Research On Torque Characteristics Optimization And Themal Problems Of Equipolar Slot Limited Angle Torque Motor

The limited angle torque motor(LATM)plays a very important role in high-precision electrical servo systems such as aerospace and robotics and it has the advantages of high reliability,simple structure and simple control method.In this paper,the equi-polar slot limited-angle torque motor is taken as the research object,and the torque performance,operating characteristics,core loss,fluid field and temperature field of the motor are studied.To solve the problems of large torque ripple and low power density in a large operating range for slotted LATM,a highly saturated soft magnetic alloy material is used as the stator.The sensitivity analysis of different stator parameters with respect to the torque characteristics is carried out,so as to obtain the weight coefficient of each parameter required for optimization.Based on genetic algorithm,the structure of the limited angle motor has been optimized to increase the electromagnetic torque,reduce the cogging torque and torque ripple in the operating range.Through the finite element analysis,the electromagnetic performance of the motor before and after optimization is compared.Based on the linear mathematical model of the conventional LATM,an accurate mathematical model considering the saturation of the magnetic field is proposed.The model can consider the changes of flux linkage,torque,and inductor with the winding current and the rotor mechanical position.At the same time,the above model is used to build a LATM position following model to obtain winding current information.The winding current information is injected into the finite element calculation software to explore the change rule of the core loss of the LATM under different swing frequencies and swing amplitudes.Aiming at the characteristic that the fluid flow between the rotor and stator is very complicated when the LATM is working,a calculation model of the LATM fluid field based on the multi-reference frame method is established.Explore the fluid flow regular pattern between the rotor and stator under different conditions,and calculate the average fluid velocity.The rotor position of the LATM changes sinusoidally with time.Under different swing amplitudes and swing frequencies of the rotor,the heat exchange between the rotor and the stator is very complicated.Through the sequential coupling method,based on the heat source calculated in the electromagnetic field and the average air flow velocity calculated in the fluid field,and the temperature field of the LATM under different conditions is studied by the finite element method to explore the temperature field distribution regular pattern.