CONCLUSIONS AND RESULTS

By using ST52x301 Fuzzy Controller it is easy to implement a real time control with few components.The

brushless motor control described in this application note represents a good compromise between sy-

stem costs and motor performances. The graphical programming environment reduces the development

time also for not expert programmers.

Fig. 12 displays a phase current and the star voltage Vu-o. PWM square wave is filtered by the oscillo-

scope.

From this picture it is possible to observe the six steps on the current wave that yields a distortion of the

theoretical sine wave. At higher speed rates the distortion becomes lower, although at low speed, motor

performance does not degrade.

To evaluate acceleration characteristics and control goodness, some trials were made during the softwa-

Figure 12 . Phase current

re development. Fig. 13 shows free acceleration characteristics starting from a given speed of the shaft

to reach a double speed by changing suddenly the speed_Ref.

The dynamic performances of this system were compared, in term of speed and load response, with a

traditional controller with six steps drive. No substantial differences were issued in the dynamic perfor-

mances, but the costs of the traditional system was higher.

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AN1113 - APPLICATION NOTE

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