Three-Dimensional Analytical Modeling of Rotational Eddy Current Speed Sensor

The main goal of this article is to present a novel 3-D analytical method for precise and fast modeling of rotational eddy current speed sensors with cylindrical structures. An equivalent linearized model is developed using a multislice structure. The cylindrical structure of rotational eddy current sensors is modeled using the multislice linearized structure. The 3-D distribution of induced eddy current in the rotating conductive rods is considered in the analytical modeling. The method of separation of variables using Fourier series is utilized for the analytical analysis of rotational eddy current speed sensors. The new calculation method is tested on the eddy current speed sensor with perpendicular coils and different rotating rods. The analytical results are compared with the calculations of 3-D time-harmonic and time-stepping finite element methods (FEMs). The measurements on the sensor prototype verified the calculations. When compared to the 3-D time-harmonic FEM, the 3-D analytical method is 12 times faster.