Buffer circuit and grid-connected system

Abstract

The invention is applicable to the technical field of power supplies, and provides a buffer circuit and a grid-connected system, and the buffer circuit is characterized in that an AC power supply is connected with a power grid through a grid-connected switch module; the buffer circuit comprises a first double-pole single-throw switch, a second double-pole single-throw switch, a third double-pole single-throw switch, a first buffer element, a second buffer element and a third buffer element; wherein every two of the three double-pole single-throw switches are arranged in a staggered mode, one switch belonging to the two different double-pole single-throw switches is connected with the corresponding buffer element in series, it is guaranteed that two switches are connected in series in each phase of path, and therefore when any switch is short-circuited, the path can still be effectively disconnected, and the safety requirement is met. Meanwhile, the double-pole single-throw switch is adopted, and only three switches need to be arranged for three phases, so that the size is small, and the cost is low.

Description

Technical field [0001] The present invention belongs to the field of power supply technology, in particular to a buffer circuit and a grid-connected system. Background [0002] When AC side equipment such as photovoltaic equipment, energy storage equipment or V2G equipment is connected to the grid, in order to avoid the damage caused by large inrush current generated by direct grid connection to the AC side equipment, a buffer circuit is usually provided to prevent large inrush currents from being connected to the grid. [0003] In the prior art, in order to meet the safety requirements, the buffer circuit is provided with two relays in series for each phase, for reference Figure 1 。 Any relay contact gap meets the insulation requirements, and when one of the relays is short-circuited, it can still ensure that the channel is stablely disconnected to meet the safety requirements. As a result, 6 relays need to be provided in the buffer circuit, which is large in size and costly. C...

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Problems solved by technology

[0004] In view of this, the embodiment of the present invention provides a buffer circuit and a grid-connected system to solve the problem in the prior art that the buffer circuit is equipped with 6 relays, which is large in size and high in cost, in order to meet the requirements of safety regulations.

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