Soft start circuit of converter

Abstract

The invention relates to a soft start circuit of a converter. The main circuit of the soft start circuit comprises a DC (direct current) / DC converting circuit, a DC / AC (alternating current) converting circuit and a paralleling switch, wherein the DC / DC converting circuit comprises one or more mutually independent DC channels, at least one DC channel is a chopper DC channel on which a DC chopper circuit is arranged; the input end of the DC channel is a load connecting end, the output end of the DC channel is provided with a DC bus capacitor for forming the output end voltage; one or more soft start branches provided with soft start switches are connected between the load connecting end and the power supply connecting end of the paralleling switch; at least one of the one or more soft start branches is provided with a soft start resister, and the at least one soft start branch provided with the soft start resister corresponds to the chopper DC channel. By using the soft start circuit of a converter, the soft start current is small, the thermal design is easier, the paralleling impact current is small, and the soft start circuit can be widely used in the charging process of a DC load.

Description

technical field [0001] The invention relates to a soft start circuit of a converter in the field of power electronic conversion technology, in particular to a soft start circuit of a converter with two DC / DC and DC / AC conversions, which can be widely used in chargers, adapters, In the charge and discharge test circuit of switching power supply, storage battery and other equipment. Background technique [0002] For the existing converters that include DC / DC and DC / AC conversion twice, the soft start circuit corresponding to its charging operation usually has the following characteristics: a soft start resistor is connected in parallel at both ends of the grid-connected switch. Let the current flow through the soft-start resistor, the larger the resistance value of the soft-start resistor, the smaller the soft-start current, so as to achieve the purpose of reducing the soft-start current. [0003] However, at the moment of grid connection, due to the large voltage difference ...

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Problems solved by technology

[0003] However, at the moment of grid connection, due to the large voltage difference on both sides of the grid-connected switch, the inrush current is also large. , the soft-start current is large, and the heat dissipation requirements for the soft-start resistor are correspondingly high; if a larger-power soft-start resistor is selected, although the soft-start current can be reduced, the volume and cost of the circuit will be increased

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