Minimum-Time Torque Control of IPMSM Drives via Flux Trajectory Optimization Under Hexagonal Voltage Constraints

Achieving the fastest possible dynamic torque response under voltage constraints remains a significant challenge for interior permanent magnet synchronous motor (IPMSM) drives. In this article, a minimum-time torque control (MTTC) method is proposed from the perspective of flux trajectory optimization. First, a vertical projection iterative (VPI) algorithm is developed to estimate the minimum-distance flux trajectory in real time, which represents the optimal flux tracking direction for achieving the fastest torque response. Building on the VPI results, a generalized space vector synthesis (GSVS) algorithm determines a sequence of voltage vectors, maximizing voltage utilization within the hexagonal voltage boundary throughout the entire torque response process, to synthesize the minimum-time flux trajectory. Compared with state-of-the-art straight-line flux trajectories, the minimum-time flux trajectory enables the proposed method to achieve the theoretical minimum-time torque response, while ensuring safe operation by avoiding overcurrent, excessive flux weakening, and torque overshoot/undershoot. Experimental results validate the effectiveness and superior performance of the proposed MTTC method.