On-line dead time compensator for PMSM drive based on current observer

An on-line compensation for the dead time strategy without the knowledge of the current direction is proposed for PMSM drive based on a current observer. The modifications of the motor reference voltages are achieved by an uncomplicated current observer working in conjunction with the feedforward dead time voltage estimator. Therefore, the distortions on phase currents and torque due to dead time are greatly reduced. The proposed method does not require look-up table and coordinate transformations. It also does not need phase current polarity information or calculation of dead time period. Since the proposed scheme requires no extra hardware and time consuming signal processing algorithms, it is appropriate to use in real-time implementation of AC drives. The proposed scheme has been validated in simulation and implemented using TMS320F28335 DSP. Simulation and practical results validate the effectiveness and the feasibility of the proposed scheme.