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Power Electronics, IEEE Transactions on

Issue 4 • Date July 2003

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Displaying Results 1 - 20 of 20
  • A generalized dynamical model for three-phase switch-mode converter circuits

    Page(s): 994 - 1001
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (441 KB) |  | HTML iconHTML  

    Advances in power electronics and high-performance electrical technology are driving a move toward switch-mode circuits for AC-DC conversion. The efficient control of these circuits is an ongoing research challenge, and to date has focussed on the more popular voltage-driven converter. This paper presents a model applicable to the study and control of generic three-phase switch-mode converters (voltage and current-driven), under the widest possible range of switching scenarios. The model permits a generalization of the "space vector" framework, and makes possible a three-tiered approach to control in which AC-side, DC-side and low-level switching control tasks are decoupled from one another. View full abstract»

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  • Minimum copper loss flux-weakening control of surface mounted permanent magnet synchronous motors

    Page(s): 929 - 936
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB) |  | HTML iconHTML  

    This study presents a novel current loop design method capable of automatic flux-weakening control with minimum copper loss for surface mounted permanent magnet synchronous motors (SPMSM). The proposed current controller can automatically re-compute the d-axis current command to defer output voltage saturation. Consequently, the motor operations in the flux-weakening region are also contained in the stable operating region. Analysis results indicate that since the output voltage vector in the flux-weakening region produced by this controller is consistently on the boundary of the maximum output voltage vector allowed by the inverter, the corresponding flux-weakening current is the optimal value in the sense of minimum copper loss. This minimum copper loss design differs from the maximum output torque design and the constant power design of the flux-weakening control methods found in the literature. Experimental results further demonstrate the feasibility of the proposed current controller and its ability to maximize the speed range of the motor drive for a given inverter capacity. View full abstract»

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  • PCB integrated inductors for low power DC/DC converter

    Page(s): 937 - 945
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1096 KB) |  | HTML iconHTML  

    This paper discusses the use of printed circuit board (PCB) integrated inductors for low power DC/DC buck converters. Coreless, magnetic plates and closed core structures are compared in terms of achievable inductance, power handling and efficiency in a footprint of 10 × 10 mm2. The magnetic layers consist of electroplated NiFe, so that the process is fully compatible with standard PCB process. Analytic and finite element method (FEM) methods are applied to predict inductor performance for typical current waveforms encountered in a buck converter. Conventional magnetic design procedures are applied to define optimum winding and core structures for typical inductor specifications. A 4.7 μH PCB integrated inductor with dc current handling of up to 500 mA is presented. This inductor is employed in a 1.5 W buck converter using a commercial control integrated circuit (IC). The footprint of the entire converter measures 10 × 10 mm2 and is built on top of the integrated inductor to demonstrate the concept of integrated passives in power electronic circuits to achieve ultra flat and compact converter solutions. View full abstract»

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  • An investigation into the fast- and slow-scale instabilities of a single phase bidirectional boost converter

    Page(s): 1063 - 1069
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (550 KB) |  | HTML iconHTML  

    We develop an analytical map for a single phase bidirectional boost converter. This map enables the analysis of the dynamics of the converter faster and without any convergence problems. For the closed-loop converter, we show how instabilities can occur on the slow and fast scales. Conventional analyzes based on averaged models can not predict the fast-scale instability because such models do not account for the switching-frequency ripple. View full abstract»

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  • Dissipativity-based adaptive and robust control of UPS in unbalanced operation

    Page(s): 1056 - 1062
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (543 KB) |  | HTML iconHTML  

    In this paper, we investigate the output voltage control for three phase uninterruptible power supply (UPS) using controllers based on ideas of dissipativity. To provide balanced sinusoidal output voltages even in the presence of nonlinear and unbalanced loads, we first derive a dissipativity-based controller using a conventional αβ (fixed frame) representation of system dynamics and a frequency-domain representation of system disturbances. Adaptive refinements have been added to the controller to cope with parametric uncertainties. Second, based on the structure of the first adaptive controller, we propose another controller that leads to a linear time-invariant (LTI) closed loop system which is directly connected to synchronous frame harmonic voltage control. This controller, denoted as robust, avoids the most computationally demanding parameter estimation during adaptation, and offers important advantages for implementation. For the proposed robust controller, a sufficient condition in terms of the design parameters is presented to guarantee stability of the desired equilibrium and robustness against certain parametric uncertainties. Finally, simulation and experimental results on a three-phase prototype show effectiveness and advantages of the proposed class of controllers. View full abstract»

