DC Bias Due to various nonideal factors, including the motor parameter mismatches, detection errors, converter nonlinearities, noise, etc. and high order harmonics exist in flux model, which make the traditional flux observer estimation inaccurate. In order to suppress DC bias and high order harmonics, an interior permanent magnet synchronous motors (IPMSM) sensorless drive method based on a fifth order flux observer (FOFO) is proposed in this paper.
DC Bias The proposed FOFO can completely remove DC bias and has strong filtering ability for high order harmonics. Additionally, the parameters of the FOFO are set through s-domain analysis. Then, the discrete FOFO is obtained to better implementation in digital systems. The proposed FOFO is verified by experiments on a 2.0-kW IPMSM drive platform.
Fig. 1. The block diagram of IPMSM sensorless drive based on the FOFO.
EXPECTED SIMULATION RESULTS:
Fig. 2. Estimated rotor flux and position estimation error at 1000 r/min. (a) SOFO. (b) FOFO.
Fig. 3. Eestimated rotor flux and position estimation error at 1800 r/min. (a) SOFO. (b) FOFO.
Fig. 4. Estimated rotor flux and position estimation error at 50 r/min. (a) SOFO. (b) FOFO.
DC Bias In this paper, to further improve the performance of the flux observer to suppress DC bias and high order harmonics, a FOFO is proposed. Theoretical analysis shows that proposed FOFO has strong attenuation ability against the DC bias and harmonics, and motor parameters mismatch and additional interference can be avoided.
DC Bias Additionally, the parameters of FOFO are set through s-domain analysis. Moreover, for better implementation in digital systems, the structure of discrete FOFO is obtained. The effectiveness of the proposed FOFO has been verified at a 2.0-kW IPMSM sensorless drive. Compared with the SOFO sensorless drive
the proposed FOFO method has strong performance of suppressing stator voltage DC bias and stator current DC bias, and the proposed method has better suppression of stator resistance mismatch and q-axis inductance mismatch under the condition of stator current DC bias.
DC Bias The main advantages of the proposed FOFO are: 1) it is insensitive to DC bias; 2) it has strong suppression ability to high order harmonics; 3) it has high rotor position estimation accuracy. Our future research work will further study the application of FOFO in synchronous reluctance motors.
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