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EPE-PEMC 2008 - Topic: Power Converters
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	A 13.56 MHz Current-Output-Type Inverter Utilizing an Immittance Conversion Element   By Yosei Sakamoto, Keiji Wada and Toshihisa Shimizu	[View]   [Download]
Abstract: High frequency plasma processing techniques are utilized in the field of industrial manufacturing. High frequency plasma generators are traditionally composed of analog amplifiers, although their conversion efficiencies are limited up to 50 \%. A current-output-type inverter, composed of an immittance conversion element, that enables constant current injections to the loads and megahertz plasma discharging with high conversion efficiency. A novel resonant gate driver is also proposed to achieve not only 10 MHz range operation, but a low driving power. Design and analysis of the proposed inverter was carried out, resulting in an increasing of efficiency up to 72.7 \% at 13 MHz.
	A Bit-Stream Based PWM Technique for Variable Frequency Sinewave Generation   By N. D. Patel	[View]   [Download]
Abstract: This paper presents a unique technique suitable for the generation of variable frequency sinusoidal waveforms with high quality. Arithmetic operations on the bit streams are performed through digital blocks. The proposed technique is simple and can be implemented on an field programmable gate array (FPGA). Results of a prototype single-phase inverter module with custom built power stage, are presented with simulations. Experimental results indicate that the technique can generate sinusoidal waveforms of frequencies from 20Hz-60Hz with total harmonic distortion (THD) 1.4-4\%, respectively, and therefore the technique would be an ideal candidate for variable speed motor applications.
	A Comparison and Optimum Design of Reluctance-Controlled Classical Load-Resonant Converters   By Stefan V. Mollov	[View]   [Download]
Abstract: Fundamental frequency analysis is used to obtain the steady-state operation of the three most popular load resonant converters, when operated with limited frequency range due to a variable inductance. The power throughput is regulated by electronically varying the reluctance of the resonant inductor. The developed design equations indicate that the converters operate efficiently in the region of maximum control gain, with a phase around 35 degrees. The validity of the proposed design equations and the identified optimum operating conditions are confirmed through time-domain simulations and measurements from a 200 W, 500 kHz prototype of a series-parallel resonant converter.
	A Low-Loss DC-DC Converter for a Renewable Energy Converter   By David S. Thompson	[View]   [Download]
Abstract: The maximization of energy transfer from a low-voltage source to a grid is investigated. The converter has two stages, a DC-DC converter followed by an inverter. Attention to the DC-DC converter losses shows how its energy transfer is maximized and found to be acceptable.
	A Modular AC/DC Rectifier Based on Cascaded H-Bridge Rectifier   By H. Iman-Eini	[View]   [Download]
Abstract: In this paper, a modular AC/DC rectifier for converting the medium voltage (MV) to the low voltage (LV) levels is presented. The proposed rectifier includes two stages: the cascaded H-bridge (CHB) converter and the isolated DC/DC converters. The CHB converter is directly connected to the MV levels and it eliminates the necessity for heavy and bulky step-down transformers, corrects the input power factor, and maintains the voltage balance across the capacitor voltages. The second stage includes the high frequency parallel-output DC/DC converters, which are connected to the primary DC buses. The second stage provides the galvanic isolation, regulates the output voltage, and attenuates the low frequency voltage ripple (2fline) generated by the first stage. The active load-current sharing technique is utilized to balance the load power among the parallel converters. The detailed analysis for modeling and control of the proposed structure is presented. The validity and performance of the proposed topology is verified by a laboratory scaled prototype.
	A Multi-Drive System Based on a Two-Stage Matrix Converter   By Dinesh Kumar, Patrick W. Wheeler, Jon C. Clare and Lee Empringham	[View]   [Download]
Abstract: Multi-drive systems can be used in situations where several motors are mechanically connected. Such systems have applications in both industrial and aerospace applications, where they can be used to provide system redundancy. In conventional systems the power converter for the motor drive is based on a rectifier and inverter, leading to the requirement for large passive components such as DC-link capacitors. This paper proposes a multi-drive system based on a two-stage direct power converter. In this topology a direct converter uses two output stages with a single input bridge, eliminating the need for large passive components. Simulation results are included to demonstrate the feasibility of the proposed topology.
	A New Approach to High Efficiency in Isolated Boost Converters for High-Power Low-Voltage Fuel Cell Applications   By Morten Nymand	[View]   [Download]
Abstract: A new low-leakage-inductance low-resistance design approach to low-voltage high-power isolated boost converters is presented. Very low levels of parasitic circuit inductances are achieved by optimizing transformer design and circuit lay-out. Primary side voltage clamp circuits can be eliminated by the use of power MOSFETs fully rated for repetitive avalanche. Voltage rating of primary switches can now be reduced, significantly reducing switch on-state losses. Finally, silicon carbide rectifying diodes allow fast diode turn-off, further reducing losses. Test results from a 1.5 kW full-bridge boost converter verify theoretical analysis and demonstrate very high efficiency. Worst case efficiency, at minimum input voltage maximum power, is 96.8 percent and maximum efficiency reaches 98 percent.
