A new design method of full-order extended electromotive force observer for position sensorless control of IPMSM

Several position sensorless control methods of PMSMs(Permanent Magnet Synchronous Motors) using the full-order observers have been proposed. However, the designs of the full-order observers are difficult, because the error equations of the observers become one of the fourth order. On the other hand, the the extended electromotive force(eemf) model which can be applied to all synchronous motors included Syn-RMs(Synchronous reluctance motors) had been proposed by authors, for the position sensorless control of IPMSMs(Interior Permanent Magnet Synchronous Motors). A full-order observer based on the eemf model(full-order eemf observer) which can be applied to the position sensorless control of all synchronous motors included SynRMs(Synchronous reluctance motors) have been proposed by authors. However, the design of a full-order eemf observer is also difficult. Therefore, this paper proposes a design method of the full-order eemf observer with the objective of the robust position estimation against the velocity estimation error using H_∞ control theory. Moreover, a new design method of the more robust full-order eemf observer is proposed by restudying the error system of the observer, and the simulation results and the experimental results show that a new design method of full-order eemf observer is very useful.