Multi-application scene communication fault ride-through control method

Abstract

The invention discloses a multi-application scene alternating current fault ride-through control method. The method comprises the following steps of establishing a converter mathematical model; establishing an alternating current fault state mathematical model of a converter; designing a nonlinear controller; and compensating the double-frequency zero-sequence common-mode voltage, and suppressingthe direct-current double frequency. According to the present invention, the nonlinear controller of the system is designed by adopting a feedback linearization principle, and the rapid independent control and the negative sequence current suppression of the active power and the reactive power are realized by decoupling a direct-axis current and a quadrature-axis current. A suppression strategy ofthe direct-current voltage and a current frequency-doubled component is provided, the direct-current voltage is calculated according to the voltage measurement values of the six bridge arms, and thefrequency-doubled zero-sequence common-mode voltage needing to be compensated is obtained after the direct-current voltage passes through a band-pass filter. Through simulation, when different AC faults occur, AC fault ride-through control is not added, operation results under three different strategies of negative sequence suppression, negative sequence suppression and DC frequency doubling suppression are only added, and the effectiveness of the control strategy is verified.

Description

technical field [0001] The invention relates to the technical field of AC fault ride-through control, in particular to an AC fault ride-through control method for multiple application scenarios. Background technique [0002] The flexible DC transmission system based on modular multilevel converter (MMC) has become a new type of flexible power transmission mode, especially suitable for large-scale renewable energy transmission, asynchronous grid interconnection, and replacing conventional DC as short-circuit Power supply in areas with insufficient capacity. [0003] The improvement of AC-DC fault ride-through capability is a key issue to be solved urgently in the development and application of flexible DC. Different from conventional AC systems, AC faults will not only cause voltage anomalies in local AC systems, but also affect the operation and control of the entire flexible DC system by invading the flexible DC system. Even a single-phase-to-ground short circuit fault ma...

AI Technical Summary

Problems solved by technology

Different from conventional AC systems, AC faults will not only cause voltage anomalies in local AC systems, but also affect the operation and control of the entire flexible DC system by invading the flexible DC system.

Even a single-phase-to-ground short-circuit fault may cause the blockage of the flexible DC converter connected to the faulty AC line, and even cause the entire flexible DC system to shut down, greatly reducing the reliability and availability of the flexible DC system

Regardless of whether the flexible DC system is blocked due to a fault on the AC side or the DC side, it will constitute a large-capacity active power impact on the AC system at the transmitting end and the receiving end, which will cause transient overvoltage, overcurrent, and frequency stability problems in the AC system; and after the blocking is cleared The restart process of the soft straight system will also have a similar impact on the AC system

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