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  • Optimal controller design for a matrix converter based surface mounted PMSM drive system

    Page(s): 1034 - 1046
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1013 KB) |  | HTML iconHTML  

    This paper proposes a new control algorithm for a matrix converter permanent magnet synchronous motor (PMSM) drive system. First, a new switching strategy, which applies a backpropagation neural network to adjust a pseudo DC bus voltage, is proposed to reduce the current harmonics of the permanent magnet synchronous motor. Next, a two-degree-of-freedom controller is proposed to improve the system performance. The parameters of this controller are obtained by using a frequency-domain optimization technique. The controller design algorithm can be applied in an adjustable speed control system and a position control system to obtain good transient responses and good load disturbance rejection abilities. The controller design procedures require only algebraic computation. The implementation of this kind of controller is only possible by using a high-speed digital signal processor. In this paper, all the control loops, including current-loop, speed-loop, and position-loop, are implemented by a 32-b TMS320C40 digital signal processor. The hardware, therefore, is very simple. Several experimental results are shown to validate the theoretical analysis. View full abstract»

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  • Comparative study of pulsed DC-link voltage converters

    Page(s): 1028 - 1033
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (420 KB) |  | HTML iconHTML  

    This paper classifies the pulse pulsed dc-link voltage (PDCLV) topologies in six types, depending on both the shape of the pulsed DC-link voltage waveform and the circuit ability to synchronize, or not, with external pulse width modulation (PWM) signals. Main features are compared for a large number of topologies in which the bridge devices commutate under zero-voltage-switching (ZVS) technique. The paper also presents a comparative study of the losses produced by these converters and discusses the principles they employ causing generation such losses. An overview of the control and PWM possibilities for these converters is given and an extensive bibliography is included. View full abstract»

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  • Low output voltage AC/DC converter with a new scheme of synchronous rectification that complies with IEC 1000-3-2 regulations

    Page(s): 966 - 974
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (662 KB) |  | HTML iconHTML  

    The aim of this paper is to study the performance of an AC/DC converter with low output voltage and low input current harmonic content. In order to obtain low output voltages with a high efficiency, synchronous rectification is mandatory. When the output voltage is low, it is very difficult to use self-driven synchronous rectification and additional windings are used to properly drive the metal oxide semiconductor field effect transmitters (MOSFETs). Besides this, IEC 1000-3-2 regulations impose low input current harmonic contents for power levels higher than 75 W. In this paper, a recently proposed synchronous rectification scheme is combined with a modified input current shaper to design a 100 W, 3.3 V AC/DC converter that complies with IEC 1000-3-2 regulations. The efficiency obtained in the prototype was very high for this application (86%) and both the size increase and the cost increase were quite low in comparison with the original topology with no synchronous rectification and no IEC 1000-3-2 compliance. View full abstract»

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  • Design consideration of the active-clamp forward converter with current mode control during large-signal transient

    Page(s): 958 - 965
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB) |  | HTML iconHTML  

    The design issues of the active-clamp forward converter circuit with peak current mode control in small signal stability and large-signal transients are discussed. A design procedure is provided to solve circuit issues under these conditions. It is the first time that with the aid of simulation, we are able to optimize the circuit design of the active-clamp forward converter for large-signal transient behaviors. View full abstract»

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  • Four-wire dynamic voltage restorer based on a three-dimensional voltage space vector PWM algorithm

    Page(s): 1093 - 1102
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1161 KB) |  | HTML iconHTML  

    A modified voltage space vector pulse-width modulated (PWM) algorithm for a four-wire dynamic voltage restorer (DVR) is described. The switching strategy based on a three-dimensional (3-D) αβO voltage space is applicable to the control of three-phase four-wire inverter systems such as the split-capacitor PWM inverter and the four-leg PWM inverter. In contrast to the conventional voltage space vector PWM method, it controls positive, negative and zero sequence components of the terminal voltages instantaneously. Three 3-D modulation schemes are analyzed with respect to total harmonic distortion (THD), weighted total harmonic distortion (WTHD), neutral line ripple and switching loss over the whole range of the modulation index when the DVR experiences both balanced and unbalanced sags with phase angle jumps. Experimental results from a 9 kW DVR system using a split-capacitor PWM inverter are presented to validate the simulation results. View full abstract»