	A New Zero Voltage Transition Synchronous Buck Converter   By Swapnajit Pattnaik
Abstract: This paper proposes a zero-voltage transition (ZVT) PWM synchronous buck converter, which is designed to operate at low output voltage and high efficiency typically required for portable systems. To make the DC-DC converter efficient at lower voltage, synchronous converter is an obvious choice because of lower conduction loss in the diode. The high-side MOSFET is dominated by the switching losses and it is eliminated by the soft switching technique. Additionally, the resonant auxiliary circuit designed is also devoid of the switching losses. Theoretical analysis, computer simulation, and experimental results are presented to explain the proposed schemes.
	A Novel Control Method for IGBT Current Source Rectifier   By Longcheng Tan	[View]   [Download]
Abstract: A novel power factor control and power flow control method for IGBT current source rectifier is proposed in this paper. Unlike the conventional control method in the a-b-c three-phase stationary frame, the proposed control is based on the d-q rotating frame. The proposed power factor compensation scheme can provide maximum achievable power factor under all operating conditions, including the regenerative mode. What's more, the scheme is parameter insensitive, which can improve the system's stability. Due to the IGBT's switching character, the Space Vector Modulation (SVM) is adopted, so the fast dynamic response and the little harmonic content can be achieved. Simulation results are provided to verify the theoretical analysis.
	A Power Converter for Fault Tolerant Machine Development in Aerospace Applications   By Liliana de Lillo	[View]   [Download]
Abstract: This paper describes an experimental tool to evaluate and support the development of fault tolerant machines designed for aerospace motor drives. Aerospace applications involve essentially safety critical systems which should be able to overcome hardware or software faults and therefore need to be fault tolerant. A way of achieving this is to introduce variable degrees of redundancy into the system by duplicating one or all of the operations within the system itself. Looking at motor drives, multiphase machines such as multiphase brushless dc machines are considered to be good candidates in the design of fault tolerant aerospace motor drives. The paper introduces a multi-phase two level inverter using a flexible and reliable FPGA/DSP controller for data acquisition, motor control and fault monitoring to study the fault tolerance of such systems.
	A Procedure to Optimize the Inductor Design in Boost PFC Applications   By Florent Liffran	[View]   [Download]
Abstract: This paper will explore the constraints for designing the inductor in a Boost Power Factor Corrected (PFC) converter working in continuous current mode (CCM). An original method will be proposed to optimize the inductor design by focusing on the possibilities offered by a given core in function of its winding parameters. Optimal current ripple and inductance value will be determined for each application. The influence of the switching frequency will also be quantified, as well as a pertinent comparison between the different powder core materials.
	A Single Active Edge-Resonant Snubber Cell-Assisted ZCS Half-Bridge DC-DC Converter with Constant Frequency Asymmetrical PWM Scheme   By Tomokazu Mishima	[View]   [Download]
Abstract: A newly-developed zero current soft-switching (ZCS)-PWM cell-assisted asymmetrical half-bridge (AHB) DC-DC converter topology with a high frequency (HF) link is presented in this paper. The soft-switching half-bridge DC-DC converter consists of a PWM-controlled singleended half-bridge HF inverter and a center-tapped rectifier linked by a HF transformer. In order to attain the wide range of ZCS commutation in the primary-side HF inverter, the active edge resonant snubber cell composed of a switched capacitor and a lossless inductor is adopted in the halfbridge leg, providing ZCS commutation for a wide range of output power under constant switching frequency. The operation characteristics of the proposed DC-DC converter are described, and its feasibility data is demonstrated and evaluated with simulation and experimental results.
	An Isolated Full-Bridge DC/DC Converter with Bidirectional Communication Capability   By Lon-Kou Chang	[View]   [Download]
Abstract: This work presents a novel isolated full-bridge DC/DC converter with bidirectional communication capability. The transformer in the proposed converter is utilized as an isolation interface for transferring energy and data. Power delivery and forward data transfer are conducted simultaneously by modifying the full-bridge switching phase. Backward data transfer is realized by manipulating the amplitude of the resonant signal through modulating the impedance of the resonant tank at the secondary side of the transformer. Finally, the operation principle of the proposed converter was verified on a 280 mW prototype operating at 400 kHz from a 12 V DC input.
