Bosnia-Herzegovina the switching frequency of the AC-DC switching power supply module?(2)

Bosnia-Herzegovina Choosing the switching frequency of the LED advertising screen power supply does not mean choosing the switching frequency of the LED advertising screen power supply with a good switching frequency, but the choice is suitable for your own use. Most of the current market is like this. The frequency of the AC-DC switching LED advertising screen power supply module is between 50K and 135K, and this frequency range can meet most applications. Let's discuss it. Some of the problems that AC-DC encounters when choosing switching frequency:

Power active filter is a new type of power electronic device that can dynamically suppress harmonics. It can overcome the shortcomings of traditional LC filters and is a promising harmonic suppression method. The filter consists of a bridge switching power converter and a specific control circuit. The difference from the traditional switching power supply is: (1) not only feedback the output voltage, but also feedback the average input current; (2) the current loop reference signal is the product of the voltage loop error signal and the full-wave rectified voltage sampling signal.

1. Why generally do not choose a switching frequency lower than 50K

We know that the lower the switching frequency, the smaller the switching loss, but on the other hand, with the reduction of the switching frequency, the volume of the LED advertising screen power supply equipment will be reduced to the maximum, which is not conducive to miniaturization. When the switching LED advertising screen power supply is working, due to the switching of the switching device, the magnetic core will vibrate, and the frequency range that the human ear can hear is about 20~20000Hz. In order to avoid audible noise, we usually choose to stay away from the 20 frequency KHz.