compared, yielding one optimum stator voltage vector that is selected ... tional vector control schemes and the same controller can be used for different motors ...
A Rule-Based Acceleration Control Scheme for an Induction Motor Shi, K.L.; Chan, T.F.; Wong, YK.; Ho, S.L. Author Affilliation: The Hong Kong Polytechnic University,
Hunghom, Kowloon, Hong Kong Abstract: This paper presents a rule-based acceleration control scheme that aims to give an inverter-fed induction motor excellent dynamic performance. In every time interval of the control process, the acceleration increments produced by two different voltage vectors are compared, yielding one optimum stator voltage vector that is selected and retained. The on-line inference control is built using a rule-based system and some heuristic knowledge about the relationship between the motor voltage and acceleration. Because evaluation of integrals is not required and the motor parameters are not involved, the new controller has no accumulation error due to the integrals as in the conventional vector control schemes and the same controller can be used for different motors without modification. Keywords: Knowledge-based systems, induction motor drives, acceleration control, simulation, intelligent control. Preprint Order Number: PE-069EC (01-2002) Discussion Deadline: June 2002
Synthesis of High-Performance PM Motors with Concentrated Windings Cros, J.; Viarouge, P Author Affiliation: LEEPCI, Laval University Ste-Foy, Quebec,
Canada Abstract: The windings concentrated around the teeth offer obvious advantages for the electrical machines with radial air-gap, because the volume of copper used in the end-windings can be reduced. The Joule losses are decreased and the efficiency is improved. These machines are still limited to applications of subfractional power and they generally present a reduced number of phases. In the three-phase machines, the concentrated winding is too often restricted to a winding with a short pitch of 120 electrical degrees, i.e., to a winding with performances reduced compared to the traditional structures. But there is a significant number of three-phase structures that can support a concentrated winding if the number of poles is increased. In this article, the authors present a synthesis of the structures of three-phase machines with concentrated windings. In the first part, the structures with a regular distribution of the slots are presented. A systematic method is proposed to determine the windings and the performances are discussed. In the second part, the authors present original structures of three-phase machines with concentrated windings that use an irregular distribution of the slots. A specific method to identify these structures is described, and a comparative analysis of the performances of the original and traditional structures is performed by using a field calculation software. Keywords: Windings, PM motors, design of electrical machines, brushless motors, concentrated windings. Preprint Order Number: PE-053EC (01-2002) Discussion Deadline: June 2002
Identiffication of Synchronous Machine
Parameters Using Load Rejection Test Data Bortoni, E.C.; Jardini, J.A. Author Affiliation: DEE-FEG-UNESP, Sao Paulo, Brazil; PEA-POLI-USP, Sao Paulo, Brazil Abstract: This work shows a computational methodology for the determination of synchronous machines parameters using load rejection test data. By machine modeling one can obtain the quadrature parameters through a load rejection under an arbitrary reference, reducing the present difficulties. The proposed method is applied to a real machine. Keywords: Synchronous machines, parameter identification. Preprint Order Number: PE-287EC (01-2002) Discussion Deadline: June 2002 74
Energy Development and Power Generation Techniques to Control the Electricity Generation in a Series Hybrid Electrical Vehicle Barsali, S.; Ceraolo, M.; Possenti, A. Author Affiliation: University of Pisa, Pisa, Italy Abstract: In a series hybrid electric vehicle (SHEV), an electric generator feeds a dc busbar (containing an electrochemical accumulator), which, in turn, feeds the vehicle traction system. A very important part of the vehicle is its control system that has to maximize the vehicle efficiency, while keeping the emissions within predetermined limits. To attain this goal it can act in two ways: it can switch the electric generator ON or OFF, or when in ON state, it can impose a given power to be delivered. To choose the control actions to perform it needs: an algorithm to understand the behavior of the battery (determine the state-of-charge, maximum power, losses) and an algorithm to make some forecast of the system load (i.e., the power required in the future of the trip, as a function of time). This paper discusses the main problems arising when trying to synthesize the control system of the vehicle, keeping into particular account the second two issues. Some lab tests are also presented, in which some of the proposed controlled techniques are experimentally checked. Keywords: Batteries, energy conversion, road vehicle electric propulsion, road vehicle control, fuel optimal control, load forecasting. Preprint Order Number: PE-302EC (01-2002) Discussion Deadline: June 2002
Power System Analysis, Computing, and Economics Comparison Between Closed-Loop and Partial Open-Loop Feedback Control Policies in Long-Term Hydrothermal Scheduling Martinez, L.; Soares, S. Author Affiliation: State University of Campinas, Campinas, Sao Paulo, Brazil Abstract: Stochastic dynamic programming has been extensively used in the optimization of long-term hydrothermal scheduling problems due to its ability to cope with the nonlinear and stochastic characteristics of such problems and the fact that it provides a closed-loop feedback control policy. Its computational requirements, however, tend to be heavy even for systems with a small number of hydro plants, requiring some sort of modeling manipulation in order to be able to handle real systems. An alternative to closed-loop optimization is an approach that combines a deterministic optimization model with an inflow forecasting model in a partial open-loop feedback control framework. At each stage in this control policy, a forecast of the inflows during the period of planning is made, and an operational decision for the following stage is obtained by a deterministic optimization model. The present paper compares such closed-loop and partial open-loop feedback control policies in long term hydrothermal scheduling, using a single hydro plant system as a case study to focus the comparison on the feedback control performance. The comparison is made by simulation using data from historical and synthetical inflow sequences in the consideration of three different Brazilian hydro plants located in different river basins. Results have demonstrated that the performance of the partial open-loop feedback control policy is similar to that of the closed-loop control policy, and is even superior in dry streamfiow periods. IEEE Power Engineering Review, April 2002
