Adaptive virtual damping control-based parallel converter circulation current suppression method for AC-DC hybrid microgrid

Abstract

The invention relates to an AC-DC hybrid microgrid, in particular to an adaptive virtual damping control-based parallel converter circulation current suppression method for the AC-DC hybrid microgrid.The AC-DC hybrid microgrid comprises an AC sub-grid and a DC sub-grid and the two sub-grids are connected through parallel bi-directional power converters. According to the provided control method, power interaction between the AC sub-grid and the DC sub-grid can be achieved and power support is carried out. A control link mainly comprises two parts of improved droop control and circulation current suppression control; an integral term of a reactive power control link is designed in improved droop control; and zero steady-state error tracking is carried out on voltage to achieve a relativelygood voltage control effect, thereby improving the suppression effect on zero-sequence circulation current. Dq0 three-axis control instead of traditional dq two-axis control is adopted by a circulation current suppression link, and an adaptive virtual damping-based circulation current suppression method is provided for the circulation current problem caused by device parameter differences, line impedance imbalance and the like of the parallel converters, thereby effectively suppressing the circulation current between the parallel bi-directional converters.

Description

technical field [0001] The invention relates to the field of AC / DC hybrid microgrids, in particular to a method for suppressing circulation of parallel converters in AC / DC hybrid microgrids based on adaptive virtual damping control. Background technique [0002] As the connection hub in the AC-DC hybrid microgrid, the bidirectional power converter has the advantages of high efficiency, low harmonics, adjustable power factor, and bidirectional power flow. application occasions. Therefore, a parallel redundant configuration of multiple modules with a common AC and DC bus is usually used to improve the capacity and operational reliability of the system. The common AC-DC bus structure provides a circulation path for zero-sequence circulating current, and due to the differences in system device parameters and unbalanced line impedance, it will inevitably lead to the generation of circulating current between parallel bidirectional power converter systems. The existence of zero-s...

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Problems solved by technology

[0004] In order to solve the circulation problem caused by the difference in device parameters and unbalanced line impedance of the AC-DC bus parallel bidirectional power converter in the AC-DC hybrid microgrid, the present invention designs a method based on adaptive virtual damping control for the defects of the prior art. Circulating Current Suppression Method for Parallel Converters in AC / DC Hybrid Microgrid

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