Peter Wood

Characterization of Programmed-Waveform Pulsewidth Modulation

Programmed-waveform pulsewidth modulated (PWM) waveforms, applicable to ac-dc/dc-ac converters, are synthesized and analyzed in terms of several structural parameters. By invoking sensitivity studies and heuristics, optimal PWM structures are identified and contrasted. The results show total harmonic performance as a function of switching levels, waveform types, commutations per cycle, and filter bandpass.

A Criterion for Performance Comparison Between High Power Inverter Circuits

The efficiency and economics of inverter circuits with high power ratings tend to be determined largely by the size of the passive elements required in the commutation circuit and, to a lesser extent, by the combined current-voltage requirements of the semiconductors. In order to facilitate comparative evaluation of inverter circuits of different configurations which are all candidates for the same application, an analytical expression representative of the total kVA rating of the passive components can be derived for each circuit from the data defining the application. Combining this with a similar expression reflecting the volt-ampere requirements of the active devices, an overall circuit figure of merit can be generated. In certain paper studies, a comparison between such figures of merit can provide a useful, if not infallible, tool for appraising several candidate circuits.

Models for thyristors and diode in digital simulations

Two models are proposed for digital simulations involving power diodes and thyristors. The models simulate all operating regions of the devices, and include transient and thermal behavior. Particular emphasis has been placed on reverse recovery behaviors, to improve simulation accuracy in high frequency and multiple device applications. Either model can be completely specified from standard data sheet parameters.