The invention discloses a
combined method of dead zone
elimination and dead zone compensation for a three-level T-type
inverter. The method comprises the following steps: respectively adopting different control strategies according to two different stages of the phase current, namely, when the phase current is greater than the set threshold value, adopting a dead zone
elimination strategy to change the output phase
voltage only by modifying the on-off state of one of switching tubes; and when the phase current near the
zero crossing point is smaller than the threshold value, adopting a dead zone
compensation strategy at this time, namely, inserting the dead zone time during a
sequential switching process, and then adjusting the corresponding vector action time to eliminate the
voltage difference and
harmonic influence caused by dead zones. Compared with a traditional
space vector modulation method, the method disclosed by the invention is small in amount of calculation and simple to implement, cannot affect the closed-
loop control, does not need additional
hardware circuits, is fast in dead zone compensation speed, and is stable in the conversion process of two control
modes. By adopting the method disclosed by the invention, the output
voltage difference can be further reduced, the
total current harmonic distortion rate can be significantly reduced, and the
modulation index cannot be decreased.