Selection of control strategies for switching power supplies

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This post was last edited by yuchenchf on 2015-9-29 14:14. In low-to-medium power switching power supplies, current-mode PWM control is a widely used method. It has the following advantages over voltage-mode control: current limitation per cycle, faster response than voltage-mode control, and it prevents damage to the switching transistors due to overcurrent; **this also helps to reduce the risks associated with overload and short circuits； Excellent grid voltage regulation rate ； Rapid transient response ； The loop is stable and easy to compensate ； The ripple-to-voltage ratio is much smaller in the voltage-controlled type. http://img.jdzj.com/UserDocument/2013b/ankyted/Picture/2013625171813.jpg Production experience shows that the output ripple of the 50W Shenzhen switching power supply with current control is around 25mV, which is significantly better than that of the voltage-controlled version. Due to the limitations imposed by switching losses, hard-switching technology typically operates at switching frequencies below 350 kHz. Soft-switching technology, on the other hand, utilizes resonance principles to enable the switching devices to turn on and off under conditions of zero voltage or zero current, thereby eliminating switching losses and allowing the switching frequency to be increased to the megahertz range. Converters that employ soft-switching technology combine the advantages of both PWM converters and resonant converters, achieving nearly ideal characteristics such as low switching losses, constant-frequency control, appropriate sizes for energy storage components, a wide control range, and a wide load range. However, this technology is mainly used in high-power power supplies, while PWM technology remains the preferred choice for low- and medium-power power supplies.