By using a 3-level inverter CHMI, more options are available
in selecting voltage vector in order to regulate torque and flux
slope. Therefore, it can improve the efficiency, reduce the
switching losses and minimize the torque ripple of 2-level
conventional inverter. Fig. 6 shows the implementation of the
CHMI system on the DTC system with the modification block
of torque status. This block was function to correct or modify
the torque status response when the slopes of torque become
poor due to the inappropriate selection of voltage vectors. This
is due to the longest voltage vector is chosen to achieve the
optimal torque slope during step change is applied. For the
better regulation of torque slope, the appropriate selection of
voltage vector is paramount in order to keep the slope of torque
does not beyond the upper band and lower band of the
hysteresis comparator. The depth explanation about the
modification block of torque status will be next publish.