The impact of temperature on the performance and life of communication switching power supplies
The main component of communication switching power supply is high-frequency switching rectifier, which has gradually matured with the development of power electronics theory and technology and power electronic devices. The rectifier using soft switching technology has reduced power consumption, lower temperature, significantly decreased volume and weight, and continuously improved overall quality and reliability. But whenever the ambient temperature rises by 10 ℃, the lifespan of the main power components decreases by 50%. The reason for the rapid decline in lifespan is due to temperature changes. Fatigue failure caused by various micro and macro mechanical stress concentrations, ferromagnetic materials and other components will develop various types of micro internal defects under continuous alternating stress during operation. Therefore, ensuring effective heat dissipation of the equipment is a necessary condition for ensuring its reliability and lifespan.
The relationship between working temperature and the reliability and lifespan of power electronic components
A power supply is an electrical energy conversion device that consumes some electrical energy during the conversion process, which is then converted into heat and released. The stability and aging rate of electronic components are closely related to the ambient temperature. Power electronic components are composed of various semiconductor materials. Due to the fact that the losses of power components during operation are dissipated by their own heat generation, the thermal cycling of various materials with different expansion coefficients can cause significant stress and even lead to instantaneous fracture, resulting in component failure. If power components operate 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 operate within a relatively stable and low temperature range.
At the same time, rapid changes in temperature can temporarily create a temperature difference in the semiconductor, resulting in thermal stress and thermal shock. Expose components to thermal mechanical stress, and when the temperature difference is too large, stress cracks may occur in different material parts of the components. Causing premature failure of components. This also requires power components to operate within a relatively stable temperature range, reducing rapid temperature changes to eliminate the impact of thermal stress and ensure long-term reliable operation of the components.
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 through the iron core. As the iron core itself is a conductor, an induced potential is generated in a plane perpendicular to the magnetic field lines, forming a closed loop on the cross-section of the iron core and generating current, which is called "eddy current". This' eddy current 'increases the losses of the transformer and causes the iron core of the transformer to heat up, resulting in an increase in the temperature rise of the transformer. The loss caused by eddy currents is called "iron loss". In addition, copper wires used for winding transformers have resistance, which consumes a certain amount of power when current flows through them. This loss becomes heat and is called "copper loss". So iron and copper losses are the main causes of temperature rise in transformer operation.
