| EPE 2001 - Topic 02b: Power Converter Circuits and Control |
| You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 02: POWER ELECTRONICS CONVERTER CIRCUITS > EPE 2001 - Topic 02b: Power Converter Circuits and Control |
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 | A High Efficiency Induction Furnace Controlled By A Resonant IGBT Inverter
By R. Fuentes; P. Lagos; J. Bustos | [View]
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Abstract: In this paper a 250 kW electric furnace designed with a controlled rectifier (thyristors) – DC boost (IGBT)
converter – resonant inverter (IGBT) is presented. It shows a high power factor and high efficiency at rated
power. Frequency of inverter varies according to the load tank resonance. It is connected directly to AC lines (380
V, 550 V) and do not need a transformer, as is done in most of the cases.
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| | A High Efficiency Large Capacity 3-Level GCT Converter with Regenerative Voltage Clamping Circuit
By H. Okayama; T. Fujii | [View]
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Abstract: This paper proposes an improved 3-level GCT converter for large capacity adjustable speed drives. The
main circuit topology of the 3-level converter is also well-known as a neutral-point-clamped converter.
In this field, improving power conversion efficiency and increasing power conversion capacity are very
important subjects to solve. Realizing high efficiency, a regenerative voltage clamping circuit is newly
applied. And introducing a transient junction temperature analysis of power devices, the maximum output
capacity is ensured. These technologies can contribute to improvement of the 3-level GCT converter
especially using 6kV/6kA GCTs which is the maximum capacity in the world at this moment.
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| | A New Concept Of The Converter For Dual System Trams
By M. Kowalczewski; W. Mysiñski; W. Zaj¹c | [View]
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Abstract: Krakow Town Council is planning to extend the local tram network (600V DC) using the railway
network. The main problem posed by this project is the need for a dual system tram car which can run
both on railway track, using the electric railway power supply network (3000V DC) and on tram track,
using the electric tram power supply network (600V DC). This paper presents a new concept of a
converter for 3000V/600V DC dual system trams. The converter is based on a three phase DC step
down converter. Some experimental and simulation results are discussed, too.
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| | A new control strategy for flyback converters
By R. Nalepa; N. Barry; P. Meaney | [View]
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Abstract: Galvanic isolation between the input and the output of the flyback switch-mode power supplies is
required in many cases. The power stage is naturally isolated by the flyback transformer. And the
feedback path is typically isolated by an opto-coupler. However the output voltage also exists (in part)
across the primary side switch in its off stage. This paper investigates the extraction of the output
voltage during the off-time [6]. Results obtained from a flyback converter with a novel control circuit
using cycle by cycle control are shown. The converter operates in both continuous and discontinuous
conduction modes. An equivalent circuit for modeling and analysis of the primary and the secondary
side oscillations is shown.
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| | A Novel Control Scheme for the Multilevel Rectifier/Inverter
By B-R. Lin | [View]
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Abstract: A novel three-level pulsewidth modulation (PWM) rectifier/inverter is proposed. The single-phase
three-level rectifier with power factor correction and current harmonic reduction is proposed to
improve the power quality. Three-phase three-level neutral point clamped (NPC) inverter is adopted to
reduce the harmonic content of the inverter output voltages and currents. In the adopted rectifier, a
switching mode rectifier with two AC power switches is adopted to draw a sinusoidal line current in
phase with mains voltage. The switching functions of power switches are based on a look-up table. To
achieve a balance DC-link capacitor voltage, a capacitor voltage compensator is employed to achieve
this goal. In the NPC inverter, the three-level PWM techniques based on the sine-triangle PWM and
space vector modulation are used to reduce the voltage harmonics and drive an induction motor. The
advantages of the adopted three-level rectifier/inverter are 1) the blocking voltage of power devices
(T1, T2, Sa1~Sc4) is clamping to half of the DC-link voltage, 2) low conduction loss with low
conduction resistance due to low voltage stress, 3) low electromagnetic interference, and 4) low
voltage harmonics in the inverter output. Based on the proposed control strategy, the rectifier can draw
a high power factor line current and achieve two balance capacitor voltages. The current harmonics
generated from the adopted rectifier can meet the international requirements. Finally, the proposed
control algorithm is illustrated through experimental results based on the laboratory prototype.