	Analysis of a Device for Converting a Unipolar Input Voltage into Two Symmetric Bidirectional Output Voltages with a Magnetically Coupled Coil   By Felix. A. Himmelstoss	[View]   [Download]
Abstract: A new principle of a DC-DC converter with a magnetic coupled coil is analyzed. The speciality of this converter is that it transforms a unipolar input voltage into two symmetrical bidirectional DC voltages with only one power switch. The value of the output voltage can be varied by the duty cycle of the switch. The generation of two symmetrical voltages, one positive and one negative related to ground, makes it possible to invert a DC voltage to a single phase AC network with only three switches. For the operation of a class - D amplifier, for multi quadrant operation of DC motors or actuactors a symmetrical bidirectional supply voltage can also be very useful. After basic analysis in continuous inductor current mode, dimensioning of the converter components, a state space model and linearized transfer functions for the control of the converter are derived.
	Analysis of Capacitor Dividers for Multilevel Inverter   By Oleg Sivkov	[View]   [Download]
Abstract: This paper analyses a possibility for realization of multilevel inverters. After general description of all famous solutions, the focus is paid on Diode Clamped Multilevel Inverters (DCMI) and Flying Capacitor Multilevel Inverters (FCMI). The comparison of topological structure differences and control strategies is presented. The special focus is paid to balancing of voltages on capacitors. Switching states and their transitions of three-level inverter allow to balance capacitor voltages in both types of inverters, DCMI and FCMI, where DCMI requires less capacitor power size than FCMI to achieve the same capacitor voltage swinging. However in higher-level DCMI (more than 3) capacitor voltage balancing generally is not able. FCMI control strategy is possible for all level. Special control strategy for five-level DCMI capacitor voltage stabilization is briefly described. Advantages and disadvantages of DCMI and FCMI are compared for the same output power.
	Analysis of Multipulse Rectifiers with Modulation in DC Circuit in Vector Space Approach   By Andrzej Kapłon and Jarosław Rolek	[View]   [Download]
Abstract: Rectifiers consisting of parallel connected 6- pulse bridges with modulation in DC current circuit show properties of 24-, 36-pulse or multipulse rectifiers. The analysis of such rectifiers was conducted by means of the space vector method. A load unbalance of the component bridges of 12-pulse rectifier generates the intermediate position of space vector on a complex plane. An increase in the number of the intermediate positions approximates the space vector to the case of rotating one. In this paper topologies of multipulse rectifiers with modulation in DC current circuit are presented. The simulation results of investigations were obtained by means of the space vector for control of modulators.
	Capacitor Clamped Multilevel Matrix Converter Controlled with Venturini Method   By Janina Rząsa	[View]   [Download]
Abstract: The article is discussion with Authors of [21], who have presented proposal of multilevel matrix converter scheme. Because the Authors have shown results of research involved only with one phase output multilevel matrix converter and suggested application one of known modulation methods to control of three phase scheme, this paper undertakes this problem. New elements of power scheme are added. Venturini modulation method is examined. Improvement of waveforms synthesized at output and reduction of reverse voltages on semiconductor elements is achieved only for the case when multilevel matrix converter operates at output frequency equal the supply voltage frequency.
	Characteristics of the Single Active Bridge Converter with Voltage Doubler   By Andreas Averberg	[View]   [Download]
Abstract: This paper investigates the single active bridge dc-dc converter with voltage doubler. An analytical investigation is given, completely describing the operating behaviour of the converter. Herewith, the impact of the transformer's properties and a calculation of the current stress of the semiconductors and passive devices is shown. The results are compared to the single active bridge with full bridge rectifier. With regard to a small ripple current at the converter input, the results can be used as a tool for an optimised converter design. All results are compared to simulations. A 1.2 kW prototype was built, and measurement results are given.
	Comparative Study on Paralleled vs. Scaled Dc-dc Converters in High Voltage Gain Applications   By Pawel Klimczak and Stig Munk-Nielsen	[View]   [Download]
Abstract: Today power converters are present in many commercial, medical and industrial applications. A lot of them are high power and high current applications. In order to increase power handling capability several transistors or diodes are paralleled often. However such paralleling may lead to converter's performance degradation or switches quick failure. A parallel modular converter built of many paralleled modules may be an interesting alternative, while a modular converter provides well known advantages like scalability, improved reliability and lower cost. This paper investigates possibility of improving an efficiency by intelligent usage of a modular boost converter in a high voltage gain application.
	Consideration for Input Current-Ripple of Pulse-Link DC-AC Converter for Fuel Cells   By Kentaro Fukushima	[View]   [Download]
Abstract: This paper mentions the static characteristics of pulse-link DC-AC converter for fuel cells, and considers the input current-ripple reduction method. Fuel cells have weakness about current-ripple because the chemical reaction time is much slower than commercial frequency. Therefore, the input current-ripple reduction is essential factor in the DC-AC converter for fuel cells applications. Input current-ripple from fuel cells gives damage the fuel consumption and life time. The conventional DC-AC converter has large smoothing capacitor between boost converter stage and PWM converter stage, in order to reduce input current-ripple. That capacitor prevents from reduction the size of unit. Authors have proposed a novel topology called as pulse-link DC-AC converter. The pulse-link DC-AC converter topology is no need to insert large capacitor. Furthermore, the series-connected LC circuit between two stages connected in parallel works as ripple canceling. This paper shows the mechanism of current-ripple reduction.
