CONSTANT SAMPLING TYPE PWM APPARATUS FOR THREE-PHASE AC-DC CONVERSION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To obtain a constant sampling-type PWM apparatus in which a gate command is formed as a neat waveform, in which the switching frequency is lowered and whose efficiency is enhanced. ;SOLUTION: With reference to a linkage current ia from a phase (a) and a linkage current ic from a phase (c), a target function ja and a target function jc are fetched into a comparator 14 and a comparator 14-1. An error current Δa(t) and an error current Δc(t) are found here. A conversion current, which is composed of α and β, is led out by a three-phase/two-phase conversion circuit 15. It is converted by an A/D conversion circuit 16 to obtain an output, and a gate command is computed by a computing circuit 17. At this time, a 0 V- mode (a mode in which U, V, W or X, Y, Z are simultaneously turned on) is used.;COPYRIGHT: (C)2000,JPO