Method for suppressing power oscillation of virtual synchronous machine of MMC interconnection converter

Abstract

The invention discloses a method for suppressing power oscillation of a virtual synchronous machine of an MMC interconnection converter. The method mainly comprises the steps of obtaining a voltage equation from the AC side angle of the MMC interconnection converter of an AC / DC hybrid microgrid, establishing a power output equation of the MMC interconnection converter, establishing a power regulation relational expression of the MMC interconnection converter, obtaining a virtual synchronous machine control mechanical equation and a virtual synchronous machine reactive excitation control equation based on a power transmission principle, solving a first-order derivative and a second-order derivative of the active power in the MMC interconnection converter power output simplification equation, obtaining a reference output power expression of the virtual synchronous machine, establishing a small signal model by the virtual synchronous machine by referring to the output power expression, carrying out Laplace transformation, and calculating a characteristic root of the small signal model, and acquiring a natural oscillation speed and a damping ratio of the system. the self-adaptive virtual inertia and the self-adaptive virtual damping coefficient are designed and substituted into a virtual synchronous machine control mechanical equation based on the power transmission principle, andthe effect of restraining MMC interconnection converter virtual synchronous machine power oscillation is achieved.

Description

Technical field [0001] The present invention relates to a method of suppressing the power of the MMC interconnect-converter virtual synchronous machine, which inhibits the method of suppressing the power of the MMC interconnect-converter, using adaptive virtual parameters instead of conventional virtual parameters, increase control Systematic power oscillating inhibitory ability. Background technique [0002] The MMC interconnect-converter interface converter in the DC mixed microglo is usually used, and the routine salary control does not have inertia and damping links, which cannot maintain a high permeability of distributed power supply. Virtual synchronous machine (VSG) control is simultaneously Generator features provide inertia and damping support for system, realizing one frequency modulation and primary regulation. The buffer energy variation in the transformation of the virtual synchronization machine uses virtual rotation inertia J Change characterization, and various f...

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Problems solved by technology

[0003]However, the conventional virtual moment of inertia J is a fixed value, if the value of J is too small, the system response time can be reduced but cannot restrain the power oscillation; Large, the system can suppress power fluctuations but increases the response time

Similarly, the selection of the virtual damping coefficient D will also affect the power oscillation suppression performance

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