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  • Design and implementation of a cost-effective quasi line-interactive UPS with novel topology

    Page(s): 1002 - 1011
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1104 KB) |  | HTML iconHTML  

    This paper presents an improved single-phase passive-standby uninterruptible power supply (UPS) for low cost applications. The proposed system includes an input rectifier/charger and a switching inverter. It is basically an offline UPS structure, but has nearly the performance of a line-interactive UPS. It can continuously regulate the sustained voltage swells and sags by injecting a voltage in series with the source voltage in the normal mode, and can be switched smoothly to back-up mode when the utility voltage goes outside the specified range, or fails. The regulation range is also larger than conventional offline and line-interactive UPSs. Additionally, the proposed system has no low frequency transformer, which would involve a heavy and bulky structure. Theoretical analysis has been achieved based on the power flow theory. Case study is demonstrated by means of a prototype experiment to prove its performance and effectiveness. View full abstract»

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  • On the use of current sensors for the control of power converters

    Page(s): 1047 - 1055
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (815 KB) |  | HTML iconHTML  

    This paper describes the use of current sensors for the control of power converters. No voltage sensor is required in the whole system. The sensed current and the rate of change of the inductor current in different circuit topologies are used to determine the input and output voltages of the converters, and for current programming and maximum current protection. Apart from reducing the number of sensors, the proposed method provides inherent electrical isolation between the power conversion stage and the controller and lessens noise-coupling problems. The proposed technique is illustrated with a current-programmed DC/DC boost regulator with feedforward and feedback control. The regulator's steady state and transient responses under input source and output load disturbances are presented. View full abstract»

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  • New high power DC-DC converter with loss limited switching and lossless secondary clamp

    Page(s): 1020 - 1027
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (585 KB) |  | HTML iconHTML  

    A new isolated high frequency high power DC-DC converter full bridge topology employing one resonant "soft" switching pole that is zero voltage switched and one phase-shifted hard switching pole with loss limited switching for primary switching is presented. The devices in the loss limited pole do not have resonant capacitors across them, but exhibit significantly lower losses than conventional hard switching as the energy dissipation is limited by the finite energy stored in the leakage inductance. This unique combination of zero voltage switching and loss limited switching reduces the switching loss in all primary devices to lower levels. Isolation is achieved by a coaxially wound high frequency transformer with ultra low leakage which increases throughput and efficiency. A novel nondissipative secondary rectifier clamp allows excellent control of reverse recovery energy. Converters that produce 128 kW at 25 kHz have been developed and are commercially available. As this topology exhibits complete control of all parasitic loss mechanisms, it can be easily scaled to higher power levels. View full abstract»

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  • Three-phase unity-power-factor star-connected switch (VIENNA) rectifier with unified constant-frequency integration control

    Page(s): 952 - 957
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (470 KB) |  | HTML iconHTML  

    A unified constant-frequency integration (UCI) controller for a three-phase star-connected switch three-level rectifier (VIENNA) with unity-power-factor-correction is proposed. One of advantages of this rectifier is that the switch voltage stress is one half of the total output voltage. The proposed control approach is based on one-cycle control and features great simplicity and reliability: all three phases will be power factor corrected using one or two integrators with reset along with several flips-flops, comparators and logic and linear components. It does not require multipliers to scale the current reference according to the output power level as used in many other control approaches. In addition, the input voltage sensor is eliminated. It employs constant switching frequency modulation that is desirable for industrial applications. The proposed controller can operate by sensing either the inductor currents or the switching currents. If the switching currents are sensed, the cost is further reduced because switching currents are easier to sense comparing with inductor currents. The proposed approach is supported by experimental results. View full abstract»

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  • Circuit-level comparison of STATCOM technologies

    Page(s): 1084 - 1092
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (850 KB)  

    This paper performs a comprehensive circuit-level evaluation of four modern STATCOM systems, namely true-48-pulse and quasi-48-pulse STATCOMs, cascade multilevel and binary multilevel inverters. The comparison is based on a number of factors including circuit topology, harmonic distortion, system losses, GTO quantities, their specific applications, and other considerations. The theoretical results are verified by simulation with the use of MATLAB-Simulink Power System Blockset. View full abstract»

