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 the electronic system, its reliability determines the reliability of the entire system. COSEL switching power supplies are widely used in various fields because of their small size and high efficiency. In application, how to improve its reliability is an important aspect of power electronics technology. 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 uses pulse width modulation (PWM) technology. The pulse waveform is rectangular, and its rising and falling edges contain a large number of harmonic components. The reverse recovery of the output rectifier will also produce electromagnetic interference (EMI), which is an impact Disadvantages to 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, the main purpose is to suppress interference sources, which are concentrated in the switching circuit and the 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
Statistics show that when the temperature rises by 2°C, the reliability of electronic components decreases 10 times; the lifespan when the temperature rises by 50°C is only 1/6 of the life when the temperature rises by 25°C. 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 the 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 increase in the number of heating devices, and thick wires The width increases the efficiency of the power supply. The second is to enhance heat dissipation, that is, using conduction, radiation and convection technologies 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. Forced air cooling can dissipate more than ten times the heat of a radiator. Use natural cooling, but fans, fan power supplies, interlocking devices, etc. should be added, and the heat dissipation method should be selected based on the actual design conditions.
