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Power Electronics, IEEE Transactions on

Issue 2 • Date March 2002

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Displaying Results 1 - 17 of 17
  • Current control strategy for brushless DC motors based on a common DC signal

    Page(s): 232 - 240
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (405 KB) |  | HTML iconHTML  

    A simplified current controlled modulation technique for brushless DC motors is presented. It is based on the generation of quasi square-wave currents, using only one current controller for the three phases. The advantages of this strategy are: (a) very simple control scheme; (b) the phase currents are kept balanced; (c) the difficult sensing of DC link current in flat plates is avoided; and (d) the current is controlled through only one DC component. These characteristics allow to use the triangular carrier as a current control strategy for the power transistors, which is simpler and better than other options. Computer simulations using power electronic simulator (PSIM), have been developed to show the good characteristics of this solution, and its simplicity. Some experiments with a 15 kW motor-inverter system, show the excellent behavior under steady-state, and transient situations, such as step response and reversal of power. View full abstract»

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  • Reviewers list

    Page(s): 298 - 299
    Save to Project icon | Request Permissions | PDF file iconPDF (142 KB)  
    Freely Available from IEEE
  • A novel resonant gate driver for high frequency synchronous buck converters

    Page(s): 180 - 186
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (311 KB) |  | HTML iconHTML  

    This paper introduces a new resonant gate driver for both the top and bottom switches of a synchronous buck converter. A coupled inductor is used to reduce the size as well as to transfer energy between the top and bottom gate driving. A possible semiconductor integration approach is proposed for this resonant gate driver based on a self-adaptive control method. Theoretical analysis, simulation and experimental results prove that the proposed driver can greatly reduce the gate driving loss and that it is well suited to high-frequency applications View full abstract»

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  • Low stray inductance bus bar design and construction for good EMC performance in power electronic circuits

    Page(s): 225 - 231
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB) |  | HTML iconHTML  

    Ten years after the publication of the EC Directive 89/336 on electromagnetic compatibility, the impact of this directive on design and lay-out of modern electrical and electronic equipment can be observed. Many research and development studies have proposed and evaluated detailed improvements in the area of component design, component selection, circuit lay-out, shielding and active and passive filtering. New and innovative solutions to minimize noise, especially common mode conducted electromagnetic interference (EMI), in power electronic circuits continue to be developed. In this paper, the authors investigate to what extent EMI caused by power electronic devices in hard switching inverter topologies can be minimized using ultra-low inductive planar busbars. The concept followed in this study is to tackle EMI directly at the source where most EMI is generated; in other words, to reduce the parasitic magnetic energy stored in the inverter DC link to reduce high voltage spikes during switching. A planar busbar was built, tested and analyzed. Measurements show the validity of the theoretical, but simple, design procedure for planar busbars in power converters View full abstract»

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  • A technique for power supply harmonic impedance estimation using a controlled voltage disturbance

    Page(s): 207 - 215
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB) |  | HTML iconHTML  

    A method for power system impedance estimation is presented. The method employs a power converter to inject a voltage transient onto the supply system. As the technique employs controlled power electronic devices it may be used as a stand alone piece of a portable measurement equipment, or it may be embedded into the functions of an active shunt filter for improved harmonic control. The impedance is estimated through correlation of the measured voltage and current transients. Simulations and experimental results demonstrate the measurement technique is highly accurate and effective View full abstract»

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  • Position control of ultrasonic motors using MRAC and dead-zone compensation with fuzzy inference

    Page(s): 265 - 272
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (343 KB) |  | HTML iconHTML  

    The ultrasonic motor has a heavy nonlinearity, which varies with driving conditions and possesses variable dead-zone in the control input associated with applied load torque. The dead-zone is a problem as an accurate positioning actuator for industrial applications and it is important to eliminate the dead-zone in order to improve the control performance. This paper proposes a new position control scheme of ultrasonic motors to overcome dead-zone employing model reference adaptive control with fuzzy inference. The dead-zone is compensated by fuzzy inference, whereas model reference adaptive control performs accurate position control. Mathematical models are formulated and experimental results are given to validate the proposed position control scheme View full abstract»

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  • Robust control using neural network uncertainty observer for linear induction motor servo drive

    Page(s): 241 - 254
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (509 KB) |  | HTML iconHTML  

