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In this paper, a single‐phase AC‐AC converter with continuous input current and without commutation problem is proposed. The output voltage regulation achieved using a single high‐frequency switch eliminates the need for complementary switches, thereby resolving high‐frequency commutation issues and obviating the necessity for snubber circuits and a safe commutation strategy. The proposed converter operates with a continuous input current, eliminating the need for a bulky LC filter. Low‐frequency switches on the output side allow for step‐changed frequency operation without encountering commutation problems. A straightforward and adaptable switching strategy generates the step‐changed frequency at the output. The proposed converter reduces volume, weight, and cost by minimizing the total stored energy of passive components. High‐speed switching is achieved by preventing the body diode conduction of power MOSFETs, which traditionally suffer from poor reverse recovery. The operational principles of the proposed converter are delineated for various modes, and their key relationships are presented. A 110Vi(rms)/50 Hz laboratory prototype validates the performance of the proposed converter. [ABSTRACT FROM AUTHOR]

Ultrawide bandgap heterojunction p–n diodes with polarization-induced AlGaN p-type layers are demonstrated using plasma-assisted molecular beam epitaxy on bulk AlN substrates. Current–voltage characteristics show a turn-on voltage of V bi ≈ 5.5 V, a minimum room temperature ideality factor of η ≈ 1.63 , and more than 12 orders of current modulation at room temperature. A stable current operation of the ultrawide bandgap semiconductor diode is measured up to a temperature of 300 °C. The one-sided n+–p heterojunction diode design enables a direct measurement of the spatial distribution of polarization-induced mobile hole density in the graded AlGaN layer from the capacitance–voltage profile. The measured average mobile hole density is p ∼ 5.7 × 10 17 cm−3, in close agreement with what is theoretically expected from distributed polarization doping. Light emission peaked at 260 nm (4.78 eV) observed in electroluminescence corresponds to interband radiative recombination in the n+ AlGaN layer. A much weaker deep-level emission band observed at 3.4 eV is attributed to cation-vacancy and silicon complexes in the heavily Si-doped AlGaN layer. These results demonstrate that distributed polarization doping enables ultrawide bandgap semiconductor heterojunction p–n diodes that have wide applications ranging from power electronics to deep-ultraviolet photonics. These devices can operate at high temperatures and in harsh environments. [ABSTRACT FROM AUTHOR]