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| | A Novel PWM Controlled AC-Chopper Circuit Based on DC-Clamped Bilateral Switching Circuit Topology and Its Typical Applications
By Y. Okuma; H. Yamamoto; Y. Shoji | [View]
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Abstract: Conventional AC-chopper circuits using bi-directional switches can be used to control ac power. These
bi-directional switches are generally anti-series connected self-commutative switches. As a result,
there are problems regarding the main circuit configuration and snubber circuit, among others, and few
AC-chopper circuits have been used in practice.
Then, we authors proposed a novel PWM controlled AC-chopper circuit based on dc-clamped bilateral
switching circuit topology. And an ac power supplies using a PWM controlled AC-chopper circuits
was commercialized.
First, this paper outlines the problems of conventional AC-chopper circuits. It then proposes a PWM
controlled ac power supply, which is a novel AC-chopper circuit topology, and describes its principle of
operation. Furthermore, an ac voltage regulator and a series voltage-compensated ac voltage
regulator are introduced as typical applications of the proposed AC-chopper circuit.
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| | A Novel Zero-Voltage Switched Converter for an Electronic Ballast.
By S. Bækhøj Kjær; T. Lundgren Andersen; B. Søndergård Henriksen; A. Ólafsson | [View]
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Abstract: This paper presents the design of a novel converter for fluorescent lamps. A standard converter
feeds the lamp with a high frequency voltage. Reduced electrical noise is obtained in the designed
ballast with DC lamp operation. Tests on the fluorescent lamp revealed that it is suitable for DC
operation.
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| | A Stochastic Inverter Model due to Switching Time Uncertainties
By A. Sangswang; C. O. Nwankpa | [View]
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Abstract: The performance of a pulse-width modulated (PWM) converter is analyzed as a result of switching
time uncertainties. In the absence of control actions, random noises will force a system to leave its
stability region in a finite time, even if the system is initially at its stable equilibrium point. From this
aspect, the deterministic model of stability will no longer apply and the cumulative effect of small
random perturbations on a dynamical system may be considerably different. The cumulative effect of
small random fluctuations on a system parameter can push the system operating point beyond a
predefined boundary. A stochastic model of an inverter with practical uncertainties, which has not
been addressed before, is pointed out. This stochastic model is based on the introduction of
perturbations in the duty ratio of switching converters as random noise processes, which has been
developed by the use of the theory of stochastic differential calculus. In this paper, random
characteristics of the system parameters are modeled by a zero mean gaussian white noise, which is
inherently associated with power electronic converters and represents the behavior of the system in a
fluctuating environment. The singular perturbation technique is employed to transform the
differential algebraic system into system differential equations with the help of a singular parameter.
Commutation rise and fall times are quantified through the singularly perturbed parameter. A
performance index, known as the mean first passage time (MFPT) is also determined. The MFPT of
the stable state of the process is defined as the passage time of the process in a certain domain of
attraction, averaged over all possible initial states. Effects of switching time uncertainties on the
inverter system are compared between the MFPT and its deterministic counterpart, critical energy (E'c).
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| | A Voltage Source Inverter without DC link Components
By K. Iimori; K. Shinohara; M. Muroya; H. Sako | [View]
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Abstract: This paper describes a commutation strategy, which does not require snubber circuits, of the rectifier section
of the voltage source inverter without dc link components. In this proposed commutation strategy, each switching
devices of the bi-directional switches are controlled independently with sensing dc current direction. The proposed
strategy has been verified by computer simulation and experimental test on 0.75kW induction motor drive.
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| | Advanced converter module for high speed maglev system TRANSRAPID
By J. Helmer; U. Henning; P. G. Kamp; J. Nothhaft | [View]
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Abstract: A new compact inverter module was developed and successfully equipped with 4.5kV IGBTs and
4.5kV hard driven GTOs respectively. The comparison between measurement and calculation shows
that for high frequency application of the TRANSRAPID maglev system press-pack IGBTs or hard
driven GTOs are more favorable than conventional GTOs.
