Analysis and design of electronic transformers for electric power distribution system

A transformer performs many functions such as voltage transformation, isola tion, and noise decoupling, and it is an indispensable component in electri c power distribution systems. However, at low frequencies (60/50 Hz), it is a bulky and expensive component. In this paper, the concept of electronic transformers is further extended and explored for its suitability in power distribution systems. It should be noted that from the input/output behavio r, the electronic transformer and the conventional transformer are identica l. Possible topologies employing static converters connected on the primary and secondary sides are explored to realize high-frequency operation of th e magnetic core. To assist the commutation process, a four-step switching h as been developed which does not require the use of snubbers, Reduced size, losses, higher efficiency, and better voltage regulation are some of the a dvantages of this approach. A 10-kVA design example along with experiment r esults are discussed. It is shown that a transformer designed with a conven tional grain-oriented silicon-steel core can process three times the power at 1-kHz operating frequency as compared to 60 Hz, The proposed method is s calable in voltage/current with the currently available insulated gate bipo lar transistor (IGBT) devices connected in series without special snubbers.