Implementation of Pulsewidth Modulated Inverter Modulation Strategies

A description is given of a number of new circuit techniques, useful primarily in the control hardware of inverter drives using ``sub-harmonic''- or ``triangulation''-based pulsewidth modulation algorithms. Most aspects of such a system are covered. These include generation of the ``reference'' and ``carrier'' waveforms, carrier merging (including an asynchronous/synchronous carrier transition), output amplitude control, and sequence filtering. While the emphasis is on the triangulation approach, the majority of the text is relevant to the implementation of pulsewidth modulation processes in general. Some experimental data are included.