What is the effect of temperature on the life of communication switching power supply？
Time of issue:2022-11-25
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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.
1. The relationship between operating temperature and the reliability and life 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 during operation is dissipated by their own heat, the thermal cycle of multiple materials with different expansion coefficients will cause very significant stress, and may even cause instantaneous fracture, causing the components to fail. 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, the rapid change of heat and cold will temporarily generate a semiconductor temperature difference, which will cause thermal stress and thermal shock. The components are subjected to thermal-mechanical stress, and when the temperature difference is too large, stress cracks are caused in different material parts of the components. premature component failure. This also requires that the power components should work in a relatively stable operating temperature range, reduce the sharp change of temperature, so as to eliminate the impact of thermal stress shock, and ensure the long-term reliable operation of the components.
2. The influence of working temperature on the insulation capacity of transformers
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.
As the working temperature of the transformer rises, the coil will inevitably age. When its insulation performance decreases, the impact resistance against mains power will weaken. At this time, if there is a lightning strike or a mains power surge, the high reverse voltage at the primary side of the transformer will break down the transformer and make the power supply invalid. At the same time, high voltage will be connected to the main communication device in series, causing the risk of damage to the main device.
In order to ensure the reliable and stable operation of the rectifier of the communication switching power supply, reducing its operating temperature rise is a key technology. It adopts the combination technology of intelligent air cooling and self-cooling. It has technical advantages such as stronger environmental adaptability, long service life, reliability and stability.
The communication switching power supply adopts a cooling method combining fan and natural cooling, which can effectively reduce the internal working temperature of the rectifier and prolong the service life of the device when the ambient temperature is high. , The fan of the rectifier works at reduced speed, prolonging the service life of the fan. The radiator is used for heat dissipation, and the device spacing and creepage distance can be relatively long. In the case of high humidity, the safety performance is high. The rectifier is small in size and light in weight, making maintenance easier.
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