Resonant Current Source Powers Arbitrary Load
by Gregory Mirsky, Design Engineer, Deer Park, Ill., How2Power Today, Jan 14 2022
Focus:
There is a little-known class of ac current sources whose operation is based on the effect
of limiting ac load current in a series resonant circuit if the load is connected in
parallel to the resonant capacitor. Since this circuit can be used as a good ac current
source, it is safe at the load short circuit and can be used as a step-up converter for
supplying loads at voltages which are not physically practical using conventional
converter circuits. Step-up coefficients in the resonant circuits can attain values of 15
to 20 and higher at efficiency above 95%. The circuit works equally well into a reactive
or a resistive load and even into a rectifier. This ability to supply unchangeable ac
current into any type of load is a very valuable—and rarely considered—property of the
resonant current source (RCS). This article analyzes operation of the resonant current
source, presents its design equations and discusses its design constraints. A design
example is presented and verified through an LTspice simulation.
What you’ll learn:
- How to design a resonant ac current source
- How to understand the operation of a resonant current source
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