| 摘要 |
PURPOSE:To provide a PWM control method for 3-level inverter in which a stabilized control is allowed without feeding any neutral point current even when the modulation factor exceeds (1.0-B) CONSTITUTION:A bias amount operating circuit 1 varies the bias amount, being added to or subtracted from a voltage command, depending on the value of modulation factor lambda*. Consequently, two voltage commands being compared with a carrier have symmetrical waveforms even in a region where the modulation factor lambda* exceeds (1.0-B). When the voltage command has a trapezoidal waveform in the region where the modulation factor lambda* exceeds (1.0-B), switching times can be decreased and switching loss can be reduced. |
