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Electric Power Applications, IEE Proceedings -

Issue 4 • Date Jul 2001

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Displaying Results 1 - 11 of 11
  • Robust quantitative speed control of a switched reluctance motor drive

    Publication Year: 2001 , Page(s): 345 - 353
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (724 KB)  

    The robust quantitative speed control for a switched reluctance motor (SRM) drive is studied. The drive circuit with proper current control for the SRM motor is implemented. Since it is difficult to obtain an accurate dynamic model of the SRM drive via physical derivation, it is estimated through measurements at nominal case. A simple two-degree-of-freedom (2DOF) speed controller, using an inverse model approach, and its quantitative design procedure are presented. According to the estimated nominal dynamic model and the prescribed speed tracking and regulation control specifications, the parameters of the proposed 2DOF speed controller can be systematically solved. A robust controller, handling the performance improvement of the perturbed motor drive and considering the effect of the system transport delay, is developed. The effects of parameter uncertainties and disturbances on the control performance can be reduced significantly. After confirming the effectiveness of the designed speed controller by simulation results, its performance is further demonstrated experimentally View full abstract»

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  • Combined magnetising flux oriented control of the cascaded doubly-fed induction machine

    Publication Year: 2001 , Page(s): 354 - 362
    Cited by:  Papers (6)  |  Patents (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (948 KB)  

    A cascaded doubly-fed induction machine (CDFM) is a connection of two wound rotor induction machines. In comparison to a single doubly-fed (wound rotor) induction machine (SDFM) brushes are obsolete. Because of recent developments in brushless doubly-fed machine design, there is a renewed interest in associated control. The paper presents theoretical and experimental studies of a combined magnetising flux oriented control method for a CDFM. After the existing control method has been described it is then modified to be applicable to any CDFM machine combination. In a second step the control method is simplified and the performance is explored. Investigations of a power control loop for the simplified control show that this control method does not lead to natural decoupled active and reactive power control as known from the SDFM View full abstract»

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  • High-power semiconductor device: a symmetric gate commutated turn-off thyristor

    Publication Year: 2001 , Page(s): 363 - 368
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (644 KB)  

    A high-power semiconductor device is presented, the symmetric gate commutated turn-off thyristor (SGCT). The current and power dissipation balances among unit cells in an SGCT chip during turn-off operation are analysed by simulation. Using this result, n-emitter widths of the cells an adjusted in inverse proportion to the distance between the cells and the gate contact point on the chip. The current uniformity among the cells is realised for the SGCT chip. The relation between dynamic and static characteristics of an SGCT and the local lifetime controlled position in the n-base layer are investigated. The multi-energy proton lifetime control technology is thus developed: the SGCT has two low lifetime areas in the n-base layer, and those lifetimes are controlled independently by photon irradiation. The improved double-positive bevel is adopted for ensuring the high blocking symmetric voltage and its stability. This SGCT is expected to contribute to such areas as high-voltage and high-power convertors, inverters and switches, because of its high symmetric voltage, high-current capability, low-power dissipation and fast switching characteristics View full abstract»

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  • Halbach permanent magnet machines and applications: a review

    Publication Year: 2001 , Page(s): 299 - 308
    Cited by:  Papers (63)  |  Patents (10)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1380 KB)  

    Permanent magnet brushless machines employing multipole Halbach magnetised rotors are being developed for various applications, since they offer a number of attractive features. Alternative Halbach machine topologies are reviewed, and the realisation of Halbach magnetised magnets from pre-magnetised sintered rare earth magnet segments (which approximate the Halbach magnetisation distribution and thereby compromise their performance), and as bonded isotropic and anisotropic NdFeB ring magnets (which are subsequently impulse magnetised with a Halbach field distribution), is considered. Radial- and axial-field, slotted and slotless, rotary and linear (tubular and planar), and spherical Halbach magnetised brushless machines are described, and potential applications, including a motor/generator for a high-speed flywheel peak power buffer, high-performance linear and rotary servo motors, and passive magnetic bearings are considered View full abstract»

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  • Single-stage photovoltaic energy conversion system

    Publication Year: 2001 , Page(s): 339 - 344
    Cited by:  Papers (30)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (476 KB)  

    For a photovoltaic (PV) array, the nonlinear output power relation of dP/dV against V and the near linear relation of dP/dV against I are discussed. Thus, using dP/dV as an index for current control is easier than for voltage control, allowing a simpler design. The current controller is employed in the PV energy conversion system to perform a rapid maximum power point tracking and to provide power to utilities with a unity power factor. As opposed to conventional two-stage designs, a single-stage PV energy conversion system is implemented, resulting in size and weight reduction, and increased efficiency. The proposed system performs a dual function; acting as a solar generator on sunny days and as an active power filter on rainy days. Computer simulations and experimental results demonstrate the superior performance of the proposed technique View full abstract»

