A High Frequency Active Clamping Source Based SiC Resonant Gate Driving Technology for Multi-kW and Tens of MHz Switched Mode Power Amplifier

Resonant gate driver (RGD) is an effective method to achieve gate driving loss reduction and noise suppression at high frequency. Most RGDs require at least two switches to constitute the bridge structure, which suffers from the difficulty of accurate dead time control at tens of MHz. The single-switch RGDs are easy to implement but can only generate fixed duty cycle driving voltage and operate at the narrow band. Thus, this article proposed a single-switch resonant gate driving technology with adjustable duty cycle and wide bandwidth operation for multi-kW and tens of MHz SiC-based power amplifiers. The proposed technology introduces an active clamping source to control the duty cycle of the gate-source voltage of the main switch by tuning the dc supply voltage, which is much easier than tuning the duty cycle of pulse width modulation (PWM) signals at the nanosecond level. In the proposed RGD, a resonant tank and two clamping diodes are employed to coordinate the active clamping source for gate driving loss reduction, fast turn-on/off gate driving, and gate oscillation suppression. An explicit design methodology was proposed to determine its circuit parameters for zero voltage switching (ZVS) and fast turn-on/off operations across duty cycle and frequency modulations. For verification, a prototyping system of the proposed RGD is built to drive a 1.2 kW Class-E power amplifier with frequency and duty cycle modulations (12 MHz–15 MHz and 40%–60%), where 82.4% gate driving loss reduction and 92.6% power amplifier efficiency are achieved.