The reliability of the switching power supply is mainly analyzed from these three aspects
The quality of electronic products is a combination of technology and reliability. As an important component of electronic systems, its reliability determines the overall reliability of the system. COSEL switching power supplies are widely used in various fields due to their small size and high efficiency. In application, how to improve its reliability is an important aspect of power electronics technology, and its reliability mainly starts from these three aspects.
1. Electrical Reliability Engineering Design Technology for Switching Power Supply
2. Electromagnetic Compatibility (EMC) Design Technology
The COSEL switching power supply mainly adopts pulse width modulation (PWM) technology, with a rectangular pulse waveform and a large number of harmonic components in its rising and falling edges. The reverse recovery of the output rectifier tube also generates electromagnetic interference (EMI), which is an adverse factor affecting reliability and makes the electromagnetic compatibility of the system an important issue. Electromagnetic interference has three necessary conditions: interference source, transmission medium, and sensitive receiving unit, and EMC design will destroy one of these three conditions. For switching power supplies, the main focus is on suppressing interference sources, which are concentrated in the switching circuit and output rectifier circuit. The technologies used include filtering technology, layout and wiring technology, shielding technology, grounding technology, sealing technology, and other technologies.
3. COSEL Switching Power Supply Heat Dissipation Design Technology
Statistical data shows that when the temperature rises by 2 ℃, the reliability of electronic components decreases by 10 times; The lifespan of a temperature increase of 50 ℃ is only 1/6 of the lifespan of a temperature increase of 25 ℃. In addition to electrical stress, temperature is also an important factor affecting equipment reliability. This requires technical measures to limit the temperature rise of the chassis and components, which is a heat dissipation design. The principle of thermal design is to reduce the generation of heat, that is, to choose better control methods and technologies, such as phase shift control technology, synchronous rectification technology, etc; Another approach is to choose low-power devices, reduce the number of heating devices, and increase the width of thick wires to improve the efficiency of the power supply. The second is to strengthen heat dissipation by using conduction, radiation, and convection techniques for heat transfer. This includes radiator design, air cooling (natural convection and forced air cooling) design, liquid cooling (water, oil) design, thermoelectric cooling design, heat pipe design, etc. The heat dissipation of forced air cooling is more than ten times that of a radiator. Natural cooling method should be adopted, but fans, fan power supply, interlocking devices, etc. should be added, and the heat dissipation method should be selected according to the actual design situation.
