German the switching frequency of the AC-DC switching power supply module?(5)

high frequency switch
The rapid development of the communication industry has greatly promoted the development of communication power. High frequency miniaturized switching power supply and its technology have become the mainstream of modern communication power supply system. In the field of communication, the rectifier is usually called the primary power supply, and the direct current-direct current (DC/DC) converter is called the secondary power supply. The role of the primary power supply is to convert the single-phase or three-phase AC power grid into a DC power supply with a nominal value of 48V. In the primary power supply for program-controlled switches, the traditional phase-controlled regulated power supply has been replaced by a high-frequency switching power supply. Controlled in the 50-100kHz range for high efficiency and miniaturization. In recent years, the power capacity of switching rectifiers has been continuously expanded, and the single-unit capacity has been expanded from 48V/12.5A, 48V/20A to 48V/200A, 48V/400A.

At present, the power carrier is mainly used for intelligent carrier in the home, remote meter reading system, and remote street lamp control system. The use range of the carrier frequency of power lines in my country is 9KHz ~ 500KHz, and the carrier bandwidth is 4KHz. The development of power carrier is very limited due to the change of power line impedance and the interference of power line noise. In order to increase the communication distance of the power carrier, we must move away from the power switching frequency of the circuit carrier unit. The carrier frequencies currently used in China are 115KHz and 132KHz. In this case, the switching frequency is around 60KHz for the 48V input power supply.