Research On Heat Dissipation Analysis And Electromagnetic Compatibility Based On Power Electronic Circuits

With the development of new energy vehicles and power electronic equipment technology,more and more power components are applied to the automotive field.The power output part is the output of large current,which can reach several amps to thousands of amps.Large current will lead to wire heating,and in serious cases,it will burn the wire and make the circuit fail.Power output device itself switch loss and tube consumption and other factors,the heat will be more serious,plus now electronic components to micro size,high integration direction of development,so as a terminal product of the vehicle circuit module heat dissipation problem is also paid attention to.The traditional heat dissipation method mainly starts from the circuit structure: such as increasing the thickness of copper skin,the number of printed circuit board layers,increasing the number of heat dissipation holes,etc.,but this often consumes a lot of time,energy and material resources to design verification;And changing the circuit structure can also cause EMC problems.In addition,the power output part of the power electronic circuit usually adopts the mode of switch operation,and the circuit often occurs the sudden change of large voltage and large current.This mutation can cause interference to the connected circuit through the power supply and signal lines(conducted interference),while producing strong electromagnetic radiation to the surrounding environment(radiation interference);The control circuit part of the power circuit belongs to the low-power circuit,its signal amplitude is low,more sensitive to noise,poor anti-interference.Noise interference may lead to logic or timing errors in parts of the control circuit,at worst affecting circuit performance,at worst,the circuit cannot work.Therefore,it is necessary to study the electromagnetic compatibility and thermal design of the electronic equipment of vehicle scale.In this paper,the PCB circuit module of a vehicle gauge level atmosphere lamp is taken as the research object,starting from the basis of heat transfer,combining Fourier and energy conservation law,the three-dimensional finite difference calculation equation of temperature field of the target research object is constructed.The electromagnetic compatibility performance of PCB board was explored by electromagnetic simulation.In addition,the simulated annealing algorithm was used to optimize the thermal layout of electronic components on PCB board to ensure the lowest LED junction temperature during normal operation,and the accuracy of the temperature field calculation model constructed was verified by thermal simulation software ICEPAK and actual board making test.The main work and innovation points are as follows:(1)Based on the basis of heat transfer,the three-dimensional steady-state finitedifference temperature field calculation model of PCB atmosphere lamp circuit module is constructed;The atmosphere lamp PCB circuit is modeled in MATLAB,and the temperature of the target research object is solved in combination with the threedimensional steady state temperature field finite difference calculation model.Nine variable position components such as resistors and four fixed position LED components were defined.Based on the three-dimensional finite difference temperature field calculation model combined with simulated annealing algorithm,an optimal layout under nine variable position components was found to make the temperature of four fixed position components lowest.(2)The thermal simulation software ANSYS-ICEPAK was used to simulate the temperature field of the atmospheric lamp PCB circuit established under Altium Designer20.At the same time,the PCB circuit model with optimized layout was simulated to verify the feasibility of the simulated annealing algorithm to optimize the thermal layout of PCB circuit modules.The temperature data of atmosphere lamp PCB circuit working at room temperature 27℃ was tested by actual plate punching,and compared with the temperature data simulated by MATLAB and ICEPAK,the results showed that: The actual temperature measurement data is closer to the temperature field data in MATLAB,which illustrates that the three-dimensional stable temperature field finite difference calculation model constructed in this paper has certain practical value.Meanwhile,combined with the actual temperature measurement data before and after layout optimization,it also proves that the simulated annealing algorithm is feasible for the thermal layout optimization of PCB circuit of vehicle-gauge atmosphere lamp.(3)Combined with the professional electromagnetic simulation software ANSYSSIWAVE,the electromagnetic compatibility analysis of the built atmosphere lamp PCB circuit was carried out: the simulation process of PCB board level electromagnetic compatibility was proposed,and the ground plane impedance of the board level power supply was analyzed theoretically and verified by simulation;For the signal integrity of PCB board,the main task is to conduct simulation analysis of pulse signal and extract S parameter,then dynamically link the three-dimensional electromagnetic simulation model to the circuit design project for field and circuit co-simulation,and finally obtain the radiation field of the whole board and evaluate the electromagnetic radiation performance of the whole board.