Overview of the Optimal Design of the Electrically Excited Doubly Salient Variable Reluctance Machine

The Electrically Excited Doubly Salient Variable Reluctance Machine (EEDSVRM) is a new type of brushless machine designed according to the principle of air gap reluctance change. There is neither permanent magnet steel nor excitation winding on the rotor. The rotor is made of silicon steel sheets, thus the structure of the variable reluctance machine is very simple. There are many optimization methods for this type of machine optimal design, such as novel machine topology optimization, finite element simulation-based optimization, mathematical analysis-based optimization, intelligent algorithm-based optimization, and multiple fusion-based optimization. Firstly, this article introduces the basic structure and working principle of the EEDSVRM and analyzes both its common regularity and individual difference. Then, the different optimization design methods of EEDSVRM are reviewed, the advantages and disadvantages of the different optimization methods are summarized, and the research interests of the optimization design of variable reluctance machines in the future are prospected.

Comprehensive Analysis On A New Type VR-Resolver with Toroidal Windings Under Healthy and Eccentric Cases

<div>A novel analysis for a new type Variable Reluctance Resolver (VR-Resolver) with toroidal windings is presented in this work. The resolver with various windings configurations as well as different rotor structures is considered for analysis. Position error of the resolvers in both healthy and eccentric cases are studied, where the effect of the eccentricity fault is analyzed for the resolvers with various windings configuration and rotor shapes. Hence, the analysis of the manufacturing tolerance due to the eccentric rotor is obtained by several analyses. Noticing the Magnetic Equivalent Circuit (MEC) method’s flexibility as well as in regards to the analysis of the several structures, a well-known flexible MEC-based method with adjustable accuracy is considered for modeling. Hence shorter processing time and more flexibility compared to Finite-Element-Method (FEM) are needed. Finally, the effectiveness of the presented works is proved by the performed validation via both FEM and experimental results.</div>

Comprehensive Analysis On A New Type VR-Resolver with Toroidal Windings Under Healthy and Eccentric Cases

<div>A novel analysis for a new type Variable Reluctance Resolver (VR-Resolver) with toroidal windings is presented in this work. The resolver with various windings configurations as well as different rotor structures is considered for analysis. Position error of the resolvers in both healthy and eccentric cases are studied, where the effect of the eccentricity fault is analyzed for the resolvers with various windings configuration and rotor shapes. Hence, the analysis of the manufacturing tolerance due to the eccentric rotor is obtained by several analyses. Noticing the Magnetic Equivalent Circuit (MEC) method’s flexibility as well as in regards to the analysis of the several structures, a well-known flexible MEC-based method with adjustable accuracy is considered for modeling. Hence shorter processing time and more flexibility compared to Finite-Element-Method (FEM) are needed. Finally, the effectiveness of the presented works is proved by the performed validation via both FEM and experimental results.</div>

System Implementation Trade-Offs for Low-Speed Rotational Variable Reluctance Energy Harvesters

Low-power energy harvesting has been demonstrated as a feasible alternative for the power supply of next-generation smart sensors and IoT end devices. In many cases, the output of kinetic energy harvesters is an alternating current (AC) requiring rectification in order to supply the electronic load. The rectifier design and selection can have a considerable influence on the energy harvesting system performance in terms of extracted output power and conversion losses. This paper presents a quantitative comparison of three passive rectifiers in a low-power, low-voltage electromagnetic energy harvesting sub-system, namely the full-wave bridge rectifier (FWR), the voltage doubler (VD), and the negative voltage converter rectifier (NVC). Based on a variable reluctance energy harvesting system, we investigate each of the rectifiers with respect to their performance and their effect on the overall energy extraction. We conduct experiments under the conditions of a low-speed rotational energy harvesting application with rotational speeds of 5 rpm to 20 rpm, and verify the experiments in an end-to-end energy harvesting evaluation. Two performance metrics—power conversion efficiency (PCE) and power extraction efficiency (PEE)—are obtained from the measurements to evaluate the performance of the system implementation adopting each of the rectifiers. The results show that the FWR with PEEs of 20% at 5 rpm to 40% at 20 rpm has a low performance in comparison to the VD (40–60%) and NVC (20–70%) rectifiers. The VD-based interface circuit demonstrates the best performance under low rotational speeds, whereas the NVC outperforms the VD at higher speeds (>18 rpm). Finally, the end-to-end system evaluation is conducted with a self-powered rpm sensing system, which demonstrates an improved performance with the VD rectifier implementation reaching the system’s maximum sampling rate (40 Hz) at a rotational speed of approximately 15.5 rpm.

Modeling and analysis of variable reluctance resolver using magnetic equivalent circuit

Purpose The purpose of this paper is to propose a saturable model based on the magnetic equivalent circuit (MEC) for evaluating the electromagnetic performance of the variable area resolver. Design/methodology/approach The equivalent circuit is developed where three different reluctance types are used to calculate permeances based on geometrical approximations. The proposed model typically has two types of equations, including the magnetic and electrical equations. The magnetic and electrical equations are related to the resolver core and the windings, respectively. Applying the well-known trapezoidal method, the magnetic and electrical equations can be simultaneously solved. A nonlinearity of the magnetic equations, the algebraic equations system, which is obtained from Kirchhoff’s laws, should be solved by the Newton-Raphson technique in each step-time. Findings The flexible MEC model, in which the number of flux tubes in different parts of the resolver can be arbitrarily selected, is proposed to analyze the variable reluctance resolver. Besides, the design parameters such as geometrical dimensions, windings arrangement and a number of the rotor saliencies can be chosen as desired. To consider the effect of time harmonics, a new nonlinear function is used for the core magnetization. Furthermore, different winding layouts can be implemented in the model to take space harmonics into account. The model obtained results are compared with the finite element method in terms of accuracy and simulation time. Originality/value Generally, the accuracy of the predictions in the MEC method is dependent on the number of flux tubes; therefore, the flexibility of the proposed MEC model in its capability to choose the desired number of flux paths is the advantage of this work. Moreover, the proposed model can analyze both wound and saliency rotor resolvers by changing the design parameters.

Variable reluctance synchronous machines in saturated mode

Electric vehicle seems largely based on electrical machines. Finding the best motor type seems be important for having more performances and a transport system robustness. In this work, we present an analytical model of the synchronous machine with variable reluctances in linear and saturated modes. The angular position of the rotor (θ) and the phase current (i) will beused as parameters. The analytical model of this machine will allow us to determinate its magnetic characteristics such inductors, magnetic flux and electromagnetic torque. The results obtained by the analytical model are compared with those obtained by the finite element method. So, basing on Matlab/Simulink tool and by working with finite element method, these results are depicted and the paper objective is illustrated.