The on-line pulsewidth modulation (PWM) of a voltage source inverter for converter-fed ac drives is presented. The modulation is realized by software, thus allowing a direct interface between the microprocessor-based speed control and the on-off commands for the inverter. An efficient modulation technique is achieved by asynchronous switching of the inverter phases; a current control loop provides fast feedback, so that a fast step response of the stator currents can be obtained. All control functions, including field-oriented speed control of an induction motor, are performed by a 16-bit microprocessor. Experimental results obtained with a 22-kW induction motor prove that the proposed scheme provides a very good performance of the drive from standstill up to the field weakening range.
[1]
Alberto Pollmann Reyes.
Ein Beitrag zur digitalen Pulsbreitenmodulation bei pulswechselrichtergespeisten Asynchronmaschinen
,
1984
.
[2]
W. Schumacher,et al.
Microprocessor-Controlled AC-Servo Drives with Synchronous or Induction Motors: Which is Preferable?
,
1986,
IEEE Transactions on Industry Applications.
[3]
Rupprecht Gabriel,et al.
Feldorientierte Regelung einer Asynchronmaschine mit einem Mikrorechner
,
1982
.
[4]
A. F. Wick,et al.
Design and Experimental Results of a Brushless AC Servo Drive
,
1984,
IEEE Transactions on Industry Applications.
[5]
W. Leonhard,et al.
Control of AC-Machines with the help of Microelectronics
,
1983
.