A Dynamic Phase-locked Synchronization Method Based on Fast Identification of Positive and Negative Sequences

Abstract

The invention discloses a dynamic phase lock synchronizing method based on rapid positive-sequence and negative-sequence recognition. The dynamic phase lock synchronizing method based on rapid positive-sequence and negative-sequence recognition comprises the following steps that the discrete instantaneous value of three-phase alternating-current voltage is obtained; Clark transformation is conducted on the discrete instantaneous value, so that the voltage space vector under the alpha-beta static coordinate system is obtained; the difference of the electrical angles existing when sampling is conducted twice sequentially is obtained according to the three latest voltage space vectors; the recognition phase of a positive-sequence component and the recognition phase of a negative-sequence component are obtained according to the difference of the electrical angles and the three latest voltage space vectors; phase locking is conducted on the recognition phase of the positive-sequence component and the recognition phase of the negative-sequence component, so that the phase-locking phase of the positive-sequence component and the phase-locking phase of the negative-sequence component are obtained; the first error between the phase-locking phase and the recognition phase of the positive-sequence component is obtained, and the second error between the phase-locking phase and the recognition phase of the negative-sequence component is obtained; when the first error or the second error is k times larger than a threshold value thetao, dynamic compensation is conducted on the phase-locking phase of the positive-sequence component and the phase-locking phase of the negative-sequence component; finally, the dynamic phase-locking phase is obtained. According to the dynamic phase lock synchronizing method based on rapid positive-sequence and negative-sequence recognition, the locked phases can be re-synchronized within the time (1ms) slightly longer than three sampling cycles after an asymmetrical transient-state fault occurs; the method has the excellent real-time performance and can be adapted to certain sampling noise.

Description

technical field [0001] The invention belongs to the field of electrical control, and more specifically relates to a dynamic phase-locked synchronization method based on fast identification of positive and negative sequences. Background technique [0002] The control strategy of grid-connected power generation equipment is often based on phase-locked loop technology. In the vector orientation control strategy, the coordinate system orientation is the basis for the implementation of the control strategy, and the dynamic response and precision directly affect the control effect. According to grid-connected guidelines, grid-connected devices such as wind power generation systems and photovoltaic inverter systems need to have the capability of transient fault ride-through of voltage asymmetry faults. When a transient fault occurs in the power grid and when the fault is cleared, that is, at the moment when the grid voltage drops and recovers, the positive and negative sequence co...

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Problems solved by technology

It can be seen that the above method is either insufficient in real-time recognition of the positive and negative sequences, or due to the limitation of the dynamic response speed of the phase-locked loop, it will take a long time for the phase-locked loop to resynchronize the positive and negative sequences under transient conditions. component; or because the positive and negative sequence identification method is too sensitive to harmonics and noise, the results of the phase-locked loop fluctuate violently, and stable results cannot be obtained

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