Title :
Staircase PWM: an uncomplicated and efficient modulation technique for AC motor drives
Author :
Thorborg, Kjeld ; Nyström, Åke
Author_Institution :
Dept. of Electr. Machines & Power Electron., Chalmers Univ. of Technol., Gothenburg, Sweden
Abstract :
An optimized staircase PWM (pulse-width modulation) technique is presented. The fundamental voltage component (U/sub (1)/) is proportional to the staircase amplitude (M). Values of U/sub (1)/ higher than 90% of the corresponding value for the nonmodulated waveform are attained for M=1. The staircase is not a sampled representation of a sine wave and the number of steps and the frequency ratio are selected for a desired output voltage quality. A criterion for evaluating the quality of the output voltage (the weighted relative harmonic content) is presented. The control logic is uncomplicated and implemented by inexpensive complementary metal-oxide semiconductor logic with high noise immunity and reliability. The results have been verified by tests.<>
Keywords :
AC motors; electric drives; machine control; pulse width modulation; AC motor drives; PWM; complementary metal-oxide semiconductor logic; control logic; electric drives; frequency ratio; fundamental voltage component; harmonic content; machine control; modulation technique; noise immunity; output voltage quality; pulse-width modulation; reliability; staircase amplitude; steps; AC motors; Frequency; Logic; MOS devices; Power electronics; Proportional control; Pulse width modulation; Pulse width modulation inverters; Semiconductor device noise; Voltage control;
Journal_Title :
Power Electronics, IEEE Transactions on
