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Relay control method and device of grid connected inverter

A relay control and inverter technology, applied in the inverter field, can solve problems such as large inrush current

Active Publication Date: 2019-06-04
SUNGROW POWER SUPPLY CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These two methods can effectively suppress the inrush current generated when the relay is closed when the grid voltage quality is good, but when the grid distortion is serious or the grid voltage harmonic is large, the inrush current generated by the relay closure is still very large

Method used

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  • Relay control method and device of grid connected inverter

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Embodiment Construction

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0043] See figure 1 , shows the control schematic diagram of the grid-connected inverter provided by the embodiment of the present invention before the grid-connected operation. Feedforward.

[0044] Such as figure 1 As shown, the voltage loop is based on the inverter voltage reference value V inv_ref As the input, take the actual value o...

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Abstract

The invention provides a relay control method and device of a grid connected inverter. According to the method, after that the inversion voltage of the grid connected inverter reaches a stabilized state, the relay is controlled to be closed, and timing is started. In the period that the timing length does not reach a time threshold, if the detected practical value of the inversion current is greater than or equivalent to the current threshold, the practical value of the inversion current is reduced to the preset current range. When the timing length is greater than or equivalent to the time threshold, it is considered that the relay completes a closing motion, and then the grid connected inverter is stopped from the present work mode, such as the inverter is directed stopped from operation, or directly switched from the present work mode to a normal grid connected work mode. The inversion current of the grid connected inverter is controlled directly and thus, not influenced by the voltage quality of the power grid, and the impact current is inhibited when the relay is closed under the condition that the voltage quality of the power grid is not high.

Description

technical field [0001] The invention belongs to the field of inverter technology, and in particular relates to a relay control method and device for a grid-connected inverter. Background technique [0002] The frequency and phase of the AC voltage output by the grid-connected inverter are synchronized with the frequency and phase of the grid voltage. Therefore, the AC output from the grid-connected inverter can be directly input into the grid. Grid-connected inverters are connected to the grid through relays. Since there is a filter capacitor on the inverter side, if the relay is closed directly, the power grid will directly charge the filter capacitor through the relay, and the inrush current during charging will be very large, which will cause damage to important components of the inverter system in severe cases. [0003] In the prior art, the methods for suppressing the inrush current when the relay is closed include the following two methods: one is to close the relay w...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/40
Inventor 张凤岗王郑张权宝姜安营李克成乔凯
Owner SUNGROW POWER SUPPLY CO LTD
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