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Electric Power Applications, IEE Proceedings B

Issue 3 • Date May 1993

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Displaying Results 1 - 8 of 8
  • Class D voltage-switching inverter with tapped resonant inductor

    Page(s): 177 - 185
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    A steady-state analysis and experimental verification are given for a Class D voltage-switching inverter whose resonant circuit consists of a resonant capacitor in series with a tapped inductor. The analysis of the inverter is carried out in the frequency domain using Fourier series techniques. Design equations describing the steady-state operation are derived. It is found that the DC-to-AC voltage transfer function of the inverter is almost independent of the load variations at a switching frequency higher than the resonant frequency. In addition, the circuit has high efficiency over a wide range of load resistance. A prototype of the inverter was built and tested at an output power of 64 W using IRF730 power MOSFETs. The theoretical and experimental results show excellent agreement View full abstract»

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  • Major design parameters of a solid canned permanent magnet motor with skewed magnets

    Page(s): 161 - 165
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (252 KB)  

    Permanent magnets buried in the rotors of synchronous machines are now accepted as a means of producing a high performance machine which can take advantage of rare earth magnets. The magnets can be nonradial, but an alternative strategy is radial magnets is with a significant skew. It that this arrangement leads to a drastic reduction in harmonics and cogging torques. The use of a supporting tube on the rotor whether magnetic or not, is also investigated with a view to overcoming problems of high-speed operation View full abstract»

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  • Method of magnetic sources applied to the basic configuration of a rotating electrical machine

    Page(s): 217 - 231
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (864 KB)  

    A method of magnetic field calculation in a cylindrical rotor electrical machine is outlined which considers the winding currents to be explicit sources of the field, and the resulting magnetisation of the stator and rotor core and shaft surfaces as implicit sources that are relaxed by a simple iterative process. The method is not intended to replace the finite element solutions that can better handle the details of the final configuration, but is advocated as a fast and useful tool in design synthesis, particularly where significant departures from conventional proportions are required, as with, for example, the possible application of high temperature superconductors to rotating machines View full abstract»

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  • AI applications and solution techniques for AC-railway-system control and simulation

    Page(s): 166 - 176
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (796 KB)  

    The authors describe a knowledge-based online consultant which assists system operators with the simulation and control of railway systems which can assist the planning engineer by providing an accurate. easy-to-use, and flexible environment for studying different aspects of proposed expansion plans according to various requirements. It can also be used for training young engineers on the familiarisation of operating policy. Using the package, an change in the supply network and any deviation in train services from those given in the basic system configuration are assessed, and the corresponding effects on the system as a whole are simulated from time to time. Proposed changes in the operating strategy can then be verified and carried out in confidence View full abstract»

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  • Optimal torque operation of digitally controlled permanent magnet synchronous motor drives

    Page(s): 232 - 240
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    The electromagnetic torque developed in permanent magnetic synchronous motor drives is analysed and discussed accounting for different motor structures. An electromagnetic model has been developed and used in digital control to obtain an optimal torque: maximal mean torque free of pulsation for a given current. This is obtained by imposing a minimised instantaneous current in the motor accounting for actual motor flux distribution which is the cause of torque pulsations. The model uses the finite elements technique to determine the motor parameters and an iterative procedure to predetermine the adequate current reference. Different motor structures have been studied and an experimental verification for one of them is given View full abstract»

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  • Steady-state and dynamic analyses of high-order parallel resonant convertors

    Page(s): 209 - 216
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    The steady-state and small-signal dynamic analyses of a four-element, high-order parallel resonant DC-DC convertor operating in the continuous-current conduction mode are presented. The analyses are based on the concepts of describing function and harmonic balance. Other lower-order parallel resonant DC-DC convertors are analysed using modified versions of the equations for the four-element convertor. For output voltage control based on variation of switching frequency, convertor characteristics are determined and in some cases are compared with experimental and simulation results. It is shown that this analysis approach does not only provide an accurate unifying technique for convertor steady-state and small-signal dynamic analyses and design, but can also be used for the prediction of the output filter ripple components View full abstract»

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  • Modelling and analysis of a three phase PWM AC-DC convertor without current sensor

    Page(s): 201 - 208
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    The familiar state space averaging technique for DC-DC convertors is extended for modelling a three-phase AC-DC convertor without current sensor. The space vector representation technique is used to simplify greatly the modelling process without sacrificing the accuracy and valid frequency range. Both steady-state and small-signal analyses are made. The results show that for the proposed duty ratio control law the convertor can achieve an ideal property, namely, sinusoidal input current with unity power factor, zero output voltage ripple resulting from line frequency and fixed switching frequency. Moreover, the convertor also possesses the regenerative capability which is useful for many applications. Finally, some experimental results are presented for verification View full abstract»

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  • Autocommissioning for voltage-referenced voltage-fed vector-controlled induction motor drives

    Page(s): 187 - 200
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (896 KB)  

    An automated self commissioning procedure for voltage-referenced voltage-fed vector-controlled induction motor drives is described. The measurement of the electrical parameters of the motor at standstill, and mechanical parameters from open loop runup and rundown tests are described. These procedures are followed by the automatic design of the two quadrature axis current controllers and the speed controller. Closed loop tests are invoked to tune constants accurately under varying operating conditions. The package provides for an intelligent vector drive in which no prior knowledge of the motor parameters is required. Implementation of the procedures using a parallel processor control rig is described and experimental verification of the procedures are given View full abstract»

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