No description available.

With the rapid development of power electronic devices and microprocessor chips, the engineers and researchers have come to pay more attentions to the feasibility of the control and drive for the switched reluctance motor. This motor has lots of advantages of low-cost, high efficiency, high stability and high hot emissive. And, it can be well operated under high temperature environment. In this paper, A newly control and monitor system is proposed with DSP-based driver system and the user-friendly LabVIEW software. The TMS320C240 chip-set is applied to construct the motor-driving system and to produce the PWM signal for the switched motor. The graphic user interface (GUI) is designed by using LabVIEW. The functions of the proposed human/machine interface (MMI) system includes the multi-channel digital I/O acquisition, the voltage/current signal acquisition,and the protocol setting.

The objective of this thesis is to integrate available commercial Software/Hardware package and to establish appropriate graphic user interface (GUI) for transverse flux linear switched-reluctance machine (TFLSRM) motion control. By changing the machine feedback signals, package will be matched with TFLSRM. The control unit of the whole system is based on digital signal processor (DSP) with its software interface being built up by Matlab/Simulink. Hence, users can operate this machine directly by observing the output result from computer monitor. By combining with suitable PI controller, friction variation can be eliminated and the control objectives of the TFLSRM under a desirable velocity also can be achieved.

The Switched Reluctance Motor (SRM) inherits a simple and reliable structure with an economical manufacturing cost. The DC power output supplies the unipolar converter to control the pulses sent to SRM. Thus, the velocity and torque are controllable for various velocity commands, and the SRM is gaining more and more applications on high torque requirement field with constant power. This paper proposes a DSP based hybrid sensor for switched reluctance motor with easy implementation. The current transducer is used to monitor the energized current and proximity sensors for rotor salient. The signals are then fed back to DSP. This design will improve the performance of SRM to operate more smoothly.

Switched reluctance motors (SRMs) are promising candidates for electric vehicles due to lower manufacturing costs, higher efficiency, and robustness operation in a harsh envi-ronment. For accurate control of the SRM, the real-time rotor position is needed for phase computation. To obtain position information, position-sensorless control techniques have been developed to take the role of position sensors in commercial SRM drives for cost reduction or sensor-fault tolerance capability. Nowadays, the position-sensorless control of SRMs still suffers from a technical problem: the dependence on magnetic characteris-tics. Existing position estimation algorithms often require time-consuming offline meas-urement of magnetic parameters, limiting the broad applications due to the low generality. It is therefore of great significance to develop universal position-sensorless control tech-niques with less magnetic parameter dependence. Zero- and low-speed position-sensorless control of the SRM needs high-frequency in-jection into the idle phase to measure the stator inductance. Rotor position is often esti-mated from the prestored inductance lookup table but is replaced by a new regional phase-locked loop (RPLL) with a self-commissioning process in this thesis. The modeling of the unsaturated stator inductance can be established automatically via the pulse voltage injection at the initial stage without offline testing. The RPLL embedded with a three-phase heterodyne design can estimate the full-cycle rotor position from the idle-phase in-ductance based on the unsaturated inductance model. The proposed low-speed position estimator can also realize robust sensorless control in four-quadrant operation and magnet-ic saturation conditions without complicated magnetic characteristics. Besides, local sta-bility of the position estimator is proved, and an optimized parameter design scheme is given. Although pulse voltage injection offers accurate position estimation in low-speed op-eration, the induced pulse current results in additional copper loss and torque ripples. This problem is overcome in the thesis by regulating the magnitude of induced current at a minimal level. The induced current regulator is designed as a terminal sliding-mode con-troller that adjusts the injection voltage online over the whole idle-phase period. Proper control parameter selection based on the convergence analysis and stability proof ensures robust control performance against parameter uncertainties. The proposed pulse injection scheme combined with the RPLL can guarantee accurate position estimation while reduc-ing copper losses and torque ripples significantly. Due to the shortened idle-phase duration when the rotor speed increases, pulse injec-tion methods are infeasible for high-speed position estimation. To solve the problem, this thesis proposes a nonlinear observer based on feature position estimation in conduction phases for high-speed sensorless control. A self-commissioning method is adopted to cap-ture a two-dimensional flux linkage curve at a feature position, which avoids offline measurement of the complete three-dimensional characteristics. However, the estimated feature position has low resolution, and its estimation accuracy is degraded by nonideal flux linkage errors. To improve the sensorless control performance, a nonlinear state ob-server using online Fourier series is then designed to eliminate disturbances in position es-timation. Parameter design based on a small-signal analysis is also given to guarantee ac-curate position and speed estimation. High-speed position-sensorless control is further simplified using a new quadrature flux estimator without using any flux linkage characteristics. The method requires neither offline measurement nor online self-commissioning. This advantage is realized by adopt-ing a speed-adaptive bandpass filter to extract the fundamental flux linkage. A three-phase phase-locked loop is then used to estimate the rotor position from the orthogonal flux linkage signals without a priori knowledge of the SRM magnetic characteristics. The magnetic-parameter-free position estimation can facilitate the application of sensorless control in a general-purpose SRM converter. A wide-speed range position estimation scheme is realized by combining both the low-speed and high-speed position estimation approaches. Consequently, a universal posi-tion-sensorless control scheme is proposed in the thesis, covering the full-speed range and not requiring offline measurement effort. The proposed position estimation schemes are verified on a 5.5 kW 12/8 SRM test bench. / Thesis / Doctor of Philosophy (PhD)

