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Power Electronics and Applications, 2007 European Conference on

Date 2-5 Sept. 2007

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Displaying Results 1 - 25 of 596
  • Harmonic draining transformer-coupled boost-type rectifier systems with sinusoidal input currents

    Page(s): 1 - 9
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1365 KB) |  | HTML iconHTML  

    Novel double- and triple-rectifier systems coupled with a harmonic draining transformer and a harmonic blocking transformer are proposed. Both the systems can produce sinusoidal line currents when the dc output currents of the diode bridges are controlled in a quasi-triangular- or quasi-trapezoidal-shape, respectively. In comparison with a conventional PWM converter, the proposed systems have the advantages of lower switching-frequencies and smaller switching-currents. View full abstract»

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  • A five-level inverter scheme with common-mode voltage elimination by cascading conventional two-level and three-level NPC inverters for an induction motor drive

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (480 KB) |  | HTML iconHTML  

    Common-mode voltage generated by the PWM inverter causes shaft voltage, bearing current and ground leakage current in induction motor drive system, resulting in an early motor failure. This paper presents a common-mode elimination scheme for a five-level inverter with reduced power circuit complexity. The proposed scheme is realised by cascading conventional two-level and conventional NPC three-level inverters in conjunction with an open-end winding three-phase induction motor drive and the common-mode voltage (CMV) elimination is achieved by using only switching states that result in zero CMV, for the entire modulation range. View full abstract»

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  • High efficiency control methods for class-E resonant converter for step-down applications using Piezoelectric Transformers (PT)

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1492 KB) |  | HTML iconHTML  

    An array of solutions to handle the losses in switching mode power supplies such as zero-voltage-switching (ZVS), or as zero-current-switching (ZCS), have been developed and applied. There is still a limitation to eliminate the losses in the switching devices to be near to zero. The loss characteristics of a switching IGBT, such as turn-off switching loss due to the tail current under either ZVS or ZCS condition is defined as an important factor that limits the efficiency of the converter, especially in small size power supplies used at high operation switching frequency. In this work the dissipative energy of a resonant converter using PT is not reduced only by ZVS condition, but also by non-switched intervals during the operation, called burst mode. The system is classified to represent two cases of output load, called full load and light load. In the light load situation, the converter can optimize the transferred energy without losing the constant output regulation behaviour, which is done by burst mode control. Different burst mode classification methods between full load and light load have been investigated for different control techniques. The frequency based burst mode classification was evaluated to be most advantageous over phase-angle or switch current time interval observation, perspectively independent of the resonant converter topology. An active burst mode technique has been derived for output voltage feed-back. The work has been proved for a class-E topology, fulfilling the "code of conduct on efficiency of external power supplies" in a 3 Watts off-line power supply application. View full abstract»

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  • Universities collaboration in teaching power electronics

    Page(s): 1 - 8
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (134 KB) |  | HTML iconHTML  

    Novel inter-institutional activities in power electronics and adjustable motor drive education are proposed. Some valuable results of the methodical, research, and experimental work carried out by Tallinn University of Technology and St. Petersburg Electrotechnical University are presented. The paper is focused on the inter-disciplinary curriculum, the virtual e-learning electronic laboratory, the versatile approach to the course and diploma design, and the first experience in team design organization. An open access to the developed educational resources is provided via Internet. View full abstract»

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  • Multi-interleaved zero-ripple VRM to power future microprocessors

    Page(s): 1 - 8
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (813 KB) |  | HTML iconHTML  

    This paper presents a converter architecture derived from the buck topology with merging principle of the multi-interleaving and zero-ripple techniques. The converter not only produces zero-ripple output, but also provides low-ripple input, so that filter requirements in input and output sides can be reduced significantly. The proposed converter shows an ideal solution for future microprocessors. View full abstract»

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  • A simple feedback for parallel operation of current controlled inverters involved in UPS

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (235 KB) |  | HTML iconHTML  

    Thanks to the use of a novel modulation strategy, the inverters of a voltage source converter are under accurate current controls. Thanks to this strategy, the inverter gains are known. Then, the system open loop transfer function is deduced and a simple PID controller permits to target a good behaviour and a stable operation of the multi-inverter structure which could be involved in an UPS. View full abstract»

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  • A new structure of a switching flux synchronous polyphased machine with hybrid excitation

    Page(s): 1 - 8
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (872 KB) |  | HTML iconHTML  

