SIMULATION AND PERFORMANCE INVESTIGATION OF ZCS DC-DC CONVERTER

Abstract

Switch Mode Power Supplies (SMPS) are the current state of the art in high efficiency power supplies. Conventional series-regulated linear power supplies maintain a constant voltage by varying their resistance to cope with input voltage changes or load current demand changes. The linear regulator can, therefore, tend to be very inefficient. The switch mode power supply, however, uses a high frequency switch (in practice a transistor) with varying duty cycle to maintain the output voltage. The output voltage variations caused by the switching are filtered out by an LC filter. SMPS has isolated topologies as well as non isolated topologies. Isolated topologies find a little advantage when compared to non-isolated because of its input-output isolation and getting wide range of output voltages. But these topologies have high switching losses when we go for hard switching. To overcome these losses one technique is introduced namely soft switching. The switching is to be done at the zero crossing of either current or voltage by using resonant circuit in the topology is known as soft switching. Closed loop control of SMPS is to be carried out by using feed back to achieve good load regulation, good line regulation and fast transient response and for stable operation over wide range of operating conditions. This dissertation aims the simulation and performance investigation of various DC-DC converters with zero current switching by implementing with current mode control technique. Simulation models are developed in PSIM for different converters to compare the results and obtain a performance evaluation. The performance of different converters with ZCS has been evaluated under various conditions by varying gain of converter, load, input voltage etc. The performance parameters are calculated for all the converters and then compared with others. A tabulation of all the performance measures is made.