A programmable low-pass filter based stator flux calculation for a direct vector control of induction motor

The paper describes a novel integration method with a programmable low-pass filter for stator flux calculation in a direct vector controlled induction motor drive system. The DC offset in a pure integrator is eliminating using a high-pass filter with fixed time constant. The time constant of programmable low-pass filter is controlled with a synchronous frequency of the induction motor for an integration, considering phase lag and attenuation due to both the hardware low-pass filter and the programmable low-pass filter. The proposed strategy is verified with experiments implemented with a 32-bit TMS320C30 DSP.