Fault-tolerant voltage-sharing control method for bidirectional AC/DC energy storage converter

Abstract

The invention discloses a fault-tolerant voltage-sharing control method for a bidirectional AC / DC energy storage converter. The fault-tolerant voltage-sharing control method comprises the steps of: step S1, constructing a switching state Si; S2, acquiring an expression of output voltage Uj and the switching state Si; S3, constructing a power secondary prediction model; S4, calculating a predicted value of DC side discrete capacitor voltage difference; S5, constructing a value function g; S6, carrying out initialization; S7, acquiring voltage and output current of a power grid; S8, calculating output voltage Uj in the current switching state; S9, calculating a first power predicted value; S10, calculating a power predicted value; S11, calculating the value function g; S12, comparing magnitude of the value function g with a comparison variable m, and assigning a minimum value to the comparison variable m; S13, and carrying out judgment and outputting a result. The fault-tolerant voltage-sharing control method conducts two-step prediction on the output power, calculates the optimal voltage vector ahead, compensates for algorithm delay effectively, and reduces the influence of the delay on system performance. When the sampling efficiency is high after the delay compensation is added, the fault-tolerant voltage-sharing control method can significantly reduce power fluctuations and decrease 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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