Power grid frequency modulation device applied to photovoltaic direct current side

Abstract

The invention provides a power grid frequency modulation device applied to a photovoltaic direct current side. The device comprises an energy storage connecting terminal, a low-voltage direct-currentbus, a charging circuit, a discharging circuit, a high-voltage direct-current bus, a charging and discharging connecting terminal and a controller, wherein the energy storage connecting terminal is used for connecting an energy storage battery, a charging and discharging control unit is used for connecting a photovoltaic module and a photovoltaic inverter in parallel, the charging circuit and thedischarging circuit are connected in parallel between the low-voltage direct-current bus and the high-voltage direct-current bus, the energy storage connecting terminal is conductively connected withthe low-voltage direct-current bus, and the charging and discharging control unit is connected with the high-voltage direct-current bus, and the controller is connected with the charging circuit and the discharging circuit and used for controlling the charging circuit and the discharging circuit to work. When the device is applied to a photovoltaic power grid, the upper limit and the lower limit of adjustment of the photovoltaic inverter can be improved, moreover, the power grid frequency modulation device applied to the photovoltaic direct-current side is applied to the photovoltaic direct-current side, and the device is simple to install and low in cost, and facilitates transformation of a photovoltaic power grid in the prior art.

Description

Technical field [0001] The present invention relates to the technical field of power grid regulation, in particular to a power grid frequency modulation device applied to the DC side of photovoltaics. Background technique [0002] The DC energy of the photovoltaic module is converted by the photovoltaic inverter, and then the AC energy is output to be integrated into the grid. The photovoltaic inverter usually runs at the maximum power. [0003] When the grid frequency is higher than the limit, the inverter can adjust the power output downward to participate in the frequency reduction of the grid; but when the grid frequency is lower than the limit, the inverter cannot increase the output upwards, that is, it cannot participate in the grid increase frequency. [0004] With the increase in the proportion of new energy in the power system, the uncertainty and risk of grid operation increase, and the flexibility of new energy access and control needs to be further improved. In the case ...

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Problems solved by technology

[0003] When the frequency limit of the grid is higher, the inverter can adjust the output of power generation downwards and play a role in reducing the frequency of the grid; but when the frequency of the grid is lower than the limit, the inverter cannot increase its output upwards, that is, it cannot participate in the frequency increase of the grid

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