According to the application of modern power electronics, we divide the modular power supply as follows:
Green modular power supply
High-speed development of computer technology has led mankind to enter the information society, and at the same time also promotes the rapid development of modular power supply technology. In the eighties, the computer fully adopted the switching power supply, the first to complete the computer power supply replacement. Then switching power supply technology has entered the field of electronic and electrical equipment. The development of computer technology, put forward the green computer and green module power supply. Green computer refers to environmentally friendly personal computers and related products, green power supply refers to the green computer related to efficient power saving power supply, according to the U.S. Environmental Protection Agency on June 17, 1992 "Energy Star Program, desktop personal computers or related peripherals, in the sleep state of the power consumption of less than 30 watts, in line with the requirements of the green computer to improve the efficiency of power supply is to reduce the consumption of power supply is the root cause of the problem. Power efficiency is the fundamental way to reduce power consumption. For a 200-watt switching power supply with 75% efficiency, the power supply itself consumes 50 watts of energy.
High-frequency switching
The rapid development of the communications industry has greatly promoted the development of communications power supplies. High-frequency miniaturization of the switching power supply and its technology has become the mainstream of modern communication power supply system. In the field of communications, the rectifier is usually referred to as the primary power supply, while the DC - DC (DC/DC) converter is called the secondary power supply. The role of the primary power supply is to single-phase or three-phase AC network into a nominal value of 48V DC power. In the primary power supply for program-controlled switches, the traditional phase-controlled voltage regulator has been replaced by a high-frequency switching power supply, high-frequency switching power supply (also known as switching rectifier SMR) through the high-frequency operation of MOSFETs or IGBTs, switching frequency is generally controlled in the range of 50-100kHz, to achieve high efficiency and miniaturization. In recent years, the power capacity of the switching rectifier has been expanding, the stand-alone capacity has been expanded from 48V/12.5A, 48V/20A to 48V/200A, 48V/400A.
Because of the wide variety of integrated circuits used in communications equipment, its power supply voltage is also different, in the communications power supply system using high power density of high-frequency DC-DC isolation of the modular power supply from the Intermediate bus voltage (generally 48V DC) into a variety of DC voltage required, which can greatly reduce losses, convenient maintenance, and installation, increase is very convenient. Generally can be directly mounted on the standard control board, the requirements of the secondary power supply is a high power density. Due to the increasing capacity of communications, communications power capacity will continue to increase.
(DC/DC) converter
DC/DC converter will be a fixed DC voltage into a variable DC voltage, this technology is widely used in trolley buses, subway trains, electric vehicles, stepless speed and control, at the same time, the control of the above to obtain a smooth acceleration, fast response performance, and at the same time to receive the effect of saving power. DC chopper instead of varistor can save power (20~30)%. DC chopper can not only play the role of voltage regulation (switching power supply), but also play an effective role in suppressing grid-side harmonic current noise.
Communication power supply DC/DC converter of the secondary power supply has been commercialized, the module using high-frequency PWM technology, switching frequency of 500kHz or so, the power density of 5W ~ 20W/in3. With the development of large-scale integrated circuits, the requirements of the module power supply to achieve miniaturization, and therefore we need to continue to improve the switching frequency and the use of new circuit topologies, there have been a number of companies to develop and produce the use of zero-current switching and zero-voltage power supply. The use of zero-current switching and zero-voltage switching technology of the secondary module power supply, power density has improved substantially.
Uninterruptible power supply (UPS)
Uninterruptible power supply (UPS) is a computer, communication systems, and the requirement to provide can not be interrupted occasions must be a highly reliable, high-performance power supply. AC utility input through the rectifier into DC, part of the energy to the battery charging, the other part of the energy through the inverter into AC, through the transfer switch to the load. In order to provide energy to the load when the inverter fails, the other way back-up power is realized through the power transfer switch.
Modern UPS commonly used pulse width modulation technology and power M0SFET, IGBT and other modern power electronic devices, power supply noise can be reduced, and efficiency and reliability can be improved. The introduction of microprocessor hardware and software technology, can realize the intelligent management of UPS, remote maintenance and remote diagnosis.
At present, the maximum capacity of on-line UPS can be made to 600kVA. ultra-small UPS development is also very rapid, there have been 0.5kVA, lVA, 2kVA, 3kVA and other specifications of the product.
Inverter module power supply
Inverter power supply is mainly used for AC motor frequency control, which occupies an increasingly important position in the electrical drive system, has been a huge energy-saving effect. The main circuit of inverter power supply adopts AC-DC-AC program. Industrial frequency power supply through the rectifier into a fixed DC voltage, and then by high-power transistors or IGBT PWM high-frequency converter, the DC voltage reversed into a voltage, frequency variable AC output, power output waveform approximate sinusoidal waveforms, used to drive AC asynchronous motors to achieve stepless speed regulation.
