Application and development of new technology of DC switching power supply
Application and development of new technology of DC switching power supply
With the rapid development of electronic technology and communication industry, the application of high-frequency switching power supply is more and more extensive. With the continuous improvement of switching frequency, the performance of switching power supply is further optimized, with higher integration, lower power consumption, simpler circuit and more reliable operation, which is the development direction of switching power supply. At present, high-frequency switching power supply has been widely used in microwave stations of radio and television in our province. Based on this, the new technology and advantages of high-frequency switching power supply are introduced by comparing traditional power supply with modern high-frequency switching power supply.
1 composition principle of high frequency switching power supply
Generally, the high-frequency switching rectifier first rectifies and filters the alternating current directly through diodes into direct current, then converts it into high-frequency alternating current through switching power supply, and outputs it after being isolated by high-frequency transformer, high-frequency rectified by fast recovery diodes and filtered by inductors and capacitors, as shown in Figure 1.
1.1 main circuit
The whole process of input and output from AC power grid includes:
(1) Input filter: Its function is to filter the clutter existing in the power grid, and at the same time, it also prevents the clutter generated by this machine from being fed back to the public power grid.
(2) Rectification and filtering: the AC power supply of the power grid is directly rectified into a smoother DC power supply, and a stable DC power supply is provided to the power factor correction circuit.
(3) Power factor correction: located between rectification filtering and inverter, in order to eliminate harmonic current pollution caused by rectification circuit and reduce reactive power loss to improve power factor.
(4) Inverter: the rectified direct current is converted into high-frequency alternating current, which is the core part of high-frequency switching power supply. The higher the frequency, the smaller the ratio of volume and weight to output power.
(5) Output rectification and filtering: provide a stable and reliable DC power supply according to the needs of the load.
1.2 control circuit
On the one hand, sampling from the output end is compared with the set standard, and then the inverter is controlled to change its frequency or pulse width to achieve stable output. On the other hand, according to the data provided by the test circuit, the control circuit is provided to carry out various protection measures for the whole machine after identification by the protection circuit.
1.3 detection circuit
In addition to providing various parameters in operation in the protection circuit, it also provides various display instrument data for the personnel on duty to observe and record.
1.4 auxiliary power supply
Provide various power supplies (AC and DC voltage supplies of various grades) required by all circuits of the switching rectifier itself.
Working principle of QPS11/10 system
The working principle of the system is that the rectifier module converts AC input into DC output, and then sends it to the DC power distribution module and the battery fuse module connected in parallel by the bus, and outputs it through the shunt switch or fuse in the power distribution module to supply power to the load and charge the battery. When the commercial power is interrupted, the battery supplies power to the load. The control module communicates with the alarm module and the rectifier module through RS485. The alarm module is responsible for data measurement and collection, and its objects include commercial power, DC distribution module, battery fuse module and battery. When the system is working, the control module monitors various states of the system, adjusts its parameters, and automatically performs predetermined tasks. When the system is abnormal, it sends out an alarm signal, which is output by the alarm module and displayed on the control module.
