Novel grid-connected interface filter and passive damping method therefor

Abstract

The invention relates to the field of power electronics. A novel grid-connected interface filter includes an inverter-side filter inductor, a network-side filter inductor, filter capacitors and a filter inductor. The left end of the inverter-side filter inductor is connected to a grid-connected inverter output port while the right end of the inverter-side filter inductor is connected to a filter node. The left end of the network-side filter inductor is connected to the filter node and the right end of the network-side filter inductor is connected to a filter output port. The filter inductor and one filter capacitor are connected in parallel and then connected in series with another capacitor filter. The upper end of the branch circuit is connected to the filter node, and the lower end of the branch circuit is connected to a common node of the filter with the inverter and the grid. In a passive damping method for the novel grid-connected interface filter, the above novel grid-connected interface filter circuit is used, and two ends of the filter capacitor connected in parallel with the filter inductor are connected in parallel with a damping resistor. The novel grid-connected interface filter has the advantages of excellent high-frequency filter property and low power consumption, thus enabling the whole grid-connected interface filter to be good in system performance, small in size, low in cost and high in efficiency.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to a novel grid-connected interface filter and a passive damping method for an inverter connected to a public power grid in a new energy power generation system. Background technique [0002] In order to prevent the grid-connected inverter pulse width modulation and system nonlinearity from polluting the grid in the new energy distributed power generation system (photovoltaic power generation, wind power generation, fuel cell power generation, etc.), the connection between the grid-connected inverter and the grid Passive filters need to be connected between them, and traditional grid-connected inverters use L-type filters. In order to reduce the size and cost of the filter inductor and improve the dynamic tracking speed of the grid-connected current of the grid-connected inverter, the main way to solve this technology is to use an LCL filter. The filter capacitor of the LCL filter i...

AI Technical Summary

Problems solved by technology

However, with the large-scale development and utilization of new energy sources, as the power level of grid-connected inverters continues to increase, the switching frequency of power devices will decrease accordingly. In order to make the harmonic content of grid-connected current still meet the relevant harmonic standards, Large inductor size and cost are still required, which will affect the efficiency and overall cost of grid-connected inverters

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