Radial Force Density Calculation of Switched Reluctance Machines Using Reluctance Mesh-Based Magnetic Equivalent Circuit

Abstract

Acoustic noise and vibration is one of the shortcomings of a switched reluctance machine (SRM). Harmonics of the radial force waveform in the airgap excite the stator structure at different vibration modes with specific frequencies. The radial force density in the airgap should be calculated before analyzing and mitigating acoustic noise and vibration. This paper proposes a reluctance mesh-based magnetic equivalent circuit (MEC) model to calculate the airgap radial force density. Reluctance mesh-based MEC models are developed for 3-phase 6/4, 6/16, 12/8 and 4-phase 8/6, 8/10, and 16/12 SRMs. A technique for the dynamic modeling of SRMs is proposed using the reluctance mesh-based MEC method. Dynamic currents are calculated using the proposed technique and, then, the radial and tangential flux density in the airgap are calculated. The radial force density in the airgap is calculated by applying the Maxwell Stress Tensor method. Fourier series is used to calculate the harmonics of the radial force density. The results obtained from the MEC model are verified using finite element method (FEM) models. The implemented MEC-based dynamic modeling method is validated using experimental results.

Keywords

• Magnetic equivalent circuit model
• Maxwell Stress Tensor
• radial force
• radial force density
• reluctance mesh
• switched reluctance machine