    A robust controller, that combines the merits of integral-proportional (IP) position control and neural network (NN) observed technique, is designed for a linear induction motor (LIM) servo drive in this study. First, the secondary flux of the LIM is estimated using a sliding-mode flux observer on the stationary reference frame and the feedback linearization theory is used to decouple the thrust and the flux amplitude of the LIM. Then, the IP position controller is designed according to the estimated mover parameters to match the time-domain command tracking specifications. Moreover, a robust controller is formulated using the NN uncertainty observer, which is implemented to estimate the lumped uncertainty of the controlled plant, as an inner-loop force controller to increase the robustness of the LIM servo drive system. Furthermore, in the derivation of the online training algorithm of the NN, an error function is used in the Lyapunov function to avoid the real-time identification of the system Jacobian. In addition, to increase the speed and accuracy of the estimated flux, the sliding-mode flux observer is implemented using a 32 bit floating-point digital signal processor (DSP) with a high sampling rate. The effectiveness of the proposed control scheme is verified by both the simulated and experimental results View full abstract»

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  • Stability and dynamic performance of current-sharing control for paralleled voltage regulator modules

    Page(s): 172 - 179
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    The parallel operation of voltage regulator modules (VRMs) for high-end microprocessors requires a current-sharing (CS) circuit to provide a uniform load distribution among the modules. A good dynamic performance of the CS circuit is very important since the microprocessors present highly dynamic loads to the VRMs. Stability and dynamic performance of the CS control are considered. To assess these issues, a comprehensive small-signal model of the paralleled VRMs was developed and verified View full abstract»

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  • A comprehensive approach to fixed-step simulation of switched circuits

    Page(s): 216 - 224
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (295 KB) |  | HTML iconHTML  

    Because of its reduced calculation effort and deterministic execution time, fixed-step simulation is a prerequisite for real-time performance. However, when simulating switched circuits, it introduces errors in the form of switching delays and inconsistent initial conditions. In order to eliminate these errors, the present paper describes a physically sound method for accurate and efficient fixed-step/real-time simulation of switched circuits. Assuming that switching is instantaneous and respecting the conservation of energy principle, the simulation method provides simple and straightforward procedures for eliminating switching delays and for calculating consistent initial conditions, even though the switching time may not coincide with a calculation time-step and the circuit may pass through a series of simultaneous switchings. Furthermore, the simulation method proposes a simple decoupling technique to isolate parts of the circuit where the switching occurs, in order to reduce the effort required for the calculation of initial conditions. Implementation of the proposed simulation method in the nodal approach and in the state space approach is shown. A 12 pulse thyristor rectifier and a PWM inverter are used to highlight simulation accuracy. Simulation results, with and without the simulation method, are compared to variable-step simulation and to other documented methods. Finally, the simulation of a full HVDC system serves to demonstrate real-time simulation performance View full abstract»

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  • Impedance specifications for stable DC distributed power systems

    Page(s): 157 - 162
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (286 KB) |  | HTML iconHTML  

    In a DC distributed power system, the interaction between individually designed power modules/subsystems may cause the instability of the whole system. In a small-signal sense, system level stability is determined by the impedance ratio Zo/Zi. Here, Z o is the output impedance of the source module/subsystem, and Zi is the input impedance of the load module/subsystem. As a result, an effective way to prevent system instability is defining impedance specifications for modules/subsystems. This paper briefly summarizes existing works and introduces the authors' contribution in defining impedance specifications. A new forbidden region for impedance ratio Zo/Zi on the S-plane is proposed as the system stability margin requirement. Based on this proposed forbidden region, the impedance specifications of individual loads are established. Further, a very practical measurement approach is developed to examine whether or not the system stability margin requirement of the forbidden region is satisfied View full abstract»

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  • Rise time reduction in high-voltage pulse transformers using auxiliary windings

    Page(s): 196 - 206
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (402 KB) |  | HTML iconHTML  

    Today high-voltage pulses are reaching more fields of application. High-voltage pulse transformers are often used in association with high-voltage pulse generating circuits to further increase the pulse output voltage level. However, because of the transformer parasitic elements involved, the transformer is the critical device in shaping the rising characteristics of the output pulse. One of the techniques usually adopted to decrease the leakage inductance of the transformer adds two auxiliary windings to the transformer. If properly used, these auxiliary windings reduce the leakage flux and, therefore, the leakage inductance. As a result the pulse rise time is reduced. In this paper, a mathematical model is used to describe the observed behavior of a transformer operating with auxiliary windings, based on the theory of electromagnetic coupled circuits. The model is discussed regarding the experimental results obtained from a high-voltage test transformer associated with a high-voltage pulse generating circuit, and the simulation results obtained from the numerical evaluation of the developed differential equations implemented in Matlab/Simulink with the measured transformer parameters View full abstract»