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| | An AC Voltage Transformation Circuits Based on Zeta or Sepic PWM AC Line Conditioners
By Z. Fedyczak; R. Strzelecki; L. Fr¹ckowiak; A. Kempski | [View]
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Abstract: This paper deals with matrix-reactance PWM AC line conditioners (MRACLCs) based on Zeta or
Sepic converter topologies, which are well known from DC/DC converter applications. These
conditioners have a capability to increase the AC load voltage above the AC line supplying voltage
without an electromagnetic transformer. Furthermore, the phase of the load voltage is the same as the
supplying one. The description of operation and steady-state basic energetic properties analysis of
averaged models of these conditioners are presented. Four-terminal chain parameters of averaged
models are employment to ones theoretical description. The theoretical analysis along with simulation
and experimental test results, obtained for a 500 VA laboratory model of the presented MRACLCs,
has been carried out for initial evaluation of their application suitability in direct AC/AC conversion
circuits.
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| | An Averaged AC Models Accuracy Evaluation of Non-Isolated Matrix-Reactance PWM AC Line Conditioners
By I. Y. Korotyeyev; Z. Fedyczak; R. Strzelecki; K. P. Sozañski | [View]
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Abstract: This paper deals with matrix-reactance PWM AC line conditioners (MRACLCs). Theoretical
preliminary to averaged modelling of these conditioners with current time averaging operator and
averaging errors estimation for fundamental harmonics of state variable is presented. On the base of
theoretical consideration there is steady-state averaged AC models quantitative accuracy evaluation
formulated in this paper. As an application of the theory, examples of the analysis of averaging errors
for conditioners based on buck-boost and Sepic topologies are presented. In this paper one can find
averaging errors analysis both as a function of switching frequency as well as a function of load
resistance.
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| | High speed, high power compressor drives with medium voltage induction motors
By M. Nahrstaedt; U. Putz; D. Wendt | [View]
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Abstract: The paper describes a 6.6 kV, 8 MVA drive for an asynchronous motor running at 15,000 rpm. The
drive is realized with a sixpulse GTO current source inverter on the motor side and a twelvepulse
thyristor bridge on the line side. In the application the high speed motor is mounted gearless with a gas
compressor on one shaft. To avoid lubrication magnetic bearings are used. The drive system has been
applied to several natural gas pumping stations in the Netherlands and Germany.
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| | IGBT auxiliary converter integrated into a traction converter
By S. Mesic; M. Jörg; G. Enzensberger | [View]
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Abstract: The subject of this paper is the description of a high power IGBT auxiliary converter (AXC) that is
integrated into a traction converter with an intermediate d.c. voltage link. This paper will describe the
application, the protection concept and the characteristics of the auxiliary converter.
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| | Implementation of Direct Torque Control using 4-Switch Inverter
By A. L. Orille; M. A. M. Azab | [View]
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Abstract: This paper presents a new method to generate PWM signals to control the Four-Switch 3-Phase
Inverter (FSTPI). The method is based on direct flux and torque control, which is usually implemented
based on the classical six-switch inverter (SSTPI) but has not been applied with the topology FSTPI
before. A new switching table has been derived, which selects the optimum inverter switching states to
fulfil the torque and flux requirements. The proposed DTC system provides quick response and
accurate control of both stator flux and motor torque. Experimental results have verified the validity
and effectiveness of the proposed system to obtain a high performance AC drive with reduced cost
suitable for low power range. Therefore the FSTPI topology can be an alternative to the classical sixswitch
topology for low power AC drives.
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| | Improved Foward Converter Integrated in a modular DSP-driven Inverter
By F. Frebel; P. Bleus; H. Libotte | [View]
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Abstract: Reliable AC back-up fed by a battery source are in a continuous evolution. The market's need drove us hard to develop a new topology of DC/DC converter integrated in a full digital control inverter. This new technical approach has been implemented over an inverter range. It has been done at rst on a 2U'/1kVA unit and a 1U'/300VA unit both naturally cooled as well as a 3kVA unit forced air of 2 U'height, outputting 120 Vac or 230 Vac. In the power inverter field, one of the best way to get the proper AC availability level is to increase the MTBF1 of the unit. Well-known means to improve
the MTBF are the decreasing of part-count number and a lower working temperature, actually
the challenge is to get the higher possible efficiency. A more than 90% overall efficiency has been achieved with a new isolated DC/DC converter called the "Symmetrical Flux Forward"(SFF), stepping up the input voltage from a low voltage to 350 Vdc. This improved topology has a very low part-count and many other advantages. The low part-count condition has been fulfilled too by applying the most recent technologies in an inverter. In fact, digital signal processing (DSP) and eld programmable gate array (FPGA) technologies become a possible and interesting solution to overcome the inverter control barrier. Closing all control feedback loops in the digital signal processor gives us also a temperature dependency compensation of analog devices, a very low part count, an efficient active filtering to comply with standard and an automatic board self-checking at the manufacturing time. This paper presents the state of the art in the inverter technology and a new DC/DC converter topology leading to a smart AC inverter solution.
