An analysis of the accuracy of indirect shaft sensor forsynchronous reluctance motor

This paper reports a rotor position sensing technique for synchronous reluctance motors (SynRMs) without using any discrete position sensors. An accuracy analysis of the new indirect SynRM position sensing scheme is presented. The analysis breaks down the position error to its fundamental causes in the position sensing scheme. The same basic approach can be taken to evaluate other SynRM rotor position sensing schemes     

Rotor time constant updating scheme for a rotor flux-orientedinduction motor drive

This paper presents a simple online rotor time constant identification scheme of an indirect field-oriented induction motor for the purpose of improving the performance and robustness of the drive. The proposed technique neither requires any special test signal nor any complex computations. This scheme is based on a special switching technique of the current-regulated pulsewidth modulation (CRPWM) voltage-source inverter (VSI), which allows measuring the induced voltage across the stator phase. The rotor time constant is then identified directly from this measured voltage. This proposed technique provides six windows within one electric cycle to update the rotor time constant, which should be sufficient for all practical purposes. Simulated results followed by experiments are presented to validate the effectiveness of the proposed technique     

Computer-aided design and application of integrated LC filters

In this paper, methods of design and application of an integrated inductor-capacitor-transformer (LCT) are presented. A generalized modeling approach is also described. On the basis of this model and by using practical data, CAD software is developed for LCT, Several integrated LC and LCT samples were designed, built, and tested. Finally, a resonant power converter, using the integrated LCT, was built and tested     

An utility interactive power electronics interface foralternate/renewable energy systems

The foreseeable shortages in conventional sources of electric power has increased the emphasis on the research and development of alternate sources of energy. In order to make a noteworthy impact, the alternate sources of energy need to be utility interactive by means of a power electronic interface (a DC to AC converter). The inherent assumption in the control of DC to AC converters is, that the DC voltage available at the input of the converter is constant. However, when the input is an unregulated DC source such as a battery, fuel cell, photovoltaic cells or any other form of alternate source, maintenance of the constant DC voltage at the input of the converter is often impossible. A modified inverter switching technique is proposed for the interface with the utility grid such that the AC output of the inverter becomes immune to fluctuations in the unregulated input DC obtained from alternate energy sources     

基于数字信号控制器的智能家电解决方案

本文将说明如何利用一个低成本的DSP控制器实现连续变速操作,进而满足低成本应用的要求.     

Two-dimensional team lifting prediction with floating-base box dynamics and grasping force coupling

The computational procedures of higher-order implicit integrators for mechanical systems with friction are provided in this paper. The dynamic equations are established using the augmented Lagrangian formulation, and set-valued friction forces are described by projection functions. To reduce the accuracy loss caused by event transitions and to eliminate spurious oscillations in the acceleration, a new robust event-driven scheme, which accurately detects event transitions and corrects the friction forces and accelerations at switching points, is proposed. The numerical performance of the proposed scheme is demonstrated by solving several benchmark problems. Numerical results show that the newly developed scheme can approximately achieve second-order accuracy, and they are more accurate than the classical Moreau time-stepping scheme under close computational efforts. Finally, a slider-crank system is simulated to prove the validity of the developed method for nonlinear mechanical systems with friction.

     

A method for dynamic simulation of air-gap eccentricity ininduction machines

In this paper, a method is proposed which enables the simulation of the air-gap eccentricity in induction machines. The method is based on the coupled magnetic circuit approach. The model is derived by means of winding functions, and no symmetry in windings layout is assumed. The parameters of the model are calculated directly from the geometry and winding layout of the machine. The effect of eccentricity is included in calculation of machine inductances. It is shown that by proper modeling of the induction motor it is possible to determine the effect of eccentricity on the machine startup, whether the machine is running off a sinusoidal supply or a converter. Theoretical foundations of the technique, as well as the detailed differential equations describing the machine performance under rotor eccentricity are presented     

Sensorless position measurement in synchronous reluctance motor

A new discrete position sensor elimination technique for a sinusoidally wound synchronous reluctance motor drive is presented. The proposed technique determines the rotor position at zero crossing of the phase currents. The rotor position between the zero crossings is determined by applying extrapolation. The proposed technique works well at all speeds, including zero speed. This technique can be used in both vector controlled and conventional constant volts/Hertz type of motor controllers