	Consideration of Conduction Losses for the Series Resonant Converter by Means of a Simple Extension to the SPA Approach   By Alexander Bucher, Thomas Duerbaum, Daniel Kuebrich and Markus Schmid	[View]   [Download]
Abstract: The cumbersome derivation of the steady-state characteristics of resonant converters can be simplified by means of the state-plane analysis. Under the assumption of ideal components, a closed-form solution can be derived in case of the series resonant converter above the resonant frequency. However, losses due to parasitic resistances cannot be easily included within this approach. Nevertheless, a more precise prediction of the converter's output characteristics taking the conduction losses into account is desirable. Therefore this paper describes a simple extension to the regular approach that leads to better agreement with measurements. This approach is based on the results derived under ideal assumptions, thus avoiding a more complicated and tedious analysis including the conduction losses.
	Control Strategies of the Quasi-Resonant DC-Link Inverter   By Slawomir Mandrek	[View]   [Download]
Abstract: Control strategies of a parallel quasi resonant dc link voltage inverter (PQRDCLI) for electrical drive applications are considered. The main objectives of the proposed strategies are feasibility and robust operation of the PQRDCLI vis-à-vis output voltage dU/dt limitation and stable duration of zero voltage intervals. The first strategy is based on controlling equal charge and discharge of the input series capacitor bank. By applying in the second strategy, external dc link voltage power supply converters one can precisely stabilize both the output voltage derivatives and zero voltage interval. Finally, in the third sensorless strategy - constant intervals are applied with the floating capacitor midpoint potential variations.
	DC-DC Converters with FPGA Control for Photovoltaic System   By Jan Leuchter	[View]   [Download]
Abstract: The paper introduces on operating principle of power management of photovoltaic system with maximum power tracker control to achieve the maximum efficiency of such systems. The paper presents different topologies of basic photovoltaic concepts with Dc-Dc converters including control design of maximum power tracker by Matlab-Simulink. The paper will be present different topologies of converter concepts that improve the total efficiency value. PWM controlling of such sophisticated system can be achieved by Field-Programmable-Gate-Array (FPGA) that more details of set up PWM signals due to FPGA technologies is shown in this paper.
	Dynamic Behaviour of a Series - Connected Multilevel Converter with Interleaved Switching   By C. Fahrni	[View]   [Download]
Abstract: This paper presents an analysis and design method for the current control of a series connected multilevel converter with interleaved switching. Based on a conventional design method for the parameters of a PI controller, the variable response of a current control circuit with one channel is presented, in dependency of the intervention time of the step on the set value. Then, a model for the equivalent transfer function of the control circuits of the interleaved solution is presented. A new approach for the design of the parameters of the current controller is proposed. The resultant step response in closed loop operation of the system will show the no more fluctuating response regarding overshoot.
	Effect of Type and Interconnection of DG Units in the Fault Current Level of Distribution Networks   By H. R. Baghaee	[View]   [Download]
Abstract: Fundamental requirements for the connection of distributed generation resources to the network are not only power quality constraints, but also voltage regulation and the total fault level, which should remain below the network desired value. This constraint is often the main limiting factor for the interconnection of these resources units to the grids. In the presented paper, the impact of installation of distributed resources in the distribution systems from the perspective of increase in the fault contribution will be discussed and comparative study will be performed to analyze the effect of type and interconnection of distributed generation unit on the fault current contribution of the distribution systems. Simulation results indicate that the increase in fault currents is often greater in the synchronous machine implementation versus a comparable inverter based design.
	Efficiency and Power Losses in PM BLDC Motor with Variable Bridge/half-bridge Structure Electronic Commutator   By K. Krykowski	[View]   [Download]
Abstract: In practice we often meet with electrical drives, where it is necessary to operate with higher speed, while load torque is less than rated torque. This type of operation is called "constant power operation" and may be defined as second range of natural motor torque-speed characteristic. In case of motors excited with permanent magnets magnetic flux is constant, and while supply voltage remains constant, motor speed is also (approximately) kept constant. In practice, different solutions are attempted in order to achieve increased rotating speed of brushless motors at decreased torque. One of the methods, which make possible PM BLDC motor operation at increased speed and decreased torque, is use of electronic commutator with switchable bridge-half-bridge structure. The investigation presented in the paper has been aimed at estimation of losses and efficiency in the drive consisting of brushless motor operating with variable structure commutator. Results of theoretical analysis, computer simulations and laboratory tests have shown that application of electronic variable structure commutator, which makes possible operation in the second speed range without increasing motor power and supply source power, causes an insignificant decrease in overall drive efficiency.