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  • Regular-sampled harmonic elimination PWM control of single-phase two-level inverters

    Publication Year: 2001 , Page(s): 309 - 314
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (528 KB)  

    A new harmonic elimination/minimisation pulse width modulation strategy for single-phase inverters is presented. The two-level harmonic elimination pulse width modulation strategy operates online and in real-time and closely approximates the switching angles produced by the offline exact harmonic elimination pulse width modulation technique. The new technique, based on the well-known regular-sampled approach, is suitable for implementation using a low-cost digital signal processor. Theoretical and experimental results are presented to demonstrate and confirm the validity of the new technique View full abstract»

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  • A bidirectional, sinusoidal, high-frequency inverter design

    Publication Year: 2001 , Page(s): 315 - 321
    Cited by:  Papers (24)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (572 KB)  

    A new method for the design of a bidirectional inverter based on the sinusoidal pulse-width modulation principle and the use of a low-cost and lightweight ferrite-core transformer is presented. The inverter is designed for either ohmic or inductive loads. In the case of inductive loads, the reactive power is transferred back to the DC input power source using a new active rectifier design. The inverter is controlled by two minimum-time feedback loops, providing relatively low output voltage distortion (less than 2% for DC input higher than 24 V) and good load regulation (better than 2%), while the inverter efficiency remains relatively constant (from 80 to 85%) over a wide output power range (75 to 200 W) and DC input voltage range (23 to 28 V). Theoretical results are experimentally verified using a laboratory prototype View full abstract»

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  • Operating partial core transformers under liquid nitrogen conditions

    Publication Year: 2001 , Page(s): 293 - 298
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    A reverse design method has been applied to partial core transformers. Three sample transformers were built and then tested under liquid nitrogen (N2) conditions. The measured results were compared to model calculated values and the differences used to modify the reverse design model in order to more accurately determine the calculated equivalent circuit parameters. A fourth transformer was then designed, built and tested. The measured performance of this transformer confirmed the validity and accuracy of the model, and showed the usefulness of the reverse design approach View full abstract»

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  • Seven self-lift DC-DC converters, voltage lift technique

    Publication Year: 2001 , Page(s): 329 - 338
    Cited by:  Papers (19)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (640 KB)  

    The voltage lift technique is a popular method widely applied in electronic circuit design. Because of the effect of parasitic elements, the output voltage and transfer efficiency of DC-DC power converters are limited. The voltage lift technique provides a good way to improve the characteristics of DC-DC converters. Applying the voltage lift technique has created seven new DC-DC step-up converters, namely self-lift DC-DC converters. These converters perform DC-DC voltage increasing conversion in simple structures. They are different from any other existing DC-DC step-up converters and possess many advantages, such as high output voltage with smooth ripples. Therefore, these converters can be used in computer peripheral equipment and industrial applications, especially for high-output voltage projects View full abstract»

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  • Novel analytical model for design and implementation of three-phase active power filter controller

    Publication Year: 2001 , Page(s): 369 - 383
    Cited by:  Papers (11)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1020 KB)  

    The paper presents a simple analytical model for the design and implementation of a three-phase active power filter controller. Voltage decouplers and pole-zero cancellation are used in current regulators to simplify the current control plant to a first-order delay type. This simplification is made by considering the delay times caused by the lowpass filter of reference current calculation circuits, line inductors of an active power filter and the feedback circuit of a DC-link voltage. From the derived analytical model, the cutoff frequency of the lowpass filter and controller parameters can be appropriately determined to increase the harmonic current compensating capability of an active power filter and accelerate the dynamic response of the DC-link voltage. Analytical and experimental results indicate that the proposed active power filter can largely improve the total harmonic distortion of current and correct the power factor to unity with balanced and unbalanced loads View full abstract»

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  • Torque ripple minimisation in a switched reluctance motor by optimum harmonic current injection

    Publication Year: 2001 , Page(s): 322 - 328
    Cited by:  Papers (10)  |  Patents (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    The evaluation at low speeds of a method for torque ripple minimisation of a switched reluctance motor by the injection of a series of current harmonics is described. Adjustment of magnitude and phase of an injected harmonic is shown to lead to a corresponding minimum of torque ripple. Sequential minimisation of the lowest five harmonics removes most of the ripple, and three iterations overcomes harmonic interactions and leads close to the global minimum. Experimental results are also given View full abstract»

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