Unity Power Factor Control for Three-Phase Three-Level Rectiﬁers Without Current Sensors Bingsen Wang, Member, IEEE, Giri Venkataramanan, Member, IEEE, and Ashish Bendre, Member, IEEE Abstract—Three-level rectiﬁers with reduced number of switches (such as the Vienna Rectiﬁer) to improve the input power quality of rectiﬁer systems have been receiving wide interest in the past years. In this paper, a new carrier-based pulsewidthmodulation control algorithm is proposed for such converters to eliminate the low-frequency harmonics in the line current while achieving unity power factor at the rectiﬁer input terminals. The operating constraints of the Vienna Rectiﬁer with the carrierbased modulation strategy are examined carefully, and the proposed control algorithm ensures that appropriate voltage/current directional constraints are met. A promising cost-reduction opportunity can be seen with the elimination of input current sensing to operate the Vienna Rectiﬁer. The control algorithm is veriﬁed via Saber simulation and experimental results. Index Terms—Carrier-based pulsewidth modulation (PWM), phase-angle control, unity power factor, Vienna Rectiﬁer.
I. I NTRODUCTION EW GENERATIONS of adjustable-speed drive and power supply producers are increasingly incorporating input power factor and waveform control to comply with the various regulatory standards . From time to time, speciﬁc applications such as aerospace power require careful regulation of the power converter front-end line current harmonics to minimize undesired interaction among the equipment connected to the same utility grid. A slew of new topologies including the ones based on three-level power conversion have been proposed to realize high-quality input waveforms –. Among these, the topology proposed by Kolar in 1994, which is called the Paper IPCSD-07-033, presented at the 2005 Industry Applications Society Annual Meeting, Hong Kong, October 2–6, and approved for publication in the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS by the Industrial Power Converter Committee of the IEEE Industry Applications Society. Manuscript submitted for review October 31, 2005 and released for publication April 5, 2007. This work was supported in part by The Boeing Company and in part by the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC) at the University of Wisconsin, Madison. This work made use of ERC-shared facilities supported by the National Science Foundation (NSF) under Award EEC-9731677. B. Wang is with the General Electric Global Research Center, Niskayuna, NY 12309 USA (e-mail: email@example.com). G. Venkataramanan is with the Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706 USA (e-mail: giri@ engr.wisc.edu). A. Bendre is with the Advanced Development Group, DRS Power and Control Technologies, Milwaukee, WI 53216 USA (e-mail: ashishrbendre@ drs-pct.com). Color versions of one or more of the ﬁgures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identiﬁer 10.1109/TIA.2007.904433
Vienna Rectiﬁer, has the additional beneﬁts of reduced controlled switch count in addition to the general beneﬁts of a three-level converter. Thus, due to the opportunities of competitive cost reduction, the Vienna Rectiﬁer is generally considered attractive , . Several control approaches have been proposed for the Vienna Rectiﬁer. The initial application proposed the use of a hysteresis current controller. The switching signals are generated by comparison of the reference current template (sinusoidal) and the measured main currents . Although this approach is easy to implement, the switching frequency is not constant, which is not desired for some applications because of interharmonics. The ramp comparison current control presented in  derives the duty cycle by comparison of...