Optimised Segmental Rotor Switched Reluctance Machines with a greater number of rotor segments than stator slots

Abstract

Segmental Rotor Switched Reluctance Machines have been demonstrated to produce significantly more torque than Conventional Switched Reluctance Machines because each coil is able to link more magnetic flux. In previous work the range of topologies studied has been relatively restricted; there has been no consideration of the range of stator tooth and rotor segment number options and the designs have not been formally optimised in any way. This paper seeks to address this: using Finite Element toolsets for optimisation it describes the resulting machines -uniquely featuring a greater number of rotor segments than stator teeth. The paper assesses the credible tooth and segment options, with each option optimised to maximise torque capability. From this assessment conclusions are drawn which contrast each machine's performance based on criteria including torque production and loss. In order to validate this optimisation process, a prototype machine is built and its performance compared with these predictions.

Design Methodology for High-Performance Segmented Rotor Switched Reluctance Motors

“…Increasing the number of rotor poles of SRM and SSRM was proposed in [5], [7], and [18]. It was reported that use of a higher number of rotor poles increases the torque output and reduces copper loss.…”

“…It was reported that such machines give about 40% higher torque Manuscript than conventional SRM for the same frame size and copper loss. A topology of segmented rotor SRM (SSRM) with higher number of rotor segments than stator poles was proposed in [7]. Such machines are reported to have about 65% higher torque for the same frame size and copper loss than conventional SRMs [7].…”

“…A topology of segmented rotor SRM (SSRM) with higher number of rotor segments than stator poles was proposed in [7]. Such machines are reported to have about 65% higher torque for the same frame size and copper loss than conventional SRMs [7]. This paper also focuses on SSRM.…”

“…Both these papers discuss axial flux SRM with segmented rotor. Though there are a few papers on the effect of number of rotor poles and stator slots on the performance of SSRM [7], [14], a comprehensive study on the effect of different parameters of SSRM on its performance is not yet reported. This paper fills this gap.…”

Comparative analysis of axial flux SRM topologies for electric vehicle application

“…This results in reduction of average torque of the motor. In order to address these issues, SSRM with higher number of rotor segments than stator slots is introduced [5]. This configuration increases the available slot area which results in increased torque output.…”