A new AC – AC converter with buck and boost options (original) (raw)
Related papers
IEEE Transactions on Power Electronics, 2016
This paper proposes a new type of ac-ac converter which can operate as traditional non-inverting buck and boost converters, and inverting buck-boost converter as well. The proposed converter uses six unidirectional current flowing and bidirectional voltage blocking switches, implemented by six reverse blocking IGBTs or series MOSFET-diode pairs, two input and output filter capacitors, and one inductor. It has no shoot-through problem of voltage source (or capacitor) even when all switches are turned-on and therefore; PWM dead times are not needed resulting in high quality waveforms, and solves the commutation problem without using bulky and lossy RC snubbers or dedicated soft-commutation strategies. It has smaller switching losses because; only two switches out of six are switched at high frequency during each half cycle of input voltage, and it can use power MOSFETs as body diode never conducts, making it immune from MOSFET failure risk which otherwise may occur due to poor reverse recovery problem of body diode. The non-inverting buck-boost mode of proposed converter can be used in applications with both step-up and step-down demand, while the inverting buck-boost mode can also be used in its application as DVR. Detailed analysis of the proposed converter is given, and experimental results are also provided.
Application of the DC-Ripple Reinjection Concept to Forced-Commutated Conversion
International Journal of Emerging Electric Power Systems, 2000
A dc-ripple reinjection concept, described in the literature with reference to the line-commutated current source converter, is applied in this paper to the self-commutated current source converter. This is achieved by means of a reinjection converter fed, via a single-phase transformer, from the triple frequency ripple signal. It is shown that the three-phase bridge can be made to operate effectively at any multiple of the six-pulse number and, thus, presents an effective alternative to the use of ac and dc side filters.
New AC-AC converter topologies
2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692), 2003
This paper presents new AC-AC converter topologies operating as AC voltage regulators. Operation stages, static gain expressions, main waveforms and simulation results are shown. Laboratory experimental results for 1 kVA converters are also presented, which demonstrate the feasibility of the study carried out. Index Terms-AC-AC converter, voltage regulator, new topologies. . The power switches are ideal; 427 0-7803-7912-8/03/$17.00 0 2003 IEEE
El convertidor DC/DC puente completo es tal vez una de las topologías más ampliamente adoptadas en aplicaciones de media y alta potencia debido a su capacidad de lograr la conmutación de sus interruptores bajo condiciones de tensión cero (Zero-Voltage-Switching ZVS) reduciendo así las pérdidas y mejorando el rendimiento general del convertidor. Este artículo presenta una revisión detallada del principio de funcionamiento y consideraciones de diseño del convertidor bajo condiciones de conmutación suave. De manera adicional se evalúan las características de desempeño a través de simulación.
Energies
In this research, a new single-phase direct AC-to-AC converter, operating in buck and boost mode, with a bipolar voltage gain, is proposed. The operation is accomplished through high frequency direct and indirect PWM control of a single switch with low voltage stresses. This reduces, not only the control effort, but also the switching losses. The low voltage stresses across the high frequency switches, reduce the dv/dt problem significantly without any loss and bulky voltage snubber arrangement. The operation, in its all-operating modes, has a low inductor ripple current and switching current. The proposed converter may be employed as an AC voltage restorer in a power distribution system to cope with the voltage sag and swell issues. The detailed analysis of the proposed converter is carried out in order to compare its performance with the existing converters. The simulation results obtained using the MATLAB/Simulink environment are verified through experimental results.
Harmonic Mitigation in Single Phase Mutually Commutated Converter Systems
An AC/DC converter comprising a cycloconverter and a capacitively snubbered voltage source converter (VSC), coupled by a medium frequency transformer, offers significant advantages. Bidirectional AC/DC power flow as well as voltage transformation and isolation can be achieved. By mutual commutation of the converters, soft switching can be achieved for all semiconductors, thus, link frequency can be increased, allowing smaller transformer and reduced filter components. However, the mutual commutation scheme imposed by the soft switching requirement puts constraints on the PWM pattern causing low frequency harmonics in certain operating points. It is shown that the low frequency harmonics can be eliminated for all points of operation, both in a single bridge configuration and interlaced configuration, common in AC-fed propulsion. A sub-optimal harmonic mitigation method based on a regularly sampled modulator is proposed. By proper oversampling of the reference waveforms substantial reduction of the low frequency harmonic contents can be achieved. The mitigation method is verified by circuit simulation and the feasibility to propulsion is demonstrated.
