| Abstract |
This paper describes a PWM pulse pattern optimization method utilizing the pulse frequency modulation (PFM). In conventional PWMs the pulse frequency is kept constant. In the proposed scheme, however, the pulse frequency is adjusted to improve the performance of PWM sinusoidal inverters. The PWM pulse patterns are basically controlled so that the time-integral function of the output voltage in the space vector representation may draw a circular locus. In addition to this, the pulse frequency as well as the pulse width are controlled so that the performance index (PI), which represents the degrees of achieved objectives, may be minimized. In this paper, two PIs, one for minimizing the distortion of the output currents and the other for minimizing the torque pulsation of driven motors, are employed. The method is finally implemented using a single-chip microprocessor, and the experimental results demonstrate its validity. |
