Resonant Power Conversion through a Saturable Reactor

The resonant converter control is usually implemented by electronic circuits that regulate the parameters of the necessarily produced energy pulses of circulating in the resonant circuit. In the same time the power circuit is characterized by fixed (or uncontrollably varying) parameters. In this article a research is described that shows a long time ago forgotten techniques: the magnetic amplifier that controls the power circuit parameters and as a result, changes the resonant frequency depending on the needs of control. The inductance that is made to vary its value in a controllable, continuous and linear mode would be a perfect (non-dissipative) regulator for the power converter. This can be achieved through a DC magnetization applied as a control command to the magnetic core. By varying this magnetization current and hence the magnetic parameters of the core, the inductance L is possible to be adjusted to a desired value. This operation is similar to the principle of the (long ago) well known "magnetic amplifier" or the "saturable core reactor" as it is often called. The magnetic amplifier usually has an AC source in series with the load and with its primary while in the secondary the DC control signal is applied. The application of a regulated inductance device in the Wireless Power Transfer (WPT) will guarantee a simple way to adjust the frequency of the transmitter and/or the receiver to achieve the required impedance adaptation and efficient energy transfer.