Phase Switched Reluctance Machine Research Articles

Development of Two Phase H-bridge Converter for 250W Switched Reluctance Machine

Background: Advancements in Power Electronics made a huge breakthrough in the industrial sector majorly in the development of Switched Reluctance Machines (SRM). The main objective of this paper is to develop a two Phase H-bridge converter for 250W SRM and compare its advantages and disadvantages over the other converters. Methods: A time based simulation has been carried out to evaluate the performance of the converter at various loads. Different parameters of the machine and converter are studied and the results are verified experimentally. Results: The obtained test results of the converter performance are found to be in good agreement with the simulation and the efficiency of the converter is compared with the existing R-Dump topology. Conclusion: It is concluded that the proposed H-Bridge converter for a two phase SRM is better than the R-Dump converter in terms of efficiency and reduced size.

An Improved Torque Sharing Function for Torque Ripple Reduction in Switched Reluctance Machines

An offline torque sharing function (TSF) is introduced in this paper for torque ripple reduction in switched reluctance machines (SRM). This TSF uses static flux linkage characteristics of the machine obtained from finite element analysis or experiments that describe the machine dynamics to determine optimal current profiles such that the torque ripple reduction is achieved with minimal copper losses. Due to this feature, the proposed TSF performs well across a wide speed range. Additionally, the objective function of the proposed TSF uses only one weight parameter, which facilitates the use of this TSF. In this paper, an intuitive justification for the selection of this weight parameter is given, and the performance of this TSF is validated in simulation and experimentally on a 5.2 kW, four phase SRM. To baseline its performance, the proposed TSF has been compared to the offline TSF in the literature, which shows that it has better current tracking performance at higher speeds due to the inclusion of flux linkage characteristics. Finally, it has been compared to conduction angle control at speeds above the base speed to show that it can be a viable alternative for the control of SRM even in an operation region normally not considered for TSF.

Evolutionary Algorithms for Optimization of 4/4 Single Phase Switched Reluctance Machine

This paper presents the application of two classes of Evolutionary Algorithms (EA) to determine optimum design of Single-Phase Switched Reluctance Machine (SPSRM). The EA used is Genetic Algorithms (GA) and Differencial Evolution (DE). Due to sensitivity of the output torque to the stator and rotor pole arcs, these are selected as design variables for a multi-objective optimization with the objective of maximizing average torque and torque density, and minimizing copper loss. The proposed optimization is tested on a 4/4 1,25 kW SPSRM, and the results of both algorithms are compared. The performance of the optimized motor are compared to the initial motor through the finite element analysis. The results show improvement in both efficiency and output torque.

Novel Two-Phase Switched Reluctance Machine Using Common-Pole E-Core Structure: Concept, Analysis, and Experimental Verification

A novel two-phase switched reluctance machine (SRM) with a stator comprised of E-core structure having minimum stator core iron is proposed. The E-core stator has three poles with two poles at the ends having windings and with the center pole containing no copper windings. The center stator pole in the E-core is shared by both phases during operation. The air gap around the common pole has constant and minimum reluctance irrespective of rotor position by its unique design and the two remaining stator poles at the ends experience variable reluctance with respect to rotor position. The stator is constructed with two independent and physically separate E- cores and the rotor is comprised of ten poles. Other pole combinations are possible. Phase excitation in the novel SRM gives short flux paths, hence reducing the magnetomotive force (MMF) required to drive the machine resulting in significant reduction of copper wire and core-losses compared to existing two-phase SRMs with flux-paths that traverse the entire stator back iron. The concept and principle of operation of this novel SRM and its comparison and contrast to existing two-phase SRMs are detailed in this paper. Comparison between finite element simulations and magnetic equivalent circuit analysis for inductance are made and compared to experimentally measured characteristics. Furthermore, a comparison between a conventional two-phase SRM and the novel SRM is be made in terms of its weight and output torque. Manufacturability and cost savings of the unique SRM structure are presented. It is shown that E-core SRM using common-pole SRM has 50% less iron in the magnetic path compared to the conventional two- phase SRM.