| In this paper,XXD brushless DC motor is used as the driving machine to study the relationship between torque and speed,and the coordinated control scheme of torque and speed is worked out.Firstly,the mathematical model of brushless DC motor is analyzed and established.Aiming at the motor control problem,the three stage starting method is used to start the motor,and the rotor position is estimated by the back EMF detection method and the reduced order rotor flux observer method.According to the actual conditions of the charged electric drill,the coordinated control scheme of torque and speed of brushless DC motor is put forward.In hardware circuit,the design scheme of torque and speed coordinated control system of brushless DC motor based on ADuC7026 processor is put forward.Besides,design the SCM system,three-phase bridge circuit,the shunt armature current sampling circuit,voltage reference circuit,bias circuit module,power supply circuit,the back EMF detection circuit,and complete the building and testing of these circuits.In software design,based on embedded real-time operating system C/OS-Ⅲ,different priority tasks are designed,and the system control program and test program are written respectively.The control program includes external synchronization control program,self-synchronization control program,constant torque control program and double closed loop speed control program.The test program is used to check the hardware fault and obtain the experimental test results.Finally,the feasibility of torque and speed coordinated control of brushless DC motor is proved by MATLAB simulation.On the basis of completing the design of hardware and software,the experimental platform is built.The experimental results show that the double closed loop speed control method improves the stability of the system,improves the dynamic performance of the system,and verifies the correctness of the torque and speed coordinated control technology of brushless DC motor. |
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