I have developed a drive based on the instaspin technology. I have found out that if the drive reaches voltage saturation ( full speed) on no load and then if load torque(motor current) is increased, the current waveform starts getting disturbed - instead of sine wave shape it starts getting more trapezoidal and then as load is increased further it shows pronounced double humps and a valley in between at the peak of sine - this hump then increases and trips drive(it has a short circuit provision). If I reduce speed setpoint, the current shape normalizes. What I am expecting is that as the drive reaches its voltage limit, it should provide necessary current required to drive the load and drop the speed on its own, somehow this is not happening, as the voltage saturates and drive actual speed falls below set speed, the current shape is disturbed and actually it reaches a stage where it completely trips by going into short circuit. I have restricted modulation index to 50% ensuring that there is no over modulation. Pl. let me know what I can check