Simulation of AC-DC step up and step down converter

Various applications in the modern world require DC supply. Some applications needs low DC voltage and some require considerably high DC voltage. We get AC supply and that needs to be converted to DC for these applications. In this paper AC - DC step up and step down converters without the use of bridge rectification is dealt. In step up converter, low AC voltage micro generators are used and the DC output voltage is boosted. The step up converter consists of a combination of boost converter in parallel with a buck-boost converter, which are operated in the positive half cycle and negative half cycle respectively. In step down converter, single phase AC voltage is converted into low DC output voltage. The step down converter consists of a combination of buck converter in parallel with a buck-boost converter, which are operated in the positive half cycle and negative half cycle respectively.