The Design Of Brushless Dc Motor Fuzzy Direct Torque Control System

Currently, because of excellent properties, the brushless DC motor applies to more and more occasions.such as in hybrid cars, household appliances, office automation and other fields, with its high efficiency, large power factor and high precision. Brushless DC motors have made a major breakthrough. But at the same time, it is undeniable that, for brushless DC motors, there is room for further improvement.In recent years, direct torque control method for its outstanding performance in the field of induction motors, permanent magnet synchronous motors, etc. sinusoidal gets more and more popular.Therefore, direct torque control method is also gradually introduced to the brushless DC motor area.It becomes a national hotspot and researchers have made a lot of technological breakthroughs.By analyzing the voltage space vector, torque will be directly controlled in this method. Therefore, it will realize stator flux and rotor flux angle control, and achieve the purpose of the direct control of torque. The size of the torque can be achieved by changing the angle between the stator and rotor flux changes. Because the angle can be adjusted by applying a voltage space vector at different times, the direct control of the motor torque can be adjusted by the instantaneous speed of rotation of the stator flux to achieve.During the in-depth study of brushless DC motor for more than two years, the direct torque control method for brushless DC motor field application background, current situation and trends are learned. For existing shortage of direct torque method, the basis of direct torque control method is proposed based on fuzzy improvements. Fuzzy direct torque control based on an important indicator for the regulation time to improve, overshoot, etc. do a corresponding improvement. For existing shortcoming, it effectively improves the speed control deficiencies, and improves the running process based on direct torque control of brushless DC motor control system in static and dynamic performance.Based on this, the main text of the content is as follows:(1) The paper elaborats on the background of brushless DC motor development status of domestic and foreign applications and future trend. It also focuses on the characteristics and control method of brushless DC motors. In addition, the paper represents the brushless DC motor drive system configuration, specifically the principle of brushless DC motors. Brushless DC motor mathematical model is introduced, and is analyzed about the operating mode between two conduction and three-phase six states.(2) In brushless DC motor research, the paper selects the improvement of direct torque control method as a research subject. First, the paper elaborats on the development and application advantages of direct torque control method, and gives priority analysis of direct torque control method for mathematical calculations and control system architecture.Second, in the simplified calculation of ideas, the paper improves formula of torque and flux.(3) In the DC brushless motor applications, direct torque control method, although effectively inhibited the torque ripple, there is room for improvement in the speed control response. To solve this problem, the paper introduces the speed loop fuzzy control. On the brushless DC motor direct torque control on fuzzy control method, the paper makes specific and detailed exposition. And as a basis, MATLAB / SIMULINK software will be applied on a permanent magnet brushless DC motor direct torque control method based on fuzzy control by verification algorithm feasibility and superiority.(4) After successful simulation, the paper builds fuzzy control brushless DC motor direct torque control system platform. On the platform, the paper details the characteristics of the rectifier, inverter and controllor of each module. And as the basis of the algorithm, the paper obtains the ideal speed response curve, proves the steady and really good speed, and verifies excellent static and dynamic performance through direct torque control of brushless DC motor fuzzy control.