International 400kVA inverter power supply series products have been introduced. In the early eighties, Japan's Toshiba was the first AC frequency conversion speed control technology used in air conditioners. By 1997, its share has reached more than 70% of the Japanese household air conditioners. Inverter air conditioners have the advantages of comfort and energy saving. Domestic in the early 1990s began to study inverter air conditioning, 96 years the introduction of production lines to produce inverter air conditioners, and gradually formed a hot spot for the development and production of inverter air conditioning. It is expected to form a climax in 2000 or so. Inverter air conditioner in addition to frequency conversion power supply, but also requires a compressor motor suitable for frequency conversion speed regulation. Optimize the control strategy, selected functional components, is the air conditioning frequency conversion power supply development of further development direction.
Inverter module power supply
High-frequency inverter rectifier power supply is a high-performance, high-efficiency, material-saving new welder power supply, representing the direction of development of today's welder power supply. Due to the commercialization of IGBT high-capacity modules, this power supply has a broader application prospects.
Inverter welder power supply most of the AC-DC-AC-DC (AC-DC-AC-DC) conversion method. 50Hz AC rectified into DC by the full-bridge, IGBT PWM high-frequency converter part of the DC inverter into a high-frequency rectangular wave of 20kHz, coupled with a high-frequency transformer, rectifier filtering to become a stable DC for the use of the arc.
Because of the harsh working conditions of the welder's power supply, frequently in the short-circuit, arc, open-circuit alternating changes in the high-frequency inverter rectifier welder power supply reliability has become the most critical issue, but also the most concerned about the problem of the user. The use of microprocessor as a pulse width modulation (PWM) of the relevant controller, through the extraction of multi-parameter, multi-information extraction and analysis, to achieve the purpose of foreknowledge of a variety of system status, and then make adjustments to the system in advance and deal with the solution to the reliability of high-power IGBT inverter power supply.
Foreign inverter welder has been able to achieve the rated welding current of 300A, load sustaining rate of 60%, full-load voltage of 60 ~ 75V, current adjustment range of 5 ~ 300A, weight 29kg.
High-voltage DC modular power supply
High-power switching high-voltage DC power supplies are widely used in electrostatic dust removal, water quality improvement, medical X-ray machines and CT machines and other large-scale equipment. equipment. The voltage is as high as 50~l59kV, the current is more than 0.5A, and the power is up to 100kW.
Since the 70's, some Japanese companies began to use the inverter technology to rectify the utility power and invert it into the medium frequency of about 3kHz, and then step up the voltage. Into the 80s, high-frequency switching power supply technology has developed rapidly. Germany Siemens used power transistors as the main switching element, the switching frequency of the power supply to more than 20kHz. And the dry-type transformer technology successfully applied to high-frequency high-voltage power supply, canceled the high-voltage transformer tank, so that the transformer system to further reduce the volume.
The domestic electrostatic precipitator high voltage DC power supply development, utility power rectified into DC, using full-bridge zero-current switching series resonance inverter circuit will be inverted to high-frequency voltage DC voltage, and then by the high-frequency transformer step-up, and finally rectified to DC high-voltage. Under resistive load conditions, the output DC voltage reaches 55kV, the current reaches 15mA, and the operating frequency is 25.6kHz.
Power active filter
The traditional AC-DC converter will inject a large amount of harmonic currents into the power grid when it is put into operation, which will cause harmonic losses and disturbances, and at the same time, there is also a deterioration of the power factor on the network side of the device.
Power active filter is a new type of power electronic device that can dynamically inhibit harmonics and overcome the shortcomings of traditional LC filters. It can overcome the shortcomings of traditional LC filters, and is a very promising means of harmonic suppression. The filter consists of a bridge switching power converter and specific control circuits. The difference with the traditional switching power supply is: (l) not only feedback output voltage, but also feedback input average current; (2) current loop reference signal for the voltage loop error signal and the full-wave rectifier voltage sampling signal product.
Distributed power supply system
Distributed power supply system using low-power modules and large-scale control integrated circuits as the basic components, the use of the latest theories and technological achievements, the composition of building blocks, intelligent high-power power supply power supply, so that the strong power and the weak power tightly integrated to reduce the development of high-power components, high-power devices (centralized) of the pressure to improve production efficiency.
In the early eighties, the distributed high-frequency switching power supply system research is basically concentrated in the converter parallel technology research. In the mid-to-late eighties, with the rapid development of high-frequency power conversion technology, a variety of converter topologies have emerged, combined with large-scale integrated circuits and power component technology, so that the integration of small and medium-power devices possible, thus rapidly promoting the development of distributed high-frequency switching power supply system research. Since the late eighties, this direction has become the international power electronics research hot spot, the number of papers increased year by year, the application field is expanding.
Distributed power supply has the advantages of energy saving, reliability, high efficiency, economy and convenient maintenance. It has been gradually adopted by large-scale computers, communication equipment, aerospace, industrial control systems, etc. It is also the most ideal power supply method for the low voltage power supply (3.3V) of ultra-high-speed integrated circuits. In high-power occasions, such as electroplating, electrolytic power supply, electric locomotive traction power supply, medium-frequency induction heating power supply, motor drive power supply and other fields also have broad prospects for application.