A method for linearising optimal PWM switching strategies to enable their computation on-line in real-time

Abstract

A general technique is presented for the piecewise linearization of optimal pulse width modulation strategies, from which a near-optimal switching strategy, able to be computed online in real-time by relatively low performance microprocessors, can be developed. The linearization technique replaces the switching patterns of an optimal PWM strategy with a series of piecewise linear segments, selected using a sensitivity analysis to minimize the generated harmonics, and these linear segments are used to create the online switching algorithm. The linearization technique is presented, along with experimental results which show the application of the technique to a particular optimal PWM switching strategy, applied to a SMES (superconducting magnetic energy storage system) system.<>