Implementation and Stability Analysis of An Improved V/f Induction Motor Control Scheme based on Constant Rotor Flux

An improved volts per hertz ( V/f ) control scheme based on constant rotor flux for induction motors is proposed in this paper to improve the low-speed performance and solve the problem of speed droop when loaded. A voltage drop compensation method is adopted to ensure correct excitation and a slip compensation method is proposed to decrease speed error. Different from adopting ideal excitation voltage in most previous research, the actual excitation voltage calculated from induction motor model is applied. Meanwhile, an oscillation suppression method is incorporated to mitigate current oscillation and ensure stability. And system's stability is proved with the small signal model analysis method. Finally, the effectiveness and correctness of the proposed scheme is verified by the experimental results on 5.5kW induction motor experimental platform.