<p>Indirect field-oriented control (IFOC) is a widely adopted vector control method for induction motors, where the slip gain (reciprocal of the rotor time constant) is a critical parameter influencing field orientation and system performance. Accurate slip gain estimation improves the calculation precision of slip frequency and enhances field orientation accuracy, improving the dynamic characteristics of system operation. This paper analyzes the impact of slip gain variation on IFOC through simulations and proposes an online slip gain estimation method based on stator transient voltage. The governing equation of slip gain is derived to achieve real-time parameter adaptation. Experimental results indicate that motors equipped with this method exhibit a faster speed response and improved speed feedback tracking performance. During operation, the&#xa0;tracking performances of the d-axis and q-axis currents are optimized, which reduces sensitivity to slip gain parameters and improves system performance. Furthermore, the method is computationally simple and can be readily applied to induction motor control systems.</p>