CONTROL OF SERIES-RESONANT INDUCTIVE PICKUPS

摘要

A series resonant inductive pickup has a bi-directional solid state switch (203) in series with an inductor (W) and a capacitor (202) is controlled by switch control means (207) capable of causing the switching means to repetitively be in either an open or a closed state, so that by varying the closed:open ratio of the switch (203) the time-averaged amount of power pick ed up by the power pickup can be controlled. Switch (203) is controlled by outp ut (214) of a voltage comparing circuit (212). A reference voltage source (213) provides a basis for comparison of some fraction of a supply voltage (208) i n order to cause the switch to operate. The magnitude of capacitance (D) in relation to the current (IO) drawn by the load (L) determines the repetition rate of ON or OFF commands to the switch (203). If the current (IO) drawn by the load (L) tends to zero, the proportion of time during which the switch (203) is open will tend to 100 %.