THE CONTROL METHOD FOR OVERMODULATION OPERATION OF NPC TYPE 3-LEVEL INVERTER

摘要

PURPOSE: According to over modulation control method of the NP C type 3- level inverter for the railway vehicle is the modulation index, the inverter output voltage is linear. The harmonic noise at over modulation domain is minimized. CONSTITUTION: According to the modulation index, over modulation domain I or more modulation domain II are instituted. By using the reference angle, the new voltage reference vector becomes on 4 branch area linear at π/2. The reference angle is induced through the Fourier series of the voltage reference vector to the size of the fundamental component.