Design of Class-E $_{\rm M}$ Oscillator With Second Harmonic Injection

This paper presents the class-E_M oscillator with the second-harmonic injection current, along with its design procedure, design curves, and design example. In the proposed oscillator, the output frequency of the proposed oscillator is locked with the input frequency of the injection circuit. Additionally, the switch-voltage and switch-current waveforms in the main circuit achieve the class-E_M zero-voltage switching, zero-voltage-derivative switching, zero-current switching, and zero-current-derivative switching (ZVS/ZVDS/ZCS/ZCDS) conditions and the switch voltage waveform in the injection circuit satisfied the class-E ZVS/ZDS conditions. In the laboratory experiment, the oscillator achieved 92.0% power-conversion efficiency at 34.8 W output power and 1 MHz operating frequency. The experimental results agreed with the numerical predictions quantitatively, which denotes the validity of the design procedure.