1. Professor: Ming-Shyan Wang Student: CIH-HUEI SHIH
Sinusoidal Current Drive System of Permanent Magnet Synchronous Motor with Low Resolution Position Sensor Shigeo Morimoto, Masayulu Sanada, Yoji Takeda Osaka Prefecture University 1-1 Gakuen-cho, Sakai, Osaka 593 JAPAN
Professor: Ming-Shyan Wang
Student: CIH-HUEI SHIH
2018/9/12

2. Robot and Servo Drive Lab.
Outline
1.Abstract
2.Introduction
3.PM Motor Drive System
4.Principle of Position Estimation
5.Error of Estimated Position
6.Experimental results
7.Conclusions
8.References
2018/9/12
Robot and Servo Drive Lab.

3. Robot and Servo Drive Lab.
Abstract
The high performance drives of the sinusoidal back-EMF type permanent magnet
synchronous motor can be achieved by the current vector control, where the
sinusoidal currents flow according to the rotor position and the current phase is
suitably controlled according to the operating condition.
In such high performance drive system, a high resolution position sensor is
desired. In this paper, a sinusoidal current drive system with a low resolution
position sensor is proposed.
The steady-state and transient characteristics are examined by the several
experiments, then it is confirmed that the sinusoidal current drive and the high
performance current vector control can be achieved by the proposed drive system.
2018/9/12
Robot and Servo Drive Lab.

4. Robot and Servo Drive Lab.
Introduction
This paper proposes a sinusoidal current drive system of the sinusoidal-wave
PM motor using a low resolution position sensor, which has accuracy of only
60 electrical degrees.
The proposed system will have advantage of the low-cost and the simple
composition compared with the drive system with a high resolution sensor and
the problems included in the sensorless system will be solved.
The high resolution position information, which has enough resolution to
produce the sinusoidal current commands and achieve a high-performance
current vector control, is obtained by the proposed position estimating circuit.
2018/9/12
Robot and Servo Drive Lab.

5. Robot and Servo Drive Lab.
PM Motor Drive System
The commanded value of an amplitude of phase current
The phase shifting angle are generated from the current vector controller.
The electrical angle is calculated as = by the digital adder.
(1)
2018/9/12
Robot and Servo Drive Lab.

6. Robot and Servo Drive Lab.
PM Motor Drive System
2018/9/12
Robot and Servo Drive Lab.

7. Principle of Position Estimation
Fig. 3 shows the block diagram of the proposed position estimating circuit, which consists of all digital ICs. Fig. 4 shows the time chart of the signals in Fig. 3. The signals M and represent the signals from the low resolution position sensor.
Fig. 3 Block diagram of the proposed position estimating circuit
2018/9/12
Robot and Servo Drive Lab.

8. Principle of Position Estimation
Fig. 4 Time chart of the signals in Fig. 3.
2018/9/12
Robot and Servo Drive Lab.

9. Error of Estimated Position
The estimated position may agree with the actual position if the motor speed is constant, where remains constant
But, the error between and exists in accelerating or decelerating operation ( for example,
in acceleration). The estimated position error can be derived as follows (see Fig. 5).
Fig.5 Relationship between speed and position in acceleration
2018/9/12
Robot and Servo Drive Lab.

10. Error of Estimated Position
When the angular acceleration is constant, the motor speed is expressed by
(2)
Where is an angular velocity of motor at t=0
If the actual rotor position (electrical) is zero at t=0, is given by
(3)
is a number of pole pairs
From(3), and are given by
(4)
(5)
2018/9/12
Robot and Servo Drive Lab.

11. Error of Estimated Position
As the estimated position , is given based on the average speed of the last period , is expressed by
(6)
The average speed corresponds to the instantaneous speed at , which is given bv
(7)
2018/9/12
Robot and Servo Drive Lab.

12. Error of Estimated Position
From(4),(6)and(7), is given by
(8)
The estimated position error becomes maximum at in the period of
because the estimated position is adjusted to the actual position by the signal
Therefore, the maximum value of the estimated position error is given by
From (3), (5) and (8),
(9)
2018/9/12
Robot and Servo Drive Lab.

13. Error of Estimated Position
2018/9/12
Robot and Servo Drive Lab.

14. Robot and Servo Drive Lab.
Experimental results
2018/9/12
Robot and Servo Drive Lab.

15. Robot and Servo Drive Lab.
Experimental results
2018/9/12
Robot and Servo Drive Lab.

16. Robot and Servo Drive Lab.
Experimental results
2018/9/12
Robot and Servo Drive Lab.

17. Robot and Servo Drive Lab.
Experimental results
2018/9/12
Robot and Servo Drive Lab.

18. Robot and Servo Drive Lab.
Experimental results
2018/9/12
Robot and Servo Drive Lab.

19. Robot and Servo Drive Lab.
Experimental results
2018/9/12
Robot and Servo Drive Lab.

20. Robot and Servo Drive Lab.
Conclusions
In this paper, a sinusoidal current drive system of sinusoidal-wave PM motor with low resolution position sensor has been proposed.
The high resolution position information is obtained by the position estimating circuit from the low resolution position signal having the accuracy of only 60 electrical degrees.
From the experimental results, it has been confirmed that the proposed drive system can achieve the sinusoidal current drive and the high performance current vector control similarly to the general drive system with a high resolution position sensor except for the accelerating and decelerating operation in low speed range.
2018/9/12
Robot and Servo Drive Lab.

21. Robot and Servo Drive Lab.
References
[l] T. M. Jahns, “Flux-weakening regime operation of an interior permanent-magnet synchronous motor drive,“ ZEEE Trans. Znd.
[2] S. Morimoto, K. Hatanaka, Y. Tong, Y. Takeda and T. Hirasa, “Servo Drive System and Control Characteristics of Salient Pole Permanent Magnet Synchronous Motor,“ IEEE Trans. Znd. Appl., vol. 29, pp , MarchiApril 1993.
[3] S. Morimoto, M. Sanada and Y. Takeda, “Effects and compensation of magnetic saturation in Flux-Weakening Controlled Permanent Magnet Synchronous Motor Drives,” IEEE Trans. Ind. Appl., vol. 30, pp , Nov./Dec
[4] S. Ogasawara and H. Akagi, “An Approach to Position Sensorless Drive for Brushless dc Motors,” ZEEE Trans. Ind. Appl., vol. 27, pp , Sep./Oct
[5] R. Wu and G. R. Slemon, “A Permanent Magnet Motor Drive Without a Shaft Sensor,” IEEE Trans. Ind. Appl., vol. 27, pp , Sep./Oct
[6] A. B. Kulkarni and M. Ehsani, “A Novel Position Sensor Elimination Technique for the Interior Permanent-Magnet Synchronous Motor Drive,”ZEEE Trans. Ind. Appl., vol. 28, pp , Jan./Feb
[7] N. Matsui and T. Takeshita, “A Novel Starting Method of Sensorless Salient-Pole Brushless Moror,” Proc. I994 IEEE ZASAnn. Meet., pp , 1994.
[8] S. Kondo, A. Takahashi and T. Nishida, “Armature Current Locus Based Estimation Method of Rotor Position of Permanent Magnet Synchronous Motor without Mechanical Sensor,” Proc IEEEZASAnn. Meet., pp , Appl., vol. 23, pp , JUly/Aug
2018/9/12
Robot and Servo Drive Lab.

22. Robot and Servo Drive Lab.
Thanks for your listening!
2018/9/12
Robot and Servo Drive Lab.