    The aim of this paper is to present the structure of a new flux switching synchronous machine with hybrid excitation. This machine uses the flux switching principle where all the active parts are located on the stator. The rotor is only a salient passive rotor and can be robust and made with a low cost technology. This new machine can be supplied with electricity by means of a traditional three phase voltage converter or can be associated with a diode rectifier. The hybrid excitation is an association of permanent magnets and a wound exciter. View full abstract»

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  • General aspects of the electrical drive systems optimal control

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (255 KB) |  | HTML iconHTML  

    The optimal control of the transient state of the electrical drive systems with DC and AC motors is presented. Similar interesting results for different motor types are obtained. A simple implementable suboptimal solution is proposed. View full abstract»

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  • Additional application fields of a modern wind generator even at no-wind

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (747 KB) |  | HTML iconHTML  

    A modern variable speed wind turbine generator is connected to the lines (grid) through a both sides PWM controlled DC link voltage source inverter. The fast current control of the line currents by the line-side converter makes possible to compensate the deviation of the line currents from their fundamental component. This possibility can be used to compensate the lower order current harmonics in the line currents (injected by nonlinear loads on the lines) and to balance the negative sequence current component (caused by asymmetrical load). Besides, advanced control strategies make possible to control the reactive (and also the active) power of the lines, resulting in power factor correction. Since all the mentioned subjects of compensations require at most pulsating active power with zero mean value, the listed compensations are possible even at no-wind condition. Of course, the pulsating active power affects the pulsation of the dc link voltage, the limits of the compensations in this sense must be investigated. All the investigated additional application fields improve the power quality of lines (grid) where the wind turbine generator is connected to. The practical aim of this paper is to attract the attention of the wind turbine makers to these additional application fields. The paper presents the advanced possible line-side converter control schemes. The physical and theoretical background of the different compensations are discussed. The issues of their implementation by the presented control methods are detailed. The methods are investigated and validated by simulations of practical examples. Design criteria are given based on the considerations. View full abstract»

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  • DC-reactor-less hybrid DC-DC converter with a core composed of four legs

    Page(s): 1 - 7
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (689 KB) |  | HTML iconHTML  

    Efficiency improvement and cost reduction are important requirements for the design of DC-DC converters. Zero voltage switching is one good solution for increasing efficiency, and an active clamp circuit is useful for implementing it effectively. A cost reduction could be achieved by devising a new transformer that functions not only as a conventional transformer but also as a DC reactor that reduces the switching device peak current. The magnetic core of the new transformer is composed of four legs. A novel hybrid DC-DC converter in which forward and fly-back converters are combined by using the transformer was developed. However, no design methodology for such a transformer has yet been established. Therefore, the modeling of the excitation circuit of the transformer is required. This paper proposes a novel method that simulates the operations of the DC-DC converter and estimates the magnetic flux distribution in the new transformer. The magnetic circuit of the transformer is transformed into its equivalent electric circuit with two ideal transformers. The performance of the DC-DC converter was examined by circuit simulations including the magnetic circuit of the transformer. Circuit simulation results agree fairly well with experimental ones. View full abstract»

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  • A novel space vector modulation control strategy for three-leg four-wire voltage source inverters

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1086 KB) |  | HTML iconHTML  

    One of the desirable characteristics of inverters in three-phase systems is the ability to feed unbalanced loads with voltage and frequency nominal values. This paper introduces an innovative control method in combination with a three dimensional space vector modulation (3D-SVM) control strategy. It is able to feed grids with unbalanced loads while reducing the switching frequency losses. The results from this study show that the developed control scheme in combination with three-leg four-wire inverters can carry out the grid feeding requirements under extreme unbalanced load conditions efficiently. View full abstract»

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  • EPE 2007 Aalborg, Denmark 2-5 September 2007

    Page(s): 1
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (842 KB)  

    First Page of the Article
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  • An online control strategy for a modular DC coupled hybrid power system

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (697 KB) |  | HTML iconHTML  

    This paper describes how different power sources of a hybrid power system may be connected together through a DC bus and then to a grid through a main inverter in such a way that a decoupling between the state variables of the power sources and the state variables of the grid is achieved. A layout showing such a structure will be presented, and an online control strategy for this layout will be developed to show that it is modular, expandable and easily controllable. The behavior of such a structure under different load and meteorological conditions will be investigated by applying the developed control strategy to a simulation model. Moreover, a PV/battery hybrid power system was successfully built up including control functions for the system management. These control functions have been developed and integrated into a standard industrial soft PLC terminal. Finally, the results of the simulation and experimental case study will be introduced and discussed. View full abstract»

