Some drive systems with PM excited motors use two zones of rotational speed control. Smooth transition from "constant torque" zone to "constant power" zone is achieved by either weakening PM field Or by gradual switching off (shunting) of parts of winding with the help of power electronics elements (IGBT transistors). The second method of speed control may be especially useful in those PM motor drives, where small rotor inertia is required or where application of IPM rotors (permanent magnets inset into rotor iron) might be difficult (disc rotors, motors with rotating external excitation). In those machines we use magnets glued onto rotor surface, and this results in rapid decrease of motor's maximum torque during field weakening. If we look at a motor dedicated to operation with parts of the winding shunted, the terminal box exhibits Tyree terminals, representing armature winding beginning, end and midpoint. Midpoints and endpoints may be shortcircuited with transistors and therefore star-connected armature bands may exhibit more or less turns. During start-up and at low rotating speeds, lower group transistors operate (those are transistors short-circuiting bands' endpoints). The motor operates in a way identical to standard brushless dc motor (BLDC). At high rotating speeds, the bands' midpoints start to become short-circuited by upper group transistors and this results in further increase of rotor speed. Application of transistors makes transition from motor mode of operation to recuperative braking operations more complex. Different variants of drives are described in the paper, all drives making possible kraking accompanied by energy recuperation into the supply source. It has been proved that in some circuits some part of conducting current is taken over by backward diodes. In order to select these diodes properly, one must be aware of magnitude of this current. The paper demonstrates how to evaluate this current.
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W artykule opisano zagadnienie kompatybilności elektromagnetycznej EMC pod kątem pracy układów mikroprocesorowych stosowanych w motoryzacji. Największą uwagę poświęcono sterownikowi silnika samochodu, ponieważ oprócz tego, że znajduje się on w komorze silnika, każdy nowoczesny sterownik steruje również zapłonem, co wzmaga wpływ zakłóceń elektromagnetycznych na jego pracę. Ponadto przedstawiono przykłady zachowań urządzeń po przekroczeniu maksymalnej odporności na zakłócenia oraz metody zmniejszenia i eliminacji zakłóceń oddziaływujących na urządzenia mikroprocesorowe. W pracy zaprezentowano również sprawdzone doświadczalne metody eliminacji zakłóceń elektromagnetycznych uniemożliwiających pracę sterowników wtrysku paliwa.
EN
Several methods of the protection of microprocessor - based system against electromagnetic interference have been proved in course of operation and presented in this study. The electromagnetic interference resulting from capacitate coupling is usually the most difficult problem occurring in practice. The methods used for the electromagnetic interference influence elimination described herein have been verified by means of real controllers where the problems associated with the electromagnetic interference in course of gas fuel injection have been recorded.
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