Output impedance characteristics of interfaced converters of energy sources are the important indicators to assess the anti-interference ability of the dc microgrids. However, the output impedance is often approximately modeled by neglecting the impacts of delay units. In order to accurately study the anti-interference ability, the output impedance of an energy storage system is modeled with the consideration of the coupling characteristics of the current control gains and the delays caused by digital control and switching. The constraint mechanism of the coupling factors to impact the effective bandwidth of current loop in a load current feedforward system is also revealed. Then, an impedance shaping method is proposed to improve the anti-interference ability by optimally shaping the high-frequency output impedance, and also to improve system performances in terms of increasing the bandwidth of inner loop and the stable margin of outer loop. The simulation and experimental results both clearly validate the correctness and feasibility of the proposed impedance shaping method.

中文翻译：

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直流微电网中分布式双向DC-DC变换器的输出阻抗建模和高频阻抗整形方法


能源接口变流器的输出阻抗特性是评价直流微电网抗干扰能力的重要指标。然而，输出阻抗通常是通过忽略延迟单元的影响来近似建模的。为了准确研究储能系统的抗干扰能力，考虑电流控制增益的耦合特性以及数字控制和开关引起的延迟，对储能系统的输出阻抗进行建模。还揭示了负载电流前馈系统中影响电流环有效带宽的耦合因素的约束机制。然后，提出了一种阻抗整形方法，通过优化整形高频输出阻抗来提高抗干扰能力，并在增加内环带宽和外环稳定裕度方面提高系统性能。仿真和实验结果都清楚地验证了所提出的阻抗整形方法的正确性和可行性。