A switching power supply suitable for places with high overvoltage level and high altitude

Abstract

The invention provides a switch power supply suitable for a high-overvoltage-grade high-altitude place. The switch power supply comprises a DC bus voltage input, an open-loop isolation DC / DC circuit and a closed-loop isolation DC / DC circuit; an input end of the DC bus voltage input is connected with a DC bus of electric power equipment, and an output end is connected with the open-loop isolation DC / DC circuit; and an output end of the open-loop isolation DC / DC circuit is connected with the closed-loop isolation DC / DC circuit, and an output end of the closed-loop isolation DC / DC circuit outputs an output voltage Vo. The switch power supply adopts two stages of the isolation DC / DC circuits, the former stage is in an open-loop state, and the latter stage is in a closed-loop state; the switch power supply can achieve a large electric gap and a creepage distance, and then the switch power supply can be suitable for the high-overvoltage-grade high-altitude place; and the switch power supply can compatibly and simultaneously take electricity from the DC bus and an external input power supply, and the switch power supply is ensured to be capable of continuously providing power in certain conditions.

Description

technical field [0001] The invention relates to a switching power supply of electric equipment, in particular to a switching power supply suitable for places with high overvoltage level and high altitude. Background technique [0002] In power equipment, such as frequency converters, wind power converters, and photovoltaic inverters, it is a common design scheme for the switching power supply of the power equipment to take power from the DC bus of the power equipment. [0003] Such as figure 1 A switching power supply is shown, which includes a DC bus voltage input, a closed-loop isolated DC / DC circuit, and an output terminal Vo of the switching power supply. figure 1 The switching power supply shown can only achieve basic insulation in general applications, and is not suitable for applications with high overvoltage levels and high altitudes. Moreover, the switching power supply has no redundant input, and is not compatible with taking power from commonly used external inp...

AI Technical Summary

Problems solved by technology

figure 1 The switching power supply shown can only achieve basic insulation in general applications, and is not suitable for applications with high overvoltage levels and high altitudes

Moreover, the switching power supply has no redundant input, and is not compatible with taking power from commonly used external input power sources, such as: single-phase AC input power, DC low-voltage input power (such as +24V, +15V, etc.)

However, for power equipment such as inverters, wind power converters, and photovoltaic inverters, under certain working conditions (for example: when the wind power converter requires low-voltage ride-through without disconnecting from the grid or the inverter requires the power grid to be powered off to achieve instantaneous stop time, etc.) require power equipment to be able to supply power continuously, figure 1 The switching power supply cannot meet the design requirements

[0004] In applications with high overvoltage levels and high altitudes, safety issues brought about by high overvoltage levels and high altitudes need to be considered. figure 1 Switching power supplies with high overvoltage levels and high altitude applications cannot even reach basic insulation

And usually only meet the overvoltage level II, can not meet the use of high overvoltage level III

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