测井耐高温AC-DC开关电源设计OA

With the continuous advancement of deep oil and gas exploration,downhole logging instruments impose extremely stringent requirements on the high-temperature tolerance and high-power output capabilities of power supply systems.To address the issues of frequent failure and poor thermal stability of conventional power supplies under extreme conditions,this paper designs and develops a high-power AC-DC switching power supply module suitable for extreme high-temperature environments up to 175℃.The module adopts a single-ended flyback converter architecture and utilizes the military-grade current-mode control chip UC1843 as the main control core.For main power transmission,the area product method is employed to design a high-temperature-resistant,high-frequency transformer.In terms of closed-loop voltage regulation,an isolated feedback network based on the linear optocoupler TLX9300 and the precision voltage reference TL431 is constructed.Combined with a front-stage electromagnetic interference(EMI)filter,this design effectively suppresses conducted interference and ensures high-precision feedback of control signals.Furthermore,an adaptive high-temperature startup circuit based on a source-follower structure and a passive resistor-capacitor-diode(RCD)clamp network are introduced,which further enhance the safety of system startup and reduce the transient voltage stress on the power switching transistors.The module utilizes wide-bandgap semiconductor devices such as silicon carbide(SiC),integrated with a highly thermally matched ceramic substrate and thick-film hybrid integration technology.Additionally,a Sn96.5Ag3Cu0.5 ternary lead-free alloy with a high liquidus point of 217℃is selected as the soldering material.Combined with overall potting using thermally conductive silicone grease,the internal heat conduction efficiency of the system is significantly enhanced.Following simulation modeling using power simulation(PSIM)software,a physical prototype is developed and subjected to 100 h extreme aging test in 175℃high-temperature oven.Experimental results demonstrate that the steady-state output voltage of the power module is stably maintained within(72±1%)V.The full-load output ripple at room temperature is merely 46 mV,the voltage linear regulation rate is as low as 0.09%,and the maximum energy conversion efficiency reaches 88.632%.This power supply solution exhibits excellent electrical performance and outstanding thermal reliability across the entire temperature range,successfully fulfilling the continuous power supply requirements of deep-well logging instruments under ultra-high-temperature conditions.