Analysis and compensation method of voltage error by dead-time with five-leg inverter for two-AC motor independent drives

This paper presents the analysis and compensation method of the voltage error by a dead-time with a five-leg inverter (FLI). The FLI is the single inverter to drive two three-phase AC motors independently. For the reason that the inverter connects one phase of each motor to a common leg, the voltage error caused by the dead-time will be different in case of a three-phase voltage source inverter (VSI). In case of motor drive with low-speed or using high speed switching devices such as insulated gate bipolar transistor (IGBT), considering about the dead-time voltage error is especially important for reduction of torque ripple. Firstly, the difference of the dead-time voltage error between the three-phase VSI and FLI is theoretically analyzed and discussed in this paper. Second, the dead-time compensation method is introduced. Moreover, the validity of these analyses and compensation method is shown by experimental results.