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The downhole positive displacement motor (PDM) plays a very important role in petroleum drilling engineering. The rotor-stator coupling is the key element in PDMs. Normally both the rotor and the stator are constituted of cylindrical helix surfaces. 3-axis and 4-axis NC milling machines are usually used to machine these helix surfaces. The current CNC milling technology for manufacturing large and...
A novel doubly salient permanent magnet motor named flux switch permanent magnet motor (FSPM) was designed and analyzed. The stator and rotor of FSPM are all salient structures. There are a marked verge domino effect and serious saturation phenomenon. Due to high nonlinearities of FSPM, finite element method (FEM) was used to analyze magnetic field distribution, permanent magnet flux linkage, electromotive...
A new rotor position sensorless method for switched reluctance motor drive system (SRD) is described in this paper. Rotor position can be considered as a function of phase current and the variation rate of it. Using the phase current obtained by sensors and the current variation the rotor position can be estimated accurately and quickly. A control strategy of SRD without position sensor is researched...
A 12/10 flux-switching permanent magnet motor (FSPM) is described. Qualitative analysis of magnetic circuit indicates that a connection between stator segments is benefit to motor operation. From the basic principle of flux-weakening speed-extension operation, weaken magnetic factor and speed-extension multiple are calculated. The analysis results show that this kind of motor has higher flux-weakening...
The stator flux observer is a key part in the method of Direct Torque Control (DTC). However, the accuracy of the stator flux estimation directly affected the performance of DTC. The traditional induction motor stator flux observation method have been analyzed in This paper. And for the Shortcomings of existing methods, a on-line identification methods based on Radial Basis Function(RBF) have been...
A real wind power generation system is given in this paper. SVM control strategy and vector control is applied for generator side converter and doubly fed induction generator respectively. First the mathematical models of the wind turbine rotor, drive train, generator side converter are described. Then the control strategy of generator side converter system is given in detail. Finally the simulation...
This article, firstly, introduced the operating principle of variable speed constant frequency (VSCF) wind power generation based on a structure of dual PWM converter. Then the mathematical model of network-side and rotor-side converter was set up. Decoupling control and vector control technique were presented based on grid voltage orientation and stator flux orientation to simplify the control strategy...
This paper presents a speed-sensorless control algorithm for induction motors, based on the stator flux-oriented control. The algorithm has the advantage of insensitivity to rotor parameters and load varying, stator flux and rotor speed is closed loop controlled respectively. The main improvement is that stator flux is estimated based on a modified integrator which is developed to solve the problems...
By replacing conventional mechanical bearing of wind power generator with magnetic bearing, the friction loss can be reduced obviously and the efficiency of power generation can be improved. Bearing capacity of radial magnetic bearing (RMB) is determined through analyzing the radial loads of wind power generator, and upon this, the structure of radial magnetic bearing is designed. Then the electromagnetic...
This paper presents a new technique for online identification of an induction motor rotor time constant. The technique is designed for a shaft-sensorless indirect field-oriented control induction motor drive with a model reference adaptive system (MRAS)-based speed estimator. The MRAS estimator is sensitive to the changes in the rotor time constant, and on line identification of that parameter is...
Interior permanent magnet-synchronous machines (IPMSM) feature many favourable properties for e-mobility application as high power density and good efficiency. However, they require careful modelling because of strong anisotropies of the rotor, as they are also known from salient-pole synchronous machines. These anisotropies are often accounted for by different values for the d-axis and q-axis inductances...
This paper presents a modal analysis of a two machine power system that includes a doubly-fed induction generator (DFIG). The DFIG's model considers rotor flux linkages as dynamic states and stator flux linkages as algebraic variables. Active- and reactive-power controllers are also modeled. Active power is tracked for optimal power extraction from the wind. Using the power system set of differential-algebraic...
Proposing a novel electric motor which stator and rotor are made of amorphous alloy instead of traditional silicon material, Based on Ansoft/MAXWELL2D, using finite element method, the Electromagnetic field of the designed motor is analyzed. The main curves are given including flux density distribution vs. angle, output torque vs. speed and the relationship between efficiency and speed. The comparison...
Magnetic bearings can not only solve the bearing wear and life problems but also reduce the loss and noise of bearings. However, the strong non-linear and uncertainty of parameter of the magnetic bearings make the traditional PID controller difficult to ensure its long-term and stable operation. Based on the T-S fuzzy model, this paper presents a design method of magnetic bearing parallel-distributed...
This paper proposes a ride-through technique of doubly-fed induction generator (DFIG) wind turbine systems. The control technique uses energy storage devices (ESD) which are controlled with current and power control loops. During grid faults, the generator output power can be reduced by increasing the generator speed, resulting in increased inertial energy of the rotational body. Also, the output...
The use of PI controllers for speed control of induction machine drives is characterised by an overshoot during start up with a poor load disturbance rejection. To overcome this problem we propose the use of an original variable gain PI (VGPI) speed controller. Each gain value of the proposed controller vary along an appropriate polynomial curve from a start up setting that permits overshoot elimination,...
A new algorithm for speed observer based on Model Reference Adaptive System (MRAS) is proposed for high performance induction motor drive. It uses stator current error based MRAS speed observer. The reference model of the stator current error based MRAS is the measured stator current components and the adaptive model is neuro-fuzzy based stator current observer. The adaptive model also needs the use...
A hierarchical Bayesian fuzzy inference nets realtime internal fault diagnostic system for induction motor is proposed. The membership functions and symptom-fault mapping relationship for motor fault diagnosis are obtained from pre-measured site experimental data as well as experts' diagnostic experience/knowledge to distinguish the effect of true fault from various external static factors. With the...
This paper will describe how finite element analysis can be utilize to design and model the performance of rotary electrical machines. Special interest placed on the induction motor since the design is simple, and has greatest influence in operation of electrical power system. Transient AC analysis has been studied as it is necessary to examine the motor's performance dynamically. Opera 2D software...
In this paper, a vector control mechanism has been suggested and applied to simulate the operation of a Doubly-Fed Induction Generator (DFIG) attached to an isolated off-the-grid wind turbine, to demonstrate that these generators can be used at lower costs to control the power quality in stand alone wind turbines. In order to achieve this end, the alignment of the d-axis of the synchronously rotating...
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