Switching power supply module DC-DC converter
Introduction
Switching power supply can be divided into two categories: AC/DC and DC/DC, DC/DC converter is now modular, and the design technology and production process at home and abroad have been mature and standardised, and has been recognised by the user, but the modularity of the AC/DC, because of its own characteristics make the process of modularity, encountered in the modular process, a more complex technology and process manufacturing problems.
DC Chopper
DC/DC conversion is to convert a fixed DC voltage into a variable DC voltage, also known as DC chopper. Chopper works in two ways, one is the pulse width modulation method Ts is unchanged, change the ton (general purpose), the second is the frequency modulation method, the ton is unchanged, change the Ts (prone to interference). Its specific circuit consists of the following categories:
(1) Buck circuits - buck choppers, whose output average voltage Uo is less than the input voltage Ui, with the same polarity.
(2) Boost circuits - boost choppers whose output average voltage Uo is greater than the input voltage Ui with the same polarity.
(3) Buck-Boost circuit - Buck or Boost chopper whose output average voltage Uo is greater or less than the input voltage Ui, with opposite polarity and inductive transfer.
(4) Cuk Circuit - Buck or Boost Chopper, whose output average voltage Uo is greater or less than the input voltage UI, opposite polarity, capacitive transmission.
AC/DC
AC/DC converter is to convert AC to DC, the power flow can be bi-directional, power flow from the power supply to the load is called "rectification", power flow from the load back to the power supply is called "active inverter". AC/DC converter input is 50/60Hz alternating current, because it must be rectified, filtered, so the relatively large size of the filter capacitor is essential, at the same time, because of the encounter of safety standards (such as UL, CCEE, etc.) and EMC directive restrictions (such as the IEC, FCC, CSA), the AC input side must be added EMC filtering and the use of components to meet the safety standards, which restricts the miniaturisation of the size of the AC/DC power supply. In addition, due to the internal high-frequency, high-voltage, high-current switching action, making it more difficult to solve the EMC electromagnetic compatibility problem, but also on the internal high-density installation circuit design puts forward high requirements, due to the same reason, high-voltage, high-current switching makes the power supply operating consumption increases, limiting the process of modularity of the AC / DC converter, so it must be used in order to make the power supply system optimal design methods to make its operating efficiency to a certain degree of satisfaction.
AC/DC converter can be divided into half-wave circuit and full-wave circuit according to the wiring of the circuit. According to the number of power supply phases can be divided into single, three-phase, multi-phase. According to the circuit operating quadrant can be divided into one quadrant, two quadrants, three quadrants, four quadrants.
Advantages
Simple design. Only one power module with a few discrete components is required to obtain power.
Shorten the development cycle. Modular power supplies are generally available with a variety of input and output options. Users can also repeat the iteration or cross iteration, constituting a building block type combination power supply, to achieve multiple inputs and outputs, greatly reducing the prototype development time.
Flexibility of change. If the product design needs to be changed, it is only necessary to convert or connect another suitable power supply module in parallel.
Low technical requirements. Modular power supplies are generally equipped with standardised front-ends, highly integrated power modules and other components, thus making power supply design simpler.
The modular power supply housing has a trinity of heat sinks, heat sinks and housings, which realises the conduction cooling of the modular power supply and brings the temperature value of the power supply close to the minimum value. At the same time, it gives the modular power supply a golden package.
High quality and reliability. Modular power supply generally adopt full automatic production, and with high-tech production technology, so the quality is stable and reliable.
Wide range of uses: Modular power supply can be widely used in aerospace, locomotives and ships, military industry and weapons, power generation and distribution, post and telecommunications, metallurgy and mining, automatic control, household appliances, instruments and scientific research experiments and other areas of social production and life, especially in the field of high-reliability and high-tech play an irreplaceable and important role.
