The Design And Implementation Of Low Temperature Materials Mixing System Based On The Direct Torque Control Theory

In modern times mixing is widely used in various fields, High viscosity liquids mixing equipment is hot-spot of research. To stir the liquid will produce a lot of load, and the stability demand of mixing motor speed and torque is higher. Direct torque control theory has good static and dynamic, able to meet these requirements. This thesis systematically analyzes the design of low temperature materials mixing machine, including targeted research to load analysis and research applied to the direct torque control theory. The main research includes the following four aspects:First，it analyzed the structural principle and operating characteristics of low temperature mixer. It focused on the load characteristics of the mixing system. Statistics and fitting of brushless DC motor load current curve are analyzed. The main factors affecting the load changes are discussed. According to load characteristic curve, deduced a temperature-load current equation, and then temperature load torque model is established.Second，analyzed the principle of classical direct torque control theory for brushless DC motor, and proposed the design of low temperature materials used in stirring system improved direct torque control theory, removing flux observer and improved voltage space vector selection table. Using Simulink to simulate the theory and achieved good control effect.Third，adopted ARM Cortex-M3core control chip STM32F103ZET6to complete the low temperature material mixing system, control system design and construction, including hardware design, software design, EMC design.Last，The development of low temperature material mixing system in cooperation with Zhong Shan Mei Ke company project application. From the point of use results, the system can still maintain stability of speed and torque in the large load conditions, has good control effect...