Performance Evaluation of a High-Torque Permanent Magnet Brake at Operating Temperature Based on Magneto-Thermal Coupling Method

Abstract

As the key component of a servo motor, the torque and temperature rise of the brake at the operating temperature affect the production quality of injection molding machines and other equipment. To achieve application of the brake and evaluate its performance at a high operating temperature, a high-torque permanent magnet brake with an axial disc structure is proposed. The permanent magnet consists of six small magnets instead of the traditional monolithic ring magnet. The key parameters of the coil are designed, and the magneto-thermal coupling method is established. The magneto-thermal coupling method considers the effect of temperature on material properties and feeds the temperature back to the electromagnetic field to correct the resistance, permeability, remanence and other coefficients. It then updates the heat source of the temperature field. The temperature rise is calculated iteratively between the electromagnetic field and the temperature field. The simulation results of the one-way method and the magneto-thermal coupling method are obtained and compared with the experimental results. The evaluation errors of the magneto-thermal coupling method for temperature and braking torque are 1.9% and 4.7% respectively, which are lower than the errors of the one-way method.