	Electric Vehicle Drive Inverters Simulation Considering Parasitic Parameters   By Wen Huiqing	[View]   [Download]
Abstract: Due to always increasing commutation speed, parasitic parameters such as interconnection inductances and stray capacitors are directly linked to voltage surge, resonance and electromagnetic interference. To guide the selection of power components, assess low-inductive film capacitors and laminated bus bar, and in the end realize the high power density and high reliability for electrical vehicle inverters, a simulation platform based on Matlab/Simulink has been developed. Parameters of the simulation platform strictly accord with the practical working conditions, even parasitic existing in components and connections are also considered. This paper introduces the switching mechanism and the distribution of circuit parasitic. The system modeling and parameters confirmation of the simulation platform are presented in detail. Experimental results are shown to verify the effectiveness of the simulation platform.
	Experimental Study of a Matrix Converter Excited Doubly-Fed Induction Machine in Generation and Motoring   By Ivan Shapoval	[View]   [Download]
Abstract: Full-scale experimental testing of the 7.5 kW doubly-fed induction machine controlled by matrix converter is reported. A number of doubly-fed induction machine and matrix converter control algorithms have been implemented in real time using a DSP-controller. The experimental rig used to control the doubly-fed induction machine is described. Experimental results demonstrate that the doubly-fed induction machine control algorithms guarantee perfect torque tracking of positive and negative trajectories of torque reference under the condition of unity stator side power factor.
	Experimental Study of a Multicell AC/AC Converter Balancing Circuit   By Robert Stala	[View]   [Download]
Abstract: The paper presents the experimental study of the balancing process forced by passive RLC circuit in a multicell ac/ac converter. To ensure its proper operation the converter employs voltages over the capacitors within its internal topology. Appropriate charging and reversing charge of cells' capacitors is achieved by means of the passive balancing circuit - a series RLC circuit connected at the converter output. The main issue is the correct choice of the balancing circuit wave impedance and the converter parameters (switching frequency, capacitances of cells capacitors) that allows maintaining a correct shape and proportion of voltages across cells capacitors at minimum balancing current.
	High Efficiency Soft Switching Boost Converter for Photovoltaic System   By Gil-Ro Cha	[View]   [Download]
Abstract: In this paper, a high efficiency soft switching boost converter is proposed for photovoltaic system. Using some resonant components, the circuit can be achieved the soft switching capability. Each of the switches in the proposed circuit performs ZV (Zero Voltage) or ZC (Zero Current) switching. Thus, the high efficiency characteristic can also be obtained, and then the size of the total system can be reduced. The operational modes of the proposed converter are explained in detail. And then some simulation results and some experimental results are presented for verifying the effectiveness of the proposed circuit.
	Invariant Modulation Strategy for Two-stage Direct Power Converter   By Radiy Bekbudov	[View]   [Download]
Abstract: The modulation strategy with the current invariance to input voltage disturbances and novel modulation algorithms for Two-stage Direct Power Converter are presented. Based on theoretical approach, the conditions for getting the current invariance are obtained. The novel modulation algorithms with minimum input current distortions are developed according to the proposed strategy. The switching sequence of the converter with power losses optimization procedure is specified. The performance efficiency of the proposed strategy and modulation algorithms in comparison with a conventional one are shown by simulation of the conversion procedure under balanced and unbalanced mains.
	LLCC-PWM Inverter for Driving High-Power Piezoelectric Actuators   By Rongyuan Li, Norbert Fröhleke and Joachim Böcker	[View]   [Download]
Abstract: In this contribution a novel LLCC-PWM inverter is presented for driving ultrasonic high power piezoelectric actuators. The proposed system of a pulse-width modulated inverter and LLCC-type filter is designed in a way to reduce the total harmonic distortion of the motor voltage and to locally compensate for the reactive power of piezoelectric actuators. In order to limit the switching frequency, a pulse width modulation using elimination technique of selected harmonics is designed and implemented on a FPGA. Due to local compensation of reactive power and high dynamic behavior of LLCC PWM inverter, the whole power supply shows an optimal performance at minimized volume and weight compared to LC and LLCC resonant converters.
	Low Loss Soft Switching Boost Converter   By So-Ri Park	[View]   [Download]
Abstract: A new soft switching boost converter is proposed in this paper. The conventional boost converter generates switching losses at turn on and off. Because of those, the whole system efficiency is reduced. The proposed converter utilizes soft switching method using an auxiliary switch and resonant circuit. Therefore, the converter reduces switching losses lower than the hard switching. The proposed soft switching boost converter can be applied to photovoltaic system, power factor correction and so forth.
	Methods for Experimental Assessment of Component Losses to Validate the Converter Loss Model   By Yi Wang	[View]   [Download]
Abstract: This paper introduces a novel loss model concept for performance evaluation and design optimization of power electronics converters based on MathCAD sheet. A dual active bridge (DAB) converter (12 V/360 V, 1 kW and 25 kHz) is used as the test platform. The practical methods for extracting useful component parameters used in loss model and for experimentally assessing losses to verify the loss model are elaborated. With the verified loss model, design optimizations of the DAB converter are done theoretically.
