The reliability of COSEL 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 part of an electronic system, its reliability determines the reliability of the entire system. COSEL switching power supply is widely used in various fields because of its 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 of switching power supply
2. Electromagnetic compatibility (EMC) design technology
COSEL switching power supply mainly adopts pulse width modulation (PWM) technology, the pulse waveform is rectangular, and its rising edge and falling edge contain a large number of harmonic components, and the reverse recovery of the output rectifier will also produce electromagnetic interference (EMI), which is the influence Unfavorable factors for reliability, which makes the electromagnetic compatibility of the system an important issue. Electromagnetic interference has three necessary conditions: interference source, transmission medium and sensitive receiving unit, EMC design will destroy one of these three conditions. For switching power supplies, it is mainly to suppress interference sources, which are concentrated in switching circuits and output rectifier circuits. The technologies used include filtering technology, layout and wiring technology, shielding technology, grounding technology, sealing technology and other technologies.
3. COSEL switching power supply cooling design technology
Statistics show that when the temperature rises by 2°C, the reliability of electronic components is reduced by 10 times; the life of the temperature rise of 50°C is only 1/6 of the life of the temperature rise of 25°C. In addition to electrical stress, temperature is also an important factor affecting device reliability. This requires technical measures to limit the temperature rise of the chassis and components, which is thermal design. The principle of thermal design is to reduce heat generation, that is, to choose better control methods and technologies, such as phase shift control technology, synchronous rectification technology, etc.; the other is to choose low-power devices, reduce the number of heating devices, and increase the thickness of the wire width improves the efficiency of the power supply. The second is to enhance heat dissipation, that is, to use conduction, radiation and convection technology for heat transfer. This includes heat sink design, air cooling (natural convection and forced air cooling) design, liquid cooling (water, oil) design, thermoelectric cooling design, heat pipe design, etc. Forced air cooling dissipates more than ten times as much heat as a radiator. The natural cooling method is adopted, but fans, fan power supplies, interlocking devices, etc. should be added, and the cooling method should be selected according to the actual design situation.
