Seamless Transition Strategy for Multi-Mode PWM in Two-Level Inverter-Fed High-Speed Drives
Electric drives featuring high-speed operation use a combination of modulation techniques; each is suitable for specific operating conditions. Furthermore, a smooth transition between different modulation schemes is necessary to avoid over-current and over-voltage issues during transitions. This paper proposes a multi-mode scheduler that combines space vector pulse-width modulation (SVPWM), generalized discontinuous PWM (GDPWM) with edge- and center-aligned triple-, five-, and seven-pulse modulation approaches. Moreover, the proposed scheduler includes a transition handler designed to ensure seamless transitions while minimizing current and torque fluctuations. We validate the performance of the proposed method on an oil pump motor used in automotive transmission systems, tested on a dry motor bench. The results demonstrate that the proposed approach can decrease DC-link current fluctuations by up to 54% of the maximum deviations. In situations where direct transitions are impractical, a tentative transition strategy enables steady and controlled mode transitions.
