The use of resonant circuits in power conditioning equipment

Four different power conditioning circuits are described showing how the series resonant circuit can be used instead of the saturating transformer to determine opeating frequency. These circuits are a dc-to-squarewave inverter and an ac-to-ac frequency sextupler, both fully qualified for aerospace, a dc-to-dc converter and a dc-to-sinewave inverter, both in the successful prototype stage. Attention is given to the relation betwen damping constants and rejection ratios, and it is shown graphically how to take advantage of these features of the resonant circuit by suitable choice of isolating transformer turns ratios as related to load constants. The four circuits show how the careful use of these principles reult in superior frequency stability and, especially in the sinewave inverter, vitual elimination of high power switching transients, with resultant low generation of electromagnetic interference and extremely low electrical stresses in switching power transistors.