A novel three-phase three-port UPS employing a single high-frequency isolation transformer

• Published in: 2004 IEEE 35th Annual Power Electronics Specialists Conference (IEEE Cat. No.04CH37551) Vol. 6; pp. 4135 - 4141 Vol.6
• Main Authors: Chuanhong Zhao, Kolar, J.W.
• Format: Conference Proceeding
• Language: English
• Published: Piscataway NJ IEEE 2004
• Subjects: Applied sciences; Batteries; Control systems; Convertors; Electrical engineering. Electrical power engineering; Electrical machines; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Energy storage; Exact sciences and technology; Load flow; Power electronics, power supplies; Power system modeling; Pulse width modulation converters; Pulse width modulation inverters; Rectifiers; Transformers and inductors; Uninterruptible power systems; Windings; Freedom degree; PWM power convertors; Phase shift; Control system; Power transmission; Phase control; Optimization method; Secondary cell; Power supply; Power electronics; Phase reversal; Power flow control; PWM invertors; Uninterruptible power supply; Transformer windings; Power rectifier; Three phase circuit; High-frequency transformers; Pulse duration modulation; Energy transfer; Energy storage; Bridge convertor; Square wave
• ISBN: 9780780383999; 0780383990
• ISSN: 0275-9306; 2377-6617
• DOI: 10.1109/PESC.2004.1354730

A three-phase PWM rectifier and a three-phase PWM inverter are coupled via two four-quadrant full-bridge converter cells and a high-frequency isolation transformer. By employing a third transformer winding and further full-bridge cell battery energy storage is incorporated into the power transfer between rectifier and inverter resulting in a three-port UPS concept. The phase shift control of the power flow between the ports is analyzed for square-wave operation of the full-bridge cells. Furthermore, the utilization of the degrees of freedom of the system control, i.e. the extension to duty cycle control for optimizing the system behavior is discussed and control laws ensuring minimum overall system losses are derived. Finally, a control-oriented converter model is proposed and the decoupled control of the power flow of the ports is treated briefly. All theoretical considerations are verified by simulations using PSIM.