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  • A high-power-factor, three-phase isolated AC-DC converter using high-frequency current injection

    Page(s): 1012 - 1019
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (755 KB) |  | HTML iconHTML  

    A single-stage, three-phase AC-to-DC converter topology is proposed for high-frequency power supply applications. The principal features of the circuit include continuous current operation of the three AC input inductors, inherent shaping of the input currents, resulting in high power factor, a transformer isolated output, and only two active devices are required, both soft-switched. Resonant conversion techniques are used, and a high power factor is achieved by injecting high-frequency currents into the three-phase rectifier, producing a high frequency modulation of the rectifier input voltages. The current injection principle is explained and the system operation is confirmed by a combination of simulation and experimental results. View full abstract»

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  • Cyclic-averaging for high-speed analysis of resonant converters

    Page(s): 985 - 993
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (597 KB) |  | HTML iconHTML  

    The paper describes the development and application of a cyclic-averaging technique for the rapid analysis of high-order resonant power converters. To provide a focus to the paper, particular emphasis is given to a 3rd-order LCC voltage output converter topology. The proposed methodology predicts steady-state voltages and currents throughout the circuit, and provides estimates of the stresses on the resonant circuit components. State-space simulations and experimental results from a 350 V-input/150 V-output converter are used to demonstrate a prediction accuracy comparable with time-domain integration-based techniques is achievable, while requiring only 1/10,000th of the computation time. In addition, a comparison with Spice simulation results shows that cyclic averaging provides commensurate predictions of voltage and current stresses on the resonant circuit components. Issues arising from the stray capacitance associated with the resonant inductor, and the corresponding sensitivity of the predicted output voltage, are also considered. View full abstract»

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  • A novel discrete control strategy for independent stabilization of parallel three-phase boost converters by combining space-vector modulation with variable-structure control

    Page(s): 1070 - 1083
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1442 KB) |  | HTML iconHTML  

    We propose a discrete nonlinear controller, developed in a synchronous frame, for a parallel three-phase boost converter consisting of two modules. The basic idea, however, can be extended to a system with N modules. Each of the closed-loop power-converter modules operates asynchronously without any communication with the other modules. The controller stabilizes the currents on the dq-axes and limits the flow of the pure-zero sequence current. It combines the space-vector modulation scheme with a variable-structure control, thereby keeping the switching frequency constant and achieving satisfactory dynamic performance. View full abstract»

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  • Isolated DC-DC converters with high-output voltage for TWTA telecommunication satellite applications

    Page(s): 975 - 984
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (828 KB) |  | HTML iconHTML  

    Two alternatives for the implementation of an isolated DC-DC converter operating with a high output voltage and supplied by an unregulated low input voltage are presented in this paper. The proposed topologies are especially qualified for the implementation of travelling wave tube amplifiers (TWTA) utilized in telecommunication satellite applications due to their low mass and volume and their high-efficiency. The converters studied follow different principles and the main operational aspects of each topology are analyzed. A two-stage structure composed by a regulator connected in series with a ZVS/ZCS isolated DC-DC converter is the first topology proposed. The second topology studied is an isolated single-stage converter that continues being highly efficient even with a large input voltage variation. The experimental results obtained from two prototypes, implemented following the design procedures developed, are presented, verifying experimentally the characteristics and the analysis of the proposed structures. The prototypes are developed for an application requiring an output power of 150 W, a total output voltage of 3.2 kV and an input voltage varying from 26 V to 44 V. The minimum efficiency obtained for both converters operating at the nominal output power, is equal to 93.4% for the two-stage structure and equal to 94.1% for the single-stage converter. View full abstract»

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  • New start-up schemes for isolated full-bridge boost converters

    Page(s): 946 - 951
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (566 KB) |  | HTML iconHTML  

    Two new start-up schemes for isolated full-bridge boost converters are proposed in this paper. The control timing for each scheme, which is compatible with pulse-width modulated (PWM) control timing for normal boost mode operation, are investigated. Design considerations on the relationship between the turns ratios of the boost choke windings and the main transformer windings, and its effects on the operation of the converter, are studied. The two proposed start-up schemes are experimentally verified on a 1.6 kW, 12 V/288 V prototype. View full abstract»

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Aims & Scope

IEEE Transactions on Power Electronics covers fundamental technologies used in the control and conversion of electric power.

Full Aims & Scope