| 摘要 |
AN IMPROVED PULSE WIDTH MODULATION METHOD FOR A POWER TRANSFORMING APPARATUS WHICH IS CAPABLE OF DECREASING A SWITCHING EFFICIENCY LOSS BY PROVIDING A PHASE HAVING THE MAXIMUM SIZE OF A PHASE CURRENT WHICH IS NOT SWITCHED. THE METHOD INCLUDES THE STEPS OF A FIRST STEP FOR COMPUTING A PHASE VOLTAGE COMMAND (VAS_C, VBS_C, VCS_C) IN ACCORDANCE WITH A PHASE OF A VOLTAGE () FROM THE LOAD CIRCUIT, A SECOND STEP FOR PERFORMING A THREEPHASE PULSE WIDTH MODULATION WITH RESPECT TO THE PHASE VOLTAGE COMMAND WHEN THE VOLTAGE AND FREQUENCY APPLIED TO THE LOAD CIRCUIT ARE BELOW A PREDETERMINED VALUE, A THIRD STEP FOR COMPUTING NEW PHASE VOLTAGE COMMANDS WHICH HAVE THE SAME PHASE AS THE PHASE OF A CURRENT (P) WHEN THE VOLTAGE AND FREQUENCY APPLIED TO THE LOAD CIRCUIT ARE ABOVE A PREDETERMINED VALUE, AND A FOURTH STEP FOR PERFORMING A PULSE WIDTH MODULATION SO THAT A SWITCHING OPERATION HAVING THE MAXIMUM ABSOLUTE VALUE OF THE CURRENT AMONG THE NEW PHASE VOLTAGE COMMANDS OBTAINED IN THE THIRD STEP BECOMES IDL (FIG.8)
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