PULSE WIDTH MODULATION METHOD BY COMPARING OFFSET VOLTAGE AND CARRIER WAVE OF THREE-PHASE FOUR-LEG INVERTER AND SWITCHING SIGNAL GENERATOR

摘要

PURPOSE: A pulse width modulation method and a switching signal generator are provided to allow for ease of pulse width modulation by comparing an offset voltage and a carrier wave. CONSTITUTION: A pulse width modulation method comprises a step of calculating an offset voltage from the output voltage command values of each of phases; a step of calculating pole voltages of each of phases from the output voltage command values and the offset voltage; and a step of controlling switches of each of legs by comparing pole voltages, offset voltage, and a carrier wave. A switching signal generator comprises an offset voltage calculator(40) for calculating an offset voltage from the output voltage command values of each of phases; adders(51,52,53) for calculating pole voltages of each of phases by adding the output voltage command values of each of phases and the offset voltage; and comparators(61,62,63,64) for generating switching signals for each of legs by comparing pole voltages, offset voltage, and a triangle wave.