Magnetic Equivalent Circuit Model for Predicting Performance of 2DOF Wound Rotor Resolver

Expansion of Two Degrees of Freedom (2-DOF) electrical machines, for simultaneous linear-rotational motions, leads to employment of more than one sensor in closed-loop control systems. Such control systems can use two separate sensors for linear and rotational motions or employ a 2DOF sensor. The last, will result in lower volume and mass and also less complexity of the control system. Therefore, development and design optimization of 2DOF sensors can be an interesting research topic. However, 3-D geometry of such sensors needs 3-D finite element analysis. Due to high computational burden of 3-D time stepping finite element method (3-D TSFEM), it can hardly applicable in iterative design and optimization methods or performance evaluation of the sensor under fault conditions. Therefore, it is preferred to predict the accuracy of such linear-rotational sensors using an accurate, computationally fast method. Hence, in this paper, a comprehensive analytical model based on Magnetic Equivalent Circuit (MEC) is proposed for a helical motion resolver. The developed model can predict the performance of the sensor in health condition, as well as that under short circuit fault. Finally, the obtained results are verified using experimental measurements on the prototype helical motion resolver.