Optimized Flux-Weakening Control with Virtue Voltage Buffer for Saturated High-Speed Induction Motor Drives

Abstract

It is known that the flux-weakening control of induction motor for maximum torque inevitably suffers the degraded dynamic performance due to the narrow voltage margin. To deal with this problem, a novel flux-weakening control method with virtue voltage buffer (VVB) is proposed. The saturated command voltage output from current regulator is compensated with a certain amount of virtue voltage margin provided by VVB before sent to the SVPWM (space vector pulse width modulation) module, and then, the magnitude and phase information of modified voltage error caused by overmodulation is employed for flux-weakening controller and VVB design. As a result, the system’s saturation condition during transient period can be well relieved, and thus a high dynamic performance in hexagon operation is achieved. In addition, the proposed approach unifies the flux-weakening controller and the anti-windup structure, simplifying the current loop structure, as well as inherently enjoys a better current-decoupling performance during load change period. Comparison results with other two existing methods verify the superiority of proposed method.