Recoverable Autonomous Sonde for subglacial lakes exploration: heating control system design

• Published in: Annals of Glaciology
• Main Authors: Haibin Yu, Tianxin Zhu, Xiao Jiang, Yongzhen Tang, Xiaodong Li, Chong Li, Shengmiao Huang, Jianguang Shi, Youhong Sun, Pavel Talalay, Xiaopeng Fan, Xiao Li, Yazhou Li, Shilin Peng
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2021
• Subjects: Fuzzy PID algorithm; heating control; hot melt drilling; recoverable autonomous sonde (RECAS); solid-state power regulator; subglacial lakes; Meteorology. Climatology; QC851-999; Antarctic; Annals of Glaciology; Antarc*
• Online Access: https://doi.org/10.1017/aog.2021.5; https://doaj.org/article/14dac402fa7048648eaa311cf4fdb8d3

Drilling and sampling are the most direct and effective methods available to study Antarctic subglacial lakes. Based on the Philberth probe, a Recoverable Autonomous Sonde (RECAS) allows for in situ lake water measurement and sampling, through the addition of an upper thermal tip and a cable recoiling mechanism. RECAS-200, a prototype of RECAS, has a drilling depth of 200 m, a surface supply voltage of 800 VAC and a downhole power of ~9.6 kW during drilling. In this study, a heating control system for RECAS-200 was designed. The system avoids the need for high-power step-down converters, by separating heating power from control power, thereby reducing the overall weight of the probe and avoiding the need to increase cable diameter. We also introduce a self-developed, small, solid-state, 800 VAC power regulator and a fuzzy PID temperature control algorithm. Their purpose was to manage the power adjustment of each heating element and to provide closed-loop temperature control of certain heating elements which can easily burn out due to overheating. Test results indicated that the proposed RECAS-200 heating control system met all our design specifications and could be easily assembled into the RECAS-200 probe.