Three-phase PWM signal generator and three-phase voltage type inverter device

摘要

PPROBLEM TO BE SOLVED: To provide a three-phase PWM signal generator which, with little limitation in the range of output voltage, can prolong the holding time of a switching pattern, using a simple method, without having to add new devices. PSOLUTION: When generating a PWM signal using two types of basic voltage vectors having a phase difference of 60 degrees sandwiching a voltage command vector, a basic voltage vector close to the voltage command vector of the two types of basic vectors, and the third type of basic voltage vector; having a phase difference of 60 degrees and differing from the two types of basic voltage vectors, the three-phase PWM signal generator 8 decides the value to be provided to the basic voltage vector that is far from the voltage command vector of the two types of basic voltage vectors, excluding the center basic voltage vector as the generation time ratio, based on the lowest possible ratio of generation time for detecting a current. PCOPYRIGHT: (C)2008,JPO&INPIT