| 摘要 |
A static inverter is disclosed for d.c. to a.c. conversion comprising a pair of switching semiconductor devices and a power transformer having primary, secondary and feedback windings associated with a linear magnetic core. A small perforation partitions the core into two localized branches at the same time forming a small magnetic loop encircling the perforation. Both power windings encircle the full core, while the feedback windings are associated with one of the branches. One branch is designed to saturate before the other branch and thus before full core saturation. Saturation of one branch affects the feedback derived in a winding encircling either branch - decreasing the feedback in the winding encircling the saturated branch and increasing the feedback in the winding encircling the branch remaining unsaturated. The arrangement permits cyclical control of the feedback to avoid full core saturation and thus avoids overstressing the switching devices. The feedback windings are typically single turn windings. The introduction of an additional single turn primary winding connected in the primary power circuit creates a virtual current transformer utilizing the small magnetic loop which makes the feedback drive proportional to load current. The arrangement is reliable and economical in its use of materials.
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