Study On Thermal Design Of Distribution Static Synchronous Compensator

With the development of electronic equipment towards high performance,high power and miniaturization,the heat dissipation space and heat flux density inside the equipment become smaller and smaller.The increasing heat dissipation per unit volume of IGBT module seriously endangers the stable operation of the system and increases the failure rate of the equipment,which makes the thermal management and thermal design of the device an important research direction of high-power equipment.In this paper,the conduction loss and switching loss of synchronous compensator in distribution network are analyzed,and the heat dissipation structure of the compensator is studied by means of equivalent thermal circuit model,thermal resistance model,thermal simulation model and engineering experiment.The transient process of IGBT and diode switch is analyzed theoretically.According to the typical waveforms of on-off process,the loss model is established.In this paper,the conduction process of switching devices in three-level compensators is studied in depth,the basic idea of loss research is proposed,and the mathematical model of SPWM modulation mode is established.Based on the analysis of data structure and various factors affecting power loss,the distribution trend of power loss in each device is quantitatively analyzed.By studying the selection basis of fan and radiator in forced air cooling heat dissipation,the general design scheme of forced air cooling heat dissipation system is summarized.Detailed thermal design of compensator is carried out,and the principle of primary selection of fan is given.An equivalent thermal circuit diagram considering NTC thermistor in IGBT module is proposed,through which the junction temperature can be checked quickly and accurately.According to the mathematical model of thermal resistance,the structure of radiator is designed.According to the heat dissipation structure of the compensator,the thermal simulation model is constructed by Icepak software to analyze the influence of heat dissipation structure to heat dissipation system.The temperature cloud and wind velocity vector of the system are obtained by finite element simulation analysis.The results show that the junction temperature of the power element is within the allowable temperature limit.The final heat dissipation scheme is tested on the engineering prototype,and the temperature of compensator is monitored by thermocouple in real time.The results of thermal test verify the rationality and applicability of thermal design simulation.