Pwm inverter with dead time correction function

TL;DR: In this paper, a dead-time correction quantity measuring device was used to calculate the output torque of an electric motor from the output current of current detectors 6a to 6c and the output voltage V of a current detector.

Abstract: PROBLEM TO BE SOLVED: To automatically adjust and set a dead-time correction quantity by adjusting the dead-time correction quantity so that the harmonic components of a frequency six times the inverter frequency contained in operation torque is minimized SOLUTION: A torque computing unit 11 computes the output torque of an electric motor 1 from the output current of current detectors 6a to 6c and the output voltage V of a current detector 10 A dead-time correction quantity measuring device 12 receives the output operation torque Tq of the torque computing unit 11 and adjusts a dead-time measuring quantity H0 so that the contained high-frequency component of a frequency six times the inverter frequency is minimized to deliver an output to a dead-time correction quantity memory device 8' The memory device 8' memorizes the inputted dead-time measuring quantity H0 while a dead-time correction quantity measuring device 12 operates and outputs it to multipliers 9a to 9c' as a dead-time correction quantity H', and when it is not operating, outputs the memorized dead-time measuring quantity H0 as a dead-time correction quantity H' As a result, an accurate dead-time correction quantity can be automatically set