.5% transient reductions of input current are observed for line and control parameter variations. The hardware investigation of the converter was carried out with a 100 W, 24 V/200 V setup. The converter achieved efficiency of 93.8%. The observations supplement the simulation results.

No abstract