A Fault Tolerant Voltage Equalization Control Method for Bidirectional AC-DC Energy Storage Converter

Abstract

The invention discloses a fault-tolerant voltage equalization control method for a bidirectional AC-DC energy storage converter, the steps are as follows: step S1, constructing a switch state S i ; S2, get the output voltage U j with switch state S i S3, constructing the power quadratic prediction model; S4, calculating the predicted value of the DC side separation capacitor voltage difference; S5, constructing the value function g; S6, initializing; S7, collecting the grid voltage and output current; S8, calculating Output voltage U in the current switching state j ;S9, calculate the predicted power value for the first time; S10, calculate the predicted power value for the second time; S11, calculate the value function g; S12, compare the size of the value function g with the comparison variable m, and assign the minimum value to the comparison variable m ; S13, judge and output. The invention calculates the optimal voltage vector in advance by performing two-step prediction on the output power, effectively compensates the delay of the algorithm, and reduces the influence of the delay on system performance. After the delay compensation is added, when the sampling frequency is high, the present invention can significantly reduce power fluctuations and grid-connected current harmonic distortion.

Description

technical field [0001] The invention belongs to the technical field of smart grids, and in particular relates to a fault-tolerant voltage equalization control method for a bidirectional AC-DC energy storage converter. Background technique [0002] The fault-tolerant operation capability of the high-reliability power conversion system is the primary basic problem of the operation of power electronic devices, and it is also the prerequisite for building a strong smart grid. In the energy storage system, the bidirectional AC-DC energy storage converter controls the bidirectional flow of electric energy between the energy storage power supply and the AC grid. important role. [0003] As the core component of bidirectional power conversion in energy storage systems, the normal operation of bidirectional converters is the basis for the safe and stable operation of the entire system. Once a failure occurs, it will cause the disconnection of the power supply from the power grid, wh...

AI Technical Summary

Problems solved by technology

[0006] The fault-tolerant control of existing converters is based on the SVPWM control method. The present invention needs to solve the problem of coordinate transformation and sector selection, which requires a large amount of calculation, complex algorithms, and less research on fault-tolerant methods for bidirectional AC-DC energy storage converters. Technical problems, thus providing a fault-tolerant voltage equalization control method for bidirectional AC-DC energy storage converters

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