Switched Reluctance Machine Topologies Research Articles

Experimental Validation of a Thermal Model for High-Speed Switched Reluctance Machines for Traction Applications

This paper presents the experimental validation of a novel cooling concept applied to a high-speed switched reluctance machine topology for traction applications. By circulating the coolant between the coils and the stator poles, the winding and the stator iron are virtually thermally decoupled. A number of test motorettes are used to demonstrate the potential of the cooling concept at current density values up to 27 A/mm2 continuously. The measurements are also used to validate a thermal model of the machine, and further improvements of both the model and the experimental setup are proposed.

Opportunities and Challenges of Switched Reluctance Motor Drives for Electric Propulsion: A Comparative Study

Selection of the proper electric traction drive is an important step in design and performance optimization of electrified powertrains. Due to the use of high energy magnets, permanent magnet synchronous machines (PMSM) have been the primary choice in the electric traction motor market. However, manufacturers are very interested to find a permanent magnet-free alternative as a fallback option due to unstable cost of rare-earth metals and fault tolerance issues related to the constant permanent magnet excitation. In this paper, a new comprehensive review of electric machines (EMs) that includes various new switched reluctance machine topologies in addition to conventional EMs such as PMSM, induction machine, synchronous reluctance machine (SynRel), and PM-assisted SynRel is presented. This paper is based on performances such as power density, efficiency, torque ripple, vibration and noise, and fault tolerance. These systematic examinations prove that recently proposed magnetic configurations such as double-stator switched reluctance machine can be a reasonable substitute for permanent magnet machines in electric traction applications.

Electromagnetic Considerations for a Six-Phase Switched Reluctance Motor Driven by a Three-Phase Inverter

The switched reluctance machine (SRM) offers advantages over other topologies, but low torque density, high torque ripple, and use of a nonstandard power converter are limitations. This paper develops a drive configuration, which facilitates the operation of a six-phase SRM using a standard three-phase inverter in order to address these limitations. The focus of the paper is an investigation of electromagnetic design aspects of two candidate SRM topologies in this six-phase context for a pure electric or hybrid electric vehicle-type application. Advances are made in the understanding of the electromagnetic design of suitable SRMs, and the conventional SRM is demonstrated as the preferred topology through parametric and finite-element analysis (FEA) design studies with reference to a given specification. Laboratory test results for a prototype machine are presented in verification of the machine design and demonstration of this drive concept as a high-torque-density candidate suitable for electric vehicle applications.

Data-Reconstruction-Based Modeling of SRM With Few Flux-Linkage Samples From Torque-Balanced Measurement

This paper proposes a combined modeling method for switched reluctance machine (SRM) with few samples of flux linkage characteristics measured without rotor clamping devices and position sensors. The proposed method mainly consists of two steps, namely data reconstruction and characteristic description. In data reconstruction, the entire flux linkage characteristics are obtained by training support vector machine (SVM) with the measured few samples. The characteristics from the trained SVM are consistent well with those from the rotor-clamping measurement. In characteristic description, back-propagation neural network (BPNN) is adopted to describe the reconstructed flux linkage characteristics and calculated static torque characteristics. On this basis, the simulation model of the SRM prototype is built in MATLAB. The results from simulation under both motoring and generating mode are compared with those from experiments, and good agreements can be found, which prove the effectiveness of the proposed modeling method. To further demonstrate the accuracy and application of the entire flux linkage characteristics obtained from data reconstruction, BPNN is used again to build the mapping from flux linkage and phase current to rotor position for rotor position estimation, and some results are presented. The applicability of the proposed method to different SRM topologies is discussed as well.

External-Rotor <inline-formula><tex-math notation="LaTeX">$6-10$</tex-math></inline-formula> Switched Reluctance Motor for an Electric Bicycle

As a cost-effective, healthy, and environmental friendly personal mode of transportation, electric bicycles (E-bikes) are gaining an increasing market share from conventional bicycles and automobiles. Considering the legal rules in Ontario, Canada, a 500-W electric motor providing power assist makes the E-bike more attractive to urban commuters. The simple structure, high torque, and power density, as well as the potential for low cost make the switched reluctance machine (SRM) a strong candidate for E-bike traction. In this paper, a three-phase, external-rotor SRM with 6 stator poles and 10 rotor poles is designed for a representative E-bike. The design of an external rotor arrangement of the $6-10$ SRM topology has not previously been reported, this brings the challenge of sizing the geometry of this topology, but the solution offers a new contribution to published works. The external-rotor arrangement is chosen to facilitate ease of integration into the wheel hub structure of a typical pedal bicycle. The increased rotor poles yield improved torque ripple reduction than more conventional (i.e., $6-4$ and $12-8$ ) SRM design, which is an essential feature for low-speed rider comfort. The final machine design is experimentally validated via a full system prototype and dynamometer test facility. Results highlight some limitation of the 2-D finite element analysis (FEA) study in terms of the winding inductance calculation, more accurate 3-D FEA model is implemented.