Research On Sensorless Control System Of Bldcm Based On DSP

The sensorless BLDCM is widely used in military and civilian fields with its simplestructure, high operating efficiency, good speed performance and some advantageswithout position sensor. Especially with the development of current mainstream motorcontrol chip DSP2812and its drive technology, the sensorless BLDCM can achieveincreasingly high control accuracy. This paper studied on sensorless BLDCM controlsystem and mainly includes:Firstly, some common position detection means using in sensorless BLDCM areintroduced in this paper. Among these position detection means, the terminal voltagedetection method is detailed analyzed and the stability of the commutation timealgorithm using in terminal voltage detection is analyzed.Then, based on the TMS320F2812, the hardware circuits of power drive, powersupply, external memory, I/O interface driver, external expansion LCD and terminalvoltage detection circuit are designed. In addition, the design concept of each part, thechip selection and timing matching are elaborated.Furthermore, selecting metro platform screen doors as load and referring to itsactual door system, the electrical parameters of motor is given. Then an idealacceleration curve is fitted according to the S-shaped curve.Besides, in order to improve motor torque ripple, the torque control methods basedon modulation schemes and current regulation are analyzed and some related flow chartsare given.Lastly, the waveform and results of the system experiment are expounded in thispaper. The experiments show that the design of the hardware and software systemapplying in sensorless BLDCM can realize the acceleration, state switching anddouble-loop control of motor based on terminal voltage detection.