The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper presents a comparison of the small-signal stability properties for virtual synchronous machines (VSMs) with dynamic and quasi-stationary representation of the internal synchronous machine (SM) model. It is shown that the dynamic electrical equations may introduce poorly damped oscillations when realistic stator impedance values for high-power SMs are used. The quasi-stationary implementation...
The average value model of the Modular Multilevel Converter (MMC) is in general non-linear with time periodic variables. Recent developments demonstrated how the MMC model can be transformed into a a Steady-State Time Invariant (SSTI) representation allowing for linearization of the model. While previous modeling efforts for small-signal eigenvalue analysis considered mainly the classical Circulating...
This paper investigates the small-signal dynamics and stability of an isolated power system where voltage, frequency and power balance are controlled by a Voltage Source Converter (VSC) operated as a Virtual Synchronous Machine (VSM). The analysis is based on a linearized state-space model of the isolated power system, including the VSM with its control loops, a grid equivalent model with local loads,...
Accurate eigenvalue analysis of High Voltage Direct Current (HVDC) transmission systems depends on state-space models that are accounting for the frequency-dependent characteristics of the dc cables. A classical simplified model with cascaded pi-sections can be enhanced to capture the frequency dependency of cable parameters by adding parallel RL branches for representing the longitudinal impedances...
This paper presents a numerical analysis of the temperature profiles within the semiconductor devices of modular multilevel converters (MMCs). These temperature profiles are essential for assessing the power-cycling lifetime of IGBT modules, which influences the converter reliability. An electro-thermal simulation model has been established, combining a dynamic thermal model of the semiconductor devices...
Small-signal state-space analysis of power system stability relies on linearized models where steady state operation corresponds to constant values of all state variables. Such models are available and commonly used for analysis of configurations with three-phase 2- or 3-level Voltage Source Converters (VSC). However, the Modular Multilevel Converter (MMC), which is emerging as a preferred topology...
This paper proposes a simple method for damping of oscillations in dc grids based on Voltage Source Converters (VSCs). The damping effect is achieved by a control loop for counteracting measured dc voltage oscillations by acting on the active current reference of the ac-side VSC controller. The design of the damping method is supported by participation factor analysis and parametric sensitivities...
The Virtual Synchronous Machine (VSM) concept is emerging as a flexible approach for controlling power electronic converters in grid-connected as well as stand-alone or microgrid applications. Several VSM implementations have been proposed, with the emulation of inertia and damping of a traditional Synchronous Machine (SM) as their common feature. This paper investigates a VSM implementation based...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.