Sensorless IPMSM Control Based on Improved Sliding Mode Observer by Using Synchronous Reference Frame Filter

This paper proposes an improved sliding mode observer (SMO) with the synchronous reference frame filter (SRFF) for interior permanent magnet synchronous machines (IPMSMs) sensorless control. By selecting the stator voltage vector as the SRF, the alternating output signals of SMO can be converted to the direct-current signals and filtered by the low-pass filter (LPF). With the constructed SRFF, the rotor position can be gotten accurately and the influence of the LPF is completely eliminated because the LPF has no effects on the phase of the direct-current input signals. Furthermore, the influence of stator resistance variations on the estimation accuracy of the rotor position is analyzed in detail. Experimental results are described to show the effectiveness of the improved SMO with the SRFF.