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  • Vector current controlled voltage source converter-deadbeat control and saturation strategies

    Page(s): 279 - 285
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (315 KB)  

    This paper presents a voltage source converter connected to a grid with software specially designed for limited control voltage. The voltage source converter uses a deadbeat vector current controller. The paper deals with limiting reference voltage, integrator windup and delay time compensation. Simulations and experimental verifications of the proposed controller are included View full abstract»

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  • Torque ripple reduction in DTC of induction motor driven by three-level inverter with low switching frequency

    Page(s): 255 - 264
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB) |  | HTML iconHTML  

    A torque ripple reduction technique of direct torque control (DTC) for high power induction motors driven by three-level inverters with the inverter switching frequency limited around 0.5-1 kHz level is presented. It is noted that conventional two-level DTC algorithms to reduce torque ripple are devised for applications with relatively high switching frequency above 2-3 kHz and cannot accomplish satisfactory torque ripple reduction for three-level inverter systems with such lower switching frequencies. A new DTC algorithm, especially for low switching frequency inverter system, illustrates quite reduced torque ripple characteristics all over the operating speed region. Simulation and experimental results show effectiveness of the proposed control algorithm View full abstract»

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  • Thermal characterization of compact electronic systems: a portable PC as a study case

    Page(s): 187 - 195
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (377 KB) |  | HTML iconHTML  

    An analysis of the thermal behavior of compact electronic systems is presented. The chosen case study is a portable PC and the analysis is performed with an experimental and a numerical approach. The temperatures of the various parts of the system were measured by thermocouples under two different working conditions. Simulations used a computational fluid dynamics (CFD) solver. Issues involving the numerical prediction of operating temperatures are highlighted and discussed. In particular the importance of radiative exchange in the system is studied. A simple, yet effective model for the heat-pipe of the system considered is presented together with the procedure for tuning it. The influence of materials on the thermal behavior of the complete system is investigated by simulation. Considerations regarding the thermal aspects of compact electronic systems are also reported View full abstract»

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  • Switching frequency imposition and ripple reduction in DTC drives by using a multilevel converter

    Page(s): 286 - 297
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (705 KB)  

    A new strategy for direct torque control with imposed switching frequency (DiCoIF) is proposed. This strategy was specially designed to operate with a multicell (flying capacitors) inverter with any number of levels, which means it can also be used for standard two-level inverters. This approach combines the well known advantages of the multicell. inverter with those of a direct torque controlled (DTC) based strategy. It is shown that the multicell topology presents enough degrees of freedom to control both torque and flux with very low ripple and high dynamics on one hand, and to impose the switching frequency and the capacitors voltage balance on the other hand. Experimental and simulation results, obtained with a standard two-level inverter and with a four-level multicell inverter, are presented and discussed. Finally, a comparative analysis either with the classical DTC and field oriented techniques is carried out View full abstract»

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  • Shunt active power filter synthesizing resistive loads

    Page(s): 273 - 278
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (274 KB) |  | HTML iconHTML  

    The paper discusses the use of a shunt active power filter to compensate for the line current distortion and to improve the power factor. The advantages of the resistive load synthesis over the sinusoidal current synthesis when the filter is used in a system where the voltage is not perfectly sinusoidal are presented. The control circuit is based on analogic multipliers, and the currents follow the same waveforms of the respective line voltages. Experimental results of connecting a three-phase active power filter to a nonsinusoidal grid are presented View full abstract»

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  • A simple single-switch single-stage AC/DC converter with fast output voltage regulation

    Page(s): 163 - 171
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (362 KB) |  | HTML iconHTML  

    In this paper, a simple single-stage AC/DC converter based on the flyback topology is presented. With a single switch, a fast-regulated output voltage is achieved and, although the line current is not sinusoidal, the converter complies with the Standard IEC 1000-3-2 about low frequency harmonies for a medium power range (50-500 W). The major advantages of this converter are the size and the efficiency. Design guidelines, analysis of the line current, and extensions to other topologies are analyzed. Experimental results are included in the paper 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