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Electric Power Applications, IEE Proceedings -

Issue 2 • Date Mar 2000

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Displaying Results 1 - 8 of 8
  • DSP-based indirect-current-controlled STATCOM. II. Multifunctional capabilities

    Page(s): 113 - 118
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (276 KB)  

    For pt.I see ibid., vol. 147, no.2, p.107-12 (2000). The multifunctional capabilities of a DSP-based three-phase static compensator (STATCOM) are covered. An IGBT-based voltage source inverter (VSI) with indirect-current control technique is taken as a STATCOM. Four different types of loads consisting of linear/nonlinear and single/three-phase elements are used. Fuzzy-logic-based closed-loop control of the system reduces the size of capacitor in the DC busbar of the VSI and it also imparts a good level of performance. The steady state and transient results of a laboratory prototype are given and discussed View full abstract»

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  • Single-phase switched reluctance motor design

    Page(s): 131 - 139
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (420 KB)  

    The evolution of a novel form of single-phase switched reluctance motor, suitable for example for high-speed fans is described. The motor has four stator and four rotor poles, but only two coils. The new motor is derived by simple analysis from the basic 2-pole machine using sweeping assumptions. It is predicted to have only half the core length, less copper loss, but significantly more iron loss than the 2-pole form. These conclusions are tested using computer-based analysis, and test results from a prototype motor are presented which confirm the attractiveness of the design. Attention then turns to the starting problem of all such machines, and a method using permanent magnets is shown to be particularly appropriate for the new motor. The operation of this method is analysed, and simulated starting responses are compared with experimental results View full abstract»

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  • New hybrid parallel active filter configuration minimising active filter size

    Page(s): 93 - 98
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    The authors propose a new topology for a hybrid parallel active filter that can further reduce the active filter (inverter) power rating. The basic idea is to install the active filter in parallel with the passive filter inductor. One advantage of this is that the passive filter can operate by itself if the inverter is in the high-impedance mode. This means that the passive filter can operate without the aid of the active filter. Another advantage is that, because the significant portion of fundamental and harmonic components flows through the passive filter, the current loading to the inverter is reduced greatly. This contributes to reducing the cost of the expensive inverter, and, hence, this makes the application of a hybrid active power filter more feasible. Through computer simulations and experiments, the authors have verified the effectiveness of the proposed topology View full abstract»

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  • Theoretical and experimental study on the opening characteristic of puffer circuit breakers

    Page(s): 141 - 145
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    According to the relationship between the operating mechanism and the arc extinguish chamber of a puffer circuit breaker, mathematical models have been developed, and the influences of the hydraulic mechanism and the chamber on the moving characteristics of the puffer circuit breaker have been studied. Therefore, adjusting the diameter of the drain oil aperture of the operating mechanism is an effective way to obtain various breaking characteristics. Hence, it is possible to realise `intelligent operation'. The simulation results are shown to be in accordance with the experiment results: and it is also shown that the models are more universal and practical View full abstract»

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  • New ZCS turn-on and ZVS turn-off unity power factor PWM rectifier with reduced conduction loss and no auxiliary switches

    Page(s): 146 - 152
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    A ZCS turn-on and ZVS turn-off unity power factor PWM rectifier, which features soft switching with no auxiliary switches and reduced conduction losses is presented. The ZVS and ZCS switching are achieved by using a simple commutation circuit with no auxiliary switches, and reduced conduction losses are achieved by employing a single converter instead of a typical front-end diode rectifier followed by a boost rectifier. Furthermore, thanks to features such as simple PWM control at constant frequency. Low switch stress and low VAr rating of commutation circuits, it is suitable for high-power applications. The principle of operation is explained and analysed, and the design considerations and experimental results of the new converter are included View full abstract»

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  • DSP-based indirect-current-controlled STATCOM. I. Evaluation of current control techniques

    Page(s): 107 - 112
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    DSP-based implementation of a 3-phase static compensator (STATCOM) is presented. The closed-loop control scheme of the compensator is based on fuzzy logic. The hardware module of an IGBT-based PWM current-controlled voltage-source-inverter (PWM-CC-VSI) is taken as a STATCOM. Two different types of current control techniques, namely, direct and indirect current control are designed for the compensator. The experimental tests on the compensator are carried out with both techniques. The STATCOM is tested as an active filter (AF) to select the most promising technique for the current control View full abstract»

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  • Rotor position control for induction machines using diametrical inversion of stator voltage

    Page(s): 99 - 106
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    To accurately solve the speed or rotor position control problem of an induction motor (IM), the key has been a proper design of a torque controller included in a cascaded control structure. The IM dynamic behaviour presents a nonlinear coupling between the flux and the torque and so the decoupling has been the first task, as in field-oriented control and direct torque control, where some feedback signals are obtained using observers. An IM command action, the diametrical inversion, whose implementation is easy and gives good results, uses the sliding mode. A mechanical first order switching function determines the successive application of IM stator voltage diametrical inversions. A torque controller is not needed, the sliding mode robustness eliminates the decoupling problem, and the fast inversion of the electromagnetic torque allows a rotor positioning faster than a torque controlled second order system. Some simulation and experimental results show the position responses and exhibit the system robustness to external disturbances and winding resistance variations with temperature View full abstract»

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  • Unified theory of extended-period quasiresonant converters

    Page(s): 119 - 130
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    A switching technique for the conversion of an ordinary switch or quasiresonant switch into an extended-period resonant switch is presented. The advantages are that a converter operates under zero-current or zero-voltage switching conditions and can be controlled by either switching frequency or duty ratio or both for the regulation of the output power. Families of extended-period circuits have been developed, and the theory of the extended-period switches is explained. Analysis, simulation and experimental test are used to verify the theory. A number of applications including DC/DC converters, power factor correction, off-line power supply and transcutaneous electrical nerve stimulation are presented View full abstract»

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