This invention introduces a compact three-phase bidirectional AC-DC converter that integrates PFC and high-frequency isolation into a single 9-switch stage. By reducing device count, eliminating capacitor DC bias, and enabling soft-switching at >200 kHz, it achieves >98% efficiency with smaller filters and lighter hardware—ideal for EVs, grid storage, and aerospace platforms.
Conventional three-phase AC-DC conversion architectures typically require two stages: a front-end PFC boost stage and a separate isolated DC-DC resonant stage. This increases semiconductor count, footprint, and cost, while forcing bulky filtering and limiting power density. Resonant capacitors often suffer from DC bias, reducing lifetime, while ripple in the DC link adds EMI challenges. High-performance applications like EV charging, aerospace electrification, and stationary storage require converters that combine high efficiency, compact size, and long component lifetimes in a simplified design.
This invention combines three-phase boost PFC and high-frequency resonant isolation into a single 9-switch front end. The topology drives three delta-connected resonant tanks using 120° interleaved modulation, generating bipolar HF voltages that eliminate capacitor DC bias and reduce DC ripple. Six of the nine devices operate under full soft-switching and three under semi-soft-switching, enabling high-frequency operation (>200 kHz) with reduced losses and smaller magnetics. Downstream rectification can be tailored: a 6-switch rectifier provides cost-efficient performance, while a 12-switch full-bridge per phase maximizes efficiency and scalability. Prototypes demonstrated validated operation at 180 W with peak efficiency exceeding 98%.
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• Reduces device count from 12 to 9, lowering BOM and footprint
• >200 kHz operation with soft switching for higher power density
• Bipolar resonant excitation eliminates DC bias, extending capacitor life
• 120° interleaving reduces DC ripple and EMI, enabling smaller filters
• Achieves >98% peak efficiency versus conventional two-stage solutions
• Modular rectifier options allow tradeoff between cost and maximum efficiency
• Simplifies system integration by unifying PFC and DC-DC isolation into one stage
• On-board and off-board EV chargers with bidirectional V2G operation
• Grid-tied battery storage converters for renewable integration
• Aerospace AC-to-DC converters for more-electric aircraft
• High-power industrial motor drives and traction electrification
• Compact inverters for renewable and distributed energy systems
• US Provisional Application 62/926,206 – Filed 10/25/2019 (Converted)
• US Patent 11,418,125 – Application 17/079,396, Filed 10/23/2020, Granted 08/16/2022, Published US 2021-0126550 A1
• US Patent 12,095,381 – Application 17/888,126, Filed 08/15/2022, Granted 09/17/2024, Published US 2022-0393607 A1
Prototype validated – Demonstrated in a 180 W setup with peak efficiency >98% and proof of reduced ripple, soft switching, and capacitor lifetime improvements. TRL ~4–5.
This technology is available for licensing.
Strong potential for EV charging, aerospace electrification, grid-scale storage, and industrial motor applications where compactness, efficiency, and bidirectional capability are critical.
Experimental validation data, resonant tank design details, and efficiency curves available upon request.