	Modeling and Measuring Results of a Shunt Current Source Active Power Filter with Series Capacitor   By P. Parkatti	[View]   [Download]
Abstract: In this paper, a method for reducing the voltage stresses on switching components and power losses in a shunt current source active power filter (CSAPF) is presented. The method is based on the series capacitor structure which is used to block the fundamental supply voltage component. The computational capacitor voltage balancing is studied to compensate the effects of the phase asymmetry. The frequency domain behavior of the harmonic control and main circuit is examined. The results show that the voltage stresses and power losses are lower in the CSAPF with a series-connected capacitor than in the conventional topology.
	Modelling and Analysis of a Matrix-Reactance Frequency Converter Based on Buck-Boost Topology by DQ0 Transformation   By Paweł Szcześniak	[View]   [Download]
Abstract: This paper deals with a three-phase matrix-reactance frequency converter (MRFC). The analysed MRFC topology is based on buck-boost matrix-reactance chopper (MRC) one with source synchronous connected switches (LSCS) set arranged as in the step-up matrix converter (MC). The MRFC in question makes it possible to obtain a load output voltage much greater than the input voltage. Presented in this paper is a description a method for the analysis of the steady and transient state properties of presented MRFC. The static and dynamic characteristics of the presented converter under the control strategy proposed by Venturini are fully analysed on the basis of the circuit model development by the DQ0 transformation. Various static converter characteristics such as voltage and current gain, input power factor are completely analysed. Transition characteristics are also analysed by a small-signal model. The usefulness of the models is verified through computer simulations with good agreements.
	Modified Multistage Semiconductor-Fitch Generator Topology with Magnetic Compression   By Stanislaw Kalisiak	[View]   [Download]
Abstract: For non-thermal plasma technology corona discharge devices high-voltage, high-current pulses are used with very high demands considering rising voltage slopes. Many solid state pulse power modulator (SSPPM) system topologies are known however most include a high power transformer compromising the overall system efficiency. A modified Fitch generator topology is introduced enlarging the output voltage to supply voltage ratio to theoretically the factor of three. Moreover the output voltage waveform enables the magnetic pulse compressor cross-section minimization with the factor of 0,67 due to a unique output voltage waveform. Test stand results are given for a 10-stage construction and a single stage magnetic compressor, power switch dynamic parameters influence on systems efficiency is discussed.
	Multiphase Coupled Converter Models Dedicated to Transient Response and Output Voltage Regulation Studies   By Nadia Bouhalli, Marc Cousineau, Emmanuel Sarraute and Thierry Meynard	[View]   [Download]
Abstract: In order to study transient response and output voltage regulation in multiphase coupled buck converter, it is proposed two models of interleaved coupled buck converter. These two models provide accurate current and voltage waveforms for any value of duty cycle. In the first part, the two proposed models are described in details. In the second part, it is shown the interest of this approach to study dynamic behaviour and determine compensation filters for voltage regulation in a multiphase coupled buck converter.
	New Family of Matrix-Reactance Frequency Converters Based on Unipolar PWM AC Matrix-Reactance Choppers   By Zbigniew Fedyczak	[View]   [Download]
Abstract: This paper deals with three-phase direct matrix-reactance frequency converters (MRFC) based on unipolar PWM AC matrix-reactance choppers (MRC). The topologies of the proposed MRFC are based on a three-phase unipolar MRC structure. Each MRC with conventional topology has two synchronous-connected switches (SCS) sets. In the MRFC, unlike the MRC topology, one of SCS sets is replaced by a matrix-connected switches (MCS) set in order to make possible of the load voltage frequency change. Six new topologies of the MRFC based on MRC boost, buck-boost, Ćuk, Zeta or SEPIC structures are presented. Through the generation concept of the proposed converters both the description of abovementioned converter topologies and general description of the control strategies are presented. The structure of the proposed MRFC contains a three-phase matrix converter (MC), which is introduced instead of the source or load SCS used in unipolar MRC. The step-down or step-up of the MC set is dependent on the input and output voltage or current source configurations. Analysis determining the location where the MC should be introduced is realized by means of the one-cycle switched models with suitable voltage and current sources introduced instead of the capacitors and inductors respectively. Furthermore, exemplary results of the simplified theoretical analysis, based on the averaged state space method, as well as simulation test results obtained for a classical Venturini control strategy of MC, are also presented as an initial verification of the properties of the proposed converters.