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| | Multiloop feedback control in sine-wave voltage inverter for an Adjustable Speed Cage Induction Motor Drive System
By R. Seliga; W. Koczara | [View]
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Abstract: The paper describes results on the development of a topology and control of a three-phase DC/AC
inverter for an adjustable speed cage induction motor drive system. A multiloop state variables
feedback control technique is proposed for a DC/AC PWM converter with LC filter to provide a wide
range frequency and amplitude sinusoidal voltage.
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| | New Control Method For Current Converters
By V. Ambrozic; D. Nedeljkovic; R. Fiser | [View]
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Abstract: In this paper, two methods for current control of multiphase systems are proposed. They are similar to
the synchronized on-off control, where phase currents (or the current space vector) are sampled and
compared to the reference currents. Depending on the difference sign, a transistor that would
decrease the error is switched on. Unlike with the latter method, in our approach the current at the
end of the interval and the corresponding current error are predicted. In the first approach either null
voltage vector or the vector pointing in approximately the same direction as the current error vector is
selected, depending on which one gives the smaller error. In the second method, the switching time
for an optimal voltage vector is calculated following a least square error equation.
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| | Optimal LQ Controller for Quasi-Resonant DC-DC Converters
By J. M. Dores Costa; | [View]
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Abstract: Optimal control techniques are used to design a linear quadratic regulator (LQR) for quasi-resonant
(QR) switching DC-DC converters with voltage-mode control. The method presented in the paper is
based on small-signal models that were obtained as an extension of the state-space averaging models
of PWM converters. These models show that the LQR structure has some similarities with currentmode
control, since they both introduce feedback paths for the inductor current and the output
capacitor voltage. However, whereas the feedback gains of current-mode control are fixed, with the
LQR these gains can be calculated in order to minimise a quadratic cost function. Moreover, it is
possible to design the LQR and the power stage of the QR converter interactively. Small-signal
models of the QR converters are reviewed and the optimal LQR for voltage-mode control is
presented. The process was experimentally tested and results from a prototype of a 1 MHz buck QRZVS
converter with a LQR are presented.
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| | parallel operation of DC/AC master-slave inverters using sliding contr
By J. Miret Tomas; J.L. Garcia de Vicuña Muñoz de la Nava; M. Lopez Garcia | [View]
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Abstract: In this paper we present a sliding mode control scheme for parallel operation of DC/AC converters.
The sliding surfaces proposed, endows linear behaviour dynamics in the output voltage. This kind of
control provides high robustness in the output voltage against step changes in the load and in the input
voltage.
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| | Phase-shifted parallel-input/series-output dual inductor-fed push-pu..
By J-i. Kang; C-W. Roh; G-W. Moon; M-J. Youn | [View]
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Abstract: A new phase-shifted parallel-input/series-output (PISO) dual inductor-fed push-pull converter for
high-power step-up applications is proposed. It is based on a two-module PISO modular dual inductorfed
push-pull converter operating at a constant duty cycle and employs an auxiliary circuit to control
the output voltage with a phase-shift between two modules. It shows a voltage conversion
characteristic which is linear and less sensitive to changes in the control input, and a high step-up ratio
with a greatly reduced switch turn-off stress resulting in a significant improvement in the power
conversion efficiency. It also shows a low ripple content and low root-mean-square (RMS) current in
the output capacitor. The operational principle is analyzed and a comparative analysis with the
conventional two-module PISO modular dual inductor-fed push-pull converter is presented. A 50kHz,
800W, 350Vdc prototype with an input of 20 – 32Vdc has also been constructed to validate the
proposed converter. The proposed converter compares favorably with the conventional counterpart
and is considered well suited to high-power step-up applications.
