Power Electronics, has revolutionized the world by direct A.C to D.C conversion and transmission for bulk power for very far load areas, which were not possible due to heavy loss in H.V.A.C transmission. In traction, A.C transmission was possible by converting A.C to D.C on engine, hence intermediate D.C supply stations(rotary converter based) are reduced, which is more economical efficient, in electrification of large railway network. D.C solar generating station, could easily be interconnected with power grid, by converting D.C to A.C, which has reduced the air pollution, produced by thermal power station and are economical and efficient without fuel cost. Many high rating compact and efficient, D.C electrical appliances are made for home and industry, due to advent in power electronics etc.....

Power electronic devices and circuits built fro them have countless applications in controlling the power flow from source to load. Also,In reforming and conditioning the electric power to match loads.

New applications are the DC/DC converters and DC to AC inverters for the grid connection of the renwable energy sources with the grid. This is really a tremendous task as the it is expected that the future electricity generation will be by photovoltaic and wind.

To increase also the electrical energy utilization they will be controlled every where every time and this will be accomplished by smart power circuits.

Best wishes

A simple answer to this question is "REDUCING SIZE OF EQUIPMENTS". Power ece has indeed revolutionized by considerably reducing equipment's size for same rating.

Made possible to transfer bulk power to extrimely long distance. Made possible, the Inter connection of solar power to grid. Made Possible large net work of rail etc...economically, efficiently and with reliability, which was not possible with old SCR(thristors), mercury arc or rotary converters.

Please see the following discussion

https://www.quora.com/How-can-electronics-change-the-world

Best Regards João Lucas de Souza Silva