Fault ride-through control method for variable-frequency transformer and related device

Abstract

The application discloses a fault ride-through control method for a variable-frequency transformer, which comprises the following steps: first, obtaining the voltage of a first grid, the voltage of asecond grid, the voltage of a stator and the current of the stator; then, calculating the voltage reference value corresponding to a single series three-phase converter after preprocessing; and finally, converting the voltage reference value into a control signal to control the series three-phase converter. The negative sequence voltage and negative sequence current of the stator caused by the negative sequence voltage of the first grid can be restrained, and the torque and power fluctuation of double rotor angular speed and double stator synchronization speed can be eliminated. The negative sequence current of the stator caused by the negative sequence voltage of the second grid can be restrained, and the electromagnetic torque and power fluctuation of double rotor synchronization speed can be greatly reduced. That is to say, the voltage imbalance problems of the left and right grids are solved at the same time by using a single series three-phase converter. Moreover, the grid cost isreduced. The application also discloses a fault ride-through control device, a circuit controller and a computer readable storage medium, which have the same beneficial effects.

Description

technical field [0001] The present application relates to the technical field of grid asynchronous interconnection, and in particular to a fault ride-through control method of a variable frequency transformer, a fault ride-through control device, a circuit controller, and a computer-readable storage medium. Background technique [0002] With the continuous development of the Energy Internet, power grids of different frequencies can share power through the asynchronous interconnection of power grids. Among them, the variable frequency transformer is especially suitable for asynchronous interconnection of short-distance face-to-face power grids. The variable frequency transformer has the following advantages: 1) The inherent rotational inertia of the rotor can provide stronger natural damping characteristics to suppress the oscillation of the power system; 2) The overload capacity is stronger; 3) The slower dynamic characteristics reduce the interaction with adjacent equipment...

AI Technical Summary

Problems solved by technology

However, the first prior art does not consider how to suppress the torque and power fluctuations caused by the unbalanced grid voltage, so it is impossible to realize the fault ride-through operation of the variable frequency transformer

Fault ride-through operation can be realized in another existing technology, but its characteristics can be attributed to "use the left converter to solve the unbalance problem on the left, and use the right converter to solve the unbalance problem on the right", so two series-connected Three-phase converters are used to implement fault ride-through, resulting in high cost of fault ride-through circuits

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