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| | Power conditioning method for SMES by use of ICB energy transfer circu
By J. Babay; T. Nittaz; Y. Shirai; Y. Hayashiy; Y. Kobayashi | [View]
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Abstract: Inverter-Converter Bridge (ICB) energy transfer circuit consists of two power converters and
the capacitor bank. Each of two superconducting magnets are connected to each of two power
converters and the stored energy is transfered by use of the circuit. The circuit has been mainly
studied as an exciter circuit for pulse superconducting magnets because it enables to excite the
large magnet quickly without a ecting the power systems. It is easy to construct the required
large capacity because the circuit can be made for natural commutation thyristors.
The circuit, which is connected to power system through the converter (utility tie converter),
has attractive features for SMES power converter, for instance, wide control region of active
and reactive power without forced commutative power devices. The relation between utility tie
converter control and the ICB circuit control is important for realizing SMES converter system.
In this paper, the power conditioning method of ICB energy transfer circuit has been discussed
to adopt ICB energy transfer circuit as power supply for SMES. The theoretical analysis and
the experimental results are shown.
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| | Power Domain of three phase PWM rectifiers
By S. Fillet Castella; J. Bergas; S. Galceran; A. Sudria | [View]
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Abstract: The power domain of three-phase pulse width modulation voltage-source rectifiers (PWM-VSR) is
not frequently taken into consideration. In this article, the active and reactive controllable domain for
PWM-VSRs is derived when connected to ideal networks. Maintaining the rectifier in the presented
controllable domain prevents their harmonic components of the currents on the main from increasing
and prevents the system from losing stability. The circular domain limits are determined by its mains
circuit parameters. The importance of DC-link voltage and input inductance is made evident.
Influence of limits when network voltage varies is also taken into consideration, showing the limits of
sags and undervoltages surpassing capacity.
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| | PWM Current Converter for electric energy production systems
By C. Rivas, A. Rufer | [View]
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Abstract: Fuel Cells are destined to supply electric energy beginning from primary resources. A static DC-AC
converter is necessarily inserted between the fuel cells and the distribution network. This paper
describes a new P.W.M. strategy for a current source inverter. This modulation strategy reduces the
energy losses and harmonics in the P.W.M. current source inverter. This technique allows the P.W.M.
current source inverter to become a new feasible solution to adapt a low continuous voltage into a
three-phase voltage of higher amplitude.
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| | Self Powering Driver Circuit For Series-Connected IGCTs
By R. Roesner; J. Holtz; R. Kennel | [View]
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Abstract: When applying series connection of power semiconductors in high voltage inverters the power supply of each driver circuit must usually be provided separately by transformers due to the different potential levels of the power devices. This paper presents a snubber scheme producing the supply voltage for the driver circuit on the same voltage level without external power supply. Remaining snubber energy is regenerated to the DC link of the inverter. Measuring results obtained from a real inverter setup with serial connected IGCTs show
that even during start-up operation it is not necessary to connect external power supplies to each driver circuit. Only a single driver circuit per inverter leg must be supplied by electrical power until its supply capacitors have been charged up. Afterwards the auxiliary power supply might be disconnected again as it is not
needed any more.
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| | Three-Phase Current-Source-Type PWM PFC Rectifier.
By Y. Nishida; T. Kondoh; M. Ishikawa; K. Yasui | [View]
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Abstract: A new 3-phase current-source-type (or buck-mode) PWM PFC rectifier is proposed. The
necessity, the advantages and disadvantages of this type PWM rectifier are discussed first.
Then, the new power circuit topology and the modulation scheme to eliminate or mitigate
the disadvantages and obtain further new advantages of the current-source-type PWM
rectifier are introduced. The features of the new rectifier, i.e., high efficiency, simple
modulation process, robustness of the line-current modulation against dc current ripples
caused by distortion and asymmetrically of the utility voltages have been confirmed
through experimental results obtained from a prototype 12[kW] rectifier.
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| | Variable Output Bidirectional dc - dc Converter
By W. Bury; D. Czarkowski; J. Dzieza | [View]
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Abstract: A bidirectional dc–dc converter
with output voltage tracking capabilities was
designed and tested with a 110 Hz reference
signal. A linear controller was designed in the
frequency domain. Experimental results are in
a good agreement with theoretical and
simulated predictions. The converter is intended to drive piezoceramic actuators.
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