Discharge Current Steering for Battery Lifetime Optimization

Portable and wearable computers can be powered by different combinations of two or more battery packs to give the user the possibility of choosing an optimal compromise between lifetime and weight/size. Recent work on battery-driven power management has demonstrated that sequential discharge is suboptimal in multibattery systems and lifetime can be maximized by distributing (steering) the current load on the available batteries, thereby discharging them in a partially concurrent fashion. Based on these observations, we formulate multibattery lifetime maximization as a continuous, constrained optimization problem, which can be efficiently solved by nonlinear optimizers. We show that significant lifetime extensions can be obtained with respect to standard sequential discharge (up to 160 percent), as well to previously proposed battery scheduling algorithms (up to 12 percent).

[1]  Keith H. Billings,et al.  Switchmode power supply handbook , 1999 .

[2]  M. C. Glass.  Battery electrochemical nonlinear/dynamic SPICE model , 1996, IECEC 96. Proceedings of the 31st Intersociety Energy Conversion Engineering Conference.

[3]  Daniel P. Siewiorek,et al.  System Level Design as Applied to CMU Wearable Computers , 1999, J. VLSI Signal Process..

[4]  Daniel P. Siewiorek,et al.  Nonideal battery and main memory effects on CPU speed-setting for low power , 2001, IEEE Trans. Very Large Scale Integr. Syst..

[5]  Sarma B. K. Vrudhula,et al.  An Analytical High-Level Battery Model for Use in Energy Management of Portable Electronic Systems , 2001, ICCAD.

[6]  Qinru Qiu,et al.  An interleaved dual-battery power supply for battery-operated electronics , 2000, Proceedings 2000. Design Automation Conference. (IEEE Cat. No.00CH37106).

[7]  Chaitali Chakrabarti,et al.  Battery-conscious task sequencing for portable devices including voltage/clock scaling , 2002, DAC '02.

[8]  Luca Benini,et al.  Discrete-time battery models for system-level low-power design , 2001, IEEE Trans. Very Large Scale Integr. Syst..

[9]  Massoud Pedram,et al.  Battery-powered digital CMOS design , 1999, DATE '99.

[10]  Luca Benini,et al.  Battery-Driven Dynamic Power Management , 2001, IEEE Des. Test Comput..

[11]  K. Schittkowski.  NLPQL: A fortran subroutine solving constrained nonlinear programming problems , 1986 .

[12]  D. Linden.  Handbook Of Batteries , 2001 .

[13]  Luca Benini,et al.  Extending lifetime of portable systems by battery scheduling , 2001, Proceedings Design, Automation and Test in Europe. Conference and Exhibition 2001.

[14]  Ramesh R. Rao,et al.  Energy efficient battery management , 2001, IEEE J. Sel. Areas Commun..