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Synchronous reluctance machines with solid rotor construction have advantages in certain high-speed applications such as flywheel energy storage systems. However, the solid rotor allows the flow of eddy currents, resulting in rotor loss and heat generation. The switching harmonics in the stator voltage supplied by a pulsewidth modulation (PWM) inverter are one of the sources of the rotor loss. This paper performs an analysis for the time harmonic loss in a solid-rotor synchronous reluctance machine, and investigates design and control issues associated with the inclusion of a three-phase LC filter for reduction of the rotor loss in solid rotor. A two-phase dynamic model of the machine which incorporates the LC filter dynamics is presented. This model is used to predict rotor losses due to switching harmonics generated by the three-phase PWM inverter. A model-based current regulator is utilized, which is modified to include the effects of the LC filter. Experimental results validate the proposed approach. Index Terms--filters, flywheels, harmonic analysis, losses, reluctance machines.

Linear switched reluctance motors (LSRMs) for the primary propulsion of a ship elevator is proposed and investigated for the first time in this paper. To achieve the stated objective, a new type of LSRM is proposed with twin stators and a translator between them with no back iron in the translator. The proposed configuration of the LSRM is designed, simulated, analyzed, compared with traditional LSRMs, and verified by experimental measurements. The number of LSRM propulsion subsystems required is studied with a view to minimize their weights and an optimization study for that purpose is developed. Unique placement of the LSRM propulsion systems on the elevator is presented. The propulsion force is generated using one phase or multiphase excitation. To reduce propulsion force pulsations, a major requirement in elevators, controlled multiphase excitation using one of the known force distribution functions (FDF) is an acceptable solution. In this paper, it is proved that the currently available FDFs are able to reduce the force pulsations but are not able to meet the peak force command for the system. Consequently, the velocity and position control do not meet even the elementary performance requirements any more. A new FDF is proposed in this paper and presented to overcome the problem caused by a conventional FDF. The control system with the proposed FDF is derived and integrated into velocity and position controllers. Extensive dynamic simulation and experimental verification of the proposed LSRM with the novel FDF is proved to give superior performance in this paper. Such high performance capable of meeting vertical elevator applications is demonstrated. Index Terms--Electromagnetic launching, elevators, force control, linear motors, reluctance motors.

In the high-technology mass manufacturing industry, high-speed and high-precision motion is an indispensable element in the automated production machines. In recent years, there has been a growing tendency to employ direct drive permanent magnet linear synchronous motors in demanding motion applications. Although the overall performance is good, its implementation cost remains high. This is mostly due to the cost of the Neodymium--Boron magnets, the manufacturing of the magnetic rails, and the precision of the overall mechanics. In this paper, a much cheaper alternative is proposed-to use a low-cost linear switched reluctance motor (LSRM) and an adaptive control strategy to overcome the tolerances and difficult control characteristics inherent in the motor. The LSRM has simple and robust structure, and it does not contain any magnets. However, its force is solely drawn from the reluctance change between the coil and the steel plates. Variations on the behavior of these two elements due to different operating conditions will change the motion behavior of the motor. Also, to keep the overall cost low, the LSRM sets a marginal mechanical tolerance during its mass production. This leads to characteristic variations in the final product. Finally, since the LSRM is a direct drive motor, any variations on the motor characteristics will directly reflect on the control system and the motion output. In this paper, a self-tuning regulator (STR) is proposed to combat the difficulties and uncertain control behaviors of the LSRM. This paper first introduces the motor winding excitation scheme, the model of the LSRM, and the current control method. The LSRM system is modeled as a single-input single-output discrete model with its parameters estimated by the recursive least square (RLS) algorithm. Then, an STR based on the pole placement algorithm is applied to the LSRM for high-performance position tracking. Both the simulation investigation and the experimental verification were conducted. In both cases, the results verified that the proposed RLS algorithm can estimate the parameters with fast convergence. The STR can provide quick response and high precision which is robust to the change of system parameters. Combined with STR control, the LSRM is a low-cost solution to fast, accurate, and reliable position tracking for many demanding motion control applications. Index Terms--Linear switched reluctance motor (LSRM), motor winding excitation scheme, position control, self-tuning regulator (STR).

This paper presents an analytical method for predicting the steady-state performance of a self-excited single-phase reluctance generator (SESPRG), which supplies R-L load. The proposed analysis is based on the d-q axis model and phasor diagram of such a generator in the steady-state condition. Excitation capacitors are connected across both the main and auxiliary windings. Magnetic saturation is taken into account and is assumed to be confined to the direct axis, and is accounted for a variable direct-axis magnetizing reactance. Conditions of self-excitation and the minimum value of the capacitance required to achieve self-excitation are also given. Special attention is focused on the machine performance when it operates as a pure single-phase reluctance generator (PSPRG). A fixed-capacitor (FC) thyristor-controlled reactor (TCR) scheme is used to regulate the generator terminal voltage by controlling the thyristor conduction angle. Further stability limits are investigated by developing the active-reactive (P-Q) power diagram. Reasonably close agreement between the measured and predicted results is observed confirming the validity of the proposed analysis. Index Terms--Reluctance generators, self-excitation, single-phase, steady-state.

A four-quadrant sensorless controller for switched reluctance motor (SRM) drives is presented in this paper. The drive system with appropriate turn-on and turn-off angles for each operating quadrant delivers excellent dynamic performance over a wide speed range including zero speed. The problems associated with practical implementation especially at low and zero speeds have been addressed and overcome with engineering solutions. Experimental results for a 1-kW SRM obtained on a dSPACE-based system are presented along with useful guidelines for practical implementation. Index Terms--Four-quadrant control, position and speed estimations, sensorless control, sliding-mode observer, switched reluctance motors (SRMs), zero-speed control.

