CONTROL METHOD FOR VOLTAGE TYPE VVVF INVERTER

摘要

PURPOSE:To suppress ripple voltage of an input capacitor and to reduce the capacity and the size of the input capacitor by performing phase difference operation between inverters connected in series. CONSTITUTION:A phase difference of 30 deg., for example, is set between the control signals for unit inverters 411 and 421. Consequently, the voltage ripples have phase difference of 180 deg. between both inverters and thereby they are canceled each other thus producing no ripple voltage in a combined input voltage. The ripple voltage is suppressed most at a phase difference of 30 deg. and it can be suppressed according to an appropriately selected phase difference. Since the voltage ripple is suppressed, inductance of an input filter reactor can be decreased.