High Frequency Power Amplifier

Since the proposal of the researcher at MIT on the merits of resonant wireless power transfer, many other researchers have engaged in proposing engineering solutions that resolve day-to-day challenges using resonant wireless power transfer. Recently, we have seen many implementations in battery charging systems using wireless power transfer systems. A simple system model of a wireless power transfer system is shown below.  The main signal is generated from a frequency generator, with which we determine the frequency. This is amplified to a high power signal that is then transmitted with resonance using a capacitor and the coil's inductance as illustrated.

To create this frequency, a simple digital signal processor, or DSP, for short, can be utilized. An additional measurement subsystem can be added to accurately measure the preset frequency generated. This subsystem is generally referred to as the main driver circuit. This is shown in the Figure below. 

The model can be extended to develop a two-phase resonant HF power amplifier or inverter for driving magnetic resonant machines. The magnetic resonant induction machine is an HF induction motor that uses resonant wireless power transfer for developing a high-speed actuator in the rotor side of the machine.  The machine has no magnetic or iron core material and introduces a pathway for extremely light motor design. The main challenge with these machines is that the torque generated is not high.  The figure below shows a two-phase PA model for driving an HF resonant induction motor. A conceptual model of the motor is also shown connected to the PA. The two-phase power generated by the PA are 90-degree out of phase.

Fig. 3. Systemic overview of the proposed high-frequency resonant inverter to drive the multi-phase magnetic resonant motor 

A model of the PA is designed using KiCad EDA. The design is done in a modular way.

Fig. 4. A complete system showing how the drivers are connected to a multiphase resonant induction motor

The final developed demonstrator hardware is shown below. Experimental tests were conducted.