ZVS Turn-on Triangular Current Mode (TCM) Control for Three-Phase Two-Level Converters With Reactive Power Control

High switching frequency operation in power converters leads to a significant reduction in size at the cost of increased switching losses. Thus, soft switching techniques become necessary to reduce the losses. WBG devices have the benefit of low turn-off losses, but the turn-on losses are still significant. Triangular Current Mode (TCM) control can achieve zero voltage switching (ZVS) turn-on without adding extra resonant components or active devices to the converter. For three-phase operation, soft switching, sinusoidal currents, and phase synchronization are achieved by operating the phases in a combination of Discontinuous Conduction Mode (DCM), TCM and clamped mode. This method is extended to reactive power cases in this article. The proposed scheme can achieve full ZVS turn-on for all the three phases. The phases still operate in a combination of DCM+TCM+Clamped modes of operation. The proposed algorithms are tested and validated on a GaN converter, achieving 99% efficiency at 700 VA with a power density of 110 W/in
³
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