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The hydraulic simulation is an important work in the design and construction of gas pipeline network in the city. It is also a necessary means to improve pipeline network, optimize the operation and management of pipe network, and ensure the safety of gas supply. In this paper, based on the model of hydraulic calculation and the finite element nodal method, the research on the hydraulic simulation...
Permanent magnet motors are coming more and more popular in wind generation applications. In the high efficient wind power generation system, the accurate information about rotor position is very important. MRAS schemes offer simpler implementation and require less computational effort. Because the voltage model involves pure integrator in the classical model reference adaptive system (MRAS). This...
Described the operating principles of permanent magnet synchronous motor used in electric vehicles. Introduced weakening principle due to its mathematical models. Traditional control after decoupling often used PI controller, often influence of motor parameters, affecting the robustness of control system, especially operated at above the rated speed on flux weakening condition. Analyzed the proportional...
Water is one of the most important natural elements on earth. Water quality directly and indirectly influences human lives and development. In this paper, a GIS-based system is designed to assist water resources professionals in making economical and efficient decision. GIS and remote sensing techniques are effectively used to replace, complement and supplement data collection in various facets of...
Permanent Magnet Synchronous Generators (PMSGs) have been widely used in modern wind power system. Direct-drive permanent magnet synchronous generator (D-PMSG) has shown significant advantages for its high efficiency, reliability, and become an attractive choice for variable-speed wind power generation. A Fast, robust, efficient, smooth controling power generated by the PMSG is essential for the D-PMSG...
In this paper, an averaged model of circulating current is proposed. Based on the model, the mechanism concerned with the circulating current occurring are explained explicitly. Owing to the circulating current which mainly consists of zero-sequence components varies with different factors such as pulse width-modulation strategies, circuit parameters and so on, therefore a new control variable associated...
This paper presents a leading angle flux-weakening control method for the wide-speed operation of permanent magnet synchronous motor (PMSM). The angle offset of flux-weakening is gained by integraling the error of given index and calculation index, which is the utilization of motor's terminal voltage to the voltage of DC bus, and then a voltage loop is established to maintain the stability of flux-weakening...
Described the surface-mount permaent magnet synchronous motor used in electric vehicles operation principle, introduce the current limit trajectory and the voltage limit trajectory based on its mathematical model, Flux-weakening control extends the speed range of the machine effectively. Conventional flux-weakening speed control above the rate speed, the q-axis current and d-axis current coupling...
A MRAS (Model Reference Adaptive System) method for evaluation of induction motor speed to achieve speed sensorless vector controlling by the variation of transient reactive power is discussed in terms of traditional methods. A mathematic model is derived, and the reliability of the speed estimator is performed in speed-torque domain using small signal analysis. The simulating model of speed-sensorless...
In this paper, we proposed a new control scheme of decoupling based decentralized robust control for a typical two-input two-output system in tandem cold rolling process. A dynamic coupled model of shape and gauge system was developed based on some field data. Then we proposed a new control scheme for the combined system. The controller consists of a decoupler and a set of robust controllers. The...
Population statistic and forecast is important basis that government establishes correlative policy, population's all characteristic has strong non-linear speciality because of all kinds of effects. A cross validation optimized parameter least support vector machine method of population statistic and forecast is presented aiming at bad precision and lack of rationality of all approximate model at...
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