	New Modulation Strategy with Low Switching Frequency and Minimum Baseband Distortion   By N. E. Rüger	[View]   [Download]
Abstract: This paper reports on a novel modulation strategy for generation of band limited signals with binary switches, which was originally developed for audio power amplifiers, and on applying it to energy conversion. This modulation strategy has the extraordinary advantage that the signal band is free of harmonics or carrier intermodulation products. This so called "Zero-Position-Coding with Separated Baseband" (SB-ZePoC) operates at low switching frequencies and thus combines the advantages of PWM and offline-optimised pulse patterns. The advantages and drawbacks are discussed in this paper, considering a single-phase converter application.
	New Practical Approach to Input Current Shaping in AC-DC Power Converters   By Kuno Janson, Viktor Bolgov, Lauri Kütt, Ants Kallaste and Heigo Mõlder	[View]   [Download]
Abstract: In principle, a distortion of a waveform shape of AC/DC converter current could be corrected by use of a fast-controlled impedance-matching transformer. Changes in the converter input impedance can be eliminated by means of the varying transformation ratio of this transformer. The paper considers a practical performance of the fast-controlled impedance-matching transformer on a basis of a non-conducting converter. It is found that the shape of current waveform can be made sinusoidal if the instant power passing through a converter is proportional to the squared instant value of the supply voltage and/or the output voltage and the output current of the converter are in inverse proportion. A non-conducting converter with alternating of parallel and series resonance meeting requirements is considered. The converter topology, an operating principle and output voltage control are described. The basics of the converter calculation and the converter current waveform modeled on computer are presented.
	Optimal Bus Capacitance Design for System Stability in On-Board Distributed Power Architecture   By Seiya Abe	[View]   [Download]
Abstract: Recently, the distributed power system is mainly used for the power supply system which requires the low-voltage / high-current output. The distributed power system consists of bus converter and POL. The most important factor is the system stability in bus architecture design. The overlap between the output impedance of bus converter and input impedance of POL causes system instability, and it has been an actual problem. Increasing the bus capacitor, system stability can be reduced easily. However, due to the limited space on the system board, increasing of bus capacitors is impractical. The urgent solution of the issue is desired strongly. This paper presents the output impedance design for on-board distributed power system by means of three control schemes of bus converter. The output impedance peak of the bus converter and the input impedance of the POL are analyzed, and it is conformed by experimentally for stability criterion. Furthermore, the optimal intermediate bus capacitance design for system stability is proposed.
	PWM Spectrum Evaluation and Over-Modulation Phenomena in a Three-Phase Inverters - Analytical Approach   By Miro Milanovič	[View]   [Download]
Abstract: This paper provides a comprehensive spectrum analysis of three-phase inverters' output voltages. The output voltages were generated by triangular Pulse Width Modulation algorithm (PWM). This approach is presented in order to improve engineering education based on the classic analytical approach where the advantages of Bessel function series and calculation of Fourier coefficients have been used. The over-modulation phenomena were also considered. This analysis offers a complete quantitative and qualitative knowledge of those PWM signals necessary for high harmonics influence study when different passive and active loads are connected to inverters' outputs.
	Reliability Consideration for a High Power Zero-Voltage-Switching Flyback Power Supply   By Arash Rahnamaee, Jafar Milimonfared, Kaveh Malekian and Mohammad Abroushan	[View]   [Download]
Abstract: In this study, a high power zero-voltageswitching flyback power supply is presented. An appropriate efficiency is achieved by designing an auxiliary circuit for reduction of dynamic losses in the power switch. Due to the importance of reliability in the switch mode power supplies, reliability assessment is discussed for this zero-voltage-switching flyback converter in details. This paper illustrates that flyback topology has suitable reliability in the high power applications. Although by implementing auxiliary circuit in this topology, softer switching for the main switch is achieved, simplicity of the flyback converter is reduced. As a result, the control and power stages are more complicated. Also, reliability calculations demonstrate that due to soft switching and, consequently, reduction of power switch stresses, zerovoltage- switching flyback has a proper failure rate.
	SEPP High-Frequency Inverter Incorporating an Auxiliary Switch and Its Performance Evaluation   By H. Ogiwara	[View]   [Download]
Abstract: This paper presents a single ended push-pull (SEPP) high frequency inverter incorporating a reverse blocking active auxiliary quasi-resonant circuit using bipolar mode static induction transistors (BSITs) as active switches. This inverter can realize soft switching of the active switches over wider output power regulation range compared with the conventional SEPP inverter. It is performed by incorporating an auxiliary active switch to the conventional SEPP inverter to feed a required current for the soft switching operation of the main switches. The current fed to the main switches during their short switching period assists their soft switching operation over wide output power regulation range. The detailed evaluation of its operational principle and characteristics is carried out with the aid of computer aided simulation and the experimental result obtained by a bread board.