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  • Dynamic characterization of power converters for distributed power supply

    Page(s): 1 - 9
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (387 KB) |  | HTML iconHTML  

    The lasts generations of microprocessors have shown an increase in the operating frequency and, of course, in the supply characteristics. The different need of power requested made necessary new solution for the distributed power supply architectures (DPA) and claimed the use of converters suitable to meet the new high efficiency and high power exigencies. This paper is focused on the design and dynamic characterization of a DC-DC converter specifically devoted for telecom/networking/computing applications: a Switch in Line Converter (SILC). Its analysis has been obtained by means of a dedicated automatic tool, FREDOMSIM, and accomplished over its whole operating area: with different output power and load typologies (resistive, current sink and constant power). The proposed power cell exhibits a pseudo-first order dynamics, optimum for the design of an external feedback network characterized by large stability margins for all the operative conditions. Comparisons with the experimental data, given in the paper, will confirm the predictions. View full abstract»

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  • Design and implementation of a fuzzy controller for wind generators performance optimisation

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (365 KB) |  | HTML iconHTML  

    Actual wind power costs together with incentives and financing options for developing renewable energy facilities make wind energy source competitive with conventional generation sources and it is believed that wind energy will be the most cost effective source of electrical power in the next future. However, the wind power production diffusion involves the development of efficient control systems able to improve wind systems effectiveness. Therefore, a design methodology, able to generate an adaptive fuzzy model for maximum energy extraction from variable speed wind turbines is proposed in this paper. The fuzzy model is designed by using fuzzy clustering combined with genetic algorithms (GA) and recursive least- squares (LS) optimisation methods. Some simulation results on a doubly-fed induction generator confirmed that the proposed design methodology is able to identify a Takagi-Sugeno-Kang (TSK) fuzzy model exhibiting adaptivity, learning capability, high speed of computation and low memory occupancy. View full abstract»

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  • A single sensor type MPPT control method for PV generation systems

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (364 KB) |  | HTML iconHTML  

    This paper introduces a new MPPT control method for solar photovoltaic (PV) power generation systems. The proposed method include its ability to perform MPPT using only a single solar cell voltage detection sensor and simultaneously predicting the voltage necessary for load voltage control, which is essential to real systems. As a result, this control method offers advantages of the simplified hardware configuration and the low cost. View full abstract»

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  • Predicting the influence of placement of passive components on EMI behaviour

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1546 KB) |  | HTML iconHTML  

    The EMI behavior of power electronic systems is severely influenced by the placement of passive components. Particularly filter components are affected by magnetic field coupling reducing filter performance. This contribution demonstrates the urgent demand for a method predicting EMI behavior on a typical power electronic system. The method comprises a combination of circuit and field simulation. Therefore investigations on stray fields of passive components had to be carried out, which enable the derivation of placement rules and furthermore an automated placement. Using the proposed method in the design stage reduces development costs and allows a statement on achievable performance with selected components. View full abstract»

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  • EPS system analysis using multi domain simulation for conventional 12V power network design in a vehicle

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (432 KB) |  | HTML iconHTML  

    An EPS system requires large electrical power depending on steering torque. Recently, the required steering torque is getting larger especially for luxury sedans and large Sports Utility Vehicles. In heavy vehicles, the steering without driving and the emergency steering are becoming a very heavy load for a conventional 12V battery system. Therefore, it is important to estimate the battery power management and the voltage behavior using the multi domain simulation for concept planning. The purpose of this research is to show that multi domain simulation is effective to discuss power electronics system and power network in the vehicle. This paper describes modeling method for an EPS system using VHDL-AMS [1] [2]. Static steering and dynamic steering results were validated in comparison with experimental data View full abstract»

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  • Speed measurement and estimation algorithms in AC Induction Motors

    Page(s): 1 - 9
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (353 KB) |  | HTML iconHTML  

    In this paper, the multiple period speed measurement is compared with the classical frequency and/or period methods used. The proposed speed method is used to examine the quality of the three implemented speed estimators. These estimators get the information from measured stator currents and from motor stator voltage. Open loop estimators or observers are used to estimate rotor or stator flux and rotor speed to use as feedback signals. An improved open loop estimator, an MRAS, and an EKF observer are tested utilizing a 7.5 kW induction motor. They have different accuracy, robustness and sensitivity against parameter variations and all of them have the same problem when the rotor speed is around zero. View full abstract»

