Modelling and measuring complex impedances of power electronic converters for stability assessment of low-voltage DC-grids

Ott, Leopold; Han, Yunchao; Stephani, Oliver; Kaiser, Julian; Wunder, Bernd; März, Martin; Rykov, Kirill

doi:10.1109/icdcm.2015.7152009

Cited by 11 publications

(3 citation statements)

References 5 publications

(6 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Switching operations may generate high-frequency ac currents and can cause the LVDC grid to oscillate, which may occur in particular when networks are reconfigured, e.g. when adding or removing loads and sources, see Ott et al (2015a). Figure 4 shows a simplified model of a four-terminal DC microgrid network (4-TLN), as can be realised in an experimental laboratory setup.…”

Section: Stability Of Lvdc Networkmentioning

confidence: 99%

Optimization over decision trees: a case study for the design of stable direct-current electricity networks

et al. 2023

View full text Add to dashboard Cite

In many real-world mixed-integer optimization problems from engineering, the side constraints can be subdivided into two categories: constraints which describe a certain logic to model a feasible allocation of resources (such as a maximal number of available assets, working time requirements, maintenance requirements, contractual obligations, etc.), and constraints which model physical processes and the related quantities (such as current, pressure, temperature, etc.). While the first type of constraints can often easily be stated in terms of a mixed-integer program (MIP), the second part may involve the incorporation of complex non-linearities, partial differential equations or even a black-box simulation of the involved physical process. In this work, we propose the integration of a trained tree-based classifier—a decision-tree or a random forest, into a mixed-integer optimization model as a possible remedy. We assume that the classifier has been trained on data points produced by a detailed simulation of a given complex process to represent the functional relationship between the involved physical quantities. We then derive MIP-representable reformulations of the trained classifier such that the resulting model can be solved using state-of-the-art solvers. At the hand of several use cases in terms of possible optimization goals, we show the broad applicability of our framework that is easily extendable to other tasks beyond engineering. In a detailed real-world computational study for the design of stable direct-current power networks, we demonstrate that our approach yields high-quality solutions in reasonable computation times.

show abstract

Section: Stability Of Lvdc Networkmentioning

confidence: 99%

Optimization over decision trees: a case study for the design of stable direct-current electricity networks

et al. 2023

View full text Add to dashboard Cite

show abstract

“…In addition to the converter's droop curve impedance, the output capacitor's impedance Z C,out and the converter's current control loop bandwidth has to be taken into account [2]. With those parameters, a simplified control loop can be set up to perform a stability analysis, as shown in [10]. The analysis can be used to check if G Droop is in range for a stable grid operation.…”

Section: A Global Properties and Mains Supplymentioning

confidence: 99%

“…The analysis can be used to check if G Droop is in range for a stable grid operation. For details, see [2] and [10].…”

Section: A Global Properties and Mains Supplymentioning

confidence: 99%

State of Charge Based Characteristic Diagram Control for Energy Storage Systems within Industrial DC Microgrids

Mannel

Knochelmann

Tappe

et al. 2019

2019 IEEE Third International Conference on DC Microgrids (ICDCM)

View full text Add to dashboard Cite

In this paper, a state of charge (SoC) based characteristic diagram control concept for energy storage systems (ESS) within an industrial direct current (DC) microgrid is proposed. The inputs are the SoC of the ESS and the terminal voltage of the DC microgrid. The output is the charge and discharge current for the converter, which connects the ESS with the DC microgrid. An appropriate design concept for the characteristic diagram is then investigated to achieve a flexible control reacting on changing conditions within the DC microgrid. These could be a temporary overload, due to a changing number of grid participants or an additional feed-in through a photovoltaic (PV) system. The characteristic diagram design concept is even applicable without a deep knowledge of the load profile of the DC microgrid. The concept was analyzed and evaluated based on simulations with load profiles from robot cells. The results show that the SoC depends on the current load of the DC microgrid. If the load returns to average, the SoC of the ESS inclines back to the nominal SoC, which is pre-defined by the grid operator. Furthermore, in case of an appropriate design of the characteristic diagram, it can protect the ESS against overcharging or deep discharging.

show abstract

Netzmanagement

Ott,

Schaab,

Männel

et al. 2020

Die Gleichstromfabrik

View full text Add to dashboard Cite

Modelling and measuring complex impedances of power electronic converters for stability assessment of low-voltage DC-grids

Cited by 11 publications

References 5 publications

Optimization over decision trees: a case study for the design of stable direct-current electricity networks

Optimization over decision trees: a case study for the design of stable direct-current electricity networks

State of Charge Based Characteristic Diagram Control for Energy Storage Systems within Industrial DC Microgrids

Netzmanagement

Contact Info

Product

Resources

About