Control method and device for virtual synchronous machine to cope with grid voltage imbalance

By suppressing the double fundamental frequency oscillation component of the virtual synchronizer and generating the negative sequence voltage effect, the overcurrent risk and distortion problems of the virtual synchronizer when the grid voltage is unbalanced is solved, and its ability to deal with grid voltage imbalance is improved. Current limiting capability.

CN113783189BActive Publication Date: 2024-12-24SHENZHEN HOPEWIND ELECTRIC CO LTD
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Patent Information

Application Number
CN202111034954.0
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2021-09-04
Publication Date
2024-12-24
Estimated Expiration
2041-09-04

AI Technical Summary

Technical Problem

The existing virtual synchronous machines have overcurrent risks and output voltage and current distortion problems when the grid voltage is unbalanced. The flexibility and dynamic response capabilities of the frequency regulation link design are limited, making it difficult to effectively deal with grid voltage imbalance.

Method used

By suppressing the double fundamental frequency oscillation components in the active power and reactive power output by the virtual synchronizer, a negative sequence voltage action is generated, and superimposed with the basic voltage action is modulated to generate a driving signal to reduce the output current risk of double frequency pulsation and overcurrent.

Benefits of technology

Effectively suppress the double frequency pulsation of the output power of the virtual synchronizer, reduce the risk of overcurrent, improve the ability to deal with grid voltage imbalance, enhance the design flexibility of active power controllers and reactive power controllers, and improve the Current limiting capability.

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Abstract

The present application discloses a control method and device for a virtual synchronous machine to cope with voltage imbalance in a power grid, the method comprising: suppressing the double fundamental frequency oscillation component in the active power and reactive power output by the virtual synchronous machine to obtain a negative sequence voltage action 1; superimposing the negative sequence voltage action 1 with the basic voltage action in the target coordinate system to obtain a final voltage action; modulating the final voltage action to generate a driving signal required for the control of the virtual synchronous machine. The present application suppresses the double fundamental frequency oscillation component in the active power and reactive power without increasing the system cost, so that the virtual synchronous machine can reduce the overcurrent risk when the power grid voltage drops while simulating the synchronous machine to realize the active frequency modulation and reactive voltage regulation output characteristics, thereby improving the ability to cope with asymmetric drops in the power grid voltage.
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