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.
High-Voltage DC (HVDC) transmission lines offer highly efficient transport of electric energy. If connected to comparatively weak AC grids, self-commutated converters are the proper choice, because they allow to stabilize the grid in case of faults by injecting reactive power. At high voltages of e.g. 400 kV Modular Multilevel Converters (MMC) fulfill all requirements. For testing all relevant aspects...
For model-based predictive control methods it is essential to predict the reaction of the whole system. Sampling of the converter-output-voltages needs unreasonably high sampling rates and is generally avoided. In consequence the converter behavior itself becomes a part of the model. This paper provides a theoretical description of the most relevant effects and gives guidelines for modeling the converter...
Hardware in the Loop (HiL) supports development processes in many types of applications. Power electronic systems with switching frequencies up to several kilo hertz constitute some of the most demanding applications for the quantization time of the HiL. The non-avoidable delay forces very short calculation periods which lead to high effort in hardware and software implementation. For PWM based controllers...
Current control systems and emulation systems (Hardware-in-the-Loop, HIL or Processor-in-the-Loop, PIL) for high-end power-electronic applications often consist of numerous components and interlinking busses: a micro controller for communication and high level control, a DSP for real-time control, an FPGA section for fast parallel actions and data acquisition, multiport RAM structures or bus systems...
In many power electronic applications the request of short development time demands reliable simulation studies to prove the control concepts in early developments stages and avoid critical behavior in real application. Simulation studies are sufficient to prove the general behavior of a control code. However, the platform architecture of the target hardware influences control behavior and code stability...
An identification of critical fault events within the power system enables situational awareness and the activation of corrective actions for HVDC systems. Recent publications deal with central implementation. This work proposes a local identification approach which is based on local measurements at the converter substations. The proposed methodology is introduced in detail subsequently. It is based...
High-voltage DC (HVDC) transmission lines offer highly efficient transport of electric energy. If applied to comparatively weak grids, self-commutated converters are the proper choice, because they allow stabilizing the grid in case of faults by injecting reactive power. At high voltages of e.g. 400 kV modular multilevel converters (MMC) fulfil all requirements. For testing all relevant aspects of...
High-voltage DC transmission lines in Germany will be established to transfer energy generated by wind power from north to south. This also compensates for the reduced generated power in the south following the phase-out of nuclear power. The associated transmission systems are planned for a rated power of 4 GW, making multiple converter stations on each side of the transmission line necessary. Also,...
Connecting renewable energy sources to the grid requires stable and reliable control algorithms. Especially in case of solar-energy systems, single-phase connection is often used at low power levels. This can be achieved by using a four-quadrant converter. For optimal reaction to variations of infeed (e.g. by shading by clouds) and grid disturbances, a fast reaction of the control is advantageous...
Induction machines are affordable and robust, presenting a valid option for electric vehicles. Many control schemes for such machines are known and have been published. With regard to fast torque dynamics and robustness against parameter variation, stator-flux-oriented control is a very favorable option. This paper presents a stator-flux oriented control which bases on a comprehensive model of the...
Model-based control of converter-connected assets is an option to establish excellent dynamics. Such a control strongly relies on the quality of the model used. In case of power-electronic converters, blanking-time effects introduces a large voltage error, especially at low output voltage. Blanking-time effects depend on the sign (and, to a lesser degree, on the magnitude) of the current flowing in...
Traction drives comprise all major challenges to electrical drive systems: High power, large torque, widely varying speed, fast dynamic reaction, compact design, high efficiency and robustness are some of the key aspects. Power-electronic devices feed the selected electric motor - their characteristics influence the design of the control by defining boundaries via maximum voltage, current and switching...
Voltage-source converters need grid-side filters to connect to the grid. These grid-side filters on the one hand couple the converter-generated grid-side voltages to the grid voltages and on the other hand mitigate the influence of the switching of the power-electronic devices of the converter on the grid. While uncontrolled diode bridges usually couple via inductances (due to their low switching...
Energy distribution currently relies mainly on ac grids, in general, and also on ships. With conventional ac motors and generators directly connected to the ac grid, this selection is sensible. As soon as converters are used for the optimized operation of devices, the advantages of ac grids become less prominent.
DC grids offer highly efficient distribution of electric energy, eliminating components and optimizing the use of cables. Efficient generation, however, is still based on AC generators. Power-electronic devices link generators and grid and customize energy flow to the loads. Efficient distribution with low losses demands high voltage, e.g. in the range of 10 kV for ship-size grids. Such voltages challenge...
Dynamic wireless charging is the process of supplying electrically driven vehicles along their driving path with electric energy via a wireless energy transfer system. To increase the range of electric vehicles, a dynamic charging lane is to be installed on a highway. With regard to the amount of power needed, supply of electric energy is a major concern. High-power overhead lines or cables are not...
Dynamic wireless electrical vehicle (EV) charging is the process of supplying electrically driven vehicles along their driving path with electric energy via a wireless energy transfer system. To increase the range of electric vehicles, a dynamic charging lane is to be installed on a highway. With regard to the amount of power needed, supply of electric energy is a major concern. High-power overhead...
Two main aspects demand for high-voltage long distance energy transfer from the north of Germany to the south: Increasing power generated by wind farms in the north and the need for secure and stable grid conditions in the south also after the nuclear phase out. Against this background Amprion and TransnetBW, two of the four Transmission System Operators in Germany, are planning the HVDC connection...
Offshore wind farms will contribute essentially to the generation of electrical energy in the coming years. In parallel, conventional power plants are going out of service. Especially in Germany the phase-out of nuclear power plants in the southern region of the country causes a significant regional power imbalance. Consequently, electrical energy has to be transported over long distances - a task...
A novel approach to flux-based control, ‘assessment-based flux trajectory optimization’ (AFO), is presented and analysed, which directly takes the properties of the converter into account. It seamlessly integrates stationary operation, slow and fast dynamics. The optimal flux trajectory is defined, based on the relatively few possibilities resulting from the discrete switching states of the converter...
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.