基于最大制冷系数调节算法的井下制冷器设计

为了提高井下电子仪器的应用温度范围，创新性地设计了基于半导体制冷技术的井下制冷器为仪器降温。通过分析半导体制冷片的性能特性，得到了最大制冷系数工况的实现条件，据此设计了能够均衡最大制冷系数工况和最大制冷量工况的分段调节控温算法，以达到高效制冷的目标。为了实现控温算法的系统设计，使用微控制器控制高精度温度传感器采集多点温度，同时用特殊功率运算放大器设计了精密电压-电流转换器为半导体制冷片供电。仿真及实验测量结果表明，该井下制冷器具有制冷效率高、自产热低、可耐高温等特点，使较低温度级别的井下电子仪器在较高的环境温度下能够正常工作，有利于降低钻井成本。

Downhole Peltier Refrigerator Design Based on Maximum COP Control Algorithm

In order to improve the application temperature range of downhole electronic instruments,creative downhole refrigerator based on Peltier cooler module is designed to cool instruments.The requirements for the realization of maximum coefficient of performance (COP) condition are obtained through performance characteristics analysis of chosen Peltier cooler module and the multi-section control algorithm is designed to balance maximum COP condition and maximum cooling capacity condition for the sake of achieving the goal of high efficiency refrigeration.A MCU controlled high-accuracy temperature sensor is arranged for multipoint temperature acquisition and a precision voltage-to-current converter is responsible for power supplying of Peltier cooler module for realizing system design with temperature control algorithm.The results of simulation and experimental measurement show that this downhole refrigerator has characteristics of high cooling efficiency,low heat production,resistant to high temperature etc.It is possible that downhole electronic instruments with lower temperature level can work normally at a higher ambient temperature to reduce drilling cost.