Dynamic Overmodulation for Improved Current Regulation of PMSM

The overmodulation scheme plays an essential role in the dynamic performance of the current control under the voltage limitation. This paper analyses how the non-linearity of the voltage hexagon affects the 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 the uniform dynamic performance according to the rotor position on the voltage hexagon. To overcome this limitation, this paper proposes an overmodulation scheme that is robust against the rotor position. The experimental results verify that the proposed method has consistent performance regardless of the rotor position with less d-axis current overshoot without losing the fast dynamics.