Does temperature have a great influence on the performance and life of communication switching power supply?
The main component of the communication switching power supply is a high-frequency switching rectifier, which gradually matures with the development of power electronics theory and technology and power electronic devices. The rectifier using soft switching technology has smaller power consumption, lower temperature, greatly reduced volume and weight, and continuous improvement in overall quality and reliability. But every time the ambient temperature rises by 10°C, the life of the main power components is reduced by 50%. The reason for such a rapid decline in life is due to temperature changes. Fatigue failure caused by various microscopic and macroscopic mechanical stress concentrations, ferromagnetic materials and other components will initiate various types of microscopic internal defects under the continuous action of alternating stress during operation. Therefore, ensuring the effective heat dissipation of the equipment is a necessary condition to ensure the reliability and life of the equipment.
Relationship between Operating Temperature and Reliability and Lifetime of Power Electronic Components
The power supply is a kind of electrical energy conversion equipment. During the conversion process, it needs to consume some electrical energy, and the electrical energy is converted into heat and released. The stability and aging speed of electronic components are closely related to the ambient temperature. Power electronic components are composed of a variety of semiconductor materials. Since the loss of power components is dissipated by their own heating, the thermal cycle of multiple materials with different expansion coefficients will cause very significant stress, and may even lead to instantaneous fracture and component failure. If the power element is operated under abnormal temperature conditions for a long time, it will cause fatigue that will lead to fracture. Due to the thermal fatigue life of semiconductors, it is required that they should work in a relatively stable and low temperature range.
At the same time, rapid cold and heat changes will temporarily generate a semiconductor temperature difference, which will cause thermal stress and thermal shock. To subject the component to thermal-mechanical stress, when the temperature difference is too large, it will cause stress cracks in different material parts of the component. premature component failure. This also requires that the power components should work in a relatively stable operating temperature range, reduce the sharp changes in temperature, so as to eliminate the impact of thermal stress shock, and ensure long-term reliable operation of the components.
Influence of working temperature on insulation capacity of transformer
After the primary winding of the transformer is energized, the magnetic flux generated by the coil flows in the iron core. Since the iron core itself is a conductor, an induced potential will be generated on a plane perpendicular to the magnetic force line, and a closed loop will be formed on the cross section of the iron core to generate current, which is called " vortex". This "eddy current" increases the loss of the transformer and increases the temperature rise of the transformer's core heating transformer. The loss caused by "eddy current" is called "iron loss". In addition, the copper wire used in the transformer needs to be wound. These copper wires have resistance. When the current flows, the resistance will consume a certain amount of power, and this part of the loss will be consumed as heat. This loss is called "copper loss". Therefore, iron loss and copper loss are the main reasons for the temperature rise of the transformer.
