Inverter control device and method based on grid voltage phase-locked and virtual synchronous machine

Abstract

The invention discloses an inverter control device and method based on network voltage phase locking and a virtual synchronous machine. At an initial work stage of an inverter, the inverter adopts a conventional inverter control scheme based on network voltage phase locking to complete grid connection work; after grid connection work of the inverter is stable, the inverter adopts a virtual synchronous machine control scheme. After grid connection of the inverter is realized through a conventional grid connection control scheme based on network voltage phase locking, a virtual synchronous machine control policy and a traditional conventional grid connection control scheme are entirely switched, thus, the grid-connected inverter is integrated with the virtual synchronous machine, and a pre-synchronization control link and corresponding terminal voltage detection points in the process from grid separation to grid connection of the inverter under the virtual synchronous machine control scheme are omitted, and a significant technological base is provided for an inverter control scheme applied to the distributed power generation and micro-grid field. Moreover, an inverter system keeps stable, safe and reliable operation from beginning to end in the switching process of the two control modes.

Description

technical field The present invention relates to an inverter control device based on the grid voltage phase-locked and virtual synchronous machine control strategy, and also relates to an inverter control method based on the grid voltage phase-locked and virtual synchronous machine control strategy, which belongs to the three-phase inverter In the field of device control technology. Background technique With the global energy crisis and environmental problems becoming increasingly prominent, distributed power generation technology and micro-grid technology have received more and more attention. As the link between distributed resources and distribution network (micro-grid), grid-connected inverter The function of the device has been deeply excavated and its beneficial role has been affirmed. However, it is still impossible to ignore the challenges brought by conventional control strategies to the safe and stable operation of distribution networks and microgrids. In particu...

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Problems solved by technology

However, the inventors have found through research that when the inverter (virtual synchronous machine) based on the virtual synchronous machine control strategy realizes switching from off-grid to grid-connected operating mode, it is usually necessary to simultaneously detect the output voltage of the inverter terminal and the grid voltage, and Grid connection is achieved through a pre-synchronization (grid synchronization) link similar to that of traditional synchronous generators before grid connection, and the entire grid connection process is relatively complicated

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