CN-224233555-U - Voltage sag protection device for medium-high voltage direct current load

Abstract

The utility model discloses voltage sag protection equipment for a medium-high voltage direct current load, which comprises six paths of Boost DC/DC converters which are connected in parallel in a staggered manner, a driving circuit, a pre-charging circuit, a singlechip control circuit and an output diode, wherein the output end of the singlechip control circuit is connected with the input ends of the driving circuit and the pre-charging circuit, the output ends of the driving circuit and the pre-charging circuit are connected with the input ends of the Boost DC/DC converters which are connected in parallel in the staggered manner, and the output ends of the Boost DC/DC converters which are connected in the staggered manner in the six paths are connected with the output diode. The utility model can be used for a medium-high voltage frequency converter, and the six-path staggered parallel Boost topological structure can reduce the current stress of the power tube, is favorable for selecting a low-current and high-performance power tube (the power tube is more widely selected), can reduce the ripple of the total output current, prolongs the service life of the output capacitor, increases the power density of the converter, allows higher switching frequency and improves the overall efficiency.

Inventors

• CHEN WENBO
• MEI ZHONGHUA
• HAN BING
• ZHANG BAO

Assignees

• 南京国臣信息自动化技术有限公司

Dates

Publication Date

20260512

Application Date

20250321

Claims (5)

1. 1. The voltage sag protection device for the medium-high voltage direct current load is arranged between a direct current power supply and a direct current bus of a frequency converter and is characterized by comprising six paths of Boost DC/DC converters which are connected in parallel in a staggered manner, a driving circuit, a singlechip control circuit and an output diode, wherein the output end of the singlechip control circuit is connected with the input end of the driving circuit, the output end of the driving circuit is connected with the input end of the Boost DC/DC converters which are connected in parallel in the staggered manner, the output end of the Boost DC/DC converters which are connected in the staggered manner in the six paths is connected with the direct current bus end of the frequency converter through the output diode, and the singlechip control circuit sends out six paths of PWM signals to control the working state of the Boost DC/DC converters which are connected in the staggered manner in the six paths through the driving circuit; The device also comprises a precharge circuit, the input end of the precharge circuit is connected with the output end of the singlechip control circuit, the output end is connected with the output capacitor of the six-path staggered parallel Boost DC/DC converter, the SCM control circuit precharges output capacitors in the six-path staggered parallel Boost DC/DC converter through the precharge circuit.
2. 2. The voltage sag protection device for a medium-high voltage direct current load according to claim 1, further comprising an RS-485 communication interface and a man-machine interaction interface, wherein the man-machine interaction interface is connected with the single chip microcomputer control circuit through the RS-485 interface.
3. 3. The voltage sag protection device for a medium-high voltage direct current load according to claim 1, wherein the capacitors adopted by the output ends of the six-path staggered parallel Boost DC/DC converter are thin-film capacitors.
4. 4. The voltage sag protection device for a medium-high voltage direct current load of claim 1, wherein the SCM control circuit is a SCM TMS320F28034.
5. 5. The voltage sag protection device for a medium-high voltage direct current load of claim 1, wherein the power tubes of the six-path staggered parallel Boost DC/DC converter are all discrete device MOSFET switching tubes.

Description

Voltage sag protection device for medium-high voltage direct current load Technical Field The utility model relates to a frequency converter control system of an industrial field, in particular to medium-high voltage sag protection equipment. Background The complex precision equipment (such as a frequency converter) widely used in modern industry is very sensitive to the problem of electric energy quality, and more than 90% of the problem of electric energy quality comes from voltage sag, and once voltage sag or fluctuation occurs, shutdown and even faults can occur, so that serious interference and huge economic loss are brought to production. Therefore, voltage sag has been considered as one of the most significant power quality problems affecting the normal and safe operation of powered devices. The prevention and treatment of the electric energy quality problem are particularly important in the process of converting an energy structure into new energy. The voltage sag protection equipment for direct current load in the current market can only be used for protecting low-voltage frequency converters, more and more medium-high-voltage frequency converters are operated in industrial sites, and meanwhile, the existing voltage sag protection equipment is large in size, low in power density, small in temperature range, short in service life and capable of increasing the cost of the equipment in an intangible way. Aiming at the problems that the prior voltage sag protection equipment cannot protect a medium-high voltage frequency converter from the influence of voltage sag, and has larger volume and shorter service life, the voltage sag protection equipment for a medium-high voltage direct current load is developed. Disclosure of utility model The utility model aims to provide voltage sag protection equipment for medium-high voltage direct current loads, which solves the problems of poor voltage sag resistance of a medium-high voltage frequency converter, low power density, large equipment volume, small temperature range and the like of the traditional voltage sag protection equipment In order to achieve the above purpose, the voltage sag protection device for the medium-high voltage direct current load comprises six paths of Boost DC/DC converters which are connected in parallel in a staggered manner, a driving circuit, a singlechip control circuit and an output diode, wherein the output end of the singlechip control circuit is connected with the input end of the driving circuit, the output end of the driving circuit is connected with the input end of the Boost DC/DC converters which are connected in parallel in the staggered manner, the output end of the Boost DC/DC converters which are connected in parallel in the staggered manner is connected with the output diode, and the singlechip control circuit sends out six paths of PWM signals to control the working state of the Boost DC/DC converters which are connected in parallel in the staggered manner through the driving circuit. Wherein, the device also comprises a precharge circuit, the input end of the precharge circuit is connected with the output end of the SCM control circuit, the output end is connected with the output capacitance of the six-path staggered parallel Boost DC/DC converter, the SCM control circuit precharges output capacitors in the six-path staggered parallel Boost DC/DC converter through the precharge circuit. The system also comprises an RS-485 communication interface and a man-machine interaction interface, wherein the man-machine interaction interface is connected with the singlechip control circuit through the RS-485 interface. The capacitors adopted by the output ends of the six-path staggered and parallel Boost DC/DC converter are thin-film capacitors. Wherein, singlechip TMS320F28034 is adopted to singlechip control circuit. The power tubes of the six-path staggered parallel Boost DC/DC converter are all discrete device MOSFET switching tubes. The high-voltage sag protection device has the advantages that 1, the Boost is realized through the six-way staggered and parallel Boost DC/DC converter, so that the current stress of the power tube is reduced, the circuit can select a low-current and high-performance power tube (thereby widening the selection range of the power tube), and a higher switching frequency is supported; 2. The output capacitor of the DC/DC converter adopts a film capacitor, and compared with the electrolytic capacitor used by the existing voltage sag protection device, the DC/DC converter has the advantages of no polarity, low equivalent series resistance, high temperature stability, long service life, high efficiency, high reliability and the like, can adapt to a high-frequency circuit and a wide-temperature environment, and effectively enhances the stability and the reliability of the DC/DC converter; 3. The high-voltage sag protection device adopts a digital control technology, realizes programmable output, has