Stabilization and Performance Preservation of DC–DC Cascaded Systems by Diminishing Output Impedance Magnitude

Aldhaheri, Ahmed; Etemadi, Amir H.

doi:10.1109/tia.2017.2766045

Cited by 31 publications

(8 citation statements)

References 26 publications

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“…Fig. 15 depicts the experimental results under the same load changes, with all droop controllers designed in the proposed way [i.e., Z d (s) follows (15)]. Remarkably, the bus voltage undershoot and overshoot are successfully eliminated, verifying the feasibility of the proposed design method.…”

Section: A Buck-based DC Microgridmentioning

confidence: 78%

“…Based on these parameters, the current loop T i (s) [see (7)] and the voltage loop T v (s) [see (9)] are designed to have zero crossings at 1.2 kHz and 400 Hz, respectively. Afterwards, following (15) and neglecting the right-half-plane pole introduced by G vi (s) since it is not causal, the droop impedance Z d (s) of the boosttype DER converter can be expressed as:…”

Section: A Proposed Droop Impedancementioning

confidence: 99%

“…• In the beginning, taking account of control parameters like the switching frequency and the control delay (including computation time and PWM delay), a reasonable voltage control bandwidth f v can be set; (15) and further simplified by performing curve fitting. In the end, it is necessary to perform an overall check of the resulted closed-loop output impedance by analytical expressions or by simulation results.…”

Section: B Simplification Of the Proposed Droop Impedancementioning

confidence: 99%

“…Besides of hardware modifications, the output impedance can be also shaped by means of control solutions. In [15] and [16], an additional output voltage feedback path is added for the voltage control loop according to Mason's gain formula, so that the output impedance can be effectively shaped while preserving the voltage loop bandwidth. Voltage regulator modules, which are mainly buck converters serving as power supplies for microprocessors, are designed to have almost constant output impedance by means of tuning the parameters of voltage regulators [17]- [19].…”

mentioning

confidence: 99%

“…Experimental results under a step change of constant power load in buck-based microgrid, with the proposed Z d (s) expressed as(15). (a) 1.2 kW load step up.…”

mentioning

confidence: 99%

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Resistive–Capacitive Output Impedance Shaping for Droop-Controlled Converters in DC Microgrids With Reduced Output Capacitance

Liu

Mattavelli

Saggini

2020

IEEE Trans. Power Electron.

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In dc microgrids, droop control is widely employed in power converters interfacing distributed energy resources and common dc bus for automatic power sharing. In order to limit the dc bus voltage variations even during load transient conditions, it is necessary to shape the output impedance of droop-controlled converters to be always lower than the dc resistive value. A commonly used way is to install bulky output capacitance, which not only increases the system cost, size and weight, but also generates higher short-circuit fault currents. In order to avoid large output capacitance, this paper proposes a design approach for droop-controlled converters, including the selection criterion of the output capacitance and the design of the droop coefficient. Herein, the required output capacitance is calculated based on the dc droop coefficient and the voltage control bandwidth. The droop coefficient is designed as a frequency-dependent term instead of a constant value. As a result, resistive-capacitive output impedance can be obtained with a much smaller output capacitance. The proposed design strategy is applied to buck and boost converters and validated by experimental results performed on a buck-based and a boost-based dc microgrid prototype, respectively.

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Section: A Buck-based DC Microgridmentioning

confidence: 78%

Section: A Proposed Droop Impedancementioning

confidence: 99%

Section: B Simplification Of the Proposed Droop Impedancementioning

confidence: 99%

mentioning

confidence: 99%

“…Experimental results under a step change of constant power load in buck-based microgrid, with the proposed Z d (s) expressed as(15). (a) 1.2 kW load step up.…”

mentioning

confidence: 99%

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