| Abstract |
The use of machine tools in flexible automation increases the requirements on spindle drives in terms of reliability and availability. Today the DC drive with speed control is a standard solution. Brushless drives are the state of the art in servo applications. Frequency controlled asynchronous machines supplied by transistor inverters are beginning to enter the area of brushless spindle drives. Urged by the demands of high reliability, ease of servicing, simple installing, high speed and a wide range of constant power to economize gear trains, several producers offer AC spindle drives to replace the DC drives. To get the same control behaviour it is necessary to use a sophisticated control algorithm which can be handled by a microcomputer much better than by analogue circuits. Using microcomputers the problem of calculation time arises. For this reason in many applications digital speed control loops are combined with analogue current control loops. In this paper a microcomputer controlled AC drive with fully digital controlled induction motor is presented. Optimizing the software structure it is possible to use only one standard industrial type of microprocessor in this drive, which will be a serial product in 1988. |
