Thermal Management Analysis And Application Research Of Pulse Power Supply For Electromagnetic Launch

Electromagnetic launch(EML)technology has broad application prospects in military and civil fields,and has entered the stage of engineering application research.As the mainstream power supply scheme of electromagnetic launch technology,the capacitive energy storage pulsed power supply(PPS)needs to have the capability of large current and high frequency continuous pulse output.Insulation packaging structure and the existence of insulation packaging structure and internal resistance leads to the continuous temperature rise of the components of the PPS under the continuous discharge condition,which greatly reduces the reliability and safety of the PPS.The research of temperature control scheme of PPS under continuous discharge condition is a technical problem to be solved urgently in the engineering application of EML.The different electrical characteristics and independent insulation packaging structure of the components of the PPS indicate that each component needs to be studied separately.The thermal management research of PPS should take pulse inductor,semiconductor power module and high-power coaxial cable as the object,and design effective temperature control scheme based on the structural characteristics and temperature rise characteristics of each component.The main contents of this paper are as follows:1.The solenoid pulse inductor has been taken as the research object.By establishing the eddy current field analysis model,it is proved that the shape and area of the hollow section have no effect on the inductance and internal resistance of the coil under the condition that the number of turns,the pitch of turns,the inside/outside diameter and the overall dimension of the section of the coil are determined.An optimization design method of hollow section with flow resistance and thermal resistance as the objective is proposed,and it is proved that the shape of hollow section should be consistent with the shape of coil section,and the larger the hollow section area is,the better the comprehensive heat dissipation performance of the scheme is.Through the establishment of coupling analysis model,it is demonstrated that the scheme of winding the inductor coil with hollow conductor and pumping coolant into the coil can meet the temperature control requirements of solenoid inductor under continuous pulse discharge conditions.In order to guide the parameter design of the scheme,the effects of coolant flow and coolant inlet temperature on the temperature control performance of the scheme are studied respectively.The results show that increasing coolant flow can effectively improve the temperature control performance of the scheme,but with the increase of coolant flow,the marginal benefit of increasing coolant flow decreases and the marginal cost increases;The benefits of reducing the coolant inlet temperature are low.Considering the risk of equipment condensation,the coolant inlet temperature should be consistent with the ambient temperature.Based on Arrhenius model,it is proved that the logarithm of the service life of solenoid inductor is linear with the reciprocal of the operating temperature.2.The power semiconductor module has been taken as the research object.Based on the structure and assembly characteristics of the device,a single-layer Archimedean flow channel flat plate liquid-cooled radiator was designed,and the turn number and section shape of the flow channel were optimized for the purpose of thermal resistance and flow resistance.Through the establishment of coupling analysis model,it is proved that the radiator can meet the temperature control requirements of power semiconductor modules under continuous pulse discharge conditions,and the counter-current design of adjacent channels can effectively maintain the uniformity of temperature distribution across the silicon wafer.In order to guide the parameter design of the scheme and explore the miniaturization and lightweight design ideas of power semiconductor devices,the effects of coolant flow,radiator material and semiconductor device socket thickness on the temperature control performance of the radiator were studied respectively.The results show that the temperature control performance of the radiator can be improved by increasing the coolant flow rate.Because the flow resistance of the radiator is small,a larger flow rate should be set in the engineering application;the heat sink material and the thickness of the semiconductor device socket have little influence on the device junction temperature.Based on the miniaturization and lightweight requirements of the system,aluminum heat sink should be used and the thickness of the device socket should be minimized.3.The high-power coaxial cable has been taken as the research object.By establishing a coupling analysis model,it is verified that the scheme of only arranging liquid-cooled copper tubes in the center of the inner conductor has poor temperature control effect on the outer conductor,and can not meet the temperature control requirements of the coaxial cable under the continuous pulse discharge condition.A scheme combining filling high thermal conductivity inorganic filler to enhance the thermal conductivity of the insulation layer and arranging liquid-cooled copper tubes is proposed,and it is demonstrated that this scheme can meet the temperature control requirements of the coaxial cable,extend the service life of the cable,and increase the current carrying capacity of the cable by about137%.Based on the rule that the variation trend of the temperature of each layer of the cable along the coolant flow direction is not affected by the cable length,a polynomial function is proposed to fit the temperature variation trend,which can greatly reduce the coupling calculation amount during the cable length design.The feasibility of glycol-deionized water solution as an alternative coolant at low temperature is proposed and demonstrated.4.A measurement scheme is proposed to indirectly obtain the maximum temperature of solenoid inductor and the maximum temperature of inner and outer conductors of high-power coaxial cable by measuring the coolant outlet temperature and the external surface temperature of the cable.A temperature measurement system consisting of PT100 thermal resistance,temperature transmitter,photoelectric isolator,data acquisition card and temperature measurement control program is designed and built.The feasibility of the temperature measurement scheme is demonstrated by the establishment of the pulse power supply experimental platform,and the accuracy of the thermal analysis model of the coupling of solenoid inductor and high-power coaxial cable is verified.In order to ensure that the PPS has the ability of high frequency and large current pulse output,this paper designs the temperature control scheme of the main power components of the PPS.The research results are of great significance for promoting the engineering application process of EML.