Methods of generating the voltage space-vector by fast real-time pulsewidth modulation

Three well-known methods of generating a voltage space-vector for VSI applications are discussed and compared with respect to DC link voltage utilization. The calculations are based on space-vector theory, hence, they are valid for arbitrary transient operation. Proceeding from a simple method of projecting the space-vector onto the phase axes, an improved algorithm using zero-sequence quantities is given and compared with space-vector modulation. The admissible zero-sequence functions depending on the space-vector argument and magnitude are calculated, yielding very simple algorithms for real-time processing. Typical applications are software-based field-oriented controllers by using a single processor and minimum hardware expense.<>