Low-voltage ride-through control method for grid-connected inverter

A low-voltage ride-through and control method technology, applied in the field of inverters, can solve problems such as unbalanced inverter three-phase current, aggravated faults, and increased difficulty in system recovery
CN103887818AInactive Publication Date: 2014-06-25UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
UNIV OF ELECTRONICS SCI & TECH OF CHINA
Publication Date
2014-06-25
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a low-voltage ride-through control method for a grid-connected inverter. Whether a power grid works properly can be judged through a dropping state judgment device, so the method has the advantage of being fast in power grid judgment. In specific configuration, the method includes the steps of controlling a given current calculation module to calculate given current target values of the power grid in a normal working state and in a dropping state, and controlling a feedforward weight calculation module to distribute reasonable specific gravity of different voltage feedforward quantities according to the voltage state of the power grid agine. Consequently, current impact at the instant of voltage drop of the power grid can be restrained, and the recovery rate of the current waveform after voltage drop of the power grid can be increased so that the balance of three-phase current output by the inverter during voltage drop of the power grid can be maintained. Thus, it is guaranteed that the grid-connected inverter is in a fault ride-through state and accords with national standard inverter grid-connection requirements.
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Description

technical field

[0001] The invention belongs to the technical field of inverters, and more specifically relates to a low-voltage ride-through control method suitable for grid-connected inverters. Background technique

[0002] As a large number of distributed power sources are connected to the power grid, affected by severe weather or sudden start of large loads (such as large motors, steelmaking electric arc furnaces, etc.), the voltage of the grid bus connected to the load will drop, affecting the normal work of other users state. Statistics show that more than 60% of voltage drops are related to severe weather (such as lightning strikes, storms, etc.), and the damage lasts for a short time.

[0003] Under normal circumstances, when the power grid fails, the grid-connected inverter will immediately disconnect from the grid, regardless of the duration and severity of the fault, so as to protect the safety of the grid-connected inverter to the greatest extent. Lower values ...

Claims

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