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  • New algorithm for grid synchronization based on Fourier series

    Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (257 KB) |  | HTML iconHTML  

    This paper presents a new digital open loop architecture as an alternative to Phase locked loops (PLLs) for grid synchronization. The system calculates in real time the Fourier coefficients of the input signal fundamental component using a heterodyning algorithm. Once the fundamental components are calculated the system can reconstruct the input fundamental signal and calculate its phase angle, frequency and amplitude. The measuring process of the Fourier components require to hlter even harmonic components internally generated; this process is made with a moving average comb filter (MVA) tuned for these even harmonics. The performance of the system is demonstrated with experimental results. View full abstract»

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  • Three phase current source auxiliary resonant commutated pole inverter using IGBTs

    Page(s): 1 - 11
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (645 KB) |  | HTML iconHTML  

    To reduce the losses of power inverters, resonant topologies replace hard switching power inverters. This paper shows the first investigations and measurements carried out to design a three phase current link power inverter in ARCP (auxiliary resonant commutated pole) topology as well as the finally measurements and results achieved with the complete system. View full abstract»

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  • Efficient scheduler-dispatcher software architecture of the spacepower facility distributed control computer

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1090 KB) |  | HTML iconHTML  

    The system software architecture of the distributed control computer (computer network) of the mechatronic scientific facility (crystallizer) for automatic high temperature material processing in a orbital space station in micro-gravitation environment is presented in this paper. The scientific facility consists of the multi-zone high temperature furnace with heating system, PWM controlled heating converters, the precise extra low speed vibration-less electric drives to make possible to manipulate the processed material samples during experiments, very precise temperature measurement module, telemetric channel, crew interface computer, free programmable central controller and several further units. Facility computer network nodes have many user tasks (processes) divided into many threads running in real time environment. Using preemptive real time operating system tends to have unacceptable high overhead therefore the system of table driven coroutines with low system resource requirement (overhead, stack space) was designed. Emphasis is given on the design of efficient, reliable and self documented scheduler-dispatcher of the user tasks with minimized overhead and easily extensible descriptors of table driven user finite state automata. Presented scheduler architecture is used in the distributed network control computer of newly designed facility (Advanced TITUS) intended to be placed in the ISS space station. It is advanced version of the proved software utilized in the distributed control computer of the TITUS scientific equipment which was successfully operated several years in the MIR orbital station especially during ESA missions EUROMIR. View full abstract»

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  • Design of avalanche capability of Power MOSFETs by device simulation

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (839 KB) |  | HTML iconHTML  

    The avalanche behavior of new 150 V trench power MOSFETs was designed with the help of two- dimensional device simulation techniques. The devices employ the compensation principle for low on-state losses. A new edge-termination structure ensures that avalanche breakdown always occurs in the cell region of the device. For the transistor cells, two different destruction regimes were identified: energy-related destruction and current-related destruction. Possible simulation approaches to account for the different effects were proposed. The found dependence on design parameters based on device simulation was qualitatively confirmed by experimental results. Furthermore, strong dependence between on-resistance and avalanche current was shown. View full abstract»

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  • Matrix converter with advanced control for contactless energy transmission

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1297 KB) |  | HTML iconHTML  

    The use of a matrix converter for contactless energy transmission in the power range of several kilowatts reduces the number of energy conversion steps, avoids electrolytic DC link capacitor on the primary side, reduces losses in power semiconductors and enables sinusoidal line currents and a four- quadrant operation. In his application as a feeding converter a high output frequency is required (greater than 100 kHz). The transferable electric power and the efficiency of contactless magnetic systems can considerably be improved. Because of the high output frequency, high-performance signal processing elements are needed. To get a constant d.c. output voltage the matrix converter offers new concepts for regulating variables. The paper describes special aspects of new control and regulating techniques of the three phase matrix converter in combination with contactless energy transmission. View full abstract»

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  • A mathematical description of control method on the basis of difference correction

    Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (182 KB) |  | HTML iconHTML  

    In this paper, a mathematical description of the control method on the basis of difference correction [1] applying to sampled-data systems is considered. The difference correction is an efficient way to improving the dynamic characteristics of the pulse power converters, which work is described by difference equations. Proposed method allows transforming a difference equation so that the roots of the characteristic equation become equal to zero. Herewith the maximum speed of convergence of transient to a steady value in the field of it's environ under perturbations of system parameters is achieved. Using the example of a system for stabilizing the load current of a buck converter it is shown that the transient is completed within two or three periods. View full abstract»

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