| Abstract |
Different methods for field oriented control of an induction machine are presented. The voltage source inverter supplying the motor is controlled by a PWM-modulator working in the modes of free running and synchronized, sinusoidal modulation, optimized modulation and fundamental switching (van der Broeck, 1986; Stanke, 1987). The superimposed machine control requires the speed, two phase currents of the machine and the dc-link voltage as input quantities. Speed and currents are used in a machine model to compute current and voltage components in a field oriented reference frame (Leonhard, 1983; Horstmann, 1988). The whole control including the PWM-modulator is performed by a single 16-bit-microcomputer. It is possible to change the control modes (feed forward control / closed loop control) during machine operation via software switches. Measurements on a 30 kW test drive show, that a very good steady state and dynamic behaviour of the drive can be achieved even at low speeds. |