Two new converter configurations for switched reluctance motors are proposed in which some motor windings are energized using recovered energy from remaining windings. The working principle and various operating modes are discussed in detail. Block diagrams explaining flow of energy are given. Simplified analysis is given and expressions for recovered power are derived. Techniques for designing the drive using a minimum number of components are discussed. Use of bleeder or charger circuits (if necessary) to get balanced output from all the phases is explained. Lastly, experimental results are also included. The proposed converters have been found to be more efficient, less complex, and cost effective. Index Terms--Converters, recovered energy, switched reluctance motor.

A soft-switched three-phase switched-reluctance circuit for motor drives that operates with only four transistors is introduced. Because of its use of soft switching and shorter current tail, this circuit generates less electromagnetic interference and more output torque. Furthermore, its use was observed to promote more system efficiency because it only employs one series of switching device between the drive circuit source and the winding.

This paper reports on progress made in the operation of switched reluctance machines with simultaneous excitation of multiple phases using just a single current sensor. This avoids individual current sensors in each motor phase, without compromising the drive performance. A new technique for operation of the classic two-transistor-per-phase converter with only one current sensor is presented, allowing two phases to be excited simultaneously. The detailed operation and implementation of this technique is shown, together with test results and comparisons with normal operation with one current sensor per phase. The paper concludes that adding a very simple electronic circuit to the existing motor control circuitry allows single-current-sensor operation with uncompromised performance. This is the first time a paper discusses the topic of multiphase switched reluctance motor (SRM) excitation using a minimum number of current sensors. Index Terms - Converter topologies, current control, sensors, switched reluctance motor drives.

A new high-performance sensorless speed vector controller that implements the maximum torque per ampere control strategy for the inverter-driven synchronous reluctance machine is presented in this paper. It is based on a parameter-dependent technique for on-line estimation of rotor position and angular velocity at the control rate. The current ripple principle is used to estimate position. The estimates are fed to a conventional closed-loop observer to predict the new position and angular velocity. The very high accuracy of the sensorless control algorithm at both low and high speeds is confirmed by experimental results. Index Terms - Angular velocity observer, sensorless control, synchronous reluctance machines.

In this paper, the concept and implementation of field-orientation control (FOC) of a doubly excited brushless reluctance machine (DEBRM) for variable-speed drives and generating systems are presented. A stator-flux-orientation scheme is employed to achieve decoupled control of torque and reactive power. A 2-hp DEBRM prototype system with a digital signal processor (DSP)-based controller and a bidirectional power converter is built to verify the theoretical analysis. Computer simulation and laboratory experimental results are shown in excellent agreement. Index Terms - Doubly fed motors, electric motors, fieldorientation control, motor control, power electronics, reluctance motors.

This paper describes a new method of indirect rotor position sensing for switched reluctance motor (SRM) drives. The principle is based on measuring the mutually induced voltage in an inactive phase which is either adjacent or opposite to the energized phase of an SRM. The mutual voltage in the 'off' phase, induced due to the current in the active phase, varies significantly as the rotor, corresponding to the energized stator, moves from its unaligned position towards complete alignment. This mutually induced voltage variation is captured by a simple electronic circuit and then processed in a microcontroller to determine the commutation instants, thereby eliminating the need for direct rotor position sensors in an SRM. Successful operation of a four-phase SRM drive has been demonstrated in the laboratory using the mutual voltage (MV) technique of indirect rotor position sensing. The theoretical aspects of mutually induced voltages in an SRM and the relevant experimental results are presented in this paper.

In industrial automation and robotic applications, direct-drive motors represent a suitable solution to friction and backlash problems typical of mechanical reduction gears. Variable reluctance (VR) motors are well suited for direct-drive implementation but, because of the strongly nonlinear electromechanical characteristics, these motors are traditionally designed as stepper motors. The main aim of the work described in the paper is the design of a high-performance ripple-free dynamic torque controller for a VR motor, intended for trajectory tracking in robotic applications. An original modeling approach is investigated in order to simplify the design of the high-performance torque controller. Model structure and parameter estimation techniques are presented. Different approaches to the overall torque controller design problem are also discussed and the solution adopted is illustrated. A cascade controller structure is considered. It consists of a feedforward nonlinear torque compensator, cascaded to a nonlinear flux or current closed-up controller. The feedforward compensator is carefully considered and optimization techniques are used for its design. Two optimization criteria are proposed: the first minimizes copper losses, whereas the second minimizes the maximum value of the motor-feeding voltage. Although developed for a specific commercial motor, the proposed modeling and optimization strategies can be used for other VR motors with magnetically decoupled phases, both rotating and linear. Laboratory experiments for model validation and preliminary simulation results of the overall torque control system are presented.

A reluctance motor drive giving high dynamic performances is proposed. The machine is sinusoidally wound, and the rotor belongs to the axially laminated type. The vector control technique used (utilizing a flux observer) is described. A prototype system has been realized, and the practical results obtained are given.

A self-tuning controller for switched reluctance motors is presented. A torque ripple minimizing controller is implemented with online system identification and adaptation technique. The controller uses a nonlinear model of the machine that is updated online using recursive identification algorithm. The real-time approach improves the overall robustness of the system. Experimental results are presented to validate the self-tuning algorithm. Index Terms--Self-timing controller, switched reluctance motor drive, torque-ripple minimization.