High-Frequency GaN-Based ANPC Three-Level Converter as a Low-Noise Arbitrary PWL Voltage Generator

Recent advances in the technology of gallium nitride (GaN) power devices and high-frequency magnetic materials are key enablers of small, compact designs of power electronic converters in the megahertz range and the power range up to several hundreds of watts. However, impact of different switch modulation strategies along with the devices and magnetic materials must be carefully characterized to fully understand the boundaries of current technology and to be able to exploit it fully. This is usually performed through a holistic, automated design procedure based on multiobjective optimization which focuses on the converter efficiency and power density for the given electrical parameters. In this article, an optimized 100-W, 1.75-MHz switching frequency, four-quadrant, piecewise linear (PWL) arbitrary voltage generator based on active neutral-point-clamped (ANPC) three-level converter is presented. Diversity of modulation techniques for the hard-switched ANPC converter suitable for high-frequency (HF) applications are revisited, and impact on switching losses is characterized in detail. The generator is capable of providing
$\pm {\mathrm {100}}~\text {V}$
and
$\pm {\mathrm {1}}~\text {A}$
at the output, with tracking speeds up to
$2~\text {V/}\mu \text {s}$
and steady-state efficiency above 95% with a physical size less than
$12~\text {cm}^{2}$
. Thermal management of the system is successfully resolved using advanced cooling plates based on pyrolytic graphite sheets (PGSs) and forced air convection. Having these characteristics, the presented generator outperforms the existing linear and hybrid power amplifiers (LPA/HPA) from the literature.