Dynamic Overmodulation Scheme for Improved Current Regulation in PMSM Drives

The overmodulation scheme plays an essential role in the dynamic performance of the current regulation under voltage limitation. This article analyses how the nonlinearity of the voltage hexagon affects dynamic overmodulation. Most dynamic overmodulation schemes had considered the voltage hexagon as the limit of the output voltage to maximize the voltage utilization. However, these schemes do not show uniform dynamic performance according to the rotor position on the voltage hexagon. To overcome this limitation, this article proposes an overmodulation scheme that is robust against the rotor position variation. The computer simulation and experimental results verify that the proposed method has the consistent performance regardless of the rotor position with less
d
-axis current overshoot keeping the fast dynamics.