Title :
Harmonic imbalance in asynchronous PWM schemes
Author :
Dunford, William G. ; Van Wyk, Jacobus D.
Author_Institution :
Dept. of Electr. & Electron. Eng., Imperial Coll., London, UK
fDate :
7/1/1992 12:00:00 AM
Abstract :
The harmonic content (both integral and nonintegral) of an asynchronous three-phase PWM (pulse width modulated) scheme is analyzed. It is shown that in a three-phase inverter with asynchronous modulation the nonintegral line currents produced form unbalanced sets. The percentage imbalance for a particular order is a function of the harmonic order only. No attempt has been made here to analyze the effect of harmonic imbalance in a load such as an induction motor. However, for practical frequency ratios the absolute amplitude of the current imbalance is small due to the small amplitude of the nonintegral components. More significant changes occur in the balanced integral orders due to small changes in frequency ratio
Keywords :
harmonics; invertors; pulse width modulation; 3-phase invertors; asynchronous PWM schemes; asynchronous modulation; harmonic imbalance; nonintegral line currents; Blanking; Bridge circuits; Frequency; Jacobian matrices; Pulse width modulation; Pulse width modulation inverters; Quantization; Space vector pulse width modulation; Switching circuits; Voltage;
Journal_Title :
Power Electronics, IEEE Transactions on
