Iranian Journal of Electrical and Electronic Engineering

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An adaptive online flux-linkage estimation method for the sensorless control of switched reluctance motor (SRM) drive is presented in this paper. Sensorless operation is achieved through a binary observer based algorithm. In order to avoid using the look up tables of motor characteristics, which makes the system, depends on motor parameters, an adaptive identification algorithm is used to estimate of the nonlinear flux-linkage parameters. This method makes position and speed estimation more accurate and robust towards any model uncertainty, also it is suitable replacement for a priori knowledge of motor characteristics.

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A switched Reluctance motor (SRM) has several desirable features, including simple construction, high reliability and low cost. However, it suffers from large torque ripple, highly non-uniform torque output and magnetization characteristics and large noise. Several studies have succeeded in torque ripple reduction for SRM using Direct Torque Control (DTC) technique. DTC method has many advantages over conventional voltage control and current chopping mode control such as simple algorithm, less torque ripple and instantaneous response to the torque command. In this paper, DTC method is proposed for a 5-phase 10/8 SRM. The performance of the motor is demonstrated through the computer simulation in Mtalab/Simulink. Then, the obtained results are verified by comparison with the corresponding results of a 3-phase 6/4 motor performance.

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Switched reluctance motor (SRM) drive has a remarkable characteristic, high efficiency, and good controllability, which makes it attractive for high-speed applications. In this paper, the basic control strategy for a switched reluctance motor drive circuit is explained and then three different resonant discharge topologies for SRM drive circuit are proposed. Due to resonantly discharging of excess energy, these topologies provide faster rate of fall for the phase current, which permits the motor to operate at higher speeds. In the new circuits a capacitor is charged resonantly by the use of motor phase windings during the phase turn off periods and then discharged via an inductor and a diode during the next working strokes. Three different drive circuits utilizing this process are proposed. A detailed explanation and demonstration of the converter circuits have been presented.

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This paper presents a new design to reduce torque ripple in Switched Reluctance Motors (SRM). Although SRM possesses many advantages in terms of motor structure, it suffers from large torque ripple that causes problems such as vibration and acoustic noise. The paper describes new rotor and stator pole shapes with a non-uniform air gap profile to reduce torque ripple while retaining its average value. An optimization using fuzzy strategy is successfully performed after sensitivity analysis. The two dimensional (2-D) finite element method (FEM) results, have demonstrated validity of the proposed new design.

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Torque ripple minimization of switched reluctance motor drives is a major subject based on these drives’ extensive use in the industry. In this paper, by using a well-known cascaded torque control structure and taking the machine physical structure characteristics into account, the proposed energy-based (passivity-based) adaptive sliding algorithm derived from the view point of energy dissipation, control stability and algorithm robustness. First, a nonlinear dynamic model is developed and decomposed into separate slow and fast passive subsystems which are interconnected by negative feedbacks. Then, an outer loop speed control is employed by adaptive sliding controller to determine the appropriate torque command. Finally, to reduce torque ripple in switched reluctance motor a high-performance passivity-based current controller is proposed. It can overcome the inherent nonlinear characteristics of the system and make the whole system robust to uncertainties and bounded disturbances. The performance of the proposed controller algorithm has been demonstrated in simulation, and experimental using a 4KW, four-phase, 8/6 pole SRM DSP-based drive system.

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This paper considers a new switched reluctance motor (SRM) structure aiming at high starting torque with low volume. For some applications such as EVs (Electrical Vehicles), the motor volume and starting torque is a critical point in its design. In many methods, reducing the motor volume causes reduction in starting torque and decreases the motor efficiency. Unlike conventional SRMs, the rotor pole is skewed in the proposed structure along the motor axis. An approximated two-dimensional finite element method (FEM) is used to speed up computational time and some comparisons with three-dimensional FEM are considered for more reliability. Final results show the efficiency of the proposed structure.

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A novel structure of switched reluctance motors (SRMs) is proposed. The proposed structure uses the benefits of the axial flux path, short flux path, segmental rotor, and flux reversal free stator motors all together to improve the torque density of the SRMs. The main geometrical, electrical and physical specifications are presented. In addition, some features of the proposed structure are compared with those of a state-of-the-art radial flux SRM, considered as a reference motor. Then, the proposed structure is modified by employing a higher number of rotor segments than the stator modules and at the same time, reshaped stator modules tips. Achieved results reveal that, compared with the reference motor, the proposed and the modified proposed motors deliver about the same torque with 36.5% and 46.7% lower active material mass, respectively. The efficiency and torque production capability for the extended current densities are also retained. These make the proposed structures a potentially proper candidate for the electric vehicles (EVs) and hybrid electric vehicles (HEVs) as an in-wheel motor.

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This paper presents analysis and comparative study of a novel high-torque three-phase switched reluctance motor (SRM) with magnetically isolated stator segments. In the proposed SRM, each segment has a concentric winding located on the center body of it and two diametrically opposite windings which form the motor phase. There are four salient poles in the stator segment. Two of them share their flux path in the center body of the segment. The rotor has a solid structure including twenty two salient poles. In this unique SRM, stator segments topology, number of the stator segments poles and the rotor poles, and angular distance of the stator segments are selected so that the motor properly operates in both directions. Two-phase design with different pole combination is also possible. During operation, there are short flux paths along two adjacent rotor poles and excited segment poles. Therefore, the proposed SRM has all benefits of the short flux path structures. The principle and fundamentals of the proposed SRM design are detailed in the paper. The motor is analysed using finite element method (FEM) and some comparisons are reasonably carried out with other SRM configurations. Finally, a prototype motor is built and experimental results validate the performance predictions in the proposed motor.

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