Maintaining Optimal Pod Performance

By: Ruth Zachariah

09 Feb 2021

We've talked about how smooth a Hyperloop ride can be by the works of levitation and propulsion. However, it does not necessarily account for how well balanced a pod travels. In this blog, we will explore how vibrations and fried batteries could affect all things around and within a Hyperloop pod!

Vibrations are unintended effects of movement by a Hyperloop pod. Vibrations can "rattle bolts loose, cause micro-fractures, or create a catastrophic failure" [1]. With an estimated mass of 3000 kg for one individual tube, pods can induce large forces as they travel at over 1200 km/h, reducing the structural integrity of the tube infrastructure. If vibrations are not dampened within time, it can offset the pod balance as well. In Musk's Alpha papers, a mere "0.5 mm to 1.3 mm of air needs to pass between the skis and the tube" [2]. A reduction in air thickness may cause the pod's skis to come in contact with the track, producing some audible noise. On the other hand, given how Hyperloop systems are expected to be underground or above ground, noise can dissipate vertically. In addition, if constructed above ground, raised pylons could be installed with sound barriers for further damping [3]. With these benchmarked solutions, it can be argued that vibrations can be mitigated to reduce the impact on Hyperloop infrastructure.

While vibrations can disrupt the pod's operations, the system's thermal management is also at risk. Based on AECOM's Preliminary Feasibility Study of Hyperloop Technology, pods can overheat in order of Megawatts (MW) from carrying complex equipment onboard such as motors, electronics and energy transfer/ storage systems. [3] This puts a strain on the pod's motors to successfully transport the hardware systems along with the pod, causing the motors to operate at maximum capacity. The battery cells experience a domino effect where they send out excessive amounts of electrical discharge in uncontrolled current conduction. This is exacerbated by how the discharge then creates breaks in battery insulation, corrosion, and/ or overloads the plug terminals.  Overtime, the batteries become overheated and experience "electrical arcing". What makes it more challenging is operating in a low pressure service environment; the pod will have a lower chance of dissipating heat by air convection.

Features of Hyperloop's Battery Management System [4]

To overcome this, pods have a battery management system (BMS) which constantly measures outputs like temperature, voltage and current flowing between battery pack(s) and other pod components. The lithium iron phosphate battery packs are multi-purposeful. Two interesting features include providing an accurate charge distribution of cells (to prevent overcharging and over discharging) and early fault diagnosis by switching off the power supply to obstruct any damages and arcing [4]. Having a robust battery management system may provide vital information on the health of the battery as well as ensure durability of its interconnected pod components.

To summarize, maintaining stability and having responsive energy systems will enable Hyperloop pods to function optimally and ensure system safety.

On a final note, as Hyperloop developments are ramping up, the University of Toronto Hyperloop Team is generating momentum for Summer 2021! On January 17, 2021 UTHT qualified into the European Hyperloop Week (EHW) set to take place in Valencia, Spain in July 2021! We hope to witness our pod's potential with the Intent to Demonstrate. UTHT aims to manufacture our very own pod by March of this year. With these great plans ahead and adapting to the lockdown measures, we hope you'll support us and cheer us on as we strive towards competing at EHW!

References

[1] I. Engineering, C. McFadden, M. Williams and I. Bayrakdar, "The Biggest Challenges That Stand in the Way of Hyperloop", Interestingengineering.com, 2017. [Online]. Available: https://interestingengineering.com/biggest-challenges-stand-in-the-way-of-hyperloop. [Accessed: 23- Jan- 2021].

[2] T. De Chant, "Promise and Perils of Hyperloop and Other High-Speed Trains", Pbs.org, 2013. [Online]. Available: https://www.pbs.org/wgbh/nova/article/hyperloop-and-high-speed-trains/. [Accessed: 23- Jan- 2021].

[3] AECOM Canada Ltd., "PRELIMINARY FEASIBILITY OF HYPERLOOP TECHNOLOGY", AECOM, 2020.

[4] N. Singh, J. Karhade, I. Bhattacharya, P. Saraf, P. Kattamuri and A. Parimi, "On-board Electrical, Electronics and Pose Estimation System for Hyperloop Pod Design", Birla Institute of Technology and Science, Pilani, 2020.

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