Sensorless speed tracking control of PMSG applied in hydraulic power regeneration

This paper presents a reliable speed tracking strategy without mechanical position sensors of a permanent magnet synchronous generator applied in power regeneration of hybrid hydraulic excavators. The sensorless scheme is based on flux linkage estimation and with an additional novel compensation. It is devised to take the stator resistance into account, which is sensitive to the environmental temperature. A disturbance observer is also designed in order to attenuate the effect of the variation of the hydraulic driving torque which is produced by a fluctuant pressure. The proposed low-cost control strategy can provide the power regeneration system with high reliability and dynamic performance, which is verified by simulation results.