Explanation of control methods of high-frequency switching power supply

High-frequency switching power supply is a power supply device widely used in various electronic equipment. Its high efficiency and stability make it an indispensable part in many fields.

Its core feature is to use switching devices to convert the input DC voltage or current into high-frequency alternating current, and then obtain a stable DC output through rectification and filtering. Due to its advantages of high efficiency, small size, and good dynamic performance, high-frequency switching power supplies are widely used in fields such as power electronics, communications, and automation control. There are many control methods for high-frequency switching power supplies. Here we will introduce four common control methods.

The first is constant switching frequency control. This control method is one of the most common and basic control methods. The switching frequency is set to a fixed value, usually between tens of kilohertz and hundreds of kilohertz. By adjusting the on and off times of the switching tube, stable control of the output voltage and current is achieved.

The second is frequency conversion control. This control method achieves control of the output voltage and current by changing the switching frequency. By changing the switching frequency, the ratio of the switching tube's on and off time can be changed, thereby changing the average value of the output voltage and current. This control method is often used in situations where the output power needs to be adjusted in real time according to load changes.

The third type is pulse width modulation control, which is a control method that adjusts the output voltage and current by changing the conduction time of the switch tube. PWM control technology changes the average value of the output voltage and current by changing the ratio of the switch conduction time, that is, the width of the pulse. The PWM control method has the characteristics of fast response and good stability, and is widely used in high-frequency switching power supplies.

Finally, there is multi-level control. This control method is a new type of control method developed in recent years. Multi-level control achieves control of output voltage and current by dividing the power supply output into multiple levels. Each level has its own switching tube and control circuit. By controlling the on and off times of the switching tubes at each level, the values of the output voltage and current can be accurately adjusted. The multi-level control method has the characteristics of high precision and high reliability, and is suitable for occasions that require high output accuracy.

In practical applications, the appropriate switching power supply control method can be selected according to the needs of different scenarios. The four control methods introduced above have their own advantages and disadvantages, and the most suitable control method needs to be selected according to the specific usage scenarios and equipment performance requirements. With the development of power electronics technology, the application of high-frequency switching power supplies will become more and more widespread, and its control methods will also be continuously innovated and improved to adapt to higher efficiency and stricter environmental protection requirements.

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