	Simple Analysis of a Flying Capacitor Converter Voltage Balance Dynamics for DC Modulation   By A. Ruderman	[View]   [Download]
Abstract: Flying capacitor multilevel PWM converter with a natural voltage balance is an attractive multilevel converter choice because it requires no voltage balance control effort. Flying capacitor converter practically does not suffer from voltage balance imposed performance limitations as opposed to multiple point clamped converter. Voltage balance dynamics analytical research methods reported to date deal mostly with an AC modulation case and are essentially based on a frequency domain analysis using double Fourier transform. Therefore, these methods require high mathematical skills, are not truly analytical and rather difficult to use in an everyday practice by electrical engineer. In this paper, we consider a DC modulation case to demonstrate that a straightforward time domain approach based on switching intervals piece-wise analytical solutions makes it easy to obtain time-averaged discrete and continuous models for voltage balance dynamics simulation. A primitive single-phase single-leg three-level converter analytical investigation yields a surprisingly simple accurate expression for capacitor charge/discharge related time constant revealing its dependence on inductive load parameters, carrier frequency, and duty ratio.
	Simulation of Simplified Seven Level Multilevel Converter Circuit   By Gerardo Ceglia	[View]   [Download]
Abstract: At present multilevel converters are technically interesting due to their high power handling capabilities, low output harmonics level and reduced requirements in blocking voltages in the switching devices ratings and lower commutation stresses and losses. The multilevel converter configurations now in use have as their main disadvantage their circuit complexity, requiring a great number of power devices and passive components in their implementation, and increasing control circuit complexity. System costs is rather high, and therefore the multilevel inverters are considered cost effective only in very high power applications. In this work a new seven level inverter having a reduced component count is presented, based upon the H bridge with auxiliary switch 5 level architecture. This new configuration may be of interest for applications working at lower and medium power levels. Also a new seven level inverter controller is introduced. The combination of the new power converter topology and the new controller circuit reduces both system cost and complexity
	Space Vector Modulation for a Capacitor Clamped Multi-Level Matrix Converter   By Xu Lie, Jon C. Clare, Patrick W. Wheeler and Lee Empringham	[View]   [Download]
Abstract: As an array of controlled bi-directional semiconductor switches, the Matrix Converter allows direct AC-AC conversion without an intermediate DC link. The Matrix Converter has several attractive advantages that have been investigated in the last twenty years. Multi level topologies have become increasingly popular in recent years due to high power quality, high-voltage capability, low harmonics and low EMI issues. This paper is concerned with applying multi-level topology and Space Vector Control algorithms to direct AC-AC power converters. Results from a small scale experimental prototype are given to validate the theoretical findings.
	Steady State Analysis of Hysteretic Control Buck Converters   By L. K. Wong	[View]   [Download]
Abstract: This paper presents the analysis of a hysteretic control buck converter by means of variable structure system theory because a hysteretic control buck converter is inherently a variable structure system owing to the presence of switching actions. Analysis results show the relationship between the steady state performance and a number of parameters, in particular the output capacitor's ESR. If the ESR is too small, the output voltage ripple will increase significantly and a phase shift is resulted. Although these phenomena are commonly known in the field, there is no analytical result to articulate them.
	The Traction Drive Topology Using the Matrix Converter with Middle-Frequency Transformer   By Martin Pittermann	[View]   [Download]
Abstract: This paper presents research motivated by industrial demand for special traction drive topology devoted to minimization of traction transformer weight against topology with classical 50Hz traction transformer. The main attention has been given to the special traction drive topology for AC power systems: input high voltage trolley converter (single phase matrix converter) - middle frequency transformer - output converter (single phase voltage-source active rectifier + three phase voltage-source inverter) - traction motor. The control algorithm (Inserting of NULL vector of matrix converter, Two-value control of secondary active rectifier, PWM and etc.) of innovative traction topology with middle-frequency transformer has been described.
	Validation and Comparison of Different PWM Converter Small Signal Models   By Alexander Bucher	[View]   [Download]
Abstract: In order to determine which small signal model most accurately describes PWM converters, a comparison with a switched model is necessary. Due to parasitic effects the comparison with hardware measurements does not clar-ify this question. Therefore published small signal models based on ideal components are compared with a time do-main simulation of a switched converter using the same idealization in this paper. The transfer function is deter-mined by emulating the quadrature detector used in practi-cal measurement set-ups. The paper shows the theoretical background, the implementation in SPICE and the com-parison with traditionally found transfer functions.
	Voltage Fed Zero-Voltage Zero-Current Switching PWM DC-DC Converter   By Jaroslav Dudrik	[View]   [Download]
Abstract: A new zero-voltage zero-current switching full-bridge phase-shifted PWM converter with controlled output rectifier is presented in this paper. IGBT switches are used in the high-frequency inverter of the DC-DC converter. Zero-voltage turn-on and zero-current turn-off for all power switches of the inverter is achieved for full load range from no-load to short circuit by using new secondary energy recovery clamp and modified PWM control strategy. Moreover by adding energy recovery clamp the zero-current turn-on and zero-voltage turn-off for rectifier switch is ensured. The principle of operation is explained and analysed and simulation results are presented.