Reduced Common-Mode Voltage PWM Scheme for Full-SiC Three-Level Uninterruptible Power Supply With Small DC-Link Capacitors

Journal Article · Mon Dec 30 00:00:00 EST 2019 · IEEE Transactions on Power Electronics

DOI:https://doi.org/10.1109/tpel.2019.2962964· OSTI ID:1799221

Ohn, Sungjae  ^[1]; Yu, Jianghui  ^[1]; Burgos, Rolando ^[1]; Boroyevich, Dushan ^[1]; Suryanarayana, Harish ^[2]

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1. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
2. ABB Corporate Research Center, Raleigh, NC (United States)

In this article, a pulsewidth modulation (PWM) scheme for three-level full-SiC uninterruptible power supplies is developed to achieve a high power density. Two key passive components are selected for size reduction of the ac-ac stage: common-mode (CM) EMI filter, and dc-link capacitors. To reduce the CM noise, a new vector combination is proposed based on synchronous switching among three-phases. The proposed combinations align CM voltage (CMV) to be a single pulse per switching period. Owing to the simple shape, CMV cancellation between a three-level rectifier and inverter can be maximally utilized. A transition between the three combinations can control the drift of neutral point voltage. An equivalent carrier-based implementation is developed. Second, a simple algorithm to compensate neutral point voltage fluctuation is proposed both for differential mode (DM) and CM output voltage. Low-order harmonics on three-phase currents and an additional high-frequency CM noise by misaligned switching instant can be eliminated. The proposed compensation can be implemented by a simple correction on carrier slopes and injected zero-sequence voltage. The proposed PWM scheme is verified with 20-kW full-SiC UPS switching at 60 kHz with 140 μF dc-link capacitors.

• Research Organization: North Carolina State University, Raleigh, NC (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Manufacturing Office
• Grant/Contract Number: EE0006521
• OSTI ID: 1799221
• Journal Information: IEEE Transactions on Power Electronics, Vol. 35, Issue 8; ISSN 0885-8993
• Publisher: IEEE
• Country of Publication: United States
• Language: English

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