Modeling Techniques In the Switched Reluctance Motor Design Process

Switched Reluctance Machines (SRMs) are a primitive class of reluctance-based electrical machines that are widely applied in projects like efficient HVAC systems, back-up power sources for electrical planes, etc. The SRM is popular due to its easy construction, high speed capabilities and ability to withstand rugged operating conditions. However, designing an SRM comes with challenges. One of the major challenges is modeling the airgap permeance. This challenge arises because the SRM is a doubly salient machine. Thus, the flux paths for this machine are complex and do not share similarities with those of synchronous and asynchronous machines. Although this hurdle can be overcome with the assistance of finite element analysis (FEA) simulations, there are two key drawbacks. First, setting up an FEA model is time consuming and requires new solutions to be generated for every change in the design process. Second, utilizing FEA models eliminates the optimization of the design procedure as the designer is disconnected from the design process. While the analytical method, as compared to a FEA model, is a more efficient way of designing an SRM, the issue of determining the airgap permeance still persists. There are two goals of this research project. First, we aim at developing a design tool that helps provide important characteristics accurately and quickly as compared to FEA simulations. The second goal is to generalize this design tool to eliminate the need to setup a new model for every change. To determine the airgap reluctance, we chose the flux-tube analysis approach developed by R. Pohl. In this approach, we create a model by which we can calculate the airgap reluctance at any given position of the rotor (relative to the stator). We also generalized this solution to develop a design tool, via MATLAB, to allow the designer to perform airgap reluctance analysis, without setting up a new model, even if the machine parameters change. After determining the airgap reluctance, we pieced together the equivalent magnetic circuit for the desired SRM and were able to extract important machine characteristics like the inductance profile, torque profile, B-field profile, etc. We validated our results with FEA simulations to see a close match. As a result of this project, we aim to build our own 8/6 SRM that can be used for demonstration purposes in future offerings of ECE 330.Ope