Research On Active Thermal Control Method Of DC Motor

As a conversion device for electrical energy and mechanical energy,the motor is widely used in many fields such as industrial control,national defense,aerospace,agricultural production,and automobile driving.When the motor temperature is low,the torque capacity of the motor can be maximized by the overload operation.However,the degree and time of the motor overload operation are usually difficult to determine,and the running time of the motor at the peak torque is often estimated by experience.In addition,the overload operation of the motor will cause its internal temperature to rise rapidly,and the excessive temperature rise of the motor will accelerate the aging of the winding insulation or cause the coercive force of the permanent magnet to decrease,thereby reducing the efficiency of the motor and causing the motor to burn out in severe cases.Therefore,thermal control research of electric motors has important engineering practical value.Because the overload capability is closely related to the motor temperature,this paper takes DC motor as the research object,and proposes a model based on single node lumped parameter thermal model to predict the active thermal control scheme of the motor.Firstly,based on active thermal control technology,combined with model predictive control and lumped parameter thermal network method,the single-node model predictive active thermal control algorithm for DC motor is deduced and analyzed,and the overall scheme of DC motor active thermal control system is designed.Secondly,the software communication module of infrared temperature sensor,Hall current sensor,torque and speed measuring instrument and the overall control model of DC motor active thermal control system are built in MATLAB/Simulink.Finally,based on the designed rotor temperature monitoring system of the motor,the hardware experimental platform of the motor active thermal control system with d SPAC E as the core is built,and the experimental verification is carried out on a permanent magnet DC motor.The experimental results show that the proposed motor model predictive active thermal control scheme based on the single node lumped parameter thermal model can adaptively generate the motor torque limit package corresponding to the motor rotor temperature lower than the limit temperature value during motor overload operation.Wire to ensure that the rotor temperature is limited to a preset temperature value during motor overload operation.While improving the motor overload capacity,it can reduce the thermal stress during motor overload operation,avoid overheating of the rotor and improve the life of the motor.The MPC-based control scheme is compared with the PI controller-based control scheme.The results show that the proposed MPC control scheme has greater torque capability during overload operation than PI-based control schemes.