The Accuracy Improvement of Electric Machine Digital Control System based on a Novel Speed Regulator

Abstract The accuracy of the speed calculation is generally reduced if the speed calculation is performed at a slower control sampling rate. In this paper, a novel speed regulator is proposed to solve the contradiction of the speed loop fast adjustment and measurement error. Firstly, the measurement speed at each control period is calculated through the differential algorithm of position signal. Then the output of the speed controller is analyzed quantitatively. Base on this, change the speed controller structure to improve the integral effect by using the position feedback directly instead of the original integral item of the PI regulator, so as to avoid the error and delay caused by the process that the position signal differential and integration. Secondly, a speed detection method by period moving average is employed to improve the continuity of the speed feedback. Finally, simulations are used to verify the performance of the proposed speed regulator. Furthermore, experiments are conducted using a surface permanent magnet synchronous machine to compare the performance of the traditional speed controller and the proposed speed regulator for variable speed operation. Both the simulation and experimental results show the improvement of dynamic and steady state performances of the proposed speed regulator.

[1]  R.M. Kennel,et al.  Encoders for Simultaneous Sensing of Position and Speed in Electrical Drives With Digital Control , 2005, IEEE Transactions on Industry Applications.

[2]  Frede Blaabjerg,et al.  Artificial Inductance Concept to Compensate Nonlinear Inductance Effects in the Back EMF-Based Sensorless Control Method for PMSM , 2013, IEEE Transactions on Energy Conversion.

[3]  Kiyoshi Ohishi,et al.  High-Performance Inverter Based on Shaft Acceleration Torque for AC Drives , 2013, IEEE Transactions on Industrial Electronics.

[4]  Se-Han Lee,et al.  Improved velocity estimation for low-speed and transient regimes using low-resolution encoders , 2004, IEEE/ASME Transactions on Mechatronics.

[5]  Richard C. Kavanagh.  Performance analysis and compensation of M/T-type digital tachometers , 2001, IEEE Trans. Instrum. Meas..

[6]  Osama Mohammed,et al.  A wavelet filtering scheme for noise and vibration reduction in high-frequency signal injection-based sensorless control of PMSM at low speed , 2012, 2013 IEEE Power & Energy Society General Meeting.

[7]  Hyun-Soo Kim,et al.  A discrete-time predictive current control for PMSM , 2003 .

[8]  L. Kovudhikulrungsri,et al.  Precise Speed Estimation From a Low-Resolution Encoder by Dual-Sampling-Rate Observer , 2006, IEEE/ASME Transactions on Mechatronics.

[9]  Richard C. Kavanagh,et al.  The effects of quantization noise and sensor nonideality on digital differentiator-based rate measurement , 1998, IEEE Trans. Instrum. Meas..

[10]  Richard C. Kavanagh,et al.  New Learning Algorithm for High-Quality Velocity Measurement and Control When Using Low-Cost Optical Encoders , 2010, IEEE Transactions on Instrumentation and Measurement.

[11]  Seung-Ki Sul,et al.  A new motor speed estimator using Kalman filter in low-speed range , 1996, IEEE Trans. Ind. Electron..

[12]  Heui-Wook Kim,et al.  A new motor speed estimator using Kalman filter in low speed range , 1994, Proceedings of IECON'94 - 20th Annual Conference of IEEE Industrial Electronics.

[13]  M. Tursini,et al.  An Embedded System for Position and Speed Measurement Adopting Incremental Encoders , 2004, IEEE Transactions on Industry Applications.

[14]  S. Hiti,et al.  Modified Current Control Schemes for High-Performance Permanent-Magnet AC Drives With Low Sampling to Operating Frequency Ratio , 2009, IEEE Transactions on Industry Applications.

[15]  Seung-Ki Sul,et al.  Novel Speed and Rotor Position Estimation Strategy Using a Dual Observer for Low-Resolution Position Sensors , 2009, IEEE Transactions on Power Electronics.