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With the rapid development of power electronic techniques and the increasing cost of permanent magnets (PMs) materials, switched reluctance motors (SRMs) have recently gained more attention. However, traditional SRMs have a relatively low torque density. For the sake of increasing the motor torque density, this paper proposes a novel segmental rotor type SRM. The proposed motor adopts hybrid stator poles and concentrated windings in the stator side and a segmental rotor structure in the rotor side, which is completely different from the structures of the traditional SRM. The special structure of the motor shortens the magnetic flux paths of the motor, separates the parts of the magnetic flux paths from one another, and eradicates the magnetic flux reversal in the motor stator in order to improve the electric utilization and output torque density of the motor. Meanwhile, the requirement of the magneto-motive force and the core loss of the motor is also decreased, thereby improving the efficiency of the motor. For the purpose of proving the proposed structure, the characteristics of the motor are analyzed using the finite element method and are compared to those of the traditional 12/8 SRM, which is designed for the same application. Moreover, the prototypes of the traditional 12/8 and proposed SRMs are manufactured, and experiments based on the prototypes are performed. Finally, the effectiveness of the structure of the proposed motor is further proven by the experimental results. [ABSTRACT FROM AUTHOR]

This paper presents a novel 6/5 segmental rotor-type switched reluctance motor (SRM) for cooling fan application. Unlike conventional structures, the rotor of the proposed structure is constructed from a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. Meanwhile, the windings are only placed around the exciting poles, resulting in short flux paths and no flux reversal in the stator of the proposed SRM. Hence, the proposed structure may increase the electrical utilization and reduce magnetomotive force (MMF) requirement compared to conventional SRMs. To verify the proposed structure, the operation principle and the design rules of the proposed structure are illustrated and expounded. The finite-element method (FEM) is employed to get the static and dynamic characteristics of the conventional 12/8 and proposed SRMs. Furthermore, the prototype is manufactured and tested. Finally, the simulation and experimental results are presented and analyzed to verify the effectiveness of the proposed SRM. [ABSTRACT FROM AUTHOR]

In this paper, three types of bearingless switched reluctance motors (BLSRMs) which have decoupled flux characteristics between the torque and suspending current are presented in detail. The analyzed BLSRMs are an 8/10 hybrid BLSRM, a 12/14 hybrid BLSRM, and a double stator BLSRM. The 8/10 hybrid BLSRM has a low electrical frequency with decoupling characteristics. The 12/14 hybrid BLSRM has a short flux path to reduce core loss with higher decoupling characteristics. The double stator BLSRM has the best decoupling characteristics with a complex mechanical structure. All three structures have two types of stator poles: torque and suspending force poles. Due to the independent characteristics between the torque and suspending force poles, the torque control can be decoupled from the suspending force control. The characteristics of the three types, such as magnetic flux distribution, inductance, torque, suspending force, torque ripple, efficiency, and number of switches used in the drive systems, are analyzed and compared to induce the better magnetic structure and control scheme of the suspending force. To verify the validity of the three types, tests are executed and compared. [ABSTRACT FROM AUTHOR]

This paper presents the design and operation of a two-phase four-two pole switched reluctance motor (SRM) for a high-speed air blower. The air blower has unidirectional rotation and requires a wide positive torque region without torque dead zone. In order to achieve the requirements, a nonuniform air gap with asymmetric inductance profile is considered. For a flattop torque with a low torque ripple, the nonuniform air gap is also effective. Based on the output torque analysis at the rotor position for the given air gap, the air gap is modified to reduce the torque ripple. The optimized air gap at a given position cannot feel the effect of the air gap at a previous rotor position. Therefore, the output torque cannot fully satisfy the target torque in one optimization process. In order to satisfy the target torque and reduce the torque ripple, the second optimization process is implemented considering the output torque of the initial optimization process. The second target torque is determined by the torque error of the initial output torque and target torque of the first process. From this optimization sequence, the final air gap, as a function of the rotor position, can be determined to satisfy the torque ripple requirement. The proposed high-speed four-two pole SRM is tested to verify the high-efficiency and low-acoustic-noise characteristics. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel 12/8 switched reluctance motor (SRM) with segmental rotor for vehicle cooling fan application. Unlike conventional SRMs, the proposed motor adopts one body stator with hybrid stator poles and segmental rotor structures, thereby making the motor operate in short flux paths and parts of the flux paths magnetically isolated between the phases. Therefore, compared with conventional SRMs, the proposed structure not only improves the output torque density and reduces the magneto-motive force requirement and core losses of the motor, but also inherits the advantages of conventional SRMs like flexible control as well as the adaptability in harsh environment. To verify the proposed structure, a finite element method is employed to get characteristics of the proposed SRM. Meanwhile, a conventional 12/8 SRM, which has been used for vehicle cooling fan application, is also analyzed for comparison. Furthermore, the prototypes for the conventional and proposed 12/8 SRMs are manufactured and tested. Finally, the simulation and experimental results are presented and analyzed to verify the effectiveness of the proposed SRM. [ABSTRACT FROM AUTHOR]

Based on the back electromotive force (back‐EMF) detection, a novel rotor position estimation strategy with adjustable turn on/off angle is proposed for the high‐speed hybrid switched reluctance motor (SRM). The minimum back‐EMF position is captured in every electrical cycle for rotor position estimation. The current comparator is employed to send out a turn‐off signal for phase winding when the maximum inductance position is detected in the first electrical cycle. By providing sufficient current rise time to the phase winding, the proposed sensorless control system enables the motor to run in high‐speed application. Besides the straightforward estimation principle, the proposed strategy has the implemental feasibility by eliminating extensive calculations and complicated look‐up tables. The experimental results of a prototype are demonstrated to verify the proposed sensorless control system. [ABSTRACT FROM AUTHOR]

This paper presents a sensorless-controlled, low-cost, low-power, and variable-speed drive system suitable for fan and pump applications. The main advantages of this drive system are the low system cost, simple converter structure, and simple but robust sensorless control technique. The drive motor is a special hybrid switched reluctance motor. The proposed sensorless control method beneficially utilizes the stator side PM field and its performance is motor parameter independent. The unique low-cost drive system solution, simple and robust sensorless control features of this drive system, is demonstrated in detail in this paper. Important design details for practical implementation of the sensorless control algorithm are included. The complete drive system performance is validated using a prototype drive system. [ABSTRACT FROM AUTHOR]

Abstract: A novel hybrid stator-pole switched reluctance motor (HSPSRM) to improve radial force for bearingless application is presented in this paper. The proposed motor can generate a constant suspending force independent of rotor position only using small current excitation. And torque control can be naturally decoupled form suspending force control. Measured data and the results of numerical analysis are given to evaluate the motor structure. In the numerical analysis, the finite element method (FEM) is employed due to the highly nonlinear nature of the motor. A prototype hybrid stator-pole SRM is manufactured and tested in the experimental studies. The obtained test and simulation results show that the hybrid stator-pole SRM structure has a constant suspending force, which can be controlled independent from torque control. [ABSTRACT FROM AUTHOR]