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Grid-connected doubly-fed induction generators suffer from limited fault ride-through capability during grid faults and disturbances. This paper proposes a control and energy management scheme for a DFIG-based wind energy conversion system with a converter-free battery energy storage that improves the quality of power delivered to the utility grid during normal operating conditions and enhances the...
The penetration level of decentralized power generation plants based on renewable energy sources are continuously increasing with wind energy having a significant share. Considering present developments towards a purely renewable energy based electricity supply, Wind Energy Conversion Systems (WECS) play an important role in securing a stable, reliable and continuous supply of energy. Particularly...
With the steady transition towards a more dominant decentralized power generation and the further reduction of conventional fossil fuel-based power plants, future utility grids require higher demands regarding voltage quality and supply reliability. Active power filters with energy storage capability, here referred to as Power Conditioning Systems (PCS), offer grid supporting and stabilizing measures...
Phase change materials can be used in various applications where thermal energy storage is needed, especially in renewable energy applications involving solar thermal and geothermal power Accurate modelling of these materials is needed for improved system design and optimization. Based on literature, two mathematical models are developed in this study, describing the one-dimensional transient heat...
The importance of mitigating Power Quality (PQ) disturbances by utilizing Active Power Filter (APF) has long since been recognized and extensive research on this field has been conducted resulting in a great diversity of solutions. Facing current ambitions e.g. in raising the share of power generation based on renewable energy sources will pose new challenges in maintaining system stability evoked...
The detection of the fundamental frequency and phase angle of the positive sequence grid voltages are utmost necessary for the proper operation of controlled active power converters, which require to operate stable and robust even during the presence of diverse power quality issues. There exist various utility grid synchronization and detection methods based on Phased-Locked Loop (PLL) techniques...
Strengthening the role of renewable energy sources for the supply of electric energy, wind energy is gaining increasing importance. The doubly-fed induction generator as preferred generator type combines several advantages of low cost, high efficiency and variable speed in a wide range. However, an appropriate control for its complex structure is essential for an efficient performance. Therefore,...
Particularly regarding the continuous development towards power systems with high penetration level of decentralized power generation units based on renewable energy sources, active power filters with energy storage capabilities are applied to perform grid supporting and stabilizing measures. Such devices, which are here referred to as power or grid conditioning systems, require appropriate control...
Wide deployment of renewable energy sources and decentralized power generation increases the need for improved power quality and advanced performance of renewable generating units under normal and abnormal conditions. The latest Grid Codes expect generators to remain connected during symmetrical and asymmetrical grid faults and to contribute to the system recovery. Asymmetrical voltage conditions...
Low power quality and supply reliability within industrial grids cause severe economic damage to Europe's key industry sectors. A modular shunt connected power conditioning systems with the objective of locally improving quality of supply within industrial grids has been proposed. One of its voltage-fed power converter based modules implements functionalities which are comparable to those of well...
The deterioration of power quality is posing an increasing problem for low and medium voltage grids. At the same time, grid codes place ever stricter requirements for the operation of distributed generation systems, especially regarding fault-ride-through capabilities during more severe grid fault events. Therefore, a proper operation of converter-based power systems needs to be guaranteed, requiring...
An increasing number of electrical motors are driven from frequency inverters. The losses in motor are increased because the produced nonsinusoidal stator voltages, supplied from IGBTs, contain significant harmonic components. Different PWM Methods cause different voltage harmonics. Depending on the control method, the motor characteristics and the partial load, the efficiency of the motor inverter...
The growing number of renewable energy sources and power electronic participants are increasingly endangering the quality of supply at distribution grid level. A modular shunt-connected power conditioning system featuring uninterruptible power supply capability is proposed to locally increase power quality and supply reliability. This paper proposes an operation-mode-adaptive cascaded control strategy...
Electric vehicles offer the capability to recover energy by electric braking and therefore to extend the range. Generally, the total demanded brake force of a vehicle is divided and allocated to the front and the rear wheels due to safety and stability issues. Consequently, common electric vehicles with only one central electric machine which drives one axle cannot exhaust the whole potential of recuperation...
Electric vehicles offer the capability to recover energy by electric braking and therefore to extend the range. Due to the dynamic axle load shift during brake applications and corresponding brake force distributions, drive train topologies with single front drive and single rear drive have different potentials with regard to recuperation. The axle load shift of a vehicle is significantly influenced...
This paper deals with a mobile phone application that allows the user to analyse their driving habits and therefore recognize whether an electric vehicle would suit the users' requirements. The application analyses the daily trips and charging possibilities, recorded as per user input. The resulting demands are compared to available electric vehicles as well as extended range electric vehicles and...
The presented paper introduces a sensor minimal battery observer, which allows the equipping of each stack with only one voltage and one current sensor, without losing the required individual cell measurement. The individual cell measurement is required not only for many Li-Ion applications with cell chemistry that can result in exothermic reactions. For a stack with 12 cells this can results in a...
Renewable energy sources have long since been recognized as environmental-friendly, sustainable and climate-neutral solution for future power systems. With the increasing penetration of renewable energy sources, particularly wind energy, as well as the growing percentage of power electronics-based devices and plants in the electrical supply grid, power quality issues ranging from voltage sags/swells,...
Sensors are established in many areas in the energy technology, drive technology or automotive industry. The range of sensors, which are used for the measurement of electrical quantities recorded over a decade in an enormous growth. The demand as well as the request to the sensor and in particular for the current, voltage sensors & temperature sensors have reshaped by technological progress. The...
This paper illustrates a LCL-filter design for a high power DCDC converter such as a buck boost converter for a battery charging application. The filter is used to reduce load current fluctuations in order to increase the quality of the charging current. It can be used in applications with high requirements on the load currents. A DCDC converter with a LCL filter can also be used to investigate different...
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