In this thesis, advanced control methods are presented for torque ripple reduction and performance improvement in switched reluctance motor (SRM) drives. Firstly, a comparative evaluation of power electronic converters including asymmetric, N+1, C dump, split AC, and split DC converters is presented for three-phase SRMs in terms of cost, efficiency and control performance. Secondly, two methods are proposed using torque sharing function (TSF) concepts for torque ripple reduction of SRM over a wide speed range. An offline TSF is proposed to minimize the copper loss and the absolute rate of change of flux linkage (ARCFL) with a Tikhonov factor. Then an online TSF is proposed by adding a proportional and integral compensator with torque error to torque reference of the phase with lower ARCFL. Therefore, the total torque of online TSF is determined by the phase with lower ARCFL rather than the phase with higher ARCFL as in conventional TSFs. The maximum torque-ripple-free speed (TRFS) of the offline TSF and online TSF is validated to be 7 times and 10 times as high as the best case in these conventional TSFs, respectively. Thirdly, two methods are proposed to eliminate mutual flux effect on rotor position estimation of SRM drives without a prior knowledge of mutual flux, one is the variable-hysteresis-band current control for the incoming-phase self-inductance estimation and the other is variable-sampling outgoing-phase self-inductance estimation. Compared with the conventional method which neglects the mutual flux effect, the proposed position estimation method demonstrates an improvement in position estimation accuracy by 2º. Fourthly, a fixed-switching-frequency integral sliding mode current controller for SRM drives is presented, which demonstrates high dynamics, strong robustness and none steady-state error. All the proposed control methods are verified by both simulations and experiments with a 2.3 kW, 6000 rpm, three-phase 12/8 SRM operating in both linear magnetic and saturated magnetic regions. / Thesis / Doctor of Philosophy (PhD)

The switched reluctance motor has the advantages of the low production cost, high operating efficiency, high stability, and high start torque. It can deliver a wide speed range, and therefore make it very attractive to the engineers and researchers. The double salient structure of SRM result in a non-linear stator inductance, so the output reluctance torque has a highly non-linear behavior. A digital signal processor based drive system for SRM is developed and implemented in this thesis using the TI TMS320F240 DSP system which is with universal peripheral interface circuits. The built-in pulse width modulation(PWM) module of the DSP system can auto-generate PWM output signal by setting the relative registers to simplify the hardware design. This research built a complete drive system for SRM, both the closed-loop velocity controller and current compensator were designed according to the proportional-integral(PI) control mechanism, and all schemes were coded in the DSP program. Simulation and experiment results demonstrate that the proposed drive system makes reluctance torque output very smoothly with a preferable velocity response.

This thesis intends to examine the principles of operation for switched reluctance machines (SRM) and examine the power electronic drive circuits that control them, in order provide a basis of understanding for evaluating total drive efficiency and responsiveness potential. This document specifically examines the characteristics of a motor drive circuit which affect motor and converter efficiency and driving performance. A drive topology suited for efficient operation and excellent responsiveness is proposed. Finally, a SRM drive system model for evaluating these systems in simulation is described as a tool for comparative evaluations in future work. The end goal of this work is to provide a foundation of knowledge for future work, developing in-wheel, SRM-based, high performance hybrid electric drivetrains in future ground combat vehicles which are modular, possess an open architecture for upgrades, and operate with high efficiency and improved mobility. / text

With the increasing environmental impact from the automotive industry, electric vehicles become more and more popular. This combined with the great breakthroughs in fast electronics the switched reluctance motor (SRM) has again gained popularity in recent years. Due to its cheap and rugged construction it is a good alternative to the permanent magnet motors and to the induction motor. The ́two main problems holding the SRM back are torque ripple and the acoustic noise generated from it. A lot of research is currently being performed in order to find a solution to these issues. This thesis has investigated different materials for the rotor in a high speed SRM. Different materials have been evaluated based on both mechanical and magnetic properties. This is done through simulations of the forces acting on the rotor combined with simulations of the magnetic field. The forces are simulate in the DASSULT SYSTEMS ABAQUS program and the magnetic field is simulate using AVL FIRE. Three different kinds of alloys are investigated, two different cobalt alloys are simulated as well as a silicon alloy with pure iron as a reference. The results show that the material needs to have a yield strength of at least 349 MPa to withstand the forces affecting the rotor. And that by using the high purity cobalt-iron alloy the generated torque could be increased with up to 20.9%, but with a cost increase of 3151.9% compared to the silicon alloy.

No description available.