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Keywords

bus impedance, DC microgrids, on line estimation, optimized control, stability

Abstract

In modern DC microgrids, distributed power sources are connected to the common DC bus through power electronic converters. Although the control loop of the converter has good stability margin, the interconnection of multiple converters may affect the microgrid dynamic performance and stability. Therefore, in order to ensure the required dynamic performance of the multi?converter system, a DC bus impedance peak estimation method based on the phase margin of the voltage loop is proposed in this paper. On this basis, an optimized control scheme for the DC bus impedance is further proposed. And through experiments to verify the effectiveness of the proposed control method. First, derive the expression of DC bus impedance based on the voltage control loop gain of the source?side converter; then, through reasonable assumptions, the DC bus impedance peak value is estimated based on the phase margin of the voltage control loop; finally, through the voltage control A sinusoidal signal is injected into the loop to continuously monitor the peak value of the bus impedance. By optimizing the control parameters of the voltage regulator, the peak value of the DC bus impedance is effectively reduced. The experimental results show that the proposed monitoring scheme could reduce the measurement and the calculation burden, and the optimized control scheme improves the stability and dynamic performance of the DC microgrid.

DOI

10.19781/j.issn.1673-9140.2023.01.018

First Page

154

Last Page

163

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