Inductor Current Measurement and Regulation Using a Single DC Link Current Sensor for Interleaved DC–DC Converters
Hongrae Kim, Member, IEEE, Milad Falahi, Student Member, IEEE, Thomas M. Jahns, Fellow, IEEE, and Michael W. Degner, Senior Member, IEEE
Abstract—Inductor current measurements using only a single dc linkcurrent sensor in an interleaved dc–dc converter is introduced in this paper. This technique is appealing for the interleaved dc– dc converter because it minimizes the number of current sensors, thereby reducing sensor cost, weight, and volume. A combination of analytical and experimental results is provided to conﬁrm that the single dc link current sensor technique is capable of achievingattractive performance characteristics in the areas of inductor current reconstruction, inductor current regulation, and output voltage regulation for the interleaved dc–dc converter. Index Terms—DC link current sensor, inductor current reconstruction, inductor current regulation, interleaved dc–dc converter, output voltage regulation, single current sensor technique.
Fig. 1. Two-stage interleaveddc–dc converter. (a) Boost converter. (b) Buck converter.
HE INTERLEAVED dc–dc converter has gained increasing attention for many applications such as the interface between the battery and the dc bus of ac inverters in hybrid electric vehicle applications. The interleaved dc–dc converter consists of identical dc–dc converter stages connected in parallel. Fig. 1 shows examplesof the two-stage interleaved dc–dc converter in both buck and boost conﬁgurations. Demands for compact and lightweight power sources with higher power density and higher efﬁciency have dramatically increased in recent years. Paralleling the converters has drawn attention as a solution to help meet these demands since this approach makes it possible to share current among several stages. By doingso, the sizes and ratings of converter components can be achieved, resulting in more compact, lightweight, and less expensive systems. In addition, interleaving of the pulse width modulation (PWM) control makes it possible to cancel much
Interleaved switching signals with 180◦ phase shift.
Manuscript received July 12, 2010; revised September 5, 2010; accepted September 24, 2010.Date of current version June 22, 2011. Recommended for publication by Associate Editor J. A. Cobos. H. Kim is with ABB U.S. Corporate Research Center, Raleigh, NC 27606 USA (e-mail: email@example.com). M. Falahi is with the Texas A&M University, College Station, TX 77843 USA (e-mail: milad.falahi@gmail. com). T. M. Jahns is with the Department of Electrical and Computer Engineering, Universityof Wisconsin–Madison, Madison, WI 53706 USA (e-mail: firstname.lastname@example.org). M. Degner is with the Ford Motor Company, Dearborn, MI 48124 USA (e-mail: email@example.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/TPEL.2010.2084108
of the input and output current ripple, leading to size and lossreductions in the ﬁltering stages –. The interleaved converters are controlled by interleaved switching signals that all have the same switching frequency and the same progressive phase shift (see Fig. 2). However, if the input current is not equally shared among the converter stages, losses and heating are not equally dissipated among them, causing reduced efﬁciency and reliability. In orderto achieve the desired input current sharing, inductor current control is necessary for the multistage interleaved dc–dc converter. For the two-stage interleaved dc–dc converter illustrated in Fig. 3, two current sensors are required for inductor current measurements. The adoption of a separate current sensor in each stage results in increased cost, volume, and weight. In this paper, inductor...