A kind of DC charging device, system and charging method

Abstract

The invention discloses a DC charging device, which comprises a control unit and a main circuit. An AC rectifying unit is used for rectifying AC to DC and outputting the DC to a DC boost unit for boost; a primary-side full-control active bridge is used for converting the DC to square wave AC; and an isolation transformer is used for outputting the square wave AC to a secondary-side active bridge for being rectified to DC to be outputted to a load. The invention also discloses a charging system, which comprises multiple DC charging assemblies in mutual parallel connection, wherein each DC charging assembly comprises multiple DC charging devices sequentially in serial connection. The invention also discloses a charging method, which comprises an independent working mode and a series-parallel networking working mode. In the independent working mode, a single charging device charges a single load; and in the series-parallel networking working mode, multiple DC charging assemblies are in parallel connection for charging the single load. The device, the system and the method of the invention have the advantages that input of multiple types of power supplies is compatible; various types of loads can be met; and the like.

Description

technical field [0001] The invention mainly relates to the technical field of charging, in particular to a DC charging device, system and charging method. Background technique [0002] With the development of electric vehicles, there are more and more demands for DC charging devices, and they are becoming more and more demanding; users have diversified input requirements for charging devices, and the input power of most charging devices is AC power from the grid. Using photovoltaic cells as input, charging devices in some emergency situations can also use other batteries as input power; electric vehicles have diverse output requirements for charging devices, for example, the charging requirements of electric buses and electric cars are different, traditional high-power DC charging The device cannot better meet the diverse charging needs. [0003] There are many types of input power sources for existing charging devices, and various types of AC and DC power sources can be us...

AI Technical Summary

Problems solved by technology

[0002] With the development of electric vehicles, there are more and more demands for DC charging devices, and they are becoming more and more demanding; users have diversified input requirements for charging devices, and the input power of most charging devices is AC power from the grid. Using photovoltaic cells as input, charging devices in some emergency situations can also use other batteries as input power; electric vehicles have diverse output requirements for charging devices, for example, the charging requirements of electric buses and electric cars are different, traditional high-power DC charging The device cannot better meet the diverse charging needs

[0003] There are many types of input power sources for existing charging devices, and various types of AC and DC power sources can be used as input power sources, most of which are AC mains power, and some are DC input; various charging loads (such as electric vehicles) have diverse charging requirements , the voltage, current, and power requirements are different; for the diversification of input power sources, the solution to existing charging devices is to add inverter units or rectifier units on the input side to unify different power sources into AC or DC , which will lead to an additional layer of transformation of the input power supply, affecting the overall efficiency; for the diversification of load requirements, the existing solution is to increase the output power and output voltage of the charging equipment as much as possible, and the high power is compatible with low power and high voltage. Compatible with low voltage, but this solution has shortcomings such as insufficient charging regulation accuracy, reduced efficiency, and insufficient use of charging capacity when the charging device charges a small load.

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