A new ZCZVT commutation cell for PWM DC-AC converters
Sba: Controle & Automação Sociedade Brasileira de Automatica, 2004
This paper proposes a new auxiliary commutation cell for PWM inverters that allows the main switches to be turned on and off at zero voltage and zero current. The main switches zero current turn-on reduces the undesired effects of parasitic inductances related to the circuit layout. The main diodes reverse recovery losses are minimized since di/dt and dv/dt are controlled. The ZCZVT commutation cell is located out of the main power path of the converters and is activated only during switching transitions. Additionally, the auxiliary switches are turned on and off at ZCS and use the same ground signals of the upper main switches. The commutation losses are practically reduced to zero. Soft switching operation is guaranteed for full load range without changes in command strategy. The operation of the ZCZVT PWM full-bridge DC-AC Converter is analyzed and an auxiliary commutation cell design procedure based on the analysis is proposed. Experimental results are presented to demonstrate t...
AN IMPROVED ZCS-PWM COMMUTATION CELL FOR IGBT's APPLICATIONS
An improved Zero-Current-Switching Pulse-Width-Modulation (ZCS-PWM) commutation cell is proposed, which is suitable for high power applications using IGBT's as the power switches. It provides ZCS operation for active switches with low current stress, without overvoltage and PWM operating at constant frequency. The main advantage of this cell is a substantial reduction of the resonant current peak through the main switch during the commutation process. Therefore, the RMS current through it, is very close to that observed in the hard-switching PWM converters. Also, small ratings auxiliary components can he used. To demonstrate the feasibility of the proposed ZCS-PWM commutation cell, it was applied to a boost converter. Operating principles, theoretical analysis, design guidelines and a design example are described and verified by experimental results obtained from a prototype operating at 40 kHz, with an input voltage rated at 155 V and 1 kWatts output power. The measured efficiency at full load was 97.5%.
Simulation of single phase buck boost matrix converter without commutation issues
European Journal of Electrical Engineering
Simulation of single phase buck boost matrix converter without commutation issues is presented in this paper. The proposed converter is capable to operate inverting as well as non-inverting operation. Generally, AC to AC converters are designed by using thyristors and it will produce more harmonics with lower power factor. To overcome the drawbacks of the AC-AC voltage controller, buck-boost based inverting and non-inverting converter have been introduced. In this topology, six numbers of unidirectional current flowing and voltage blocking switches are used. The proposed topology can be applied for both step down and step up applications with non-inverting modes of operations and inverting operations suitable for dynamic voltage restorer (DVR) applications. The main feature of this topology is buck-boost with inverting and buck-boost with non-inverting capability with a topology. The performances of the proposed work will be analyzed through MATLAB/Simulink. RESUMÉ. Cet article pré sente une simulation du convertisseur matriciel buck boost monophasé sans problè mes de commutation. Le convertisseur proposé est capable d'opé rer des opé rations d'inversion et non d'inversion. Gé né ralement, les convertisseurs alternatif à alternatif sont conçus en utilisant des thyristors et produisent plus d'harmoniques avec un facteur de puissance plus faible. Pour surmonter les inconvé nients du contrôleur de tension AC-AC, un convertisseur inverseur et non inverseur basé sur un Buck-Boost a é té introduit. Dans cette topologie, six numé ros de commutateurs de blocage de courant et de tension unidirectionnels sont utilisé s. La topologie proposé e peut ê tre appliqué e à la fois aux applications de ré duction et d'augmentation avec des modes de fonctionnement non inversé s et aux opé rations d'inversion adapté es aux applications de restauration dynamique de la tension (DVR). La principale caracté ristique de cette topologie est buck-boost avec inversion et buck-boost avec capacité non-inversion avec topologie. Les performances des travaux proposé s seront analysé es par MATLAB / Simulink.
POWER ELECTRONICS Converters, Applications, and Design THIRD EDITION
In most power electronic applications, the power input is in the form of a 50or 60-Hz sine wave ac voltage provided by the electric utility, that is first converted to a dc voltage. Increasingly, the trend is to use the inexpensive rectifiers with diodes to convert the input ac into dc in an uncontrolled manner, using rectifiers with diodes, as illustrated by the block diagram of . In such diode rectifiers, the power flow can only be from the utility ac side to the dc side. A majority of the power electronics applications such as switching dc power supplies, ac motor drives, dc servo drives, and so on, use such uncontrolled rectifiers. The role of a diode rectifier in an ac motor drive was discussed by means of in Chapter 1. In most of these applications, the rectifiers are supplied directly from the utility source without a 60-Hz transformer. The avoidance of this costly and bulky 60-Hz transformer is important in most modem power electronic systems.