FOC + Induction Motor + MATLAB + Flux waveform

Hello buddies,
As it is obvious for anyone dig into FOC for induction motor, flux of rotor on d and q axis are as below:
phir_d in steady state gets a fixed value
phir_q in transients change and in steady state gets zero
I downloaded two FOC simulation files implemented in MATLAB Simulink from MathWorks, when I watched these signals from motor model, the signals were sinusoidal. If anyone has idea, why it is so, please help me.

thanks