Research And Design Of Double Forward Switching Power Supply Charging Battery

Feeder terminal device FTU is installed on 10 KV feeder road, monitoring the column switch, which complete telemetry, fault detection, and communicate with the master station of the distribution automation, It regulate and control the distribution equipment, so as to implement the function that fault location, fault isolation and the quick restore power for non-fault area.FTU high-frequency switching power not only supply electricity for FTU itself, but also supply the communication module and the control loop jump combination switch, and so on. Years of operation shows that FTU runs in harsh outdoor environments for a long time, it needs to have the requirements such as lightning protection, rainproof, moistureproof. Its power is the largest component of the problem, which has become the key technology to influence its stable and reliable.In this paper, two-transistor forward topology is used to design a battery charging power supply module to meet the power requirements of FTU. The article analyzes the development and present situation of high-frequency switching power supplies, introduces the common DC-DC converter topology and the principle characteristics of the switching power supplies, and then focuses on the working principle and the waveform analysis of two-transistor forward converter, and then designs and analyzes for each part of the switching power supply, Starting from the modeling averaged switch model, it studies the structure features of power topological part, and establishes its transfer function. After analyzing the power section to get the simplified transfer function; from the features of the current loop, it establishes the transfer function, and put it into the power part of the transfer function; Chip UC3844, optocoupler, TL431 and other elements are used to component the voltage loop system, and it gives the model analysis and pole zero voltage loop analysis. It studies the power section of the system and the compensated open-loop Bode plot through Matlab, which shows that the model is accurate and reliable. Finally, through a series of tests and test of the power module, it analyzes the main parts of the power waveform. Experiments show that the designed modules superior dynamic performance, it can work stably in the setting voltage, and the working efficiency can reach above 80%, each protection circuit can work reliably and can fully meet the design requirements.Due to the complexity of the switching power supply environment and the diversity of internal components species, it is prone to a variety of failures at work, finally the paper simply introduces the common faults of switching power supply and the corresponding solutions.