Research on Anti DC Bias and High Order Harmonics of Fifth Order Flux Observer for IEEE Electrical Projects


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

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.


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.


[1] S. Kim, J. Im, E. Song, and R. Kim, “A new rotor position estimation method of IPMSM using all-pass filter on high-frequency rotating voltage signal injection,” IEEE Trans. Ind. Electron., vol. 63, no. 10, pp. 6499-6509, Oct. 2016.

[2] H, Zhang, W. Liu, Z. Chen, S. Mao, T. Meng, J. Peng, and N. Jiao, “A time-delay compensation method for IPMSM hybrid sensorless drives in rail transit applications,” IEEE Trans. Ind. Electron., vol.66, no. 9, pp. 6715-6726, Sept. 2019.

[3] R. Antonello, L. Ortombina, F. Tinazzi, and M. Zigliotto, “Enhanced low-speed operations for sensorless anisotropic PM synchronous motor drives by a modified back-EKF observer,” IEEE Trans. Ind. Electron., vol. 65, no. 4, pp. 3069-3076, Apr. 2018.

[4] C. Li, G.Wang, G. Zhang, N. Zhao, and D. Xu, “Adaptive pseudorandom high-frequency square-wave voltage injection based sensorless control for SynRM drives,” IEEE Trans. Power Electron., vol. 36, no. 3, pp. 3200-3210, Mar. 2021.

[5] G. Zhang, G. Wang, H. Zhang, H. Wang, G. Bi, X. Zhang, and D. Xu, “Pseudo-random-frequency sinusoidal injection for position sensorless IPMSM drives considering sample and hold effect,” IEEE Trans. Power Electron., vol. 34, no. 10, pp. 9929-9941, Oct. 2019.

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