Power Supply

General power supply

    It can also be subdivided into: switching power supply, inverter power supply, AC regulated power supply, DC regulated power supply, DC / DC power supply, communication power supply, module power supply, variable frequency power supply, UPS power supply, EPS emergency power supply, purification power supply, PC power supply, rectifier power supply, customized power supply, heating power supply, welding power supply / arc power supply, electroplating power supply, network power supply, power operation power supply, adapter power supply, etc Linear power supply, power controller / driver, power supply, other common power supply, inverter power supply, parameter power supply, voltage regulating power supply, transformer power supply.
 

Special power supply

    Special power supply can be subdivided into shore power supply, security power supply, high voltage power supply, medical power supply, military power supply, aerospace power supply, laser power supply and other special power supply.

 

Special power supply is a special kind of power supply. The so-called special power supply is mainly due to the technical index requirements of power supply are different from those of common power supply. The main reasons are that the output voltage is particularly high, the output current is particularly large, or the stability, dynamic response and ripple are particularly high, or the output voltage or current of power supply is pulse or other requirements. This makes the design and production of this kind of power supply have special or even strict requirements than ordinary power supply. Special power supply is generally designed for special load or occasion requirements, it is widely used. Mainly include: electroplating electrolysis, anodizing, induction heating, medical equipment, power operation, power test, environmental dust removal, air purification, food sterilization, laser infrared, photoelectric display, etc. In the field of national defense and military, special power supply can not be replaced by ordinary power supply. It is mainly used in radar navigation, high energy physics, plasma physics and nuclear technology research.

 

1. High voltage power supply for radar transmitter

    In modern radar transmitter, TWT as microwave power amplifier occupies a large proportion. As a high-power part, its reliability and technical indicators have a direct impact on the radar transmitter and even the whole radar. The high voltage power supply (system) supporting the TWT is very important. As a high-frequency and power electronic technology, switching power supply technology has been developed with the continuous development of electronic components and products and the replacement of high-power devices. The high-voltage switching power supply for radar TWT can adopt full bridge resonant PWM modulation mode, and the high-power switching device adopts advanced IGBT module and advanced reliable driving circuit, which makes the overall performance of the power supply good, stability good, and has various protection functions.

    Working principle: the 50Hz three-phase 380V is supplied to series resonant converter by rectifying and filtering through grid filter to obtain more than 500 volts DC voltage. Because the output of the power supply is up to 20kV, in order to reduce the design difficulty of the transformer, reduce the voltage withstand value of the high voltage rectifier diode and improve the reliability of the power supply, two secondary rectifying of the transformer are adopted, and then the output is superimposed. The full bridge converter is composed of four IGBT, one high frequency transformer and rectifier circuit. The control circuit provides two pairs of insulation and phase difference of 180 ° The pulse input to IGBT drive circuit, control IGBT on-off. The DC voltage is transformed into 20kHz pulse voltage, and the voltage of dozens of kV is obtained through transformer and full bridge rectifier and filter circuit.
 

2. High power and high voltage power supply for electron beam welder

    Electron beam welding (EBW) is widely used in aerospace, atomic energy, national defense and military industry, automobile, electrical instrument and many other industries due to its advantages of no electrode, no oxidation, good process repeatability and small thermal deformation. The basic principle of electron beam welding is that the cathode in the electron gun emits electrons due to direct or indirect heating. Under the acceleration of high-voltage electrostatic field, the electron beam with high energy density can be formed by focusing the electromagnetic field. When the electron beam is used to bombard the workpiece, the huge dynamic energy is converted into heat, which makes the workpiece melt and form a molten pool, So as to realize the welding of the workpiece.

    High voltage power supply is one of the key technologies of equipment, which mainly provides accelerating voltage for electronic gun. Its performance directly determines the welding process and welding quality of electron beam. Compared with other types of high voltage power supply, the high voltage power supply for electron beam welding machine has different technical characteristics. The technical requirements are mainly ripple coefficient and stability, ripple coefficient requirement is less than 1%, and stability is ± 1%, even the ripple coefficient is less than 0.5%, and the stability is ± The repeatability requirement was less than 0.5%. All the above requirements are determined by the electron beam spot and welding process. The operation of high voltage power supply for electron beam welding machine is to interlock with related systems, mainly including vacuum interlock, cathode interlock, gate valve interlock, focusing interlock, etc., to ensure the safety of equipment and personnel. High voltage power supply shall meet EMC standard, and have soft start function to prevent sudden closing impact on power supply.

Due to its high power (up to 30kW), high output voltage (150kV) and high working frequency (20kHz), this power supply has high requirements for stability accuracy, ripple and voltage regulation rate. Advanced three-phase fully controlled rectifier technology, high-power high-frequency inverter and new power device IGBT are used as power switch. Three phase fully controlled rectifier and inverter adopt independent control board, IGBT drive adopts imported thick film drive circuit, plus filter circuit composed of input grid filter, smoothing reactor and capacitor. The power conversion part of the power supply has advanced technology and good power conversion.

    High voltage part: the magnetic core of high voltage transformer adopts amorphous material, adopts unique high frequency and high voltage winding process, and the double high voltage transformer is superimposed. Advanced rectifying, reasonable voltage doubling circuit and high voltage equalizing technology ensure the high voltage part of high voltage power supply is stable and reliable. The voltage divider for feedback and high-voltage indication signal is directly sampled by the high-voltage output end to ensure that the power supply has high voltage stabilization accuracy, voltage adjustment rate and accurate and reliable high voltage measurement accuracy. The reasonable high voltage filter technology is adopted to ensure the power supply has good ripple. The high pressure part is placed in a tank.
 

3. High voltage pulse power supply

    In the radar navigation equipment, the transmitting part generally needs a high voltage, narrow pulse, different repetition rate strong power pulse source. This kind of high-power pulse source generally increases the power supply to several thousand to tens of kilovolts DC high voltage through a high-voltage power supply, and then modulates the DC high voltage to a pulse source with the required pulse width and frequency by a modulator for use by the transmitter.

    The pulse source is mainly composed of high-voltage power supply and modulator. The high-voltage power supply adopts switching power supply, and the modulator adopts solid-state modulator of semiconductor devices.

    The trigger pulse given by the user is the signal of TTL level, so the interface circuit should be added before the input to the isolation transformer. The interface circuit is to pre amplify the TTL pulse signal and match with the isolation transformer. In order to achieve the purpose of isolation, the user can provide the power supply for the interface circuit, and the manufacturer only needs to put forward the power demand and design the corresponding transformation and filtering circuit in the circuit.

    After the pulse transformer is isolated, the trigger pulse is shaped by the pre regulator pulse, and then the power amplifier will trigger the operation of the modulation board and the tail cutting board. The excitation pulse generated by the pre regulator is isolated by the transformer to drive each field effect tube of the modulation board. At this time, the modulation board is connected with high voltage power to the anode of the microwave triode. The cathode electron of the microwave triode starts to transmit, and the microwave triode amplifies the low power high frequency signal sent to the input end into high-power high-frequency signal. When the pulse is over, the tail cutting pulse generated by the pre regulator triggers the tailboard. After the tailboard is turned on, the distributed capacitance of the microwave triode is released, so a good pulse back edge can be obtained.