This paper introduces an over-modulation technique, a continuous extension of space vector PWM (SVPWM) linear control scheme for the three-phase current source rectifier (CSR). The over-modulation range is divided int...
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ISBN:
(纸本)9781424449347
This paper introduces an over-modulation technique, a continuous extension of space vector PWM (SVPWM) linear control scheme for the three-phase current source rectifier (CSR). The over-modulation range is divided into two modes depending on the modulation index (MI). In mode I, the reference angles are derived from the Fourier series expansion of the reference voltage which corresponds to the MI. In mode II, the holding angles are also derived in the same way. The strategy, which is easier to understand graphically, produces a linear relationship between the output voltage and the MI up to six-step operation. The relationship between those angles and the MI can be written in lookup tables or, for real-time implementation, can be piecewise linearized. In addition, harmonic components and total harmonic distortion (THD) of the output voltage are analyzed. When the method is applied to the V/f control of the induction motor, a smooth operation during transition from the linear control range to the six-step mode is demonstrated through experimental results.
The location and sizing of distribution substations integrated with urban spatial information is a optimization problem which primary characteristics are the existence of many suboptimal cost peaks and the solution sp...
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Simulation veracity is very important to the plan and operation of a powersystem. Too optimistic a simulation will put the system at risk whereas too pessimistic a simulation will waste investments. Wide area measure...
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The prediction analysis in nonlinear systems will be discussed carefully in this paper. We are mainly using CM (1,1) model to forecast data sequences, and the usual forecast precision is approximate to 90％. In this p...
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The prediction analysis in nonlinear systems will be discussed carefully in this paper. We are mainly using CM (1,1) model to forecast data sequences, and the usual forecast precision is approximate to 90％. In this place we have found a generating rule that may realize chaotic synchronization at least in short and medium term, and we can analysis and forecast in this way. We hope to offer an effective prediction method to study certain properties of DNA base sequences, 20 amino acids symbolic sequences of protein structure, and the time series that can be symbolic in finance market et al.
The electric propulsive shipping power grid is a typical independent power supply system, and the anti-jamming ability to non-linear load is quit weak because of the limitation of generation capacity. So the influence...
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The electric propulsive shipping power grid is a typical independent power supply system, and the anti-jamming ability to non-linear load is quit weak because of the limitation of generation capacity. So the influence of the harmonics becomes more serious. Meanwhile, the variation range of the voltage and frequency is often large, which can cause the tuning point deviation of the passive filter easily. A novel method to suppress the harmonics of this kind grid by adopting the phase-shifting strategy is put forward in this paper. The phase current can be divided into two branches through phase-shifting windings, and specific phase-shifting angle can be achieved by choosing proper winding turns and connection way. The configuration of the phase-shifting windings is analyzed in detail and the optimal selection of the phase-shifting angle is also done. The accuracy and the effectiveness are verified by the EMTDC/PSCAD based simulation results.
This paper introduced a real-time digital modeling approach for Electrical Arc Furnace (EAF) based on recorded field data. The model equaled the arc furnace to a current source controlled by the field data, and via ad...
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This paper introduced a real-time digital modeling approach for Electrical Arc Furnace (EAF) based on recorded field data. The model equaled the arc furnace to a current source controlled by the field data, and via adopting a phase locked technique, the synchronization between simulation and field data was performed, which made a long time real-time simulation possible. Besides, the model was used for evaluating the performance of SVC system which contributes to compensate Var and mitigate the harmonic and flicker caused by EAF. The simulation was implemented on the Real Time Digital Simulators (RTDS) and the results of simulation illustrate that the proposed EAF model and evaluation system can be used for testing a physical controlsystem of SVC system and evaluating the control strategy.
The dynamical complexity of a typical nonlinear system will be clarified in this paper. These stochastic symbolic sequences bear three features. The distribution of frequency, inter-occurrence times, the first passage...
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The dynamical complexity of a typical nonlinear system will be clarified in this paper. These stochastic symbolic sequences bear three features. The distribution of frequency, inter-occurrence times, the first passage time and the r-th passage time are discussed carefully. Especially, one introduces ordinal passage time and gives certain distribution functions in this typical nonlinear system. Finally, the visitation density function is obtained by Frobenius-Perron(F-P) operator P.
For a large-scale power grid, how to obtain load model for the substation without load characteristics recorder is the problem facing measurement-based load modeling. The feasibility that the measurement-based load mo...
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under the general backgrounds of fast development of economy, China' power industry is undergoing a new upsurge of infrastructure construction. With the urgent need of the whole society for reliable power supply, ...
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It has been well recognized that the load model has great effects on the powersystem analysis and control. However, it is also widely known that the load modeling is a quite difficult problem due to its special prope...
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