Abstract The inductance of synchronous reluctance motor (SynRM) varies with current in operation. If the inductor is linearized during the control process, it will cause a large error on the result. Therefore, it is necessary to identify the inductance of the SynRM. Because the rotor structure of the motor has strong salient polarity, it is easy to genarate the large harmonic components in the current, which will affect the accuracy of inductance identification. Aiming at the error caused by harmonic components, a signal amplitude demodulation scheme based on directional rotation transformation by injecting the rotating voltage is proposed in this paper. The scheme eliminates the need to use filters and avoids the problem of distortion of the identification result due to the filter. At the same time, the recursive DFT is used in the scheme to calculate the amplitude of positive and negative sequence currents in the stationary shafting. The algorithm has the advantages of small computation and easy digital implementation. Finally, the comparative verification experiments were carried out on the 5.5kW SynRM experimental platform. The experimental results show that the experimental process does not depend on the rotor position estimation, and the proposed scheme has higher detection accuracy.
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2019, Vol. 34 
