Solid-state power electronics in the U.S.A.

This article focuses on the conversion and control of large blocks of electric energy by solid-state power devices such as silicon rectifier diodes and thyristors. Power conversion fulfills the important requirement of delivering a desired type of electric energy when the available form is unsuitable. Examples include the energization of dc machines, dc fields, and batteries when the available source is single-phase or polyphase alternating current. Another example relates to variable-speed drives for Induction and synchronous motors when the power source is either dc or fixed-frequency ac. Power control is concerned with varying the level of power delivered to a load, as in on-off switching, or varying the output voltage of a rectifier.