| Brushless DC motor is widely used in People's Daily life and a large number of industrial automation control.The market demand,and wide development space.Traditional way of using square-wave brushless dc motor control is simple and easy to implement,but it has torque ripple and phase noise problems.For these applications,the use of the sine wave vector control can well solve the problem.In this paper,a DC brushless motor with a quasi-sine wave is used to avoid the shortcomings of the traditional square wave control method.The sensorless vector control is used to realize the current and speed double closed-loop control.The improvement of the position and velocity of the rotor is mainly based on the improved sliding mode observer with the switching function as the saturation function to suppress the chattering at the switching surface and improve the accuracy of the rotor position estimation.And through Matlab modeling and simulation of this strategy to verify the feasibility of the strategy;In order to solve the problem of slow start speed of traditional sinusoidal control,a square wave starting method based on synchronous rectification and square wave smoothing is proposed.Finally,the STM32F103RC as the control core,to complete the FOC(field-oriented control)electronic and mechanical design,and ultimately the motor function test.The test results show that the control system designed in this paper can be quickly started and stable and reliable;square wave start can be smoothly switched to closed-loop sinusoidal operation and high stability;speed closed-loop stability,work within plus or minus five percentage points;Current closed loop stability,work within plus or minus eight percentage points.The vector control strategy based on improved sliding mode observer has the advantages of small torque ripple,fast response and strong anti-load disturbance.The research results has a certain engineering application value for the vector control of the brushless dc motor. |
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